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namibia / public / js / vendor / fullcalendar.js

/*!
 * FullCalendar v2.3.1
 * Docs & License: http://fullcalendar.io/
 * (c) 2015 Adam Shaw
 */

(function(factory) {
    if (typeof define === 'function' && define.amd) {
        define([ 'jquery', 'moment' ], factory);
    }
    else if (typeof exports === 'object') { // Node/CommonJS
        module.exports = factory(require('jquery'), require('moment'));
    }
    else {
        factory(jQuery, moment);
    }
})(function($, moment) {

    ;;

    var fc = $.fullCalendar = { version: "2.3.1" };
    var fcViews = fc.views = {};


    $.fn.fullCalendar = function(options) {
        var args = Array.prototype.slice.call(arguments, 1); // for a possible method call
        var res = this; // what this function will return (this jQuery object by default)

        this.each(function(i, _element) { // loop each DOM element involved
            var element = $(_element);
            var calendar = element.data('fullCalendar'); // get the existing calendar object (if any)
            var singleRes; // the returned value of this single method call

            // a method call
            if (typeof options === 'string') {
                if (calendar && $.isFunction(calendar[options])) {
                    singleRes = calendar[options].apply(calendar, args);
                    if (!i) {
                        res = singleRes; // record the first method call result
                    }
                    if (options === 'destroy') { // for the destroy method, must remove Calendar object data
                        element.removeData('fullCalendar');
                    }
                }
            }
            // a new calendar initialization
            else if (!calendar) { // don't initialize twice
                calendar = new fc.CalendarBase(element, options);
                element.data('fullCalendar', calendar);
                calendar.render();
            }
        });

        return res;
    };


    var complexOptions = [ // names of options that are objects whose properties should be combined
        'header',
        'buttonText',
        'buttonIcons',
        'themeButtonIcons'
    ];


// Recursively combines all passed-in option-hash arguments into a new single option-hash.
// Given option-hashes are ordered from lowest to highest priority.
    function mergeOptions() {
        var chain = Array.prototype.slice.call(arguments); // convert to a real array
        var complexVals = {}; // hash for each complex option's combined values
        var i, name;
        var combinedVal;
        var j;
        var val;

        // for each complex option, loop through each option-hash and accumulate the combined values
        for (i = 0; i < complexOptions.length; i++) {
            name = complexOptions[i];
            combinedVal = null; // an object holding the merge of all the values

            for (j = 0; j < chain.length; j++) {
                val = chain[j][name];

                if ($.isPlainObject(val)) {
                    combinedVal = $.extend(combinedVal || {}, val); // merge new properties
                }
                else if (val != null) { // a non-null non-undefined atomic option
                    combinedVal = null; // signal to use the atomic value
                }
            }

            // if not null, the final value was a combination of other objects. record it
            if (combinedVal !== null) {
                complexVals[name] = combinedVal;
            }
        }

        chain.unshift({}); // $.extend will mutate this with the result
        chain.push(complexVals); // computed complex values are applied last
        return $.extend.apply($, chain); // combine
    }


// Given options specified for the calendar's constructor, massages any legacy options into a non-legacy form.
// Converts View-Option-Hashes into the View-Specific-Options format.
    function massageOverrides(input) {
        var overrides = { views: input.views || {} }; // the output. ensure a `views` hash
        var subObj;

        // iterate through all option override properties (except `views`)
        $.each(input, function(name, val) {
            if (name != 'views') {

                // could the value be a legacy View-Option-Hash?
                if (
                    $.isPlainObject(val) &&
                    !/(time|duration|interval)$/i.test(name) && // exclude duration options. might be given as objects
                    $.inArray(name, complexOptions) == -1 // complex options aren't allowed to be View-Option-Hashes
                ) {
                    subObj = null;

                    // iterate through the properties of this possible View-Option-Hash value
                    $.each(val, function(subName, subVal) {

                        // is the property targeting a view?
                        if (/^(month|week|day|default|basic(Week|Day)?|agenda(Week|Day)?)$/.test(subName)) {
                            if (!overrides.views[subName]) { // ensure the view-target entry exists
                                overrides.views[subName] = {};
                            }
                            overrides.views[subName][name] = subVal; // record the value in the `views` object
                        }
                        else { // a non-View-Option-Hash property
                            if (!subObj) {
                                subObj = {};
                            }
                            subObj[subName] = subVal; // accumulate these unrelated values for later
                        }
                    });

                    if (subObj) { // non-View-Option-Hash properties? transfer them as-is
                        overrides[name] = subObj;
                    }
                }
                else {
                    overrides[name] = val; // transfer normal options as-is
                }
            }
        });

        return overrides;
    }

    ;;

// exports
    fc.intersectionToSeg = intersectionToSeg;
    fc.applyAll = applyAll;
    fc.debounce = debounce;
    fc.isInt = isInt;
    fc.htmlEscape = htmlEscape;
    fc.cssToStr = cssToStr;
    fc.proxy = proxy;


    /* FullCalendar-specific DOM Utilities
     ----------------------------------------------------------------------------------------------------------------------*/


// Given the scrollbar widths of some other container, create borders/margins on rowEls in order to match the left
// and right space that was offset by the scrollbars. A 1-pixel border first, then margin beyond that.
    function compensateScroll(rowEls, scrollbarWidths) {
        if (scrollbarWidths.left) {
            rowEls.css({
                'border-left-width': 1,
                'margin-left': scrollbarWidths.left - 1
            });
        }
        if (scrollbarWidths.right) {
            rowEls.css({
                'border-right-width': 1,
                'margin-right': scrollbarWidths.right - 1
            });
        }
    }


// Undoes compensateScroll and restores all borders/margins
    function uncompensateScroll(rowEls) {
        rowEls.css({
            'margin-left': '',
            'margin-right': '',
            'border-left-width': '',
            'border-right-width': ''
        });
    }


// Make the mouse cursor express that an event is not allowed in the current area
    function disableCursor() {
        $('body').addClass('fc-not-allowed');
    }


// Returns the mouse cursor to its original look
    function enableCursor() {
        $('body').removeClass('fc-not-allowed');
    }


// Given a total available height to fill, have `els` (essentially child rows) expand to accomodate.
// By default, all elements that are shorter than the recommended height are expanded uniformly, not considering
// any other els that are already too tall. if `shouldRedistribute` is on, it considers these tall rows and 
// reduces the available height.
    function distributeHeight(els, availableHeight, shouldRedistribute) {

        // *FLOORING NOTE*: we floor in certain places because zoom can give inaccurate floating-point dimensions,
        // and it is better to be shorter than taller, to avoid creating unnecessary scrollbars.

        var minOffset1 = Math.floor(availableHeight / els.length); // for non-last element
        var minOffset2 = Math.floor(availableHeight - minOffset1 * (els.length - 1)); // for last element *FLOORING NOTE*
        var flexEls = []; // elements that are allowed to expand. array of DOM nodes
        var flexOffsets = []; // amount of vertical space it takes up
        var flexHeights = []; // actual css height
        var usedHeight = 0;

        undistributeHeight(els); // give all elements their natural height

        // find elements that are below the recommended height (expandable).
        // important to query for heights in a single first pass (to avoid reflow oscillation).
        els.each(function(i, el) {
            var minOffset = i === els.length - 1 ? minOffset2 : minOffset1;
            var naturalOffset = $(el).outerHeight(true);

            if (naturalOffset < minOffset) {
                flexEls.push(el);
                flexOffsets.push(naturalOffset);
                flexHeights.push($(el).height());
            }
            else {
                // this element stretches past recommended height (non-expandable). mark the space as occupied.
                usedHeight += naturalOffset;
            }
        });

        // readjust the recommended height to only consider the height available to non-maxed-out rows.
        if (shouldRedistribute) {
            availableHeight -= usedHeight;
            minOffset1 = Math.floor(availableHeight / flexEls.length);
            minOffset2 = Math.floor(availableHeight - minOffset1 * (flexEls.length - 1)); // *FLOORING NOTE*
        }

        // assign heights to all expandable elements
        $(flexEls).each(function(i, el) {
            var minOffset = i === flexEls.length - 1 ? minOffset2 : minOffset1;
            var naturalOffset = flexOffsets[i];
            var naturalHeight = flexHeights[i];
            var newHeight = minOffset - (naturalOffset - naturalHeight); // subtract the margin/padding

            if (naturalOffset < minOffset) { // we check this again because redistribution might have changed things
                $(el).height(newHeight);
            }
        });
    }


// Undoes distrubuteHeight, restoring all els to their natural height
    function undistributeHeight(els) {
        els.height('');
    }


// Given `els`, a jQuery set of <td> cells, find the cell with the largest natural width and set the widths of all the
// cells to be that width.
// PREREQUISITE: if you want a cell to take up width, it needs to have a single inner element w/ display:inline
    function matchCellWidths(els) {
        var maxInnerWidth = 0;

        els.find('> *').each(function(i, innerEl) {
            var innerWidth = $(innerEl).outerWidth();
            if (innerWidth > maxInnerWidth) {
                maxInnerWidth = innerWidth;
            }
        });

        maxInnerWidth++; // sometimes not accurate of width the text needs to stay on one line. insurance

        els.width(maxInnerWidth);

        return maxInnerWidth;
    }


// Turns a container element into a scroller if its contents is taller than the allotted height.
// Returns true if the element is now a scroller, false otherwise.
// NOTE: this method is best because it takes weird zooming dimensions into account
    function setPotentialScroller(containerEl, height) {
        containerEl.height(height).addClass('fc-scroller');

        // are scrollbars needed?
        if (containerEl[0].scrollHeight - 1 > containerEl[0].clientHeight) { // !!! -1 because IE is often off-by-one :(
            return true;
        }

        unsetScroller(containerEl); // undo
        return false;
    }


// Takes an element that might have been a scroller, and turns it back into a normal element.
    function unsetScroller(containerEl) {
        containerEl.height('').removeClass('fc-scroller');
    }


    /* General DOM Utilities
     ----------------------------------------------------------------------------------------------------------------------*/

    fc.getClientRect = getClientRect;
    fc.getContentRect = getContentRect;
    fc.getScrollbarWidths = getScrollbarWidths;


// borrowed from https://github.com/jquery/jquery-ui/blob/1.11.0/ui/core.js#L51
    function getScrollParent(el) {
        var position = el.css('position'),
            scrollParent = el.parents().filter(function() {
                var parent = $(this);
                return (/(auto|scroll)/).test(
                    parent.css('overflow') + parent.css('overflow-y') + parent.css('overflow-x')
                );
            }).eq(0);

        return position === 'fixed' || !scrollParent.length ? $(el[0].ownerDocument || document) : scrollParent;
    }


// Queries the outer bounding area of a jQuery element.
// Returns a rectangle with absolute coordinates: left, right (exclusive), top, bottom (exclusive).
    function getOuterRect(el) {
        var offset = el.offset();

        return {
            left: offset.left,
            right: offset.left + el.outerWidth(),
            top: offset.top,
            bottom: offset.top + el.outerHeight()
        };
    }


// Queries the area within the margin/border/scrollbars of a jQuery element. Does not go within the padding.
// Returns a rectangle with absolute coordinates: left, right (exclusive), top, bottom (exclusive).
// NOTE: should use clientLeft/clientTop, but very unreliable cross-browser.
    function getClientRect(el) {
        var offset = el.offset();
        var scrollbarWidths = getScrollbarWidths(el);
        var left = offset.left + getCssFloat(el, 'border-left-width') + scrollbarWidths.left;
        var top = offset.top + getCssFloat(el, 'border-top-width') + scrollbarWidths.top;

        return {
            left: left,
            right: left + el[0].clientWidth, // clientWidth includes padding but NOT scrollbars
            top: top,
            bottom: top + el[0].clientHeight // clientHeight includes padding but NOT scrollbars
        };
    }


// Queries the area within the margin/border/padding of a jQuery element. Assumed not to have scrollbars.
// Returns a rectangle with absolute coordinates: left, right (exclusive), top, bottom (exclusive).
    function getContentRect(el) {
        var offset = el.offset(); // just outside of border, margin not included
        var left = offset.left + getCssFloat(el, 'border-left-width') + getCssFloat(el, 'padding-left');
        var top = offset.top + getCssFloat(el, 'border-top-width') + getCssFloat(el, 'padding-top');

        return {
            left: left,
            right: left + el.width(),
            top: top,
            bottom: top + el.height()
        };
    }


// Returns the computed left/right/top/bottom scrollbar widths for the given jQuery element.
// NOTE: should use clientLeft/clientTop, but very unreliable cross-browser.
    function getScrollbarWidths(el) {
        var leftRightWidth = el.innerWidth() - el[0].clientWidth; // the paddings cancel out, leaving the scrollbars
        var widths = {
            left: 0,
            right: 0,
            top: 0,
            bottom: el.innerHeight() - el[0].clientHeight // the paddings cancel out, leaving the bottom scrollbar
        };

        if (getIsLeftRtlScrollbars() && el.css('direction') == 'rtl') { // is the scrollbar on the left side?
            widths.left = leftRightWidth;
        }
        else {
            widths.right = leftRightWidth;
        }

        return widths;
    }


// Logic for determining if, when the element is right-to-left, the scrollbar appears on the left side

    var _isLeftRtlScrollbars = null;

    function getIsLeftRtlScrollbars() { // responsible for caching the computation
        if (_isLeftRtlScrollbars === null) {
            _isLeftRtlScrollbars = computeIsLeftRtlScrollbars();
        }
        return _isLeftRtlScrollbars;
    }

    function computeIsLeftRtlScrollbars() { // creates an offscreen test element, then removes it
        var el = $('<div><div/></div>')
            .css({
                position: 'absolute',
                top: -1000,
                left: 0,
                border: 0,
                padding: 0,
                overflow: 'scroll',
                direction: 'rtl'
            })
            .appendTo('body');
        var innerEl = el.children();
        var res = innerEl.offset().left > el.offset().left; // is the inner div shifted to accommodate a left scrollbar?
        el.remove();
        return res;
    }


// Retrieves a jQuery element's computed CSS value as a floating-point number.
// If the queried value is non-numeric (ex: IE can return "medium" for border width), will just return zero.
    function getCssFloat(el, prop) {
        return parseFloat(el.css(prop)) || 0;
    }


// Returns a boolean whether this was a left mouse click and no ctrl key (which means right click on Mac)
    function isPrimaryMouseButton(ev) {
        return ev.which == 1 && !ev.ctrlKey;
    }


    /* Geometry
     ----------------------------------------------------------------------------------------------------------------------*/


// Returns a new rectangle that is the intersection of the two rectangles. If they don't intersect, returns false
    function intersectRects(rect1, rect2) {
        var res = {
            left: Math.max(rect1.left, rect2.left),
            right: Math.min(rect1.right, rect2.right),
            top: Math.max(rect1.top, rect2.top),
            bottom: Math.min(rect1.bottom, rect2.bottom)
        };

        if (res.left < res.right && res.top < res.bottom) {
            return res;
        }
        return false;
    }


// Returns a new point that will have been moved to reside within the given rectangle
    function constrainPoint(point, rect) {
        return {
            left: Math.min(Math.max(point.left, rect.left), rect.right),
            top: Math.min(Math.max(point.top, rect.top), rect.bottom)
        };
    }


// Returns a point that is the center of the given rectangle
    function getRectCenter(rect) {
        return {
            left: (rect.left + rect.right) / 2,
            top: (rect.top + rect.bottom) / 2
        };
    }


// Subtracts point2's coordinates from point1's coordinates, returning a delta
    function diffPoints(point1, point2) {
        return {
            left: point1.left - point2.left,
            top: point1.top - point2.top
        };
    }


    /* FullCalendar-specific Misc Utilities
     ----------------------------------------------------------------------------------------------------------------------*/


// Creates a basic segment with the intersection of the two ranges. Returns undefined if no intersection.
// Expects all dates to be normalized to the same timezone beforehand.
// TODO: move to date section?
    function intersectionToSeg(subjectRange, constraintRange) {
        var subjectStart = subjectRange.start;
        var subjectEnd = subjectRange.end;
        var constraintStart = constraintRange.start;
        var constraintEnd = constraintRange.end;
        var segStart, segEnd;
        var isStart, isEnd;

        if (subjectEnd > constraintStart && subjectStart < constraintEnd) { // in bounds at all?

            if (subjectStart >= constraintStart) {
                segStart = subjectStart.clone();
                isStart = true;
            }
            else {
                segStart = constraintStart.clone();
                isStart =  false;
            }

            if (subjectEnd <= constraintEnd) {
                segEnd = subjectEnd.clone();
                isEnd = true;
            }
            else {
                segEnd = constraintEnd.clone();
                isEnd = false;
            }

            return {
                start: segStart,
                end: segEnd,
                isStart: isStart,
                isEnd: isEnd
            };
        }
    }


    /* Date Utilities
     ----------------------------------------------------------------------------------------------------------------------*/

    fc.computeIntervalUnit = computeIntervalUnit;
    fc.durationHasTime = durationHasTime;

    var dayIDs = [ 'sun', 'mon', 'tue', 'wed', 'thu', 'fri', 'sat' ];
    var intervalUnits = [ 'year', 'month', 'week', 'day', 'hour', 'minute', 'second', 'millisecond' ];


// Diffs the two moments into a Duration where full-days are recorded first, then the remaining time.
// Moments will have their timezones normalized.
    function diffDayTime(a, b) {
        return moment.duration({
            days: a.clone().stripTime().diff(b.clone().stripTime(), 'days'),
            ms: a.time() - b.time() // time-of-day from day start. disregards timezone
        });
    }


// Diffs the two moments via their start-of-day (regardless of timezone). Produces whole-day durations.
    function diffDay(a, b) {
        return moment.duration({
            days: a.clone().stripTime().diff(b.clone().stripTime(), 'days')
        });
    }


// Diffs two moments, producing a duration, made of a whole-unit-increment of the given unit. Uses rounding.
    function diffByUnit(a, b, unit) {
        return moment.duration(
            Math.round(a.diff(b, unit, true)), // returnFloat=true
            unit
        );
    }


// Computes the unit name of the largest whole-unit period of time.
// For example, 48 hours will be "days" whereas 49 hours will be "hours".
// Accepts start/end, a range object, or an original duration object.
    function computeIntervalUnit(start, end) {
        var i, unit;
        var val;

        for (i = 0; i < intervalUnits.length; i++) {
            unit = intervalUnits[i];
            val = computeRangeAs(unit, start, end);

            if (val >= 1 && isInt(val)) {
                break;
            }
        }

        return unit; // will be "milliseconds" if nothing else matches
    }


// Computes the number of units (like "hours") in the given range.
// Range can be a {start,end} object, separate start/end args, or a Duration.
// Results are based on Moment's .as() and .diff() methods, so results can depend on internal handling
// of month-diffing logic (which tends to vary from version to version).
    function computeRangeAs(unit, start, end) {

        if (end != null) { // given start, end
            return end.diff(start, unit, true);
        }
        else if (moment.isDuration(start)) { // given duration
            return start.as(unit);
        }
        else { // given { start, end } range object
            return start.end.diff(start.start, unit, true);
        }
    }


// Returns a boolean about whether the given duration has any time parts (hours/minutes/seconds/ms)
    function durationHasTime(dur) {
        return Boolean(dur.hours() || dur.minutes() || dur.seconds() || dur.milliseconds());
    }


    function isNativeDate(input) {
        return  Object.prototype.toString.call(input) === '[object Date]' || input instanceof Date;
    }


// Returns a boolean about whether the given input is a time string, like "06:40:00" or "06:00"
    function isTimeString(str) {
        return /^\d+\:\d+(?:\:\d+\.?(?:\d{3})?)?$/.test(str);
    }


    /* General Utilities
     ----------------------------------------------------------------------------------------------------------------------*/

    var hasOwnPropMethod = {}.hasOwnProperty;


// Create an object that has the given prototype. Just like Object.create
    function createObject(proto) {
        var f = function() {};
        f.prototype = proto;
        return new f();
    }


    function copyOwnProps(src, dest) {
        for (var name in src) {
            if (hasOwnProp(src, name)) {
                dest[name] = src[name];
            }
        }
    }


// Copies over certain methods with the same names as Object.prototype methods. Overcomes an IE<=8 bug:
// https://developer.mozilla.org/en-US/docs/ECMAScript_DontEnum_attribute#JScript_DontEnum_Bug
    function copyNativeMethods(src, dest) {
        var names = [ 'constructor', 'toString', 'valueOf' ];
        var i, name;

        for (i = 0; i < names.length; i++) {
            name = names[i];

            if (src[name] !== Object.prototype[name]) {
                dest[name] = src[name];
            }
        }
    }


    function hasOwnProp(obj, name) {
        return hasOwnPropMethod.call(obj, name);
    }


// Is the given value a non-object non-function value?
    function isAtomic(val) {
        return /undefined|null|boolean|number|string/.test($.type(val));
    }


    function applyAll(functions, thisObj, args) {
        if ($.isFunction(functions)) {
            functions = [ functions ];
        }
        if (functions) {
            var i;
            var ret;
            for (i=0; i<functions.length; i++) {
                ret = functions[i].apply(thisObj, args) || ret;
            }
            return ret;
        }
    }


    function firstDefined() {
        for (var i=0; i<arguments.length; i++) {
            if (arguments[i] !== undefined) {
                return arguments[i];
            }
        }
    }


    function htmlEscape(s) {
        return (s + '').replace(/&/g, '&amp;')
            .replace(/</g, '&lt;')
            .replace(/>/g, '&gt;')
            .replace(/'/g, '&#039;')
            .replace(/"/g, '&quot;')
            .replace(/\n/g, '<br />');
    }


    function stripHtmlEntities(text) {
        return text.replace(/&.*?;/g, '');
    }


// Given a hash of CSS properties, returns a string of CSS.
// Uses property names as-is (no camel-case conversion). Will not make statements for null/undefined values.
    function cssToStr(cssProps) {
        var statements = [];

        $.each(cssProps, function(name, val) {
            if (val != null) {
                statements.push(name + ':' + val);
            }
        });

        return statements.join(';');
    }


    function capitaliseFirstLetter(str) {
        return str.charAt(0).toUpperCase() + str.slice(1);
    }


    function compareNumbers(a, b) { // for .sort()
        return a - b;
    }


    function isInt(n) {
        return n % 1 === 0;
    }


// Returns a method bound to the given object context.
// Just like one of the jQuery.proxy signatures, but without the undesired behavior of treating the same method with
// different contexts as identical when binding/unbinding events.
    function proxy(obj, methodName) {
        var method = obj[methodName];

        return function() {
            return method.apply(obj, arguments);
        };
    }


// Returns a function, that, as long as it continues to be invoked, will not
// be triggered. The function will be called after it stops being called for
// N milliseconds.
// https://github.com/jashkenas/underscore/blob/1.6.0/underscore.js#L714
    function debounce(func, wait) {
        var timeoutId;
        var args;
        var context;
        var timestamp; // of most recent call
        var later = function() {
            var last = +new Date() - timestamp;
            if (last < wait && last > 0) {
                timeoutId = setTimeout(later, wait - last);
            }
            else {
                timeoutId = null;
                func.apply(context, args);
                if (!timeoutId) {
                    context = args = null;
                }
            }
        };

        return function() {
            context = this;
            args = arguments;
            timestamp = +new Date();
            if (!timeoutId) {
                timeoutId = setTimeout(later, wait);
            }
        };
    }

    ;;

    var ambigDateOfMonthRegex = /^\s*\d{4}-\d\d$/;
    var ambigTimeOrZoneRegex =
        /^\s*\d{4}-(?:(\d\d-\d\d)|(W\d\d$)|(W\d\d-\d)|(\d\d\d))((T| )(\d\d(:\d\d(:\d\d(\.\d+)?)?)?)?)?$/;
    var newMomentProto = moment.fn; // where we will attach our new methods
    var oldMomentProto = $.extend({}, newMomentProto); // copy of original moment methods
    var allowValueOptimization;
    var setUTCValues; // function defined below
    var setLocalValues; // function defined below


// Creating
// -------------------------------------------------------------------------------------------------

// Creates a new moment, similar to the vanilla moment(...) constructor, but with
// extra features (ambiguous time, enhanced formatting). When given an existing moment,
// it will function as a clone (and retain the zone of the moment). Anything else will
// result in a moment in the local zone.
    fc.moment = function() {
        return makeMoment(arguments);
    };

// Sames as fc.moment, but forces the resulting moment to be in the UTC timezone.
    fc.moment.utc = function() {
        var mom = makeMoment(arguments, true);

        // Force it into UTC because makeMoment doesn't guarantee it
        // (if given a pre-existing moment for example)
        if (mom.hasTime()) { // don't give ambiguously-timed moments a UTC zone
            mom.utc();
        }

        return mom;
    };

// Same as fc.moment, but when given an ISO8601 string, the timezone offset is preserved.
// ISO8601 strings with no timezone offset will become ambiguously zoned.
    fc.moment.parseZone = function() {
        return makeMoment(arguments, true, true);
    };

// Builds an enhanced moment from args. When given an existing moment, it clones. When given a
// native Date, or called with no arguments (the current time), the resulting moment will be local.
// Anything else needs to be "parsed" (a string or an array), and will be affected by:
//    parseAsUTC - if there is no zone information, should we parse the input in UTC?
//    parseZone - if there is zone information, should we force the zone of the moment?
    function makeMoment(args, parseAsUTC, parseZone) {
        var input = args[0];
        var isSingleString = args.length == 1 && typeof input === 'string';
        var isAmbigTime;
        var isAmbigZone;
        var ambigMatch;
        var mom;

        if (moment.isMoment(input)) {
            mom = moment.apply(null, args); // clone it
            transferAmbigs(input, mom); // the ambig flags weren't transfered with the clone
        }
        else if (isNativeDate(input) || input === undefined) {
            mom = moment.apply(null, args); // will be local
        }
        else { // "parsing" is required
            isAmbigTime = false;
            isAmbigZone = false;

            if (isSingleString) {
                if (ambigDateOfMonthRegex.test(input)) {
                    // accept strings like '2014-05', but convert to the first of the month
                    input += '-01';
                    args = [ input ]; // for when we pass it on to moment's constructor
                    isAmbigTime = true;
                    isAmbigZone = true;
                }
                else if ((ambigMatch = ambigTimeOrZoneRegex.exec(input))) {
                    isAmbigTime = !ambigMatch[5]; // no time part?
                    isAmbigZone = true;
                }
            }
            else if ($.isArray(input)) {
                // arrays have no timezone information, so assume ambiguous zone
                isAmbigZone = true;
            }
            // otherwise, probably a string with a format

            if (parseAsUTC || isAmbigTime) {
                mom = moment.utc.apply(moment, args);
            }
            else {
                mom = moment.apply(null, args);
            }

            if (isAmbigTime) {
                mom._ambigTime = true;
                mom._ambigZone = true; // ambiguous time always means ambiguous zone
            }
            else if (parseZone) { // let's record the inputted zone somehow
                if (isAmbigZone) {
                    mom._ambigZone = true;
                }
                else if (isSingleString) {
                    if (mom.utcOffset) {
                        mom.utcOffset(input); // if not a valid zone, will assign UTC
                    }
                    else {
                        mom.zone(input); // for moment-pre-2.9
                    }
                }
            }
        }

        mom._fullCalendar = true; // flag for extended functionality

        return mom;
    }


// A clone method that works with the flags related to our enhanced functionality.
// In the future, use moment.momentProperties
    newMomentProto.clone = function() {
        var mom = oldMomentProto.clone.apply(this, arguments);

        // these flags weren't transfered with the clone
        transferAmbigs(this, mom);
        if (this._fullCalendar) {
            mom._fullCalendar = true;
        }

        return mom;
    };


// Week Number
// -------------------------------------------------------------------------------------------------


// Returns the week number, considering the locale's custom week number calcuation
// `weeks` is an alias for `week`
    newMomentProto.week = newMomentProto.weeks = function(input) {
        var weekCalc = (this._locale || this._lang) // works pre-moment-2.8
            ._fullCalendar_weekCalc;

        if (input == null && typeof weekCalc === 'function') { // custom function only works for getter
            return weekCalc(this);
        }
        else if (weekCalc === 'ISO') {
            return oldMomentProto.isoWeek.apply(this, arguments); // ISO getter/setter
        }

        return oldMomentProto.week.apply(this, arguments); // local getter/setter
    };


// Time-of-day
// -------------------------------------------------------------------------------------------------

// GETTER
// Returns a Duration with the hours/minutes/seconds/ms values of the moment.
// If the moment has an ambiguous time, a duration of 00:00 will be returned.
//
// SETTER
// You can supply a Duration, a Moment, or a Duration-like argument.
// When setting the time, and the moment has an ambiguous time, it then becomes unambiguous.
    newMomentProto.time = function(time) {

        // Fallback to the original method (if there is one) if this moment wasn't created via FullCalendar.
        // `time` is a generic enough method name where this precaution is necessary to avoid collisions w/ other plugins.
        if (!this._fullCalendar) {
            return oldMomentProto.time.apply(this, arguments);
        }

        if (time == null) { // getter
            return moment.duration({
                hours: this.hours(),
                minutes: this.minutes(),
                seconds: this.seconds(),
                milliseconds: this.milliseconds()
            });
        }
        else { // setter

            this._ambigTime = false; // mark that the moment now has a time

            if (!moment.isDuration(time) && !moment.isMoment(time)) {
                time = moment.duration(time);
            }

            // The day value should cause overflow (so 24 hours becomes 00:00:00 of next day).
            // Only for Duration times, not Moment times.
            var dayHours = 0;
            if (moment.isDuration(time)) {
                dayHours = Math.floor(time.asDays()) * 24;
            }

            // We need to set the individual fields.
            // Can't use startOf('day') then add duration. In case of DST at start of day.
            return this.hours(dayHours + time.hours())
                .minutes(time.minutes())
                .seconds(time.seconds())
                .milliseconds(time.milliseconds());
        }
    };

// Converts the moment to UTC, stripping out its time-of-day and timezone offset,
// but preserving its YMD. A moment with a stripped time will display no time
// nor timezone offset when .format() is called.
    newMomentProto.stripTime = function() {
        var a;

        if (!this._ambigTime) {

            // get the values before any conversion happens
            a = this.toArray(); // array of y/m/d/h/m/s/ms

            // TODO: use keepLocalTime in the future
            this.utc(); // set the internal UTC flag (will clear the ambig flags)
            setUTCValues(this, a.slice(0, 3)); // set the year/month/date. time will be zero

            // Mark the time as ambiguous. This needs to happen after the .utc() call, which might call .utcOffset(),
            // which clears all ambig flags. Same with setUTCValues with moment-timezone.
            this._ambigTime = true;
            this._ambigZone = true; // if ambiguous time, also ambiguous timezone offset
        }

        return this; // for chaining
    };

// Returns if the moment has a non-ambiguous time (boolean)
    newMomentProto.hasTime = function() {
        return !this._ambigTime;
    };


// Timezone
// -------------------------------------------------------------------------------------------------

// Converts the moment to UTC, stripping out its timezone offset, but preserving its
// YMD and time-of-day. A moment with a stripped timezone offset will display no
// timezone offset when .format() is called.
// TODO: look into Moment's keepLocalTime functionality
    newMomentProto.stripZone = function() {
        var a, wasAmbigTime;

        if (!this._ambigZone) {

            // get the values before any conversion happens
            a = this.toArray(); // array of y/m/d/h/m/s/ms
            wasAmbigTime = this._ambigTime;

            this.utc(); // set the internal UTC flag (might clear the ambig flags, depending on Moment internals)
            setUTCValues(this, a); // will set the year/month/date/hours/minutes/seconds/ms

            // the above call to .utc()/.utcOffset() unfortunately might clear the ambig flags, so restore
            this._ambigTime = wasAmbigTime || false;

            // Mark the zone as ambiguous. This needs to happen after the .utc() call, which might call .utcOffset(),
            // which clears the ambig flags. Same with setUTCValues with moment-timezone.
            this._ambigZone = true;
        }

        return this; // for chaining
    };

// Returns of the moment has a non-ambiguous timezone offset (boolean)
    newMomentProto.hasZone = function() {
        return !this._ambigZone;
    };


// this method implicitly marks a zone
    newMomentProto.local = function() {
        var a = this.toArray(); // year,month,date,hours,minutes,seconds,ms as an array
        var wasAmbigZone = this._ambigZone;

        oldMomentProto.local.apply(this, arguments);

        // ensure non-ambiguous
        // this probably already happened via local() -> utcOffset(), but don't rely on Moment's internals
        this._ambigTime = false;
        this._ambigZone = false;

        if (wasAmbigZone) {
            // If the moment was ambiguously zoned, the date fields were stored as UTC.
            // We want to preserve these, but in local time.
            // TODO: look into Moment's keepLocalTime functionality
            setLocalValues(this, a);
        }

        return this; // for chaining
    };


// implicitly marks a zone
    newMomentProto.utc = function() {
        oldMomentProto.utc.apply(this, arguments);

        // ensure non-ambiguous
        // this probably already happened via utc() -> utcOffset(), but don't rely on Moment's internals
        this._ambigTime = false;
        this._ambigZone = false;

        return this;
    };


// methods for arbitrarily manipulating timezone offset.
// should clear time/zone ambiguity when called.
    $.each([
        'zone', // only in moment-pre-2.9. deprecated afterwards
        'utcOffset'
    ], function(i, name) {
        if (oldMomentProto[name]) { // original method exists?

            // this method implicitly marks a zone (will probably get called upon .utc() and .local())
            newMomentProto[name] = function(tzo) {

                if (tzo != null) { // setter
                    // these assignments needs to happen before the original zone method is called.
                    // I forget why, something to do with a browser crash.
                    this._ambigTime = false;
                    this._ambigZone = false;
                }

                return oldMomentProto[name].apply(this, arguments);
            };
        }
    });


// Formatting
// -------------------------------------------------------------------------------------------------

    newMomentProto.format = function() {
        if (this._fullCalendar && arguments[0]) { // an enhanced moment? and a format string provided?
            return formatDate(this, arguments[0]); // our extended formatting
        }
        if (this._ambigTime) {
            return oldMomentFormat(this, 'YYYY-MM-DD');
        }
        if (this._ambigZone) {
            return oldMomentFormat(this, 'YYYY-MM-DD[T]HH:mm:ss');
        }
        return oldMomentProto.format.apply(this, arguments);
    };

    newMomentProto.toISOString = function() {
        if (this._ambigTime) {
            return oldMomentFormat(this, 'YYYY-MM-DD');
        }
        if (this._ambigZone) {
            return oldMomentFormat(this, 'YYYY-MM-DD[T]HH:mm:ss');
        }
        return oldMomentProto.toISOString.apply(this, arguments);
    };


// Querying
// -------------------------------------------------------------------------------------------------

// Is the moment within the specified range? `end` is exclusive.
// FYI, this method is not a standard Moment method, so always do our enhanced logic.
    newMomentProto.isWithin = function(start, end) {
        var a = commonlyAmbiguate([ this, start, end ]);
        return a[0] >= a[1] && a[0] < a[2];
    };

// When isSame is called with units, timezone ambiguity is normalized before the comparison happens.
// If no units specified, the two moments must be identically the same, with matching ambig flags.
    newMomentProto.isSame = function(input, units) {
        var a;

        // only do custom logic if this is an enhanced moment
        if (!this._fullCalendar) {
            return oldMomentProto.isSame.apply(this, arguments);
        }

        if (units) {
            a = commonlyAmbiguate([ this, input ], true); // normalize timezones but don't erase times
            return oldMomentProto.isSame.call(a[0], a[1], units);
        }
        else {
            input = fc.moment.parseZone(input); // normalize input
            return oldMomentProto.isSame.call(this, input) &&
                Boolean(this._ambigTime) === Boolean(input._ambigTime) &&
                Boolean(this._ambigZone) === Boolean(input._ambigZone);
        }
    };

// Make these query methods work with ambiguous moments
    $.each([
        'isBefore',
        'isAfter'
    ], function(i, methodName) {
        newMomentProto[methodName] = function(input, units) {
            var a;

            // only do custom logic if this is an enhanced moment
            if (!this._fullCalendar) {
                return oldMomentProto[methodName].apply(this, arguments);
            }

            a = commonlyAmbiguate([ this, input ]);
            return oldMomentProto[methodName].call(a[0], a[1], units);
        };
    });


// Misc Internals
// -------------------------------------------------------------------------------------------------

// given an array of moment-like inputs, return a parallel array w/ moments similarly ambiguated.
// for example, of one moment has ambig time, but not others, all moments will have their time stripped.
// set `preserveTime` to `true` to keep times, but only normalize zone ambiguity.
// returns the original moments if no modifications are necessary.
    function commonlyAmbiguate(inputs, preserveTime) {
        var anyAmbigTime = false;
        var anyAmbigZone = false;
        var len = inputs.length;
        var moms = [];
        var i, mom;

        // parse inputs into real moments and query their ambig flags
        for (i = 0; i < len; i++) {
            mom = inputs[i];
            if (!moment.isMoment(mom)) {
                mom = fc.moment.parseZone(mom);
            }
            anyAmbigTime = anyAmbigTime || mom._ambigTime;
            anyAmbigZone = anyAmbigZone || mom._ambigZone;
            moms.push(mom);
        }

        // strip each moment down to lowest common ambiguity
        // use clones to avoid modifying the original moments
        for (i = 0; i < len; i++) {
            mom = moms[i];
            if (!preserveTime && anyAmbigTime && !mom._ambigTime) {
                moms[i] = mom.clone().stripTime();
            }
            else if (anyAmbigZone && !mom._ambigZone) {
                moms[i] = mom.clone().stripZone();
            }
        }

        return moms;
    }

// Transfers all the flags related to ambiguous time/zone from the `src` moment to the `dest` moment
// TODO: look into moment.momentProperties for this.
    function transferAmbigs(src, dest) {
        if (src._ambigTime) {
            dest._ambigTime = true;
        }
        else if (dest._ambigTime) {
            dest._ambigTime = false;
        }

        if (src._ambigZone) {
            dest._ambigZone = true;
        }
        else if (dest._ambigZone) {
            dest._ambigZone = false;
        }
    }


// Sets the year/month/date/etc values of the moment from the given array.
// Inefficient because it calls each individual setter.
    function setMomentValues(mom, a) {
        mom.year(a[0] || 0)
            .month(a[1] || 0)
            .date(a[2] || 0)
            .hours(a[3] || 0)
            .minutes(a[4] || 0)
            .seconds(a[5] || 0)
            .milliseconds(a[6] || 0);
    }

// Can we set the moment's internal date directly?
    allowValueOptimization = '_d' in moment() && 'updateOffset' in moment;

// Utility function. Accepts a moment and an array of the UTC year/month/date/etc values to set.
// Assumes the given moment is already in UTC mode.
    setUTCValues = allowValueOptimization ? function(mom, a) {
        // simlate what moment's accessors do
        mom._d.setTime(Date.UTC.apply(Date, a));
        moment.updateOffset(mom, false); // keepTime=false
    } : setMomentValues;

// Utility function. Accepts a moment and an array of the local year/month/date/etc values to set.
// Assumes the given moment is already in local mode.
    setLocalValues = allowValueOptimization ? function(mom, a) {
        // simlate what moment's accessors do
        mom._d.setTime(+new Date( // FYI, there is now way to apply an array of args to a constructor
            a[0] || 0,
            a[1] || 0,
            a[2] || 0,
            a[3] || 0,
            a[4] || 0,
            a[5] || 0,
            a[6] || 0
        ));
        moment.updateOffset(mom, false); // keepTime=false
    } : setMomentValues;

    ;;

// Single Date Formatting
// -------------------------------------------------------------------------------------------------


// call this if you want Moment's original format method to be used
    function oldMomentFormat(mom, formatStr) {
        return oldMomentProto.format.call(mom, formatStr); // oldMomentProto defined in moment-ext.js
    }


// Formats `date` with a Moment formatting string, but allow our non-zero areas and
// additional token.
    function formatDate(date, formatStr) {
        return formatDateWithChunks(date, getFormatStringChunks(formatStr));
    }


    function formatDateWithChunks(date, chunks) {
        var s = '';
        var i;

        for (i=0; i<chunks.length; i++) {
            s += formatDateWithChunk(date, chunks[i]);
        }

        return s;
    }


// addition formatting tokens we want recognized
    var tokenOverrides = {
        t: function(date) { // "a" or "p"
            return oldMomentFormat(date, 'a').charAt(0);
        },
        T: function(date) { // "A" or "P"
            return oldMomentFormat(date, 'A').charAt(0);
        }
    };


    function formatDateWithChunk(date, chunk) {
        var token;
        var maybeStr;

        if (typeof chunk === 'string') { // a literal string
            return chunk;
        }
        else if ((token = chunk.token)) { // a token, like "YYYY"
            if (tokenOverrides[token]) {
                return tokenOverrides[token](date); // use our custom token
            }
            return oldMomentFormat(date, token);
        }
        else if (chunk.maybe) { // a grouping of other chunks that must be non-zero
            maybeStr = formatDateWithChunks(date, chunk.maybe);
            if (maybeStr.match(/[1-9]/)) {
                return maybeStr;
            }
        }

        return '';
    }


// Date Range Formatting
// -------------------------------------------------------------------------------------------------
// TODO: make it work with timezone offset

// Using a formatting string meant for a single date, generate a range string, like
// "Sep 2 - 9 2013", that intelligently inserts a separator where the dates differ.
// If the dates are the same as far as the format string is concerned, just return a single
// rendering of one date, without any separator.
    function formatRange(date1, date2, formatStr, separator, isRTL) {
        var localeData;

        date1 = fc.moment.parseZone(date1);
        date2 = fc.moment.parseZone(date2);

        localeData = (date1.localeData || date1.lang).call(date1); // works with moment-pre-2.8

        // Expand localized format strings, like "LL" -> "MMMM D YYYY"
        formatStr = localeData.longDateFormat(formatStr) || formatStr;
        // BTW, this is not important for `formatDate` because it is impossible to put custom tokens
        // or non-zero areas in Moment's localized format strings.

        separator = separator || ' - ';

        return formatRangeWithChunks(
            date1,
            date2,
            getFormatStringChunks(formatStr),
            separator,
            isRTL
        );
    }
    fc.formatRange = formatRange; // expose


    function formatRangeWithChunks(date1, date2, chunks, separator, isRTL) {
        var chunkStr; // the rendering of the chunk
        var leftI;
        var leftStr = '';
        var rightI;
        var rightStr = '';
        var middleI;
        var middleStr1 = '';
        var middleStr2 = '';
        var middleStr = '';

        // Start at the leftmost side of the formatting string and continue until you hit a token
        // that is not the same between dates.
        for (leftI=0; leftI<chunks.length; leftI++) {
            chunkStr = formatSimilarChunk(date1, date2, chunks[leftI]);
            if (chunkStr === false) {
                break;
            }
            leftStr += chunkStr;
        }

        // Similarly, start at the rightmost side of the formatting string and move left
        for (rightI=chunks.length-1; rightI>leftI; rightI--) {
            chunkStr = formatSimilarChunk(date1, date2, chunks[rightI]);
            if (chunkStr === false) {
                break;
            }
            rightStr = chunkStr + rightStr;
        }

        // The area in the middle is different for both of the dates.
        // Collect them distinctly so we can jam them together later.
        for (middleI=leftI; middleI<=rightI; middleI++) {
            middleStr1 += formatDateWithChunk(date1, chunks[middleI]);
            middleStr2 += formatDateWithChunk(date2, chunks[middleI]);
        }

        if (middleStr1 || middleStr2) {
            if (isRTL) {
                middleStr = middleStr2 + separator + middleStr1;
            }
            else {
                middleStr = middleStr1 + separator + middleStr2;
            }
        }

        return leftStr + middleStr + rightStr;
    }


    var similarUnitMap = {
        Y: 'year',
        M: 'month',
        D: 'day', // day of month
        d: 'day', // day of week
        // prevents a separator between anything time-related...
        A: 'second', // AM/PM
        a: 'second', // am/pm
        T: 'second', // A/P
        t: 'second', // a/p
        H: 'second', // hour (24)
        h: 'second', // hour (12)
        m: 'second', // minute
        s: 'second' // second
    };
// TODO: week maybe?


// Given a formatting chunk, and given that both dates are similar in the regard the
// formatting chunk is concerned, format date1 against `chunk`. Otherwise, return `false`.
    function formatSimilarChunk(date1, date2, chunk) {
        var token;
        var unit;

        if (typeof chunk === 'string') { // a literal string
            return chunk;
        }
        else if ((token = chunk.token)) {
            unit = similarUnitMap[token.charAt(0)];
            // are the dates the same for this unit of measurement?
            if (unit && date1.isSame(date2, unit)) {
                return oldMomentFormat(date1, token); // would be the same if we used `date2`
                // BTW, don't support custom tokens
            }
        }

        return false; // the chunk is NOT the same for the two dates
        // BTW, don't support splitting on non-zero areas
    }


// Chunking Utils
// -------------------------------------------------------------------------------------------------


    var formatStringChunkCache = {};


    function getFormatStringChunks(formatStr) {
        if (formatStr in formatStringChunkCache) {
            return formatStringChunkCache[formatStr];
        }
        return (formatStringChunkCache[formatStr] = chunkFormatString(formatStr));
    }


// Break the formatting string into an array of chunks
    function chunkFormatString(formatStr) {
        var chunks = [];
        var chunker = /\[([^\]]*)\]|\(([^\)]*)\)|(LTS|LT|(\w)\4*o?)|([^\w\[\(]+)/g; // TODO: more descrimination
        var match;

        while ((match = chunker.exec(formatStr))) {
            if (match[1]) { // a literal string inside [ ... ]
                chunks.push(match[1]);
            }
            else if (match[2]) { // non-zero formatting inside ( ... )
                chunks.push({ maybe: chunkFormatString(match[2]) });
            }
            else if (match[3]) { // a formatting token
                chunks.push({ token: match[3] });
            }
            else if (match[5]) { // an unenclosed literal string
                chunks.push(match[5]);
            }
        }

        return chunks;
    }

    ;;

    fc.Class = Class; // export

// class that all other classes will inherit from
    function Class() { }

// called upon a class to create a subclass
    Class.extend = function(members) {
        var superClass = this;
        var subClass;

        members = members || {};

        // ensure a constructor for the subclass, forwarding all arguments to the super-constructor if it doesn't exist
        if (hasOwnProp(members, 'constructor')) {
            subClass = members.constructor;
        }
        if (typeof subClass !== 'function') {
            subClass = members.constructor = function() {
                superClass.apply(this, arguments);
            };
        }

        // build the base prototype for the subclass, which is an new object chained to the superclass's prototype
        subClass.prototype = createObject(superClass.prototype);

        // copy each member variable/method onto the the subclass's prototype
        copyOwnProps(members, subClass.prototype);
        copyNativeMethods(members, subClass.prototype); // hack for IE8

        // copy over all class variables/methods to the subclass, such as `extend` and `mixin`
        copyOwnProps(superClass, subClass);

        return subClass;
    };

// adds new member variables/methods to the class's prototype.
// can be called with another class, or a plain object hash containing new members.
    Class.mixin = function(members) {
        copyOwnProps(members.prototype || members, this.prototype);
    };
    ;;

    /* A rectangular panel that is absolutely positioned over other content
     ------------------------------------------------------------------------------------------------------------------------
     Options:
     - className (string)
     - content (HTML string or jQuery element set)
     - parentEl
     - top
     - left
     - right (the x coord of where the right edge should be. not a "CSS" right)
     - autoHide (boolean)
     - show (callback)
     - hide (callback)
     */

    var Popover = Class.extend({

        isHidden: true,
        options: null,
        el: null, // the container element for the popover. generated by this object
        documentMousedownProxy: null, // document mousedown handler bound to `this`
        margin: 10, // the space required between the popover and the edges of the scroll container


        constructor: function(options) {
            this.options = options || {};
        },


        // Shows the popover on the specified position. Renders it if not already
        show: function() {
            if (this.isHidden) {
                if (!this.el) {
                    this.render();
                }
                this.el.show();
                this.position();
                this.isHidden = false;
                this.trigger('show');
            }
        },


        // Hides the popover, through CSS, but does not remove it from the DOM
        hide: function() {
            if (!this.isHidden) {
                this.el.hide();
                this.isHidden = true;
                this.trigger('hide');
            }
        },


        // Creates `this.el` and renders content inside of it
        render: function() {
            var _this = this;
            var options = this.options;

            this.el = $('<div class="fc-popover"/>')
                .addClass(options.className || '')
                .css({
                    // position initially to the top left to avoid creating scrollbars
                    top: 0,
                    left: 0
                })
                .append(options.content)
                .appendTo(options.parentEl);

            // when a click happens on anything inside with a 'fc-close' className, hide the popover
            this.el.on('click', '.fc-close', function() {
                _this.hide();
            });

            if (options.autoHide) {
                $(document).on('mousedown', this.documentMousedownProxy = proxy(this, 'documentMousedown'));
            }
        },


        // Triggered when the user clicks *anywhere* in the document, for the autoHide feature
        documentMousedown: function(ev) {
            // only hide the popover if the click happened outside the popover
            if (this.el && !$(ev.target).closest(this.el).length) {
                this.hide();
            }
        },


        // Hides and unregisters any handlers
        destroy: function() {
            this.hide();

            if (this.el) {
                this.el.remove();
                this.el = null;
            }

            $(document).off('mousedown', this.documentMousedownProxy);
        },


        // Positions the popover optimally, using the top/left/right options
        position: function() {
            var options = this.options;
            var origin = this.el.offsetParent().offset();
            var width = this.el.outerWidth();
            var height = this.el.outerHeight();
            var windowEl = $(window);
            var viewportEl = getScrollParent(this.el);
            var viewportTop;
            var viewportLeft;
            var viewportOffset;
            var top; // the "position" (not "offset") values for the popover
            var left; //

            // compute top and left
            top = options.top || 0;
            if (options.left !== undefined) {
                left = options.left;
            }
            else if (options.right !== undefined) {
                left = options.right - width; // derive the left value from the right value
            }
            else {
                left = 0;
            }

            if (viewportEl.is(window) || viewportEl.is(document)) { // normalize getScrollParent's result
                viewportEl = windowEl;
                viewportTop = 0; // the window is always at the top left
                viewportLeft = 0; // (and .offset() won't work if called here)
            }
            else {
                viewportOffset = viewportEl.offset();
                viewportTop = viewportOffset.top;
                viewportLeft = viewportOffset.left;
            }

            // if the window is scrolled, it causes the visible area to be further down
            viewportTop += windowEl.scrollTop();
            viewportLeft += windowEl.scrollLeft();

            // constrain to the view port. if constrained by two edges, give precedence to top/left
            if (options.viewportConstrain !== false) {
                top = Math.min(top, viewportTop + viewportEl.outerHeight() - height - this.margin);
                top = Math.max(top, viewportTop + this.margin);
                left = Math.min(left, viewportLeft + viewportEl.outerWidth() - width - this.margin);
                left = Math.max(left, viewportLeft + this.margin);
            }

            this.el.css({
                top: top - origin.top,
                left: left - origin.left
            });
        },


        // Triggers a callback. Calls a function in the option hash of the same name.
        // Arguments beyond the first `name` are forwarded on.
        // TODO: better code reuse for this. Repeat code
        trigger: function(name) {
            if (this.options[name]) {
                this.options[name].apply(this, Array.prototype.slice.call(arguments, 1));
            }
        }

    });

    ;;

    /* A "coordinate map" converts pixel coordinates into an associated cell, which has an associated date
     ------------------------------------------------------------------------------------------------------------------------
     Common interface:

     CoordMap.prototype = {
     build: function() {},
     getCell: function(x, y) {}
     };

     */

    /* Coordinate map for a grid component
     ----------------------------------------------------------------------------------------------------------------------*/

    var GridCoordMap = Class.extend({

        grid: null, // reference to the Grid
        rowCoords: null, // array of {top,bottom} objects
        colCoords: null, // array of {left,right} objects

        containerEl: null, // container element that all coordinates are constrained to. optionally assigned
        bounds: null,


        constructor: function(grid) {
            this.grid = grid;
        },


        // Queries the grid for the coordinates of all the cells
        build: function() {
            this.rowCoords = this.grid.computeRowCoords();
            this.colCoords = this.grid.computeColCoords();
            this.computeBounds();
        },


        // Clears the coordinates data to free up memory
        clear: function() {
            this.rowCoords = null;
            this.colCoords = null;
        },


        // Given a coordinate of the document, gets the associated cell. If no cell is underneath, returns null
        getCell: function(x, y) {
            var rowCoords = this.rowCoords;
            var rowCnt = rowCoords.length;
            var colCoords = this.colCoords;
            var colCnt = colCoords.length;
            var hitRow = null;
            var hitCol = null;
            var i, coords;
            var cell;

            if (this.inBounds(x, y)) {

                for (i = 0; i < rowCnt; i++) {
                    coords = rowCoords[i];
                    if (y >= coords.top && y < coords.bottom) {
                        hitRow = i;
                        break;
                    }
                }

                for (i = 0; i < colCnt; i++) {
                    coords = colCoords[i];
                    if (x >= coords.left && x < coords.right) {
                        hitCol = i;
                        break;
                    }
                }

                if (hitRow !== null && hitCol !== null) {

                    cell = this.grid.getCell(hitRow, hitCol); // expected to return a fresh object we can modify
                    cell.grid = this.grid; // for CellDragListener's isCellsEqual. dragging between grids

                    // make the coordinates available on the cell object
                    $.extend(cell, rowCoords[hitRow], colCoords[hitCol]);

                    return cell;
                }
            }

            return null;
        },


        // If there is a containerEl, compute the bounds into min/max values
        computeBounds: function() {
            this.bounds = this.containerEl ?
                getClientRect(this.containerEl) : // area within scrollbars
                null;
        },


        // Determines if the given coordinates are in bounds. If no `containerEl`, always true
        inBounds: function(x, y) {
            var bounds = this.bounds;

            if (bounds) {
                return x >= bounds.left && x < bounds.right && y >= bounds.top && y < bounds.bottom;
            }

            return true;
        }

    });


    /* Coordinate map that is a combination of multiple other coordinate maps
     ----------------------------------------------------------------------------------------------------------------------*/

    var ComboCoordMap = Class.extend({

        coordMaps: null, // an array of CoordMaps


        constructor: function(coordMaps) {
            this.coordMaps = coordMaps;
        },


        // Builds all coordMaps
        build: function() {
            var coordMaps = this.coordMaps;
            var i;

            for (i = 0; i < coordMaps.length; i++) {
                coordMaps[i].build();
            }
        },


        // Queries all coordMaps for the cell underneath the given coordinates, returning the first result
        getCell: function(x, y) {
            var coordMaps = this.coordMaps;
            var cell = null;
            var i;

            for (i = 0; i < coordMaps.length && !cell; i++) {
                cell = coordMaps[i].getCell(x, y);
            }

            return cell;
        },


        // Clears all coordMaps
        clear: function() {
            var coordMaps = this.coordMaps;
            var i;

            for (i = 0; i < coordMaps.length; i++) {
                coordMaps[i].clear();
            }
        }

    });

    ;;

    /* Tracks a drag's mouse movement, firing various handlers
     ----------------------------------------------------------------------------------------------------------------------*/

    var DragListener = fc.DragListener = Class.extend({

        options: null,

        isListening: false,
        isDragging: false,

        // coordinates of the initial mousedown
        originX: null,
        originY: null,

        // handler attached to the document, bound to the DragListener's `this`
        mousemoveProxy: null,
        mouseupProxy: null,

        // for IE8 bug-fighting behavior, for now
        subjectEl: null, // the element being draged. optional
        subjectHref: null,

        scrollEl: null,
        scrollBounds: null, // { top, bottom, left, right }
        scrollTopVel: null, // pixels per second
        scrollLeftVel: null, // pixels per second
        scrollIntervalId: null, // ID of setTimeout for scrolling animation loop
        scrollHandlerProxy: null, // this-scoped function for handling when scrollEl is scrolled

        scrollSensitivity: 30, // pixels from edge for scrolling to start
        scrollSpeed: 200, // pixels per second, at maximum speed
        scrollIntervalMs: 50, // millisecond wait between scroll increment


        constructor: function(options) {
            options = options || {};
            this.options = options;
            this.subjectEl = options.subjectEl;
        },


        // Call this when the user does a mousedown. Will probably lead to startListening
        mousedown: function(ev) {
            if (isPrimaryMouseButton(ev)) {

                ev.preventDefault(); // prevents native selection in most browsers

                this.startListening(ev);

                // start the drag immediately if there is no minimum distance for a drag start
                if (!this.options.distance) {
                    this.startDrag(ev);
                }
            }
        },


        // Call this to start tracking mouse movements
        startListening: function(ev) {
            var scrollParent;

            if (!this.isListening) {

                // grab scroll container and attach handler
                if (ev && this.options.scroll) {
                    scrollParent = getScrollParent($(ev.target));
                    if (!scrollParent.is(window) && !scrollParent.is(document)) {
                        this.scrollEl = scrollParent;

                        // scope to `this`, and use `debounce` to make sure rapid calls don't happen
                        this.scrollHandlerProxy = debounce(proxy(this, 'scrollHandler'), 100);
                        this.scrollEl.on('scroll', this.scrollHandlerProxy);
                    }
                }

                $(document)
                    .on('mousemove', this.mousemoveProxy = proxy(this, 'mousemove'))
                    .on('mouseup', this.mouseupProxy = proxy(this, 'mouseup'))
                    .on('selectstart', this.preventDefault); // prevents native selection in IE<=8

                if (ev) {
                    this.originX = ev.pageX;
                    this.originY = ev.pageY;
                }
                else {
                    // if no starting information was given, origin will be the topleft corner of the screen.
                    // if so, dx/dy in the future will be the absolute coordinates.
                    this.originX = 0;
                    this.originY = 0;
                }

                this.isListening = true;
                this.listenStart(ev);
            }
        },


        // Called when drag listening has started (but a real drag has not necessarily began)
        listenStart: function(ev) {
            this.trigger('listenStart', ev);
        },


        // Called when the user moves the mouse
        mousemove: function(ev) {
            var dx = ev.pageX - this.originX;
            var dy = ev.pageY - this.originY;
            var minDistance;
            var distanceSq; // current distance from the origin, squared

            if (!this.isDragging) { // if not already dragging...
                // then start the drag if the minimum distance criteria is met
                minDistance = this.options.distance || 1;
                distanceSq = dx * dx + dy * dy;
                if (distanceSq >= minDistance * minDistance) { // use pythagorean theorem
                    this.startDrag(ev);
                }
            }

            if (this.isDragging) {
                this.drag(dx, dy, ev); // report a drag, even if this mousemove initiated the drag
            }
        },


        // Call this to initiate a legitimate drag.
        // This function is called internally from this class, but can also be called explicitly from outside
        startDrag: function(ev) {

            if (!this.isListening) { // startDrag must have manually initiated
                this.startListening();
            }

            if (!this.isDragging) {
                this.isDragging = true;
                this.dragStart(ev);
            }
        },


        // Called when the actual drag has started (went beyond minDistance)
        dragStart: function(ev) {
            var subjectEl = this.subjectEl;

            this.trigger('dragStart', ev);

            // remove a mousedown'd <a>'s href so it is not visited (IE8 bug)
            if ((this.subjectHref = subjectEl ? subjectEl.attr('href') : null)) {
                subjectEl.removeAttr('href');
            }
        },


        // Called while the mouse is being moved and when we know a legitimate drag is taking place
        drag: function(dx, dy, ev) {
            this.trigger('drag', dx, dy, ev);
            this.updateScroll(ev); // will possibly cause scrolling
        },


        // Called when the user does a mouseup
        mouseup: function(ev) {
            this.stopListening(ev);
        },


        // Called when the drag is over. Will not cause listening to stop however.
        // A concluding 'cellOut' event will NOT be triggered.
        stopDrag: function(ev) {
            if (this.isDragging) {
                this.stopScrolling();
                this.dragStop(ev);
                this.isDragging = false;
            }
        },


        // Called when dragging has been stopped
        dragStop: function(ev) {
            var _this = this;

            this.trigger('dragStop', ev);

            // restore a mousedown'd <a>'s href (for IE8 bug)
            setTimeout(function() { // must be outside of the click's execution
                if (_this.subjectHref) {
                    _this.subjectEl.attr('href', _this.subjectHref);
                }
            }, 0);
        },


        // Call this to stop listening to the user's mouse events
        stopListening: function(ev) {
            this.stopDrag(ev); // if there's a current drag, kill it

            if (this.isListening) {

                // remove the scroll handler if there is a scrollEl
                if (this.scrollEl) {
                    this.scrollEl.off('scroll', this.scrollHandlerProxy);
                    this.scrollHandlerProxy = null;
                }

                $(document)
                    .off('mousemove', this.mousemoveProxy)
                    .off('mouseup', this.mouseupProxy)
                    .off('selectstart', this.preventDefault);

                this.mousemoveProxy = null;
                this.mouseupProxy = null;

                this.isListening = false;
                this.listenStop(ev);
            }
        },


        // Called when drag listening has stopped
        listenStop: function(ev) {
            this.trigger('listenStop', ev);
        },


        // Triggers a callback. Calls a function in the option hash of the same name.
        // Arguments beyond the first `name` are forwarded on.
        trigger: function(name) {
            if (this.options[name]) {
                this.options[name].apply(this, Array.prototype.slice.call(arguments, 1));
            }
        },


        // Stops a given mouse event from doing it's native browser action. In our case, text selection.
        preventDefault: function(ev) {
            ev.preventDefault();
        },


        /* Scrolling
         ------------------------------------------------------------------------------------------------------------------*/


        // Computes and stores the bounding rectangle of scrollEl
        computeScrollBounds: function() {
            var el = this.scrollEl;

            this.scrollBounds = el ? getOuterRect(el) : null;
            // TODO: use getClientRect in future. but prevents auto scrolling when on top of scrollbars
        },


        // Called when the dragging is in progress and scrolling should be updated
        updateScroll: function(ev) {
            var sensitivity = this.scrollSensitivity;
            var bounds = this.scrollBounds;
            var topCloseness, bottomCloseness;
            var leftCloseness, rightCloseness;
            var topVel = 0;
            var leftVel = 0;

            if (bounds) { // only scroll if scrollEl exists

                // compute closeness to edges. valid range is from 0.0 - 1.0
                topCloseness = (sensitivity - (ev.pageY - bounds.top)) / sensitivity;
                bottomCloseness = (sensitivity - (bounds.bottom - ev.pageY)) / sensitivity;
                leftCloseness = (sensitivity - (ev.pageX - bounds.left)) / sensitivity;
                rightCloseness = (sensitivity - (bounds.right - ev.pageX)) / sensitivity;

                // translate vertical closeness into velocity.
                // mouse must be completely in bounds for velocity to happen.
                if (topCloseness >= 0 && topCloseness <= 1) {
                    topVel = topCloseness * this.scrollSpeed * -1; // negative. for scrolling up
                }
                else if (bottomCloseness >= 0 && bottomCloseness <= 1) {
                    topVel = bottomCloseness * this.scrollSpeed;
                }

                // translate horizontal closeness into velocity
                if (leftCloseness >= 0 && leftCloseness <= 1) {
                    leftVel = leftCloseness * this.scrollSpeed * -1; // negative. for scrolling left
                }
                else if (rightCloseness >= 0 && rightCloseness <= 1) {
                    leftVel = rightCloseness * this.scrollSpeed;
                }
            }

            this.setScrollVel(topVel, leftVel);
        },


        // Sets the speed-of-scrolling for the scrollEl
        setScrollVel: function(topVel, leftVel) {

            this.scrollTopVel = topVel;
            this.scrollLeftVel = leftVel;

            this.constrainScrollVel(); // massages into realistic values

            // if there is non-zero velocity, and an animation loop hasn't already started, then START
            if ((this.scrollTopVel || this.scrollLeftVel) && !this.scrollIntervalId) {
                this.scrollIntervalId = setInterval(
                    proxy(this, 'scrollIntervalFunc'), // scope to `this`
                    this.scrollIntervalMs
                );
            }
        },


        // Forces scrollTopVel and scrollLeftVel to be zero if scrolling has already gone all the way
        constrainScrollVel: function() {
            var el = this.scrollEl;

            if (this.scrollTopVel < 0) { // scrolling up?
                if (el.scrollTop() <= 0) { // already scrolled all the way up?
                    this.scrollTopVel = 0;
                }
            }
            else if (this.scrollTopVel > 0) { // scrolling down?
                if (el.scrollTop() + el[0].clientHeight >= el[0].scrollHeight) { // already scrolled all the way down?
                    this.scrollTopVel = 0;
                }
            }

            if (this.scrollLeftVel < 0) { // scrolling left?
                if (el.scrollLeft() <= 0) { // already scrolled all the left?
                    this.scrollLeftVel = 0;
                }
            }
            else if (this.scrollLeftVel > 0) { // scrolling right?
                if (el.scrollLeft() + el[0].clientWidth >= el[0].scrollWidth) { // already scrolled all the way right?
                    this.scrollLeftVel = 0;
                }
            }
        },


        // This function gets called during every iteration of the scrolling animation loop
        scrollIntervalFunc: function() {
            var el = this.scrollEl;
            var frac = this.scrollIntervalMs / 1000; // considering animation frequency, what the vel should be mult'd by

            // change the value of scrollEl's scroll
            if (this.scrollTopVel) {
                el.scrollTop(el.scrollTop() + this.scrollTopVel * frac);
            }
            if (this.scrollLeftVel) {
                el.scrollLeft(el.scrollLeft() + this.scrollLeftVel * frac);
            }

            this.constrainScrollVel(); // since the scroll values changed, recompute the velocities

            // if scrolled all the way, which causes the vels to be zero, stop the animation loop
            if (!this.scrollTopVel && !this.scrollLeftVel) {
                this.stopScrolling();
            }
        },


        // Kills any existing scrolling animation loop
        stopScrolling: function() {
            if (this.scrollIntervalId) {
                clearInterval(this.scrollIntervalId);
                this.scrollIntervalId = null;

                // when all done with scrolling, recompute positions since they probably changed
                this.scrollStop();
            }
        },


        // Get called when the scrollEl is scrolled (NOTE: this is delayed via debounce)
        scrollHandler: function() {
            // recompute all coordinates, but *only* if this is *not* part of our scrolling animation
            if (!this.scrollIntervalId) {
                this.scrollStop();
            }
        },


        // Called when scrolling has stopped, whether through auto scroll, or the user scrolling
        scrollStop: function() {
        }

    });

    ;;

    /* Tracks mouse movements over a CoordMap and raises events about which cell the mouse is over.
     ------------------------------------------------------------------------------------------------------------------------
     options:
     - subjectEl
     - subjectCenter
     */

    var CellDragListener = DragListener.extend({

        coordMap: null, // converts coordinates to date cells
        origCell: null, // the cell the mouse was over when listening started
        cell: null, // the cell the mouse is over
        coordAdjust: null, // delta that will be added to the mouse coordinates when computing collisions


        constructor: function(coordMap, options) {
            DragListener.prototype.constructor.call(this, options); // call the super-constructor

            this.coordMap = coordMap;
        },


        // Called when drag listening starts (but a real drag has not necessarily began).
        // ev might be undefined if dragging was started manually.
        listenStart: function(ev) {
            var subjectEl = this.subjectEl;
            var subjectRect;
            var origPoint;
            var point;

            DragListener.prototype.listenStart.apply(this, arguments); // call the super-method

            this.computeCoords();

            if (ev) {
                origPoint = { left: ev.pageX, top: ev.pageY };
                point = origPoint;

                // constrain the point to bounds of the element being dragged
                if (subjectEl) {
                    subjectRect = getOuterRect(subjectEl); // used for centering as well
                    point = constrainPoint(point, subjectRect);
                }

                this.origCell = this.getCell(point.left, point.top);

                // treat the center of the subject as the collision point?
                if (subjectEl && this.options.subjectCenter) {

                    // only consider the area the subject overlaps the cell. best for large subjects
                    if (this.origCell) {
                        subjectRect = intersectRects(this.origCell, subjectRect) ||
                        subjectRect; // in case there is no intersection
                    }

                    point = getRectCenter(subjectRect);
                }

                this.coordAdjust = diffPoints(point, origPoint); // point - origPoint
            }
            else {
                this.origCell = null;
                this.coordAdjust = null;
            }
        },


        // Recomputes the drag-critical positions of elements
        computeCoords: function() {
            this.coordMap.build();
            this.computeScrollBounds();
        },


        // Called when the actual drag has started
        dragStart: function(ev) {
            var cell;

            DragListener.prototype.dragStart.apply(this, arguments); // call the super-method

            cell = this.getCell(ev.pageX, ev.pageY); // might be different from this.origCell if the min-distance is large

            // report the initial cell the mouse is over
            // especially important if no min-distance and drag starts immediately
            if (cell) {
                this.cellOver(cell);
            }
        },


        // Called when the drag moves
        drag: function(dx, dy, ev) {
            var cell;

            DragListener.prototype.drag.apply(this, arguments); // call the super-method

            cell = this.getCell(ev.pageX, ev.pageY);

            if (!isCellsEqual(cell, this.cell)) { // a different cell than before?
                if (this.cell) {
                    this.cellOut();
                }
                if (cell) {
                    this.cellOver(cell);
                }
            }
        },


        // Called when dragging has been stopped
        dragStop: function() {
            this.cellDone();
            DragListener.prototype.dragStop.apply(this, arguments); // call the super-method
        },


        // Called when a the mouse has just moved over a new cell
        cellOver: function(cell) {
            this.cell = cell;
            this.trigger('cellOver', cell, isCellsEqual(cell, this.origCell), this.origCell);
        },


        // Called when the mouse has just moved out of a cell
        cellOut: function() {
            if (this.cell) {
                this.trigger('cellOut', this.cell);
                this.cellDone();
                this.cell = null;
            }
        },


        // Called after a cellOut. Also called before a dragStop
        cellDone: function() {
            if (this.cell) {
                this.trigger('cellDone', this.cell);
            }
        },


        // Called when drag listening has stopped
        listenStop: function() {
            DragListener.prototype.listenStop.apply(this, arguments); // call the super-method

            this.origCell = this.cell = null;
            this.coordMap.clear();
        },


        // Called when scrolling has stopped, whether through auto scroll, or the user scrolling
        scrollStop: function() {
            DragListener.prototype.scrollStop.apply(this, arguments); // call the super-method

            this.computeCoords(); // cells' absolute positions will be in new places. recompute
        },


        // Gets the cell underneath the coordinates for the given mouse event
        getCell: function(left, top) {

            if (this.coordAdjust) {
                left += this.coordAdjust.left;
                top += this.coordAdjust.top;
            }

            return this.coordMap.getCell(left, top);
        }

    });


// Returns `true` if the cells are identically equal. `false` otherwise.
// They must have the same row, col, and be from the same grid.
// Two null values will be considered equal, as two "out of the grid" states are the same.
    function isCellsEqual(cell1, cell2) {

        if (!cell1 && !cell2) {
            return true;
        }

        if (cell1 && cell2) {
            return cell1.grid === cell2.grid &&
                cell1.row === cell2.row &&
                cell1.col === cell2.col;
        }

        return false;
    }

    ;;

    /* Creates a clone of an element and lets it track the mouse as it moves
     ----------------------------------------------------------------------------------------------------------------------*/

    var MouseFollower = Class.extend({

        options: null,

        sourceEl: null, // the element that will be cloned and made to look like it is dragging
        el: null, // the clone of `sourceEl` that will track the mouse
        parentEl: null, // the element that `el` (the clone) will be attached to

        // the initial position of el, relative to the offset parent. made to match the initial offset of sourceEl
        top0: null,
        left0: null,

        // the initial position of the mouse
        mouseY0: null,
        mouseX0: null,

        // the number of pixels the mouse has moved from its initial position
        topDelta: null,
        leftDelta: null,

        mousemoveProxy: null, // document mousemove handler, bound to the MouseFollower's `this`

        isFollowing: false,
        isHidden: false,
        isAnimating: false, // doing the revert animation?

        constructor: function(sourceEl, options) {
            this.options = options = options || {};
            this.sourceEl = sourceEl;
            this.parentEl = options.parentEl ? $(options.parentEl) : sourceEl.parent(); // default to sourceEl's parent
        },


        // Causes the element to start following the mouse
        start: function(ev) {
            if (!this.isFollowing) {
                this.isFollowing = true;

                this.mouseY0 = ev.pageY;
                this.mouseX0 = ev.pageX;
                this.topDelta = 0;
                this.leftDelta = 0;

                if (!this.isHidden) {
                    this.updatePosition();
                }

                $(document).on('mousemove', this.mousemoveProxy = proxy(this, 'mousemove'));
            }
        },


        // Causes the element to stop following the mouse. If shouldRevert is true, will animate back to original position.
        // `callback` gets invoked when the animation is complete. If no animation, it is invoked immediately.
        stop: function(shouldRevert, callback) {
            var _this = this;
            var revertDuration = this.options.revertDuration;

            function complete() {
                this.isAnimating = false;
                _this.destroyEl();

                this.top0 = this.left0 = null; // reset state for future updatePosition calls

                if (callback) {
                    callback();
                }
            }

            if (this.isFollowing && !this.isAnimating) { // disallow more than one stop animation at a time
                this.isFollowing = false;

                $(document).off('mousemove', this.mousemoveProxy);

                if (shouldRevert && revertDuration && !this.isHidden) { // do a revert animation?
                    this.isAnimating = true;
                    this.el.animate({
                        top: this.top0,
                        left: this.left0
                    }, {
                        duration: revertDuration,
                        complete: complete
                    });
                }
                else {
                    complete();
                }
            }
        },


        // Gets the tracking element. Create it if necessary
        getEl: function() {
            var el = this.el;

            if (!el) {
                this.sourceEl.width(); // hack to force IE8 to compute correct bounding box
                el = this.el = this.sourceEl.clone()
                    .css({
                        position: 'absolute',
                        visibility: '', // in case original element was hidden (commonly through hideEvents())
                        display: this.isHidden ? 'none' : '', // for when initially hidden
                        margin: 0,
                        right: 'auto', // erase and set width instead
                        bottom: 'auto', // erase and set height instead
                        width: this.sourceEl.width(), // explicit height in case there was a 'right' value
                        height: this.sourceEl.height(), // explicit width in case there was a 'bottom' value
                        opacity: this.options.opacity || '',
                        zIndex: this.options.zIndex
                    })
                    .appendTo(this.parentEl);
            }

            return el;
        },


        // Removes the tracking element if it has already been created
        destroyEl: function() {
            if (this.el) {
                this.el.remove();
                this.el = null;
            }
        },


        // Update the CSS position of the tracking element
        updatePosition: function() {
            var sourceOffset;
            var origin;

            this.getEl(); // ensure this.el

            // make sure origin info was computed
            if (this.top0 === null) {
                this.sourceEl.width(); // hack to force IE8 to compute correct bounding box
                sourceOffset = this.sourceEl.offset();
                origin = this.el.offsetParent().offset();
                this.top0 = sourceOffset.top - origin.top;
                this.left0 = sourceOffset.left - origin.left;
            }

            this.el.css({
                top: this.top0 + this.topDelta,
                left: this.left0 + this.leftDelta
            });
        },


        // Gets called when the user moves the mouse
        mousemove: function(ev) {
            this.topDelta = ev.pageY - this.mouseY0;
            this.leftDelta = ev.pageX - this.mouseX0;

            if (!this.isHidden) {
                this.updatePosition();
            }
        },


        // Temporarily makes the tracking element invisible. Can be called before following starts
        hide: function() {
            if (!this.isHidden) {
                this.isHidden = true;
                if (this.el) {
                    this.el.hide();
                }
            }
        },


        // Show the tracking element after it has been temporarily hidden
        show: function() {
            if (this.isHidden) {
                this.isHidden = false;
                this.updatePosition();
                this.getEl().show();
            }
        }

    });

    ;;

    /* A utility class for rendering <tr> rows.
     ----------------------------------------------------------------------------------------------------------------------*/
// It leverages methods of the subclass and the View to determine custom rendering behavior for each row "type"
// (such as highlight rows, day rows, helper rows, etc).

    var RowRenderer = Class.extend({

        view: null, // a View object
        isRTL: null, // shortcut to the view's isRTL option
        cellHtml: '<td/>', // plain default HTML used for a cell when no other is available


        constructor: function(view) {
            this.view = view;
            this.isRTL = view.opt('isRTL');
        },


        // Renders the HTML for a row, leveraging custom cell-HTML-renderers based on the `rowType`.
        // Also applies the "intro" and "outro" cells, which are specified by the subclass and views.
        // `row` is an optional row number.
        rowHtml: function(rowType, row) {
            var renderCell = this.getHtmlRenderer('cell', rowType);
            var rowCellHtml = '';
            var col;
            var cell;

            row = row || 0;

            for (col = 0; col < this.colCnt; col++) {
                cell = this.getCell(row, col);
                rowCellHtml += renderCell(cell);
            }

            rowCellHtml = this.bookendCells(rowCellHtml, rowType, row); // apply intro and outro

            return '<tr>' + rowCellHtml + '</tr>';
        },


        // Applies the "intro" and "outro" HTML to the given cells.
        // Intro means the leftmost cell when the calendar is LTR and the rightmost cell when RTL. Vice-versa for outro.
        // `cells` can be an HTML string of <td>'s or a jQuery <tr> element
        // `row` is an optional row number.
        bookendCells: function(cells, rowType, row) {
            var intro = this.getHtmlRenderer('intro', rowType)(row || 0);
            var outro = this.getHtmlRenderer('outro', rowType)(row || 0);
            var prependHtml = this.isRTL ? outro : intro;
            var appendHtml = this.isRTL ? intro : outro;

            if (typeof cells === 'string') {
                return prependHtml + cells + appendHtml;
            }
            else { // a jQuery <tr> element
                return cells.prepend(prependHtml).append(appendHtml);
            }
        },


        // Returns an HTML-rendering function given a specific `rendererName` (like cell, intro, or outro) and a specific
        // `rowType` (like day, eventSkeleton, helperSkeleton), which is optional.
        // If a renderer for the specific rowType doesn't exist, it will fall back to a generic renderer.
        // We will query the View object first for any custom rendering functions, then the methods of the subclass.
        getHtmlRenderer: function(rendererName, rowType) {
            var view = this.view;
            var generalName; // like "cellHtml"
            var specificName; // like "dayCellHtml". based on rowType
            var provider; // either the View or the RowRenderer subclass, whichever provided the method
            var renderer;

            generalName = rendererName + 'Html';
            if (rowType) {
                specificName = rowType + capitaliseFirstLetter(rendererName) + 'Html';
            }

            if (specificName && (renderer = view[specificName])) {
                provider = view;
            }
            else if (specificName && (renderer = this[specificName])) {
                provider = this;
            }
            else if ((renderer = view[generalName])) {
                provider = view;
            }
            else if ((renderer = this[generalName])) {
                provider = this;
            }

            if (typeof renderer === 'function') {
                return function() {
                    return renderer.apply(provider, arguments) || ''; // use correct `this` and always return a string
                };
            }

            // the rendered can be a plain string as well. if not specified, always an empty string.
            return function() {
                return renderer || '';
            };
        }

    });

    ;;

    /* An abstract class comprised of a "grid" of cells that each represent a specific datetime
     ----------------------------------------------------------------------------------------------------------------------*/

    var Grid = fc.Grid = RowRenderer.extend({

        start: null, // the date of the first cell
        end: null, // the date after the last cell

        rowCnt: 0, // number of rows
        colCnt: 0, // number of cols
        rowData: null, // array of objects, holding misc data for each row
        colData: null, // array of objects, holding misc data for each column

        el: null, // the containing element
        coordMap: null, // a GridCoordMap that converts pixel values to datetimes
        elsByFill: null, // a hash of jQuery element sets used for rendering each fill. Keyed by fill name.

        externalDragStartProxy: null, // binds the Grid's scope to externalDragStart (in DayGrid.events)

        // derived from options
        colHeadFormat: null, // TODO: move to another class. not applicable to all Grids
        eventTimeFormat: null,
        displayEventTime: null,
        displayEventEnd: null,

        // if all cells are the same length of time, the duration they all share. optional.
        // when defined, allows the computeCellRange shortcut, as well as improved resizing behavior.
        cellDuration: null,

        // if defined, holds the unit identified (ex: "year" or "month") that determines the level of granularity
        // of the date cells. if not defined, assumes to be day and time granularity.
        largeUnit: null,


        constructor: function() {
            RowRenderer.apply(this, arguments); // call the super-constructor

            this.coordMap = new GridCoordMap(this);
            this.elsByFill = {};
            this.externalDragStartProxy = proxy(this, 'externalDragStart');
        },


        /* Options
         ------------------------------------------------------------------------------------------------------------------*/


        // Generates the format string used for the text in column headers, if not explicitly defined by 'columnFormat'
        // TODO: move to another class. not applicable to all Grids
        computeColHeadFormat: function() {
            // subclasses must implement if they want to use headHtml()
        },


        // Generates the format string used for event time text, if not explicitly defined by 'timeFormat'
        computeEventTimeFormat: function() {
            return this.view.opt('smallTimeFormat');
        },


        // Determines whether events should have their end times displayed, if not explicitly defined by 'displayEventTime'.
        // Only applies to non-all-day events.
        computeDisplayEventTime: function() {
            return true;
        },


        // Determines whether events should have their end times displayed, if not explicitly defined by 'displayEventEnd'
        computeDisplayEventEnd: function() {
            return true;
        },


        /* Dates
         ------------------------------------------------------------------------------------------------------------------*/


        // Tells the grid about what period of time to display. Grid will subsequently compute dates for cell system.
        setRange: function(range) {
            var view = this.view;
            var displayEventTime;
            var displayEventEnd;

            this.start = range.start.clone();
            this.end = range.end.clone();

            this.rowData = [];
            this.colData = [];
            this.updateCells();

            // Populate option-derived settings. Look for override first, then compute if necessary.
            this.colHeadFormat = view.opt('columnFormat') || this.computeColHeadFormat();

            this.eventTimeFormat =
                view.opt('eventTimeFormat') ||
                view.opt('timeFormat') || // deprecated
                this.computeEventTimeFormat();

            displayEventTime = view.opt('displayEventTime');
            if (displayEventTime == null) {
                displayEventTime = this.computeDisplayEventTime(); // might be based off of range
            }

            displayEventEnd = view.opt('displayEventEnd');
            if (displayEventEnd == null) {
                displayEventEnd = this.computeDisplayEventEnd(); // might be based off of range
            }

            this.displayEventTime = displayEventTime;
            this.displayEventEnd = displayEventEnd;
        },


        // Responsible for setting rowCnt/colCnt and any other row/col data
        updateCells: function() {
            // subclasses must implement
        },


        // Converts a range with an inclusive `start` and an exclusive `end` into an array of segment objects
        rangeToSegs: function(range) {
            // subclasses must implement
        },


        // Diffs the two dates, returning a duration, based on granularity of the grid
        diffDates: function(a, b) {
            if (this.largeUnit) {
                return diffByUnit(a, b, this.largeUnit);
            }
            else {
                return diffDayTime(a, b);
            }
        },


        /* Cells
         ------------------------------------------------------------------------------------------------------------------*/
        // NOTE: columns are ordered left-to-right


        // Gets an object containing row/col number, misc data, and range information about the cell.
        // Accepts row/col values, an object with row/col properties, or a single-number offset from the first cell.
        getCell: function(row, col) {
            var cell;

            if (col == null) {
                if (typeof row === 'number') { // a single-number offset
                    col = row % this.colCnt;
                    row = Math.floor(row / this.colCnt);
                }
                else { // an object with row/col properties
                    col = row.col;
                    row = row.row;
                }
            }

            cell = { row: row, col: col };

            $.extend(cell, this.getRowData(row), this.getColData(col));
            $.extend(cell, this.computeCellRange(cell));

            return cell;
        },


        // Given a cell object with index and misc data, generates a range object
        // If the grid is leveraging cellDuration, this doesn't need to be defined. Only computeCellDate does.
        // If being overridden, should return a range with reference-free date copies.
        computeCellRange: function(cell) {
            var date = this.computeCellDate(cell);

            return {
                start: date,
                end: date.clone().add(this.cellDuration)
            };
        },


        // Given a cell, returns its start date. Should return a reference-free date copy.
        computeCellDate: function(cell) {
            // subclasses can implement
        },


        // Retrieves misc data about the given row
        getRowData: function(row) {
            return this.rowData[row] || {};
        },


        // Retrieves misc data baout the given column
        getColData: function(col) {
            return this.colData[col] || {};
        },


        // Retrieves the element representing the given row
        getRowEl: function(row) {
            // subclasses should implement if leveraging the default getCellDayEl() or computeRowCoords()
        },


        // Retrieves the element representing the given column
        getColEl: function(col) {
            // subclasses should implement if leveraging the default getCellDayEl() or computeColCoords()
        },


        // Given a cell object, returns the element that represents the cell's whole-day
        getCellDayEl: function(cell) {
            return this.getColEl(cell.col) || this.getRowEl(cell.row);
        },


        /* Cell Coordinates
         ------------------------------------------------------------------------------------------------------------------*/


        // Computes the top/bottom coordinates of all rows.
        // By default, queries the dimensions of the element provided by getRowEl().
        computeRowCoords: function() {
            var items = [];
            var i, el;
            var top;

            for (i = 0; i < this.rowCnt; i++) {
                el = this.getRowEl(i);
                top = el.offset().top;
                items.push({
                    top: top,
                    bottom: top + el.outerHeight()
                });
            }

            return items;
        },


        // Computes the left/right coordinates of all rows.
        // By default, queries the dimensions of the element provided by getColEl(). Columns can be LTR or RTL.
        computeColCoords: function() {
            var items = [];
            var i, el;
            var left;

            for (i = 0; i < this.colCnt; i++) {
                el = this.getColEl(i);
                left = el.offset().left;
                items.push({
                    left: left,
                    right: left + el.outerWidth()
                });
            }

            return items;
        },


        /* Rendering
         ------------------------------------------------------------------------------------------------------------------*/


        // Sets the container element that the grid should render inside of.
        // Does other DOM-related initializations.
        setElement: function(el) {
            var _this = this;

            this.el = el;

            // attach a handler to the grid's root element.
            // jQuery will take care of unregistering them when removeElement gets called.
            el.on('mousedown', function(ev) {
                if (
                    !$(ev.target).is('.fc-event-container *, .fc-more') && // not an an event element, or "more.." link
                    !$(ev.target).closest('.fc-popover').length // not on a popover (like the "more.." events one)
                ) {
                    _this.dayMousedown(ev);
                }
            });

            // attach event-element-related handlers. in Grid.events
            // same garbage collection note as above.
            this.bindSegHandlers();

            this.bindGlobalHandlers();
        },


        // Removes the grid's container element from the DOM. Undoes any other DOM-related attachments.
        // DOES NOT remove any content before hand (doens't clear events or call destroyDates), unlike View
        removeElement: function() {
            this.unbindGlobalHandlers();

            this.el.remove();

            // NOTE: we don't null-out this.el for the same reasons we don't do it within View::removeElement
        },


        // Renders the basic structure of grid view before any content is rendered
        renderSkeleton: function() {
            // subclasses should implement
        },


        // Renders the grid's date-related content (like cells that represent days/times).
        // Assumes setRange has already been called and the skeleton has already been rendered.
        renderDates: function() {
            // subclasses should implement
        },


        // Unrenders the grid's date-related content
        destroyDates: function() {
            // subclasses should implement
        },


        /* Handlers
         ------------------------------------------------------------------------------------------------------------------*/


        // Binds DOM handlers to elements that reside outside the grid, such as the document
        bindGlobalHandlers: function() {
            $(document).on('dragstart sortstart', this.externalDragStartProxy); // jqui
        },


        // Unbinds DOM handlers from elements that reside outside the grid
        unbindGlobalHandlers: function() {
            $(document).off('dragstart sortstart', this.externalDragStartProxy); // jqui
        },


        // Process a mousedown on an element that represents a day. For day clicking and selecting.
        dayMousedown: function(ev) {
            var _this = this;
            var view = this.view;
            var isSelectable = view.opt('selectable');
            var dayClickCell; // null if invalid dayClick
            var selectionRange; // null if invalid selection

            // this listener tracks a mousedown on a day element, and a subsequent drag.
            // if the drag ends on the same day, it is a 'dayClick'.
            // if 'selectable' is enabled, this listener also detects selections.
            var dragListener = new CellDragListener(this.coordMap, {
                //distance: 5, // needs more work if we want dayClick to fire correctly
                scroll: view.opt('dragScroll'),
                dragStart: function() {
                    view.unselect(); // since we could be rendering a new selection, we want to clear any old one
                },
                cellOver: function(cell, isOrig, origCell) {
                    if (origCell) { // click needs to have started on a cell
                        dayClickCell = isOrig ? cell : null; // single-cell selection is a day click
                        if (isSelectable) {
                            selectionRange = _this.computeSelection(origCell, cell);
                            if (selectionRange) {
                                _this.renderSelection(selectionRange);
                            }
                            else {
                                disableCursor();
                            }
                        }
                    }
                },
                cellOut: function(cell) {
                    dayClickCell = null;
                    selectionRange = null;
                    _this.destroySelection();
                    enableCursor();
                },
                listenStop: function(ev) {
                    if (dayClickCell) {
                        view.trigger('dayClick', _this.getCellDayEl(dayClickCell), dayClickCell.start, ev);
                    }
                    if (selectionRange) {
                        // the selection will already have been rendered. just report it
                        view.reportSelection(selectionRange, ev);
                    }
                    enableCursor();
                }
            });

            dragListener.mousedown(ev); // start listening, which will eventually initiate a dragStart
        },


        /* Event Helper
         ------------------------------------------------------------------------------------------------------------------*/
        // TODO: should probably move this to Grid.events, like we did event dragging / resizing


        // Renders a mock event over the given range
        renderRangeHelper: function(range, sourceSeg) {
            var fakeEvent = this.fabricateHelperEvent(range, sourceSeg);

            this.renderHelper(fakeEvent, sourceSeg); // do the actual rendering
        },


        // Builds a fake event given a date range it should cover, and a segment is should be inspired from.
        // The range's end can be null, in which case the mock event that is rendered will have a null end time.
        // `sourceSeg` is the internal segment object involved in the drag. If null, something external is dragging.
        fabricateHelperEvent: function(range, sourceSeg) {
            var fakeEvent = sourceSeg ? createObject(sourceSeg.event) : {}; // mask the original event object if possible

            fakeEvent.start = range.start.clone();
            fakeEvent.end = range.end ? range.end.clone() : null;
            fakeEvent.allDay = null; // force it to be freshly computed by normalizeEventRange
            this.view.calendar.normalizeEventRange(fakeEvent);

            // this extra className will be useful for differentiating real events from mock events in CSS
            fakeEvent.className = (fakeEvent.className || []).concat('fc-helper');

            // if something external is being dragged in, don't render a resizer
            if (!sourceSeg) {
                fakeEvent.editable = false;
            }

            return fakeEvent;
        },


        // Renders a mock event
        renderHelper: function(event, sourceSeg) {
            // subclasses must implement
        },


        // Unrenders a mock event
        destroyHelper: function() {
            // subclasses must implement
        },


        /* Selection
         ------------------------------------------------------------------------------------------------------------------*/


        // Renders a visual indication of a selection. Will highlight by default but can be overridden by subclasses.
        renderSelection: function(range) {
            this.renderHighlight(range);
        },


        // Unrenders any visual indications of a selection. Will unrender a highlight by default.
        destroySelection: function() {
            this.destroyHighlight();
        },


        // Given the first and last cells of a selection, returns a range object.
        // Will return something falsy if the selection is invalid (when outside of selectionConstraint for example).
        // Subclasses can override and provide additional data in the range object. Will be passed to renderSelection().
        computeSelection: function(firstCell, lastCell) {
            var dates = [
                firstCell.start,
                firstCell.end,
                lastCell.start,
                lastCell.end
            ];
            var range;

            dates.sort(compareNumbers); // sorts chronologically. works with Moments

            range = {
                start: dates[0].clone(),
                end: dates[3].clone()
            };

            if (!this.view.calendar.isSelectionRangeAllowed(range)) {
                return null;
            }

            return range;
        },


        /* Highlight
         ------------------------------------------------------------------------------------------------------------------*/


        // Renders an emphasis on the given date range. `start` is inclusive. `end` is exclusive.
        renderHighlight: function(range) {
            this.renderFill('highlight', this.rangeToSegs(range));
        },


        // Unrenders the emphasis on a date range
        destroyHighlight: function() {
            this.destroyFill('highlight');
        },


        // Generates an array of classNames for rendering the highlight. Used by the fill system.
        highlightSegClasses: function() {
            return [ 'fc-highlight' ];
        },


        /* Fill System (highlight, background events, business hours)
         ------------------------------------------------------------------------------------------------------------------*/


        // Renders a set of rectangles over the given segments of time.
        // Returns a subset of segs, the segs that were actually rendered.
        // Responsible for populating this.elsByFill. TODO: better API for expressing this requirement
        renderFill: function(type, segs) {
            // subclasses must implement
        },


        // Unrenders a specific type of fill that is currently rendered on the grid
        destroyFill: function(type) {
            var el = this.elsByFill[type];

            if (el) {
                el.remove();
                delete this.elsByFill[type];
            }
        },


        // Renders and assigns an `el` property for each fill segment. Generic enough to work with different types.
        // Only returns segments that successfully rendered.
        // To be harnessed by renderFill (implemented by subclasses).
        // Analagous to renderFgSegEls.
        renderFillSegEls: function(type, segs) {
            var _this = this;
            var segElMethod = this[type + 'SegEl'];
            var html = '';
            var renderedSegs = [];
            var i;

            if (segs.length) {

                // build a large concatenation of segment HTML
                for (i = 0; i < segs.length; i++) {
                    html += this.fillSegHtml(type, segs[i]);
                }

                // Grab individual elements from the combined HTML string. Use each as the default rendering.
                // Then, compute the 'el' for each segment.
                $(html).each(function(i, node) {
                    var seg = segs[i];
                    var el = $(node);

                    // allow custom filter methods per-type
                    if (segElMethod) {
                        el = segElMethod.call(_this, seg, el);
                    }

                    if (el) { // custom filters did not cancel the render
                        el = $(el); // allow custom filter to return raw DOM node

                        // correct element type? (would be bad if a non-TD were inserted into a table for example)
                        if (el.is(_this.fillSegTag)) {
                            seg.el = el;
                            renderedSegs.push(seg);
                        }
                    }
                });
            }

            return renderedSegs;
        },


        fillSegTag: 'div', // subclasses can override


        // Builds the HTML needed for one fill segment. Generic enought o work with different types.
        fillSegHtml: function(type, seg) {

            // custom hooks per-type
            var classesMethod = this[type + 'SegClasses'];
            var cssMethod = this[type + 'SegCss'];

            var classes = classesMethod ? classesMethod.call(this, seg) : [];
            var css = cssToStr(cssMethod ? cssMethod.call(this, seg) : {});

            return '<' + this.fillSegTag +
                (classes.length ? ' class="' + classes.join(' ') + '"' : '') +
                (css ? ' style="' + css + '"' : '') +
                ' />';
        },


        /* Generic rendering utilities for subclasses
         ------------------------------------------------------------------------------------------------------------------*/


        // Renders a day-of-week header row.
        // TODO: move to another class. not applicable to all Grids
        headHtml: function() {
            return '' +
                '<div class="fc-row ' + this.view.widgetHeaderClass + '">' +
                '<table>' +
                '<thead>' +
                this.rowHtml('head') + // leverages RowRenderer
                '</thead>' +
                '</table>' +
                '</div>';
        },


        // Used by the `headHtml` method, via RowRenderer, for rendering the HTML of a day-of-week header cell
        // TODO: move to another class. not applicable to all Grids
        headCellHtml: function(cell) {
            var view = this.view;
            var date = cell.start;

            return '' +
                '<th class="fc-day-header ' + view.widgetHeaderClass + ' fc-' + dayIDs[date.day()] + '">' +
                htmlEscape(date.format(this.colHeadFormat)) +
                '</th>';
        },


        // Renders the HTML for a single-day background cell
        bgCellHtml: function(cell) {
            var view = this.view;
            var date = cell.start;
            var classes = this.getDayClasses(date);

            classes.unshift('fc-day', view.widgetContentClass);

            return '<td class="' + classes.join(' ') + '"' +
                ' data-date="' + date.format('YYYY-MM-DD') + '"' + // if date has a time, won't format it
                '></td>';
        },


        // Computes HTML classNames for a single-day cell
        getDayClasses: function(date) {
            var view = this.view;
            var today = view.calendar.getNow().stripTime();
            var classes = [ 'fc-' + dayIDs[date.day()] ];

            if (
                view.intervalDuration.as('months') == 1 &&
                date.month() != view.intervalStart.month()
            ) {
                classes.push('fc-other-month');
            }

            if (date.isSame(today, 'day')) {
                classes.push(
                    'fc-today',
                    view.highlightStateClass
                );
            }
            else if (date < today) {
                classes.push('fc-past');
            }
            else {
                classes.push('fc-future');
            }

            return classes;
        }

    });

    ;;

    /* Event-rendering and event-interaction methods for the abstract Grid class
     ----------------------------------------------------------------------------------------------------------------------*/

    Grid.mixin({

        mousedOverSeg: null, // the segment object the user's mouse is over. null if over nothing
        isDraggingSeg: false, // is a segment being dragged? boolean
        isResizingSeg: false, // is a segment being resized? boolean
        isDraggingExternal: false, // jqui-dragging an external element? boolean
        segs: null, // the event segments currently rendered in the grid


        // Renders the given events onto the grid
        renderEvents: function(events) {
            var segs = this.eventsToSegs(events);
            var bgSegs = [];
            var fgSegs = [];
            var i, seg;

            for (i = 0; i < segs.length; i++) {
                seg = segs[i];

                if (isBgEvent(seg.event)) {
                    bgSegs.push(seg);
                }
                else {
                    fgSegs.push(seg);
                }
            }

            // Render each different type of segment.
            // Each function may return a subset of the segs, segs that were actually rendered.
            bgSegs = this.renderBgSegs(bgSegs) || bgSegs;
            fgSegs = this.renderFgSegs(fgSegs) || fgSegs;

            this.segs = bgSegs.concat(fgSegs);
        },


        // Unrenders all events currently rendered on the grid
        destroyEvents: function() {
            this.triggerSegMouseout(); // trigger an eventMouseout if user's mouse is over an event

            this.destroyFgSegs();
            this.destroyBgSegs();

            this.segs = null;
        },


        // Retrieves all rendered segment objects currently rendered on the grid
        getEventSegs: function() {
            return this.segs || [];
        },


        /* Foreground Segment Rendering
         ------------------------------------------------------------------------------------------------------------------*/


        // Renders foreground event segments onto the grid. May return a subset of segs that were rendered.
        renderFgSegs: function(segs) {
            // subclasses must implement
        },


        // Unrenders all currently rendered foreground segments
        destroyFgSegs: function() {
            // subclasses must implement
        },


        // Renders and assigns an `el` property for each foreground event segment.
        // Only returns segments that successfully rendered.
        // A utility that subclasses may use.
        renderFgSegEls: function(segs, disableResizing) {
            var view = this.view;
            var html = '';
            var renderedSegs = [];
            var i;

            if (segs.length) { // don't build an empty html string

                // build a large concatenation of event segment HTML
                for (i = 0; i < segs.length; i++) {
                    html += this.fgSegHtml(segs[i], disableResizing);
                }

                // Grab individual elements from the combined HTML string. Use each as the default rendering.
                // Then, compute the 'el' for each segment. An el might be null if the eventRender callback returned false.
                $(html).each(function(i, node) {
                    var seg = segs[i];
                    var el = view.resolveEventEl(seg.event, $(node));

                    if (el) {
                        el.data('fc-seg', seg); // used by handlers
                        seg.el = el;
                        renderedSegs.push(seg);
                    }
                });
            }

            return renderedSegs;
        },


        // Generates the HTML for the default rendering of a foreground event segment. Used by renderFgSegEls()
        fgSegHtml: function(seg, disableResizing) {
            // subclasses should implement
        },


        /* Background Segment Rendering
         ------------------------------------------------------------------------------------------------------------------*/


        // Renders the given background event segments onto the grid.
        // Returns a subset of the segs that were actually rendered.
        renderBgSegs: function(segs) {
            return this.renderFill('bgEvent', segs);
        },


        // Unrenders all the currently rendered background event segments
        destroyBgSegs: function() {
            this.destroyFill('bgEvent');
        },


        // Renders a background event element, given the default rendering. Called by the fill system.
        bgEventSegEl: function(seg, el) {
            return this.view.resolveEventEl(seg.event, el); // will filter through eventRender
        },


        // Generates an array of classNames to be used for the default rendering of a background event.
        // Called by the fill system.
        bgEventSegClasses: function(seg) {
            var event = seg.event;
            var source = event.source || {};

            return [ 'fc-bgevent' ].concat(
                event.className,
                source.className || []
            );
        },


        // Generates a semicolon-separated CSS string to be used for the default rendering of a background event.
        // Called by the fill system.
        // TODO: consolidate with getEventSkinCss?
        bgEventSegCss: function(seg) {
            var view = this.view;
            var event = seg.event;
            var source = event.source || {};

            return {
                'background-color':
                event.backgroundColor ||
                event.color ||
                source.backgroundColor ||
                source.color ||
                view.opt('eventBackgroundColor') ||
                view.opt('eventColor')
            };
        },


        // Generates an array of classNames to be used for the rendering business hours overlay. Called by the fill system.
        businessHoursSegClasses: function(seg) {
            return [ 'fc-nonbusiness', 'fc-bgevent' ];
        },


        /* Handlers
         ------------------------------------------------------------------------------------------------------------------*/


        // Attaches event-element-related handlers to the container element and leverage bubbling
        bindSegHandlers: function() {
            var _this = this;
            var view = this.view;

            $.each(
                {
                    mouseenter: function(seg, ev) {
                        _this.triggerSegMouseover(seg, ev);
                    },
                    mouseleave: function(seg, ev) {
                        _this.triggerSegMouseout(seg, ev);
                    },
                    click: function(seg, ev) {
                        return view.trigger('eventClick', this, seg.event, ev); // can return `false` to cancel
                    },
                    mousedown: function(seg, ev) {
                        if ($(ev.target).is('.fc-resizer') && view.isEventResizable(seg.event)) {
                            _this.segResizeMousedown(seg, ev, $(ev.target).is('.fc-start-resizer'));
                        }
                        else if (view.isEventDraggable(seg.event)) {
                            _this.segDragMousedown(seg, ev);
                        }
                    }
                },
                function(name, func) {
                    // attach the handler to the container element and only listen for real event elements via bubbling
                    _this.el.on(name, '.fc-event-container > *', function(ev) {
                        var seg = $(this).data('fc-seg'); // grab segment data. put there by View::renderEvents

                        // only call the handlers if there is not a drag/resize in progress
                        if (seg && !_this.isDraggingSeg && !_this.isResizingSeg) {
                            return func.call(this, seg, ev); // `this` will be the event element
                        }
                    });
                }
            );
        },


        // Updates internal state and triggers handlers for when an event element is moused over
        triggerSegMouseover: function(seg, ev) {
            if (!this.mousedOverSeg) {
                this.mousedOverSeg = seg;
                this.view.trigger('eventMouseover', seg.el[0], seg.event, ev);
            }
        },


        // Updates internal state and triggers handlers for when an event element is moused out.
        // Can be given no arguments, in which case it will mouseout the segment that was previously moused over.
        triggerSegMouseout: function(seg, ev) {
            ev = ev || {}; // if given no args, make a mock mouse event

            if (this.mousedOverSeg) {
                seg = seg || this.mousedOverSeg; // if given no args, use the currently moused-over segment
                this.mousedOverSeg = null;
                this.view.trigger('eventMouseout', seg.el[0], seg.event, ev);
            }
        },


        /* Event Dragging
         ------------------------------------------------------------------------------------------------------------------*/


        // Called when the user does a mousedown on an event, which might lead to dragging.
        // Generic enough to work with any type of Grid.
        segDragMousedown: function(seg, ev) {
            var _this = this;
            var view = this.view;
            var calendar = view.calendar;
            var el = seg.el;
            var event = seg.event;
            var dropLocation;

            // A clone of the original element that will move with the mouse
            var mouseFollower = new MouseFollower(seg.el, {
                parentEl: view.el,
                opacity: view.opt('dragOpacity'),
                revertDuration: view.opt('dragRevertDuration'),
                zIndex: 2 // one above the .fc-view
            });

            // Tracks mouse movement over the *view's* coordinate map. Allows dragging and dropping between subcomponents
            // of the view.
            var dragListener = new CellDragListener(view.coordMap, {
                distance: 5,
                scroll: view.opt('dragScroll'),
                subjectEl: el,
                subjectCenter: true,
                listenStart: function(ev) {
                    mouseFollower.hide(); // don't show until we know this is a real drag
                    mouseFollower.start(ev);
                },
                dragStart: function(ev) {
                    _this.triggerSegMouseout(seg, ev); // ensure a mouseout on the manipulated event has been reported
                    _this.segDragStart(seg, ev);
                    view.hideEvent(event); // hide all event segments. our mouseFollower will take over
                },
                cellOver: function(cell, isOrig, origCell) {

                    // starting cell could be forced (DayGrid.limit)
                    if (seg.cell) {
                        origCell = seg.cell;
                    }

                    dropLocation = _this.computeEventDrop(origCell, cell, event);

                    if (dropLocation && !calendar.isEventRangeAllowed(dropLocation, event)) {
                        disableCursor();
                        dropLocation = null;
                    }

                    // if a valid drop location, have the subclass render a visual indication
                    if (dropLocation && view.renderDrag(dropLocation, seg)) {
                        mouseFollower.hide(); // if the subclass is already using a mock event "helper", hide our own
                    }
                    else {
                        mouseFollower.show(); // otherwise, have the helper follow the mouse (no snapping)
                    }

                    if (isOrig) {
                        dropLocation = null; // needs to have moved cells to be a valid drop
                    }
                },
                cellOut: function() { // called before mouse moves to a different cell OR moved out of all cells
                    view.destroyDrag(); // unrender whatever was done in renderDrag
                    mouseFollower.show(); // show in case we are moving out of all cells
                    dropLocation = null;
                },
                cellDone: function() { // Called after a cellOut OR before a dragStop
                    enableCursor();
                },
                dragStop: function(ev) {
                    // do revert animation if hasn't changed. calls a callback when finished (whether animation or not)
                    mouseFollower.stop(!dropLocation, function() {
                        view.destroyDrag();
                        view.showEvent(event);
                        _this.segDragStop(seg, ev);

                        if (dropLocation) {
                            view.reportEventDrop(event, dropLocation, this.largeUnit, el, ev);
                        }
                    });
                },
                listenStop: function() {
                    mouseFollower.stop(); // put in listenStop in case there was a mousedown but the drag never started
                }
            });

            dragListener.mousedown(ev); // start listening, which will eventually lead to a dragStart
        },


        // Called before event segment dragging starts
        segDragStart: function(seg, ev) {
            this.isDraggingSeg = true;
            this.view.trigger('eventDragStart', seg.el[0], seg.event, ev, {}); // last argument is jqui dummy
        },


        // Called after event segment dragging stops
        segDragStop: function(seg, ev) {
            this.isDraggingSeg = false;
            this.view.trigger('eventDragStop', seg.el[0], seg.event, ev, {}); // last argument is jqui dummy
        },


        // Given the cell an event drag began, and the cell event was dropped, calculates the new start/end/allDay
        // values for the event. Subclasses may override and set additional properties to be used by renderDrag.
        // A falsy returned value indicates an invalid drop.
        computeEventDrop: function(startCell, endCell, event) {
            var calendar = this.view.calendar;
            var dragStart = startCell.start;
            var dragEnd = endCell.start;
            var delta;
            var dropLocation;

            if (dragStart.hasTime() === dragEnd.hasTime()) {
                delta = this.diffDates(dragEnd, dragStart);

                // if an all-day event was in a timed area and it was dragged to a different time,
                // guarantee an end and adjust start/end to have times
                if (event.allDay && durationHasTime(delta)) {
                    dropLocation = {
                        start: event.start.clone(),
                        end: calendar.getEventEnd(event), // will be an ambig day
                        allDay: false // for normalizeEventRangeTimes
                    };
                    calendar.normalizeEventRangeTimes(dropLocation);
                }
                // othewise, work off existing values
                else {
                    dropLocation = {
                        start: event.start.clone(),
                        end: event.end ? event.end.clone() : null,
                        allDay: event.allDay // keep it the same
                    };
                }

                dropLocation.start.add(delta);
                if (dropLocation.end) {
                    dropLocation.end.add(delta);
                }
            }
            else {
                // if switching from day <-> timed, start should be reset to the dropped date, and the end cleared
                dropLocation = {
                    start: dragEnd.clone(),
                    end: null, // end should be cleared
                    allDay: !dragEnd.hasTime()
                };
            }

            return dropLocation;
        },


        // Utility for apply dragOpacity to a jQuery set
        applyDragOpacity: function(els) {
            var opacity = this.view.opt('dragOpacity');

            if (opacity != null) {
                els.each(function(i, node) {
                    // Don't use jQuery (will set an IE filter), do it the old fashioned way.
                    // In IE8, a helper element will disappears if there's a filter.
                    node.style.opacity = opacity;
                });
            }
        },


        /* External Element Dragging
         ------------------------------------------------------------------------------------------------------------------*/


        // Called when a jQuery UI drag is initiated anywhere in the DOM
        externalDragStart: function(ev, ui) {
            var view = this.view;
            var el;
            var accept;

            if (view.opt('droppable')) { // only listen if this setting is on
                el = $((ui ? ui.item : null) || ev.target);

                // Test that the dragged element passes the dropAccept selector or filter function.
                // FYI, the default is "*" (matches all)
                accept = view.opt('dropAccept');
                if ($.isFunction(accept) ? accept.call(el[0], el) : el.is(accept)) {
                    if (!this.isDraggingExternal) { // prevent double-listening if fired twice
                        this.listenToExternalDrag(el, ev, ui);
                    }
                }
            }
        },


        // Called when a jQuery UI drag starts and it needs to be monitored for cell dropping
        listenToExternalDrag: function(el, ev, ui) {
            var _this = this;
            var meta = getDraggedElMeta(el); // extra data about event drop, including possible event to create
            var dragListener;
            var dropLocation; // a null value signals an unsuccessful drag

            // listener that tracks mouse movement over date-associated pixel regions
            dragListener = new CellDragListener(this.coordMap, {
                listenStart: function() {
                    _this.isDraggingExternal = true;
                },
                cellOver: function(cell) {
                    dropLocation = _this.computeExternalDrop(cell, meta);
                    if (dropLocation) {
                        _this.renderDrag(dropLocation); // called without a seg parameter
                    }
                    else { // invalid drop cell
                        disableCursor();
                    }
                },
                cellOut: function() {
                    dropLocation = null; // signal unsuccessful
                    _this.destroyDrag();
                    enableCursor();
                },
                dragStop: function() {
                    _this.destroyDrag();
                    enableCursor();

                    if (dropLocation) { // element was dropped on a valid date/time cell
                        _this.view.reportExternalDrop(meta, dropLocation, el, ev, ui);
                    }
                },
                listenStop: function() {
                    _this.isDraggingExternal = false;
                }
            });

            dragListener.startDrag(ev); // start listening immediately
        },


        // Given a cell to be dropped upon, and misc data associated with the jqui drag (guaranteed to be a plain object),
        // returns start/end dates for the event that would result from the hypothetical drop. end might be null.
        // Returning a null value signals an invalid drop cell.
        computeExternalDrop: function(cell, meta) {
            var dropLocation = {
                start: cell.start.clone(),
                end: null
            };

            // if dropped on an all-day cell, and element's metadata specified a time, set it
            if (meta.startTime && !dropLocation.start.hasTime()) {
                dropLocation.start.time(meta.startTime);
            }

            if (meta.duration) {
                dropLocation.end = dropLocation.start.clone().add(meta.duration);
            }

            if (!this.view.calendar.isExternalDropRangeAllowed(dropLocation, meta.eventProps)) {
                return null;
            }

            return dropLocation;
        },



        /* Drag Rendering (for both events and an external elements)
         ------------------------------------------------------------------------------------------------------------------*/


        // Renders a visual indication of an event or external element being dragged.
        // `dropLocation` contains hypothetical start/end/allDay values the event would have if dropped. end can be null.
        // `seg` is the internal segment object that is being dragged. If dragging an external element, `seg` is null.
        // A truthy returned value indicates this method has rendered a helper element.
        renderDrag: function(dropLocation, seg) {
            // subclasses must implement
        },


        // Unrenders a visual indication of an event or external element being dragged
        destroyDrag: function() {
            // subclasses must implement
        },


        /* Resizing
         ------------------------------------------------------------------------------------------------------------------*/


        // Called when the user does a mousedown on an event's resizer, which might lead to resizing.
        // Generic enough to work with any type of Grid.
        segResizeMousedown: function(seg, ev, isStart) {
            var _this = this;
            var view = this.view;
            var calendar = view.calendar;
            var el = seg.el;
            var event = seg.event;
            var eventEnd = calendar.getEventEnd(event);
            var dragListener;
            var resizeLocation; // falsy if invalid resize

            // Tracks mouse movement over the *grid's* coordinate map
            dragListener = new CellDragListener(this.coordMap, {
                distance: 5,
                scroll: view.opt('dragScroll'),
                subjectEl: el,
                dragStart: function(ev) {
                    _this.triggerSegMouseout(seg, ev); // ensure a mouseout on the manipulated event has been reported
                    _this.segResizeStart(seg, ev);
                },
                cellOver: function(cell, isOrig, origCell) {
                    resizeLocation = isStart ?
                        _this.computeEventStartResize(origCell, cell, event) :
                        _this.computeEventEndResize(origCell, cell, event);

                    if (resizeLocation) {
                        if (!calendar.isEventRangeAllowed(resizeLocation, event)) {
                            disableCursor();
                            resizeLocation = null;
                        }
                        // no change? (TODO: how does this work with timezones?)
                        else if (resizeLocation.start.isSame(event.start) && resizeLocation.end.isSame(eventEnd)) {
                            resizeLocation = null;
                        }
                    }

                    if (resizeLocation) {
                        view.hideEvent(event);
                        _this.renderEventResize(resizeLocation, seg);
                    }
                },
                cellOut: function() { // called before mouse moves to a different cell OR moved out of all cells
                    resizeLocation = null;
                },
                cellDone: function() { // resets the rendering to show the original event
                    _this.destroyEventResize();
                    view.showEvent(event);
                    enableCursor();
                },
                dragStop: function(ev) {
                    _this.segResizeStop(seg, ev);

                    if (resizeLocation) { // valid date to resize to?
                        view.reportEventResize(event, resizeLocation, this.largeUnit, el, ev);
                    }
                }
            });

            dragListener.mousedown(ev); // start listening, which will eventually lead to a dragStart
        },


        // Called before event segment resizing starts
        segResizeStart: function(seg, ev) {
            this.isResizingSeg = true;
            this.view.trigger('eventResizeStart', seg.el[0], seg.event, ev, {}); // last argument is jqui dummy
        },


        // Called after event segment resizing stops
        segResizeStop: function(seg, ev) {
            this.isResizingSeg = false;
            this.view.trigger('eventResizeStop', seg.el[0], seg.event, ev, {}); // last argument is jqui dummy
        },


        // Returns new date-information for an event segment being resized from its start
        computeEventStartResize: function(startCell, endCell, event) {
            return this.computeEventResize('start', startCell, endCell, event);
        },


        // Returns new date-information for an event segment being resized from its end
        computeEventEndResize: function(startCell, endCell, event) {
            return this.computeEventResize('end', startCell, endCell, event);
        },


        // Returns new date-information for an event segment being resized from its start OR end
        // `type` is either 'start' or 'end'
        computeEventResize: function(type, startCell, endCell, event) {
            var calendar = this.view.calendar;
            var delta = this.diffDates(endCell[type], startCell[type]);
            var range;
            var defaultDuration;

            // build original values to work from, guaranteeing a start and end
            range = {
                start: event.start.clone(),
                end: calendar.getEventEnd(event),
                allDay: event.allDay
            };

            // if an all-day event was in a timed area and was resized to a time, adjust start/end to have times
            if (range.allDay && durationHasTime(delta)) {
                range.allDay = false;
                calendar.normalizeEventRangeTimes(range);
            }

            range[type].add(delta); // apply delta to start or end

            // if the event was compressed too small, find a new reasonable duration for it
            if (!range.start.isBefore(range.end)) {

                defaultDuration = event.allDay ?
                    calendar.defaultAllDayEventDuration :
                    calendar.defaultTimedEventDuration;

                // between the cell's duration and the event's default duration, use the smaller of the two.
                // example: if year-length slots, and compressed to one slot, we don't want the event to be a year long
                if (this.cellDuration && this.cellDuration < defaultDuration) {
                    defaultDuration = this.cellDuration;
                }

                if (type == 'start') { // resizing the start?
                    range.start = range.end.clone().subtract(defaultDuration);
                }
                else { // resizing the end?
                    range.end = range.start.clone().add(defaultDuration);
                }
            }

            return range;
        },


        // Renders a visual indication of an event being resized.
        // `range` has the updated dates of the event. `seg` is the original segment object involved in the drag.
        renderEventResize: function(range, seg) {
            // subclasses must implement
        },


        // Unrenders a visual indication of an event being resized.
        destroyEventResize: function() {
            // subclasses must implement
        },


        /* Rendering Utils
         ------------------------------------------------------------------------------------------------------------------*/


        // Compute the text that should be displayed on an event's element.
        // `range` can be the Event object itself, or something range-like, with at least a `start`.
        // If event times are disabled, or the event has no time, will return a blank string.
        // If not specified, formatStr will default to the eventTimeFormat setting,
        // and displayEnd will default to the displayEventEnd setting.
        getEventTimeText: function(range, formatStr, displayEnd) {

            if (formatStr == null) {
                formatStr = this.eventTimeFormat;
            }

            if (displayEnd == null) {
                displayEnd = this.displayEventEnd;
            }

            if (this.displayEventTime && range.start.hasTime()) {
                if (displayEnd && range.end) {
                    return this.view.formatRange(range, formatStr);
                }
                else {
                    return range.start.format(formatStr);
                }
            }

            return '';
        },


        // Generic utility for generating the HTML classNames for an event segment's element
        getSegClasses: function(seg, isDraggable, isResizable) {
            var event = seg.event;
            var classes = [
                'fc-event',
                seg.isStart ? 'fc-start' : 'fc-not-start',
                seg.isEnd ? 'fc-end' : 'fc-not-end'
            ].concat(
                event.className,
                event.source ? event.source.className : []
            );

            if (isDraggable) {
                classes.push('fc-draggable');
            }
            if (isResizable) {
                classes.push('fc-resizable');
            }

            return classes;
        },


        // Utility for generating event skin-related CSS properties
        getEventSkinCss: function(event) {
            var view = this.view;
            var source = event.source || {};
            var eventColor = event.color;
            var sourceColor = source.color;
            var optionColor = view.opt('eventColor');

            return {
                'background-color':
                event.backgroundColor ||
                eventColor ||
                source.backgroundColor ||
                sourceColor ||
                view.opt('eventBackgroundColor') ||
                optionColor,
                'border-color':
                event.borderColor ||
                eventColor ||
                source.borderColor ||
                sourceColor ||
                view.opt('eventBorderColor') ||
                optionColor,
                color:
                event.textColor ||
                source.textColor ||
                view.opt('eventTextColor')
            };
        },


        /* Converting events -> ranges -> segs
         ------------------------------------------------------------------------------------------------------------------*/


        // Converts an array of event objects into an array of event segment objects.
        // A custom `rangeToSegsFunc` may be given for arbitrarily slicing up events.
        // Doesn't guarantee an order for the resulting array.
        eventsToSegs: function(events, rangeToSegsFunc) {
            var eventRanges = this.eventsToRanges(events);
            var segs = [];
            var i;

            for (i = 0; i < eventRanges.length; i++) {
                segs.push.apply(
                    segs,
                    this.eventRangeToSegs(eventRanges[i], rangeToSegsFunc)
                );
            }

            return segs;
        },


        // Converts an array of events into an array of "range" objects.
        // A "range" object is a plain object with start/end properties denoting the time it covers. Also an event property.
        // For "normal" events, this will be identical to the event's start/end, but for "inverse-background" events,
        // will create an array of ranges that span the time *not* covered by the given event.
        // Doesn't guarantee an order for the resulting array.
        eventsToRanges: function(events) {
            var _this = this;
            var eventsById = groupEventsById(events);
            var ranges = [];

            // group by ID so that related inverse-background events can be rendered together
            $.each(eventsById, function(id, eventGroup) {
                if (eventGroup.length) {
                    ranges.push.apply(
                        ranges,
                        isInverseBgEvent(eventGroup[0]) ?
                            _this.eventsToInverseRanges(eventGroup) :
                            _this.eventsToNormalRanges(eventGroup)
                    );
                }
            });

            return ranges;
        },


        // Converts an array of "normal" events (not inverted rendering) into a parallel array of ranges
        eventsToNormalRanges: function(events) {
            var calendar = this.view.calendar;
            var ranges = [];
            var i, event;
            var eventStart, eventEnd;

            for (i = 0; i < events.length; i++) {
                event = events[i];

                // make copies and normalize by stripping timezone
                eventStart = event.start.clone().stripZone();
                eventEnd = calendar.getEventEnd(event).stripZone();

                ranges.push({
                    event: event,
                    start: eventStart,
                    end: eventEnd,
                    eventStartMS: +eventStart,
                    eventDurationMS: eventEnd - eventStart
                });
            }

            return ranges;
        },


        // Converts an array of events, with inverse-background rendering, into an array of range objects.
        // The range objects will cover all the time NOT covered by the events.
        eventsToInverseRanges: function(events) {
            var view = this.view;
            var viewStart = view.start.clone().stripZone(); // normalize timezone
            var viewEnd = view.end.clone().stripZone(); // normalize timezone
            var normalRanges = this.eventsToNormalRanges(events); // will give us normalized dates we can use w/o copies
            var inverseRanges = [];
            var event0 = events[0]; // assign this to each range's `.event`
            var start = viewStart; // the end of the previous range. the start of the new range
            var i, normalRange;

            // ranges need to be in order. required for our date-walking algorithm
            normalRanges.sort(compareNormalRanges);

            for (i = 0; i < normalRanges.length; i++) {
                normalRange = normalRanges[i];

                // add the span of time before the event (if there is any)
                if (normalRange.start > start) { // compare millisecond time (skip any ambig logic)
                    inverseRanges.push({
                        event: event0,
                        start: start,
                        end: normalRange.start
                    });
                }

                start = normalRange.end;
            }

            // add the span of time after the last event (if there is any)
            if (start < viewEnd) { // compare millisecond time (skip any ambig logic)
                inverseRanges.push({
                    event: event0,
                    start: start,
                    end: viewEnd
                });
            }

            return inverseRanges;
        },


        // Slices the given event range into one or more segment objects.
        // A `rangeToSegsFunc` custom slicing function can be given.
        eventRangeToSegs: function(eventRange, rangeToSegsFunc) {
            var segs;
            var i, seg;

            if (rangeToSegsFunc) {
                segs = rangeToSegsFunc(eventRange);
            }
            else {
                segs = this.rangeToSegs(eventRange); // defined by the subclass
            }

            for (i = 0; i < segs.length; i++) {
                seg = segs[i];
                seg.event = eventRange.event;
                seg.eventStartMS = eventRange.eventStartMS;
                seg.eventDurationMS = eventRange.eventDurationMS;
            }

            return segs;
        }

    });


    /* Utilities
     ----------------------------------------------------------------------------------------------------------------------*/


    function isBgEvent(event) { // returns true if background OR inverse-background
        var rendering = getEventRendering(event);
        return rendering === 'background' || rendering === 'inverse-background';
    }


    function isInverseBgEvent(event) {
        return getEventRendering(event) === 'inverse-background';
    }


    function getEventRendering(event) {
        return firstDefined((event.source || {}).rendering, event.rendering);
    }


    function groupEventsById(events) {
        var eventsById = {};
        var i, event;

        for (i = 0; i < events.length; i++) {
            event = events[i];
            (eventsById[event._id] || (eventsById[event._id] = [])).push(event);
        }

        return eventsById;
    }


// A cmp function for determining which non-inverted "ranges" (see above) happen earlier
    function compareNormalRanges(range1, range2) {
        return range1.eventStartMS - range2.eventStartMS; // earlier ranges go first
    }


// A cmp function for determining which segments should take visual priority
// DOES NOT WORK ON INVERTED BACKGROUND EVENTS because they have no eventStartMS/eventDurationMS
    function compareSegs(seg1, seg2) {
        return seg1.eventStartMS - seg2.eventStartMS || // earlier events go first
            seg2.eventDurationMS - seg1.eventDurationMS || // tie? longer events go first
            seg2.event.allDay - seg1.event.allDay || // tie? put all-day events first (booleans cast to 0/1)
            (seg1.event.title || '').localeCompare(seg2.event.title); // tie? alphabetically by title
    }

    fc.compareSegs = compareSegs; // export


    /* External-Dragging-Element Data
     ----------------------------------------------------------------------------------------------------------------------*/

// Require all HTML5 data-* attributes used by FullCalendar to have this prefix.
// A value of '' will query attributes like data-event. A value of 'fc' will query attributes like data-fc-event.
    fc.dataAttrPrefix = '';

// Given a jQuery element that might represent a dragged FullCalendar event, returns an intermediate data structure
// to be used for Event Object creation.
// A defined `.eventProps`, even when empty, indicates that an event should be created.
    function getDraggedElMeta(el) {
        var prefix = fc.dataAttrPrefix;
        var eventProps; // properties for creating the event, not related to date/time
        var startTime; // a Duration
        var duration;
        var stick;

        if (prefix) { prefix += '-'; }
        eventProps = el.data(prefix + 'event') || null;

        if (eventProps) {
            if (typeof eventProps === 'object') {
                eventProps = $.extend({}, eventProps); // make a copy
            }
            else { // something like 1 or true. still signal event creation
                eventProps = {};
            }

            // pluck special-cased date/time properties
            startTime = eventProps.start;
            if (startTime == null) { startTime = eventProps.time; } // accept 'time' as well
            duration = eventProps.duration;
            stick = eventProps.stick;
            delete eventProps.start;
            delete eventProps.time;
            delete eventProps.duration;
            delete eventProps.stick;
        }

        // fallback to standalone attribute values for each of the date/time properties
        if (startTime == null) { startTime = el.data(prefix + 'start'); }
        if (startTime == null) { startTime = el.data(prefix + 'time'); } // accept 'time' as well
        if (duration == null) { duration = el.data(prefix + 'duration'); }
        if (stick == null) { stick = el.data(prefix + 'stick'); }

        // massage into correct data types
        startTime = startTime != null ? moment.duration(startTime) : null;
        duration = duration != null ? moment.duration(duration) : null;
        stick = Boolean(stick);

        return { eventProps: eventProps, startTime: startTime, duration: duration, stick: stick };
    }


    ;;

    /* A component that renders a grid of whole-days that runs horizontally. There can be multiple rows, one per week.
     ----------------------------------------------------------------------------------------------------------------------*/

    var DayGrid = Grid.extend({

        numbersVisible: false, // should render a row for day/week numbers? set by outside view. TODO: make internal
        bottomCoordPadding: 0, // hack for extending the hit area for the last row of the coordinate grid
        breakOnWeeks: null, // should create a new row for each week? set by outside view

        cellDates: null, // flat chronological array of each cell's dates
        dayToCellOffsets: null, // maps days offsets from grid's start date, to cell offsets

        rowEls: null, // set of fake row elements
        dayEls: null, // set of whole-day elements comprising the row's background
        helperEls: null, // set of cell skeleton elements for rendering the mock event "helper"


        constructor: function() {
            Grid.apply(this, arguments);

            this.cellDuration = moment.duration(1, 'day'); // for Grid system
        },


        // Renders the rows and columns into the component's `this.el`, which should already be assigned.
        // isRigid determins whether the individual rows should ignore the contents and be a constant height.
        // Relies on the view's colCnt and rowCnt. In the future, this component should probably be self-sufficient.
        renderDates: function(isRigid) {
            var view = this.view;
            var rowCnt = this.rowCnt;
            var colCnt = this.colCnt;
            var cellCnt = rowCnt * colCnt;
            var html = '';
            var row;
            var i, cell;

            for (row = 0; row < rowCnt; row++) {
                html += this.dayRowHtml(row, isRigid);
            }
            this.el.html(html);

            this.rowEls = this.el.find('.fc-row');
            this.dayEls = this.el.find('.fc-day');

            // trigger dayRender with each cell's element
            for (i = 0; i < cellCnt; i++) {
                cell = this.getCell(i);
                view.trigger('dayRender', null, cell.start, this.dayEls.eq(i));
            }
        },


        destroyDates: function() {
            this.destroySegPopover();
        },


        renderBusinessHours: function() {
            var events = this.view.calendar.getBusinessHoursEvents(true); // wholeDay=true
            var segs = this.eventsToSegs(events);

            this.renderFill('businessHours', segs, 'bgevent');
        },


        // Generates the HTML for a single row. `row` is the row number.
        dayRowHtml: function(row, isRigid) {
            var view = this.view;
            var classes = [ 'fc-row', 'fc-week', view.widgetContentClass ];

            if (isRigid) {
                classes.push('fc-rigid');
            }

            return '' +
                '<div class="' + classes.join(' ') + '">' +
                '<div class="fc-bg">' +
                '<table>' +
                this.rowHtml('day', row) + // leverages RowRenderer. calls dayCellHtml()
                '</table>' +
                '</div>' +
                '<div class="fc-content-skeleton">' +
                '<table>' +
                (this.numbersVisible ?
                '<thead>' +
                this.rowHtml('number', row) + // leverages RowRenderer. View will define render method
                '</thead>' :
                    ''
                ) +
                '</table>' +
                '</div>' +
                '</div>';
        },


        // Renders the HTML for a whole-day cell. Will eventually end up in the day-row's background.
        // We go through a 'day' row type instead of just doing a 'bg' row type so that the View can do custom rendering
        // specifically for whole-day rows, whereas a 'bg' might also be used for other purposes (TimeGrid bg for example).
        dayCellHtml: function(cell) {
            return this.bgCellHtml(cell);
        },


        /* Options
         ------------------------------------------------------------------------------------------------------------------*/


        // Computes a default column header formatting string if `colFormat` is not explicitly defined
        computeColHeadFormat: function() {
            if (this.rowCnt > 1) { // more than one week row. day numbers will be in each cell
                return 'ddd'; // "Sat"
            }
            else if (this.colCnt > 1) { // multiple days, so full single date string WON'T be in title text
                return this.view.opt('dayOfMonthFormat'); // "Sat 12/10"
            }
            else { // single day, so full single date string will probably be in title text
                return 'dddd'; // "Saturday"
            }
        },


        // Computes a default event time formatting string if `timeFormat` is not explicitly defined
        computeEventTimeFormat: function() {
            return this.view.opt('extraSmallTimeFormat'); // like "6p" or "6:30p"
        },


        // Computes a default `displayEventEnd` value if one is not expliclty defined
        computeDisplayEventEnd: function() {
            return this.colCnt == 1; // we'll likely have space if there's only one day
        },


        /* Cell System
         ------------------------------------------------------------------------------------------------------------------*/


        // Initializes row/col information
        updateCells: function() {
            var cellDates;
            var firstDay;
            var rowCnt;
            var colCnt;

            this.updateCellDates(); // populates cellDates and dayToCellOffsets
            cellDates = this.cellDates;

            if (this.breakOnWeeks) {
                // count columns until the day-of-week repeats
                firstDay = cellDates[0].day();
                for (colCnt = 1; colCnt < cellDates.length; colCnt++) {
                    if (cellDates[colCnt].day() == firstDay) {
                        break;
                    }
                }
                rowCnt = Math.ceil(cellDates.length / colCnt);
            }
            else {
                rowCnt = 1;
                colCnt = cellDates.length;
            }

            this.rowCnt = rowCnt;
            this.colCnt = colCnt;
        },


        // Populates cellDates and dayToCellOffsets
        updateCellDates: function() {
            var view = this.view;
            var date = this.start.clone();
            var dates = [];
            var offset = -1;
            var offsets = [];

            while (date.isBefore(this.end)) { // loop each day from start to end
                if (view.isHiddenDay(date)) {
                    offsets.push(offset + 0.5); // mark that it's between offsets
                }
                else {
                    offset++;
                    offsets.push(offset);
                    dates.push(date.clone());
                }
                date.add(1, 'days');
            }

            this.cellDates = dates;
            this.dayToCellOffsets = offsets;
        },


        // Given a cell object, generates its start date. Returns a reference-free copy.
        computeCellDate: function(cell) {
            var colCnt = this.colCnt;
            var index = cell.row * colCnt + (this.isRTL ? colCnt - cell.col - 1 : cell.col);

            return this.cellDates[index].clone();
        },


        // Retrieves the element representing the given row
        getRowEl: function(row) {
            return this.rowEls.eq(row);
        },


        // Retrieves the element representing the given column
        getColEl: function(col) {
            return this.dayEls.eq(col);
        },


        // Gets the whole-day element associated with the cell
        getCellDayEl: function(cell) {
            return this.dayEls.eq(cell.row * this.colCnt + cell.col);
        },


        // Overrides Grid's method for when row coordinates are computed
        computeRowCoords: function() {
            var rowCoords = Grid.prototype.computeRowCoords.call(this); // call the super-method

            // hack for extending last row (used by AgendaView)
            rowCoords[rowCoords.length - 1].bottom += this.bottomCoordPadding;

            return rowCoords;
        },


        /* Dates
         ------------------------------------------------------------------------------------------------------------------*/


        // Slices up a date range by row into an array of segments
        rangeToSegs: function(range) {
            var isRTL = this.isRTL;
            var rowCnt = this.rowCnt;
            var colCnt = this.colCnt;
            var segs = [];
            var first, last; // inclusive cell-offset range for given range
            var row;
            var rowFirst, rowLast; // inclusive cell-offset range for current row
            var isStart, isEnd;
            var segFirst, segLast; // inclusive cell-offset range for segment
            var seg;

            range = this.view.computeDayRange(range); // make whole-day range, considering nextDayThreshold
            first = this.dateToCellOffset(range.start);
            last = this.dateToCellOffset(range.end.subtract(1, 'days')); // offset of inclusive end date

            for (row = 0; row < rowCnt; row++) {
                rowFirst = row * colCnt;
                rowLast = rowFirst + colCnt - 1;

                // intersect segment's offset range with the row's
                segFirst = Math.max(rowFirst, first);
                segLast = Math.min(rowLast, last);

                // deal with in-between indices
                segFirst = Math.ceil(segFirst); // in-between starts round to next cell
                segLast = Math.floor(segLast); // in-between ends round to prev cell

                if (segFirst <= segLast) { // was there any intersection with the current row?

                    // must be matching integers to be the segment's start/end
                    isStart = segFirst === first;
                    isEnd = segLast === last;

                    // translate offsets to be relative to start-of-row
                    segFirst -= rowFirst;
                    segLast -= rowFirst;

                    seg = { row: row, isStart: isStart, isEnd: isEnd };
                    if (isRTL) {
                        seg.leftCol = colCnt - segLast - 1;
                        seg.rightCol = colCnt - segFirst - 1;
                    }
                    else {
                        seg.leftCol = segFirst;
                        seg.rightCol = segLast;
                    }
                    segs.push(seg);
                }
            }

            return segs;
        },


        // Given a date, returns its chronolocial cell-offset from the first cell of the grid.
        // If the date lies between cells (because of hiddenDays), returns a floating-point value between offsets.
        // If before the first offset, returns a negative number.
        // If after the last offset, returns an offset past the last cell offset.
        // Only works for *start* dates of cells. Will not work for exclusive end dates for cells.
        dateToCellOffset: function(date) {
            var offsets = this.dayToCellOffsets;
            var day = date.diff(this.start, 'days');

            if (day < 0) {
                return offsets[0] - 1;
            }
            else if (day >= offsets.length) {
                return offsets[offsets.length - 1] + 1;
            }
            else {
                return offsets[day];
            }
        },


        /* Event Drag Visualization
         ------------------------------------------------------------------------------------------------------------------*/
        // TODO: move to DayGrid.event, similar to what we did with Grid's drag methods


        // Renders a visual indication of an event or external element being dragged.
        // The dropLocation's end can be null. seg can be null. See Grid::renderDrag for more info.
        renderDrag: function(dropLocation, seg) {

            // always render a highlight underneath
            this.renderHighlight(
                this.view.calendar.ensureVisibleEventRange(dropLocation) // needs to be a proper range
            );

            // if a segment from the same calendar but another component is being dragged, render a helper event
            if (seg && !seg.el.closest(this.el).length) {

                this.renderRangeHelper(dropLocation, seg);
                this.applyDragOpacity(this.helperEls);

                return true; // a helper has been rendered
            }
        },


        // Unrenders any visual indication of a hovering event
        destroyDrag: function() {
            this.destroyHighlight();
            this.destroyHelper();
        },


        /* Event Resize Visualization
         ------------------------------------------------------------------------------------------------------------------*/


        // Renders a visual indication of an event being resized
        renderEventResize: function(range, seg) {
            this.renderHighlight(range);
            this.renderRangeHelper(range, seg);
        },


        // Unrenders a visual indication of an event being resized
        destroyEventResize: function() {
            this.destroyHighlight();
            this.destroyHelper();
        },


        /* Event Helper
         ------------------------------------------------------------------------------------------------------------------*/


        // Renders a mock "helper" event. `sourceSeg` is the associated internal segment object. It can be null.
        renderHelper: function(event, sourceSeg) {
            var helperNodes = [];
            var segs = this.eventsToSegs([ event ]);
            var rowStructs;

            segs = this.renderFgSegEls(segs); // assigns each seg's el and returns a subset of segs that were rendered
            rowStructs = this.renderSegRows(segs);

            // inject each new event skeleton into each associated row
            this.rowEls.each(function(row, rowNode) {
                var rowEl = $(rowNode); // the .fc-row
                var skeletonEl = $('<div class="fc-helper-skeleton"><table/></div>'); // will be absolutely positioned
                var skeletonTop;

                // If there is an original segment, match the top position. Otherwise, put it at the row's top level
                if (sourceSeg && sourceSeg.row === row) {
                    skeletonTop = sourceSeg.el.position().top;
                }
                else {
                    skeletonTop = rowEl.find('.fc-content-skeleton tbody').position().top;
                }

                skeletonEl.css('top', skeletonTop)
                    .find('table')
                    .append(rowStructs[row].tbodyEl);

                rowEl.append(skeletonEl);
                helperNodes.push(skeletonEl[0]);
            });

            this.helperEls = $(helperNodes); // array -> jQuery set
        },


        // Unrenders any visual indication of a mock helper event
        destroyHelper: function() {
            if (this.helperEls) {
                this.helperEls.remove();
                this.helperEls = null;
            }
        },


        /* Fill System (highlight, background events, business hours)
         ------------------------------------------------------------------------------------------------------------------*/


        fillSegTag: 'td', // override the default tag name


        // Renders a set of rectangles over the given segments of days.
        // Only returns segments that successfully rendered.
        renderFill: function(type, segs, className) {
            var nodes = [];
            var i, seg;
            var skeletonEl;

            segs = this.renderFillSegEls(type, segs); // assignes `.el` to each seg. returns successfully rendered segs

            for (i = 0; i < segs.length; i++) {
                seg = segs[i];
                skeletonEl = this.renderFillRow(type, seg, className);
                this.rowEls.eq(seg.row).append(skeletonEl);
                nodes.push(skeletonEl[0]);
            }

            this.elsByFill[type] = $(nodes);

            return segs;
        },


        // Generates the HTML needed for one row of a fill. Requires the seg's el to be rendered.
        renderFillRow: function(type, seg, className) {
            var colCnt = this.colCnt;
            var startCol = seg.leftCol;
            var endCol = seg.rightCol + 1;
            var skeletonEl;
            var trEl;

            className = className || type.toLowerCase();

            skeletonEl = $(
                '<div class="fc-' + className + '-skeleton">' +
                '<table><tr/></table>' +
                '</div>'
            );
            trEl = skeletonEl.find('tr');

            if (startCol > 0) {
                trEl.append('<td colspan="' + startCol + '"/>');
            }

            trEl.append(
                seg.el.attr('colspan', endCol - startCol)
            );

            if (endCol < colCnt) {
                trEl.append('<td colspan="' + (colCnt - endCol) + '"/>');
            }

            this.bookendCells(trEl, type);

            return skeletonEl;
        }

    });

    ;;

    /* Event-rendering methods for the DayGrid class
     ----------------------------------------------------------------------------------------------------------------------*/

    DayGrid.mixin({

        rowStructs: null, // an array of objects, each holding information about a row's foreground event-rendering


        // Unrenders all events currently rendered on the grid
        destroyEvents: function() {
            this.destroySegPopover(); // removes the "more.." events popover
            Grid.prototype.destroyEvents.apply(this, arguments); // calls the super-method
        },


        // Retrieves all rendered segment objects currently rendered on the grid
        getEventSegs: function() {
            return Grid.prototype.getEventSegs.call(this) // get the segments from the super-method
                .concat(this.popoverSegs || []); // append the segments from the "more..." popover
        },


        // Renders the given background event segments onto the grid
        renderBgSegs: function(segs) {

            // don't render timed background events
            var allDaySegs = $.grep(segs, function(seg) {
                return seg.event.allDay;
            });

            return Grid.prototype.renderBgSegs.call(this, allDaySegs); // call the super-method
        },


        // Renders the given foreground event segments onto the grid
        renderFgSegs: function(segs) {
            var rowStructs;

            // render an `.el` on each seg
            // returns a subset of the segs. segs that were actually rendered
            segs = this.renderFgSegEls(segs);

            rowStructs = this.rowStructs = this.renderSegRows(segs);

            // append to each row's content skeleton
            this.rowEls.each(function(i, rowNode) {
                $(rowNode).find('.fc-content-skeleton > table').append(
                    rowStructs[i].tbodyEl
                );
            });

            return segs; // return only the segs that were actually rendered
        },


        // Unrenders all currently rendered foreground event segments
        destroyFgSegs: function() {
            var rowStructs = this.rowStructs || [];
            var rowStruct;

            while ((rowStruct = rowStructs.pop())) {
                rowStruct.tbodyEl.remove();
            }

            this.rowStructs = null;
        },


        // Uses the given events array to generate <tbody> elements that should be appended to each row's content skeleton.
        // Returns an array of rowStruct objects (see the bottom of `renderSegRow`).
        // PRECONDITION: each segment shoud already have a rendered and assigned `.el`
        renderSegRows: function(segs) {
            var rowStructs = [];
            var segRows;
            var row;

            segRows = this.groupSegRows(segs); // group into nested arrays

            // iterate each row of segment groupings
            for (row = 0; row < segRows.length; row++) {
                rowStructs.push(
                    this.renderSegRow(row, segRows[row])
                );
            }

            return rowStructs;
        },


        // Builds the HTML to be used for the default element for an individual segment
        fgSegHtml: function(seg, disableResizing) {
            var view = this.view;
            var event = seg.event;
            var isDraggable = view.isEventDraggable(event);
            var isResizableFromStart = !disableResizing && event.allDay &&
                seg.isStart && view.isEventResizableFromStart(event);
            var isResizableFromEnd = !disableResizing && event.allDay &&
                seg.isEnd && view.isEventResizableFromEnd(event);
            var classes = this.getSegClasses(seg, isDraggable, isResizableFromStart || isResizableFromEnd);
            var skinCss = cssToStr(this.getEventSkinCss(event));
            var timeHtml = '';
            var timeText;
            var titleHtml;

            classes.unshift('fc-day-grid-event', 'fc-h-event');

            // Only display a timed events time if it is the starting segment
            if (seg.isStart) {
                timeText = this.getEventTimeText(event);
                if (timeText) {
                    timeHtml = '<span class="fc-time">' + htmlEscape(timeText) + '</span>';
                }
            }

            titleHtml =
                '<span class="fc-title">' +
                (htmlEscape(event.title || '') || '&nbsp;') + // we always want one line of height
                '</span>';

            return '<a class="' + classes.join(' ') + '"' +
                (event.url ?
                ' href="' + htmlEscape(event.url) + '"' :
                    ''
                ) +
                (skinCss ?
                ' style="' + skinCss + '"' :
                    ''
                ) +
                '>' +
                '<div class="fc-content">' +
                (this.isRTL ?
                titleHtml + ' ' + timeHtml : // put a natural space in between
                timeHtml + ' ' + titleHtml   //
                ) +
                '</div>' +
                (isResizableFromStart ?
                    '<div class="fc-resizer fc-start-resizer" />' :
                    ''
                ) +
                (isResizableFromEnd ?
                    '<div class="fc-resizer fc-end-resizer" />' :
                    ''
                ) +
                '</a>';
        },


        // Given a row # and an array of segments all in the same row, render a <tbody> element, a skeleton that contains
        // the segments. Returns object with a bunch of internal data about how the render was calculated.
        // NOTE: modifies rowSegs
        renderSegRow: function(row, rowSegs) {
            var colCnt = this.colCnt;
            var segLevels = this.buildSegLevels(rowSegs); // group into sub-arrays of levels
            var levelCnt = Math.max(1, segLevels.length); // ensure at least one level
            var tbody = $('<tbody/>');
            var segMatrix = []; // lookup for which segments are rendered into which level+col cells
            var cellMatrix = []; // lookup for all <td> elements of the level+col matrix
            var loneCellMatrix = []; // lookup for <td> elements that only take up a single column
            var i, levelSegs;
            var col;
            var tr;
            var j, seg;
            var td;

            // populates empty cells from the current column (`col`) to `endCol`
            function emptyCellsUntil(endCol) {
                while (col < endCol) {
                    // try to grab a cell from the level above and extend its rowspan. otherwise, create a fresh cell
                    td = (loneCellMatrix[i - 1] || [])[col];
                    if (td) {
                        td.attr(
                            'rowspan',
                            parseInt(td.attr('rowspan') || 1, 10) + 1
                        );
                    }
                    else {
                        td = $('<td/>');
                        tr.append(td);
                    }
                    cellMatrix[i][col] = td;
                    loneCellMatrix[i][col] = td;
                    col++;
                }
            }

            for (i = 0; i < levelCnt; i++) { // iterate through all levels
                levelSegs = segLevels[i];
                col = 0;
                tr = $('<tr/>');

                segMatrix.push([]);
                cellMatrix.push([]);
                loneCellMatrix.push([]);

                // levelCnt might be 1 even though there are no actual levels. protect against this.
                // this single empty row is useful for styling.
                if (levelSegs) {
                    for (j = 0; j < levelSegs.length; j++) { // iterate through segments in level
                        seg = levelSegs[j];

                        emptyCellsUntil(seg.leftCol);

                        // create a container that occupies or more columns. append the event element.
                        td = $('<td class="fc-event-container"/>').append(seg.el);
                        if (seg.leftCol != seg.rightCol) {
                            td.attr('colspan', seg.rightCol - seg.leftCol + 1);
                        }
                        else { // a single-column segment
                            loneCellMatrix[i][col] = td;
                        }

                        while (col <= seg.rightCol) {
                            cellMatrix[i][col] = td;
                            segMatrix[i][col] = seg;
                            col++;
                        }

                        tr.append(td);
                    }
                }

                emptyCellsUntil(colCnt); // finish off the row
                this.bookendCells(tr, 'eventSkeleton');
                tbody.append(tr);
            }

            return { // a "rowStruct"
                row: row, // the row number
                tbodyEl: tbody,
                cellMatrix: cellMatrix,
                segMatrix: segMatrix,
                segLevels: segLevels,
                segs: rowSegs
            };
        },


        // Stacks a flat array of segments, which are all assumed to be in the same row, into subarrays of vertical levels.
        // NOTE: modifies segs
        buildSegLevels: function(segs) {
            var levels = [];
            var i, seg;
            var j;

            // Give preference to elements with certain criteria, so they have
            // a chance to be closer to the top.
            segs.sort(compareSegs);

            for (i = 0; i < segs.length; i++) {
                seg = segs[i];

                // loop through levels, starting with the topmost, until the segment doesn't collide with other segments
                for (j = 0; j < levels.length; j++) {
                    if (!isDaySegCollision(seg, levels[j])) {
                        break;
                    }
                }
                // `j` now holds the desired subrow index
                seg.level = j;

                // create new level array if needed and append segment
                (levels[j] || (levels[j] = [])).push(seg);
            }

            // order segments left-to-right. very important if calendar is RTL
            for (j = 0; j < levels.length; j++) {
                levels[j].sort(compareDaySegCols);
            }

            return levels;
        },


        // Given a flat array of segments, return an array of sub-arrays, grouped by each segment's row
        groupSegRows: function(segs) {
            var segRows = [];
            var i;

            for (i = 0; i < this.rowCnt; i++) {
                segRows.push([]);
            }

            for (i = 0; i < segs.length; i++) {
                segRows[segs[i].row].push(segs[i]);
            }

            return segRows;
        }

    });


// Computes whether two segments' columns collide. They are assumed to be in the same row.
    function isDaySegCollision(seg, otherSegs) {
        var i, otherSeg;

        for (i = 0; i < otherSegs.length; i++) {
            otherSeg = otherSegs[i];

            if (
                otherSeg.leftCol <= seg.rightCol &&
                otherSeg.rightCol >= seg.leftCol
            ) {
                return true;
            }
        }

        return false;
    }


// A cmp function for determining the leftmost event
    function compareDaySegCols(a, b) {
        return a.leftCol - b.leftCol;
    }

    ;;

    /* Methods relate to limiting the number events for a given day on a DayGrid
     ----------------------------------------------------------------------------------------------------------------------*/
// NOTE: all the segs being passed around in here are foreground segs

    DayGrid.mixin({

        segPopover: null, // the Popover that holds events that can't fit in a cell. null when not visible
        popoverSegs: null, // an array of segment objects that the segPopover holds. null when not visible


        destroySegPopover: function() {
            if (this.segPopover) {
                this.segPopover.hide(); // will trigger destruction of `segPopover` and `popoverSegs`
            }
        },


        // Limits the number of "levels" (vertically stacking layers of events) for each row of the grid.
        // `levelLimit` can be false (don't limit), a number, or true (should be computed).
        limitRows: function(levelLimit) {
            var rowStructs = this.rowStructs || [];
            var row; // row #
            var rowLevelLimit;

            for (row = 0; row < rowStructs.length; row++) {
                this.unlimitRow(row);

                if (!levelLimit) {
                    rowLevelLimit = false;
                }
                else if (typeof levelLimit === 'number') {
                    rowLevelLimit = levelLimit;
                }
                else {
                    rowLevelLimit = this.computeRowLevelLimit(row);
                }

                if (rowLevelLimit !== false) {
                    this.limitRow(row, rowLevelLimit);
                }
            }
        },


        // Computes the number of levels a row will accomodate without going outside its bounds.
        // Assumes the row is "rigid" (maintains a constant height regardless of what is inside).
        // `row` is the row number.
        computeRowLevelLimit: function(row) {
            var rowEl = this.rowEls.eq(row); // the containing "fake" row div
            var rowHeight = rowEl.height(); // TODO: cache somehow?
            var trEls = this.rowStructs[row].tbodyEl.children();
            var i, trEl;
            var trHeight;

            function iterInnerHeights(i, childNode) {
                trHeight = Math.max(trHeight, $(childNode).outerHeight());
            }

            // Reveal one level <tr> at a time and stop when we find one out of bounds
            for (i = 0; i < trEls.length; i++) {
                trEl = trEls.eq(i).removeClass('fc-limited'); // reset to original state (reveal)

                // with rowspans>1 and IE8, trEl.outerHeight() would return the height of the largest cell,
                // so instead, find the tallest inner content element.
                trHeight = 0;
                trEl.find('> td > :first-child').each(iterInnerHeights);

                if (trEl.position().top + trHeight > rowHeight) {
                    return i;
                }
            }

            return false; // should not limit at all
        },


        // Limits the given grid row to the maximum number of levels and injects "more" links if necessary.
        // `row` is the row number.
        // `levelLimit` is a number for the maximum (inclusive) number of levels allowed.
        limitRow: function(row, levelLimit) {
            var _this = this;
            var rowStruct = this.rowStructs[row];
            var moreNodes = []; // array of "more" <a> links and <td> DOM nodes
            var col = 0; // col #, left-to-right (not chronologically)
            var cell;
            var levelSegs; // array of segment objects in the last allowable level, ordered left-to-right
            var cellMatrix; // a matrix (by level, then column) of all <td> jQuery elements in the row
            var limitedNodes; // array of temporarily hidden level <tr> and segment <td> DOM nodes
            var i, seg;
            var segsBelow; // array of segment objects below `seg` in the current `col`
            var totalSegsBelow; // total number of segments below `seg` in any of the columns `seg` occupies
            var colSegsBelow; // array of segment arrays, below seg, one for each column (offset from segs's first column)
            var td, rowspan;
            var segMoreNodes; // array of "more" <td> cells that will stand-in for the current seg's cell
            var j;
            var moreTd, moreWrap, moreLink;

            // Iterates through empty level cells and places "more" links inside if need be
            function emptyCellsUntil(endCol) { // goes from current `col` to `endCol`
                while (col < endCol) {
                    cell = _this.getCell(row, col);
                    segsBelow = _this.getCellSegs(cell, levelLimit);
                    if (segsBelow.length) {
                        td = cellMatrix[levelLimit - 1][col];
                        moreLink = _this.renderMoreLink(cell, segsBelow);
                        moreWrap = $('<div/>').append(moreLink);
                        td.append(moreWrap);
                        moreNodes.push(moreWrap[0]);
                    }
                    col++;
                }
            }

            if (levelLimit && levelLimit < rowStruct.segLevels.length) { // is it actually over the limit?
                levelSegs = rowStruct.segLevels[levelLimit - 1];
                cellMatrix = rowStruct.cellMatrix;

                limitedNodes = rowStruct.tbodyEl.children().slice(levelLimit) // get level <tr> elements past the limit
                    .addClass('fc-limited').get(); // hide elements and get a simple DOM-nodes array

                // iterate though segments in the last allowable level
                for (i = 0; i < levelSegs.length; i++) {
                    seg = levelSegs[i];
                    emptyCellsUntil(seg.leftCol); // process empty cells before the segment

                    // determine *all* segments below `seg` that occupy the same columns
                    colSegsBelow = [];
                    totalSegsBelow = 0;
                    while (col <= seg.rightCol) {
                        cell = this.getCell(row, col);
                        segsBelow = this.getCellSegs(cell, levelLimit);
                        colSegsBelow.push(segsBelow);
                        totalSegsBelow += segsBelow.length;
                        col++;
                    }

                    if (totalSegsBelow) { // do we need to replace this segment with one or many "more" links?
                        td = cellMatrix[levelLimit - 1][seg.leftCol]; // the segment's parent cell
                        rowspan = td.attr('rowspan') || 1;
                        segMoreNodes = [];

                        // make a replacement <td> for each column the segment occupies. will be one for each colspan
                        for (j = 0; j < colSegsBelow.length; j++) {
                            moreTd = $('<td class="fc-more-cell"/>').attr('rowspan', rowspan);
                            segsBelow = colSegsBelow[j];
                            cell = this.getCell(row, seg.leftCol + j);
                            moreLink = this.renderMoreLink(cell, [ seg ].concat(segsBelow)); // count seg as hidden too
                            moreWrap = $('<div/>').append(moreLink);
                            moreTd.append(moreWrap);
                            segMoreNodes.push(moreTd[0]);
                            moreNodes.push(moreTd[0]);
                        }

                        td.addClass('fc-limited').after($(segMoreNodes)); // hide original <td> and inject replacements
                        limitedNodes.push(td[0]);
                    }
                }

                emptyCellsUntil(this.colCnt); // finish off the level
                rowStruct.moreEls = $(moreNodes); // for easy undoing later
                rowStruct.limitedEls = $(limitedNodes); // for easy undoing later
            }
        },


        // Reveals all levels and removes all "more"-related elements for a grid's row.
        // `row` is a row number.
        unlimitRow: function(row) {
            var rowStruct = this.rowStructs[row];

            if (rowStruct.moreEls) {
                rowStruct.moreEls.remove();
                rowStruct.moreEls = null;
            }

            if (rowStruct.limitedEls) {
                rowStruct.limitedEls.removeClass('fc-limited');
                rowStruct.limitedEls = null;
            }
        },


        // Renders an <a> element that represents hidden event element for a cell.
        // Responsible for attaching click handler as well.
        renderMoreLink: function(cell, hiddenSegs) {
            var _this = this;
            var view = this.view;

            return $('<a class="fc-more"/>')
                .text(
                this.getMoreLinkText(hiddenSegs.length)
            )
                .on('click', function(ev) {
                    var clickOption = view.opt('eventLimitClick');
                    var date = cell.start;
                    var moreEl = $(this);
                    var dayEl = _this.getCellDayEl(cell);
                    var allSegs = _this.getCellSegs(cell);

                    // rescope the segments to be within the cell's date
                    var reslicedAllSegs = _this.resliceDaySegs(allSegs, date);
                    var reslicedHiddenSegs = _this.resliceDaySegs(hiddenSegs, date);

                    if (typeof clickOption === 'function') {
                        // the returned value can be an atomic option
                        clickOption = view.trigger('eventLimitClick', null, {
                            date: date,
                            dayEl: dayEl,
                            moreEl: moreEl,
                            segs: reslicedAllSegs,
                            hiddenSegs: reslicedHiddenSegs
                        }, ev);
                    }

                    if (clickOption === 'popover') {
                        _this.showSegPopover(cell, moreEl, reslicedAllSegs);
                    }
                    else if (typeof clickOption === 'string') { // a view name
                        view.calendar.zoomTo(date, clickOption);
                    }
                });
        },


        // Reveals the popover that displays all events within a cell
        showSegPopover: function(cell, moreLink, segs) {
            var _this = this;
            var view = this.view;
            var moreWrap = moreLink.parent(); // the <div> wrapper around the <a>
            var topEl; // the element we want to match the top coordinate of
            var options;

            if (this.rowCnt == 1) {
                topEl = view.el; // will cause the popover to cover any sort of header
            }
            else {
                topEl = this.rowEls.eq(cell.row); // will align with top of row
            }

            options = {
                className: 'fc-more-popover',
                content: this.renderSegPopoverContent(cell, segs),
                parentEl: this.el,
                top: topEl.offset().top,
                autoHide: true, // when the user clicks elsewhere, hide the popover
                viewportConstrain: view.opt('popoverViewportConstrain'),
                hide: function() {
                    // destroy everything when the popover is hidden
                    _this.segPopover.destroy();
                    _this.segPopover = null;
                    _this.popoverSegs = null;
                }
            };

            // Determine horizontal coordinate.
            // We use the moreWrap instead of the <td> to avoid border confusion.
            if (this.isRTL) {
                options.right = moreWrap.offset().left + moreWrap.outerWidth() + 1; // +1 to be over cell border
            }
            else {
                options.left = moreWrap.offset().left - 1; // -1 to be over cell border
            }

            this.segPopover = new Popover(options);
            this.segPopover.show();
        },


        // Builds the inner DOM contents of the segment popover
        renderSegPopoverContent: function(cell, segs) {
            var view = this.view;
            var isTheme = view.opt('theme');
            var title = cell.start.format(view.opt('dayPopoverFormat'));
            var content = $(
                '<div class="fc-header ' + view.widgetHeaderClass + '">' +
                '<span class="fc-close ' +
                (isTheme ? 'ui-icon ui-icon-closethick' : 'fc-icon fc-icon-x') +
                '"></span>' +
                '<span class="fc-title">' +
                htmlEscape(title) +
                '</span>' +
                '<div class="fc-clear"/>' +
                '</div>' +
                '<div class="fc-body ' + view.widgetContentClass + '">' +
                '<div class="fc-event-container"></div>' +
                '</div>'
            );
            var segContainer = content.find('.fc-event-container');
            var i;

            // render each seg's `el` and only return the visible segs
            segs = this.renderFgSegEls(segs, true); // disableResizing=true
            this.popoverSegs = segs;

            for (i = 0; i < segs.length; i++) {

                // because segments in the popover are not part of a grid coordinate system, provide a hint to any
                // grids that want to do drag-n-drop about which cell it came from
                segs[i].cell = cell;

                segContainer.append(segs[i].el);
            }

            return content;
        },


        // Given the events within an array of segment objects, reslice them to be in a single day
        resliceDaySegs: function(segs, dayDate) {

            // build an array of the original events
            var events = $.map(segs, function(seg) {
                return seg.event;
            });

            var dayStart = dayDate.clone().stripTime();
            var dayEnd = dayStart.clone().add(1, 'days');
            var dayRange = { start: dayStart, end: dayEnd };

            // slice the events with a custom slicing function
            segs = this.eventsToSegs(
                events,
                function(range) {
                    var seg = intersectionToSeg(range, dayRange); // undefind if no intersection
                    return seg ? [ seg ] : []; // must return an array of segments
                }
            );

            // force an order because eventsToSegs doesn't guarantee one
            segs.sort(compareSegs);

            return segs;
        },


        // Generates the text that should be inside a "more" link, given the number of events it represents
        getMoreLinkText: function(num) {
            var opt = this.view.opt('eventLimitText');

            if (typeof opt === 'function') {
                return opt(num);
            }
            else {
                return '+' + num + ' ' + opt;
            }
        },


        // Returns segments within a given cell.
        // If `startLevel` is specified, returns only events including and below that level. Otherwise returns all segs.
        getCellSegs: function(cell, startLevel) {
            var segMatrix = this.rowStructs[cell.row].segMatrix;
            var level = startLevel || 0;
            var segs = [];
            var seg;

            while (level < segMatrix.length) {
                seg = segMatrix[level][cell.col];
                if (seg) {
                    segs.push(seg);
                }
                level++;
            }

            return segs;
        }

    });

    ;;

    /* A component that renders one or more columns of vertical time slots
     ----------------------------------------------------------------------------------------------------------------------*/

    var TimeGrid = Grid.extend({

        slotDuration: null, // duration of a "slot", a distinct time segment on given day, visualized by lines
        snapDuration: null, // granularity of time for dragging and selecting

        minTime: null, // Duration object that denotes the first visible time of any given day
        maxTime: null, // Duration object that denotes the exclusive visible end time of any given day

        axisFormat: null, // formatting string for times running along vertical axis

        dayEls: null, // cells elements in the day-row background
        slatEls: null, // elements running horizontally across all columns

        slatTops: null, // an array of top positions, relative to the container. last item holds bottom of last slot

        helperEl: null, // cell skeleton element for rendering the mock event "helper"

        businessHourSegs: null,


        constructor: function() {
            Grid.apply(this, arguments); // call the super-constructor
            this.processOptions();
        },


        // Renders the time grid into `this.el`, which should already be assigned.
        // Relies on the view's colCnt. In the future, this component should probably be self-sufficient.
        renderDates: function() {
            this.el.html(this.renderHtml());
            this.dayEls = this.el.find('.fc-day');
            this.slatEls = this.el.find('.fc-slats tr');
        },


        renderBusinessHours: function() {
            var events = this.view.calendar.getBusinessHoursEvents();
            this.businessHourSegs = this.renderFill('businessHours', this.eventsToSegs(events), 'bgevent');
        },


        // Renders the basic HTML skeleton for the grid
        renderHtml: function() {
            return '' +
                '<div class="fc-bg">' +
                '<table>' +
                this.rowHtml('slotBg') + // leverages RowRenderer, which will call slotBgCellHtml
                '</table>' +
                '</div>' +
                '<div class="fc-slats">' +
                '<table>' +
                this.slatRowHtml() +
                '</table>' +
                '</div>';
        },


        // Renders the HTML for a vertical background cell behind the slots.
        // This method is distinct from 'bg' because we wanted a new `rowType` so the View could customize the rendering.
        slotBgCellHtml: function(cell) {
            return this.bgCellHtml(cell);
        },


        // Generates the HTML for the horizontal "slats" that run width-wise. Has a time axis on a side. Depends on RTL.
        slatRowHtml: function() {
            var view = this.view;
            var isRTL = this.isRTL;
            var html = '';
            var slotNormal = this.slotDuration.asMinutes() % 15 === 0;
            var slotTime = moment.duration(+this.minTime); // wish there was .clone() for durations
            var slotDate; // will be on the view's first day, but we only care about its time
            var minutes;
            var axisHtml;

            // Calculate the time for each slot
            while (slotTime < this.maxTime) {
                slotDate = this.start.clone().time(slotTime); // will be in UTC but that's good. to avoid DST issues
                minutes = slotDate.minutes();

                axisHtml =
                    '<td class="fc-axis fc-time ' + view.widgetContentClass + '" ' + view.axisStyleAttr() + '>' +
                    ((!slotNormal || !minutes) ? // if irregular slot duration, or on the hour, then display the time
                    '<span>' + // for matchCellWidths
                    htmlEscape(slotDate.format(this.axisFormat)) +
                    '</span>' :
                        ''
                    ) +
                    '</td>';

                html +=
                    '<tr ' + (!minutes ? '' : 'class="fc-minor"') + '>' +
                    (!isRTL ? axisHtml : '') +
                    '<td class="' + view.widgetContentClass + '"/>' +
                    (isRTL ? axisHtml : '') +
                    "</tr>";

                slotTime.add(this.slotDuration);
            }

            return html;
        },


        /* Options
         ------------------------------------------------------------------------------------------------------------------*/


        // Parses various options into properties of this object
        processOptions: function() {
            var view = this.view;
            var slotDuration = view.opt('slotDuration');
            var snapDuration = view.opt('snapDuration');

            slotDuration = moment.duration(slotDuration);
            snapDuration = snapDuration ? moment.duration(snapDuration) : slotDuration;

            this.slotDuration = slotDuration;
            this.snapDuration = snapDuration;
            this.cellDuration = snapDuration; // for Grid system

            this.minTime = moment.duration(view.opt('minTime'));
            this.maxTime = moment.duration(view.opt('maxTime'));

            this.axisFormat = view.opt('axisFormat') || view.opt('smallTimeFormat');
        },


        // Computes a default column header formatting string if `colFormat` is not explicitly defined
        computeColHeadFormat: function() {
            if (this.colCnt > 1) { // multiple days, so full single date string WON'T be in title text
                return this.view.opt('dayOfMonthFormat'); // "Sat 12/10"
            }
            else { // single day, so full single date string will probably be in title text
                return 'dddd'; // "Saturday"
            }
        },


        // Computes a default event time formatting string if `timeFormat` is not explicitly defined
        computeEventTimeFormat: function() {
            return this.view.opt('noMeridiemTimeFormat'); // like "6:30" (no AM/PM)
        },


        // Computes a default `displayEventEnd` value if one is not expliclty defined
        computeDisplayEventEnd: function() {
            return true;
        },


        /* Cell System
         ------------------------------------------------------------------------------------------------------------------*/


        // Initializes row/col information
        updateCells: function() {
            var view = this.view;
            var colData = [];
            var date;

            date = this.start.clone();
            while (date.isBefore(this.end)) {
                colData.push({
                    day: date.clone()
                });
                date.add(1, 'day');
                date = view.skipHiddenDays(date);
            }

            if (this.isRTL) {
                colData.reverse();
            }

            this.colData = colData;
            this.colCnt = colData.length;
            this.rowCnt = Math.ceil((this.maxTime - this.minTime) / this.snapDuration); // # of vertical snaps
        },


        // Given a cell object, generates its start date. Returns a reference-free copy.
        computeCellDate: function(cell) {
            var time = this.computeSnapTime(cell.row);

            return this.view.calendar.rezoneDate(cell.day).time(time);
        },


        // Retrieves the element representing the given column
        getColEl: function(col) {
            return this.dayEls.eq(col);
        },


        /* Dates
         ------------------------------------------------------------------------------------------------------------------*/


        // Given a row number of the grid, representing a "snap", returns a time (Duration) from its start-of-day
        computeSnapTime: function(row) {
            return moment.duration(this.minTime + this.snapDuration * row);
        },


        // Slices up a date range by column into an array of segments
        rangeToSegs: function(range) {
            var colCnt = this.colCnt;
            var segs = [];
            var seg;
            var col;
            var colDate;
            var colRange;

            // normalize :(
            range = {
                start: range.start.clone().stripZone(),
                end: range.end.clone().stripZone()
            };

            for (col = 0; col < colCnt; col++) {
                colDate = this.colData[col].day; // will be ambig time/timezone
                colRange = {
                    start: colDate.clone().time(this.minTime),
                    end: colDate.clone().time(this.maxTime)
                };
                seg = intersectionToSeg(range, colRange); // both will be ambig timezone
                if (seg) {
                    seg.col = col;
                    segs.push(seg);
                }
            }

            return segs;
        },


        /* Coordinates
         ------------------------------------------------------------------------------------------------------------------*/


        updateSize: function(isResize) { // NOT a standard Grid method
            this.computeSlatTops();

            if (isResize) {
                this.updateSegVerticals();
            }
        },


        // Computes the top/bottom coordinates of each "snap" rows
        computeRowCoords: function() {
            var originTop = this.el.offset().top;
            var items = [];
            var i;
            var item;

            for (i = 0; i < this.rowCnt; i++) {
                item = {
                    top: originTop + this.computeTimeTop(this.computeSnapTime(i))
                };
                if (i > 0) {
                    items[i - 1].bottom = item.top;
                }
                items.push(item);
            }
            item.bottom = item.top + this.computeTimeTop(this.computeSnapTime(i));

            return items;
        },


        // Computes the top coordinate, relative to the bounds of the grid, of the given date.
        // A `startOfDayDate` must be given for avoiding ambiguity over how to treat midnight.
        computeDateTop: function(date, startOfDayDate) {
            return this.computeTimeTop(
                moment.duration(
                    date.clone().stripZone() - startOfDayDate.clone().stripTime()
                )
            );
        },


        // Computes the top coordinate, relative to the bounds of the grid, of the given time (a Duration).
        computeTimeTop: function(time) {
            var slatCoverage = (time - this.minTime) / this.slotDuration; // floating-point value of # of slots covered
            var slatIndex;
            var slatRemainder;
            var slatTop;
            var slatBottom;

            // constrain. because minTime/maxTime might be customized
            slatCoverage = Math.max(0, slatCoverage);
            slatCoverage = Math.min(this.slatEls.length, slatCoverage);

            slatIndex = Math.floor(slatCoverage); // an integer index of the furthest whole slot
            slatRemainder = slatCoverage - slatIndex;
            slatTop = this.slatTops[slatIndex]; // the top position of the furthest whole slot

            if (slatRemainder) { // time spans part-way into the slot
                slatBottom = this.slatTops[slatIndex + 1];
                return slatTop + (slatBottom - slatTop) * slatRemainder; // part-way between slots
            }
            else {
                return slatTop;
            }
        },


        // Queries each `slatEl` for its position relative to the grid's container and stores it in `slatTops`.
        // Includes the the bottom of the last slat as the last item in the array.
        computeSlatTops: function() {
            var tops = [];
            var top;

            this.slatEls.each(function(i, node) {
                top = $(node).position().top;
                tops.push(top);
            });

            tops.push(top + this.slatEls.last().outerHeight()); // bottom of the last slat

            this.slatTops = tops;
        },


        /* Event Drag Visualization
         ------------------------------------------------------------------------------------------------------------------*/


        // Renders a visual indication of an event being dragged over the specified date(s).
        // dropLocation's end might be null, as well as `seg`. See Grid::renderDrag for more info.
        // A returned value of `true` signals that a mock "helper" event has been rendered.
        renderDrag: function(dropLocation, seg) {

            if (seg) { // if there is event information for this drag, render a helper event
                this.renderRangeHelper(dropLocation, seg);
                this.applyDragOpacity(this.helperEl);

                return true; // signal that a helper has been rendered
            }
            else {
                // otherwise, just render a highlight
                this.renderHighlight(
                    this.view.calendar.ensureVisibleEventRange(dropLocation) // needs to be a proper range
                );
            }
        },


        // Unrenders any visual indication of an event being dragged
        destroyDrag: function() {
            this.destroyHelper();
            this.destroyHighlight();
        },


        /* Event Resize Visualization
         ------------------------------------------------------------------------------------------------------------------*/


        // Renders a visual indication of an event being resized
        renderEventResize: function(range, seg) {
            this.renderRangeHelper(range, seg);
        },


        // Unrenders any visual indication of an event being resized
        destroyEventResize: function() {
            this.destroyHelper();
        },


        /* Event Helper
         ------------------------------------------------------------------------------------------------------------------*/


        // Renders a mock "helper" event. `sourceSeg` is the original segment object and might be null (an external drag)
        renderHelper: function(event, sourceSeg) {
            var segs = this.eventsToSegs([ event ]);
            var tableEl;
            var i, seg;
            var sourceEl;

            segs = this.renderFgSegEls(segs); // assigns each seg's el and returns a subset of segs that were rendered
            tableEl = this.renderSegTable(segs);

            // Try to make the segment that is in the same row as sourceSeg look the same
            for (i = 0; i < segs.length; i++) {
                seg = segs[i];
                if (sourceSeg && sourceSeg.col === seg.col) {
                    sourceEl = sourceSeg.el;
                    seg.el.css({
                        left: sourceEl.css('left'),
                        right: sourceEl.css('right'),
                        'margin-left': sourceEl.css('margin-left'),
                        'margin-right': sourceEl.css('margin-right')
                    });
                }
            }

            this.helperEl = $('<div class="fc-helper-skeleton"/>')
                .append(tableEl)
                .appendTo(this.el);
        },


        // Unrenders any mock helper event
        destroyHelper: function() {
            if (this.helperEl) {
                this.helperEl.remove();
                this.helperEl = null;
            }
        },


        /* Selection
         ------------------------------------------------------------------------------------------------------------------*/


        // Renders a visual indication of a selection. Overrides the default, which was to simply render a highlight.
        renderSelection: function(range) {
            if (this.view.opt('selectHelper')) { // this setting signals that a mock helper event should be rendered
                this.renderRangeHelper(range);
            }
            else {
                this.renderHighlight(range);
            }
        },


        // Unrenders any visual indication of a selection
        destroySelection: function() {
            this.destroyHelper();
            this.destroyHighlight();
        },


        /* Fill System (highlight, background events, business hours)
         ------------------------------------------------------------------------------------------------------------------*/


        // Renders a set of rectangles over the given time segments.
        // Only returns segments that successfully rendered.
        renderFill: function(type, segs, className) {
            var segCols;
            var skeletonEl;
            var trEl;
            var col, colSegs;
            var tdEl;
            var containerEl;
            var dayDate;
            var i, seg;

            if (segs.length) {

                segs = this.renderFillSegEls(type, segs); // assignes `.el` to each seg. returns successfully rendered segs
                segCols = this.groupSegCols(segs); // group into sub-arrays, and assigns 'col' to each seg

                className = className || type.toLowerCase();
                skeletonEl = $(
                    '<div class="fc-' + className + '-skeleton">' +
                    '<table><tr/></table>' +
                    '</div>'
                );
                trEl = skeletonEl.find('tr');

                for (col = 0; col < segCols.length; col++) {
                    colSegs = segCols[col];
                    tdEl = $('<td/>').appendTo(trEl);

                    if (colSegs.length) {
                        containerEl = $('<div class="fc-' + className + '-container"/>').appendTo(tdEl);
                        dayDate = this.colData[col].day;

                        for (i = 0; i < colSegs.length; i++) {
                            seg = colSegs[i];
                            containerEl.append(
                                seg.el.css({
                                    top: this.computeDateTop(seg.start, dayDate),
                                    bottom: -this.computeDateTop(seg.end, dayDate) // the y position of the bottom edge
                                })
                            );
                        }
                    }
                }

                this.bookendCells(trEl, type);

                this.el.append(skeletonEl);
                this.elsByFill[type] = skeletonEl;
            }

            return segs;
        }

    });

    ;;

    /* Event-rendering methods for the TimeGrid class
     ----------------------------------------------------------------------------------------------------------------------*/

    TimeGrid.mixin({

        eventSkeletonEl: null, // has cells with event-containers, which contain absolutely positioned event elements


        // Renders the given foreground event segments onto the grid
        renderFgSegs: function(segs) {
            segs = this.renderFgSegEls(segs); // returns a subset of the segs. segs that were actually rendered

            this.el.append(
                this.eventSkeletonEl = $('<div class="fc-content-skeleton"/>')
                    .append(this.renderSegTable(segs))
            );

            return segs; // return only the segs that were actually rendered
        },


        // Unrenders all currently rendered foreground event segments
        destroyFgSegs: function(segs) {
            if (this.eventSkeletonEl) {
                this.eventSkeletonEl.remove();
                this.eventSkeletonEl = null;
            }
        },


        // Renders and returns the <table> portion of the event-skeleton.
        // Returns an object with properties 'tbodyEl' and 'segs'.
        renderSegTable: function(segs) {
            var tableEl = $('<table><tr/></table>');
            var trEl = tableEl.find('tr');
            var segCols;
            var i, seg;
            var col, colSegs;
            var containerEl;

            segCols = this.groupSegCols(segs); // group into sub-arrays, and assigns 'col' to each seg

            this.computeSegVerticals(segs); // compute and assign top/bottom

            for (col = 0; col < segCols.length; col++) { // iterate each column grouping
                colSegs = segCols[col];
                placeSlotSegs(colSegs); // compute horizontal coordinates, z-index's, and reorder the array

                containerEl = $('<div class="fc-event-container"/>');

                // assign positioning CSS and insert into container
                for (i = 0; i < colSegs.length; i++) {
                    seg = colSegs[i];
                    seg.el.css(this.generateSegPositionCss(seg));

                    // if the height is short, add a className for alternate styling
                    if (seg.bottom - seg.top < 30) {
                        seg.el.addClass('fc-short');
                    }

                    containerEl.append(seg.el);
                }

                trEl.append($('<td/>').append(containerEl));
            }

            this.bookendCells(trEl, 'eventSkeleton');

            return tableEl;
        },


        // Refreshes the CSS top/bottom coordinates for each segment element. Probably after a window resize/zoom.
        // Repositions business hours segs too, so not just for events. Maybe shouldn't be here.
        updateSegVerticals: function() {
            var allSegs = (this.segs || []).concat(this.businessHourSegs || []);
            var i;

            this.computeSegVerticals(allSegs);

            for (i = 0; i < allSegs.length; i++) {
                allSegs[i].el.css(
                    this.generateSegVerticalCss(allSegs[i])
                );
            }
        },


        // For each segment in an array, computes and assigns its top and bottom properties
        computeSegVerticals: function(segs) {
            var i, seg;

            for (i = 0; i < segs.length; i++) {
                seg = segs[i];
                seg.top = this.computeDateTop(seg.start, seg.start);
                seg.bottom = this.computeDateTop(seg.end, seg.start);
            }
        },


        // Renders the HTML for a single event segment's default rendering
        fgSegHtml: function(seg, disableResizing) {
            var view = this.view;
            var event = seg.event;
            var isDraggable = view.isEventDraggable(event);
            var isResizableFromStart = !disableResizing && seg.isStart && view.isEventResizableFromStart(event);
            var isResizableFromEnd = !disableResizing && seg.isEnd && view.isEventResizableFromEnd(event);
            var classes = this.getSegClasses(seg, isDraggable, isResizableFromStart || isResizableFromEnd);
            var skinCss = cssToStr(this.getEventSkinCss(event));
            var timeText;
            var fullTimeText; // more verbose time text. for the print stylesheet
            var startTimeText; // just the start time text

            classes.unshift('fc-time-grid-event', 'fc-v-event');

            if (view.isMultiDayEvent(event)) { // if the event appears to span more than one day...
                // Don't display time text on segments that run entirely through a day.
                // That would appear as midnight-midnight and would look dumb.
                // Otherwise, display the time text for the *segment's* times (like 6pm-midnight or midnight-10am)
                if (seg.isStart || seg.isEnd) {
                    timeText = this.getEventTimeText(seg);
                    fullTimeText = this.getEventTimeText(seg, 'LT');
                    startTimeText = this.getEventTimeText(seg, null, false); // displayEnd=false
                }
            } else {
                // Display the normal time text for the *event's* times
                timeText = this.getEventTimeText(event);
                fullTimeText = this.getEventTimeText(event, 'LT');
                startTimeText = this.getEventTimeText(event, null, false); // displayEnd=false
            }

            return '<a class="' + classes.join(' ') + '"' +
                (event.url ?
                ' href="' + htmlEscape(event.url) + '"' :
                    ''
                ) +
                (skinCss ?
                ' style="' + skinCss + '"' :
                    ''
                ) +
                '>' +
                '<div class="fc-content">' +
                (timeText ?
                '<div class="fc-time"' +
                ' data-start="' + htmlEscape(startTimeText) + '"' +
                ' data-full="' + htmlEscape(fullTimeText) + '"' +
                '>' +
                '<span>' + htmlEscape(timeText) + '</span>' +
                '</div>' :
                    ''
                ) +
                (event.title ?
                '<div class="fc-title">' +
                htmlEscape(event.title) +
                '</div>' :
                    ''
                ) +
                '</div>' +
                '<div class="fc-bg"/>' +
                    /* TODO: write CSS for this
                     (isResizableFromStart ?
                     '<div class="fc-resizer fc-start-resizer" />' :
                     ''
                     ) +
                     */
                (isResizableFromEnd ?
                    '<div class="fc-resizer fc-end-resizer" />' :
                    ''
                ) +
                '</a>';
        },


        // Generates an object with CSS properties/values that should be applied to an event segment element.
        // Contains important positioning-related properties that should be applied to any event element, customized or not.
        generateSegPositionCss: function(seg) {
            var shouldOverlap = this.view.opt('slotEventOverlap');
            var backwardCoord = seg.backwardCoord; // the left side if LTR. the right side if RTL. floating-point
            var forwardCoord = seg.forwardCoord; // the right side if LTR. the left side if RTL. floating-point
            var props = this.generateSegVerticalCss(seg); // get top/bottom first
            var left; // amount of space from left edge, a fraction of the total width
            var right; // amount of space from right edge, a fraction of the total width

            if (shouldOverlap) {
                // double the width, but don't go beyond the maximum forward coordinate (1.0)
                forwardCoord = Math.min(1, backwardCoord + (forwardCoord - backwardCoord) * 2);
            }

            if (this.isRTL) {
                left = 1 - forwardCoord;
                right = backwardCoord;
            }
            else {
                left = backwardCoord;
                right = 1 - forwardCoord;
            }

            props.zIndex = seg.level + 1; // convert from 0-base to 1-based
            props.left = left * 100 + '%';
            props.right = right * 100 + '%';

            if (shouldOverlap && seg.forwardPressure) {
                // add padding to the edge so that forward stacked events don't cover the resizer's icon
                props[this.isRTL ? 'marginLeft' : 'marginRight'] = 10 * 2; // 10 is a guesstimate of the icon's width
            }

            return props;
        },


        // Generates an object with CSS properties for the top/bottom coordinates of a segment element
        generateSegVerticalCss: function(seg) {
            return {
                top: seg.top,
                bottom: -seg.bottom // flipped because needs to be space beyond bottom edge of event container
            };
        },


        // Given a flat array of segments, return an array of sub-arrays, grouped by each segment's col
        groupSegCols: function(segs) {
            var segCols = [];
            var i;

            for (i = 0; i < this.colCnt; i++) {
                segCols.push([]);
            }

            for (i = 0; i < segs.length; i++) {
                segCols[segs[i].col].push(segs[i]);
            }

            return segCols;
        }

    });


// Given an array of segments that are all in the same column, sets the backwardCoord and forwardCoord on each.
// NOTE: Also reorders the given array by date!
    function placeSlotSegs(segs) {
        var levels;
        var level0;
        var i;

        segs.sort(compareSegs); // order by date
        levels = buildSlotSegLevels(segs);
        computeForwardSlotSegs(levels);

        if ((level0 = levels[0])) {

            for (i = 0; i < level0.length; i++) {
                computeSlotSegPressures(level0[i]);
            }

            for (i = 0; i < level0.length; i++) {
                computeSlotSegCoords(level0[i], 0, 0);
            }
        }
    }


// Builds an array of segments "levels". The first level will be the leftmost tier of segments if the calendar is
// left-to-right, or the rightmost if the calendar is right-to-left. Assumes the segments are already ordered by date.
    function buildSlotSegLevels(segs) {
        var levels = [];
        var i, seg;
        var j;

        for (i=0; i<segs.length; i++) {
            seg = segs[i];

            // go through all the levels and stop on the first level where there are no collisions
            for (j=0; j<levels.length; j++) {
                if (!computeSlotSegCollisions(seg, levels[j]).length) {
                    break;
                }
            }

            seg.level = j;

            (levels[j] || (levels[j] = [])).push(seg);
        }

        return levels;
    }


// For every segment, figure out the other segments that are in subsequent
// levels that also occupy the same vertical space. Accumulate in seg.forwardSegs
    function computeForwardSlotSegs(levels) {
        var i, level;
        var j, seg;
        var k;

        for (i=0; i<levels.length; i++) {
            level = levels[i];

            for (j=0; j<level.length; j++) {
                seg = level[j];

                seg.forwardSegs = [];
                for (k=i+1; k<levels.length; k++) {
                    computeSlotSegCollisions(seg, levels[k], seg.forwardSegs);
                }
            }
        }
    }


// Figure out which path forward (via seg.forwardSegs) results in the longest path until
// the furthest edge is reached. The number of segments in this path will be seg.forwardPressure
    function computeSlotSegPressures(seg) {
        var forwardSegs = seg.forwardSegs;
        var forwardPressure = 0;
        var i, forwardSeg;

        if (seg.forwardPressure === undefined) { // not already computed

            for (i=0; i<forwardSegs.length; i++) {
                forwardSeg = forwardSegs[i];

                // figure out the child's maximum forward path
                computeSlotSegPressures(forwardSeg);

                // either use the existing maximum, or use the child's forward pressure
                // plus one (for the forwardSeg itself)
                forwardPressure = Math.max(
                    forwardPressure,
                    1 + forwardSeg.forwardPressure
                );
            }

            seg.forwardPressure = forwardPressure;
        }
    }


// Calculate seg.forwardCoord and seg.backwardCoord for the segment, where both values range
// from 0 to 1. If the calendar is left-to-right, the seg.backwardCoord maps to "left" and
// seg.forwardCoord maps to "right" (via percentage). Vice-versa if the calendar is right-to-left.
//
// The segment might be part of a "series", which means consecutive segments with the same pressure
// who's width is unknown until an edge has been hit. `seriesBackwardPressure` is the number of
// segments behind this one in the current series, and `seriesBackwardCoord` is the starting
// coordinate of the first segment in the series.
    function computeSlotSegCoords(seg, seriesBackwardPressure, seriesBackwardCoord) {
        var forwardSegs = seg.forwardSegs;
        var i;

        if (seg.forwardCoord === undefined) { // not already computed

            if (!forwardSegs.length) {

                // if there are no forward segments, this segment should butt up against the edge
                seg.forwardCoord = 1;
            }
            else {

                // sort highest pressure first
                forwardSegs.sort(compareForwardSlotSegs);

                // this segment's forwardCoord will be calculated from the backwardCoord of the
                // highest-pressure forward segment.
                computeSlotSegCoords(forwardSegs[0], seriesBackwardPressure + 1, seriesBackwardCoord);
                seg.forwardCoord = forwardSegs[0].backwardCoord;
            }

            // calculate the backwardCoord from the forwardCoord. consider the series
            seg.backwardCoord = seg.forwardCoord -
            (seg.forwardCoord - seriesBackwardCoord) / // available width for series
            (seriesBackwardPressure + 1); // # of segments in the series

            // use this segment's coordinates to computed the coordinates of the less-pressurized
            // forward segments
            for (i=0; i<forwardSegs.length; i++) {
                computeSlotSegCoords(forwardSegs[i], 0, seg.forwardCoord);
            }
        }
    }


// Find all the segments in `otherSegs` that vertically collide with `seg`.
// Append into an optionally-supplied `results` array and return.
    function computeSlotSegCollisions(seg, otherSegs, results) {
        results = results || [];

        for (var i=0; i<otherSegs.length; i++) {
            if (isSlotSegCollision(seg, otherSegs[i])) {
                results.push(otherSegs[i]);
            }
        }

        return results;
    }


// Do these segments occupy the same vertical space?
    function isSlotSegCollision(seg1, seg2) {
        return seg1.bottom > seg2.top && seg1.top < seg2.bottom;
    }


// A cmp function for determining which forward segment to rely on more when computing coordinates.
    function compareForwardSlotSegs(seg1, seg2) {
        // put higher-pressure first
        return seg2.forwardPressure - seg1.forwardPressure ||
                // put segments that are closer to initial edge first (and favor ones with no coords yet)
            (seg1.backwardCoord || 0) - (seg2.backwardCoord || 0) ||
                // do normal sorting...
            compareSegs(seg1, seg2);
    }

    ;;

    /* An abstract class from which other views inherit from
     ----------------------------------------------------------------------------------------------------------------------*/

    var View = fc.View = Class.extend({

        type: null, // subclass' view name (string)
        name: null, // deprecated. use `type` instead
        title: null, // the text that will be displayed in the header's title

        calendar: null, // owner Calendar object
        options: null, // hash containing all options. already merged with view-specific-options
        coordMap: null, // a CoordMap object for converting pixel regions to dates
        el: null, // the view's containing element. set by Calendar

        isDisplayed: false,
        isSkeletonRendered: false,
        isEventsRendered: false,

        // range the view is actually displaying (moments)
        start: null,
        end: null, // exclusive

        // range the view is formally responsible for (moments)
        // may be different from start/end. for example, a month view might have 1st-31st, excluding padded dates
        intervalStart: null,
        intervalEnd: null, // exclusive
        intervalDuration: null,
        intervalUnit: null, // name of largest unit being displayed, like "month" or "week"

        isSelected: false, // boolean whether a range of time is user-selected or not

        // subclasses can optionally use a scroll container
        scrollerEl: null, // the element that will most likely scroll when content is too tall
        scrollTop: null, // cached vertical scroll value

        // classNames styled by jqui themes
        widgetHeaderClass: null,
        widgetContentClass: null,
        highlightStateClass: null,

        // for date utils, computed from options
        nextDayThreshold: null,
        isHiddenDayHash: null,

        // document handlers, bound to `this` object
        documentMousedownProxy: null, // TODO: doesn't work with touch


        constructor: function(calendar, type, options, intervalDuration) {

            this.calendar = calendar;
            this.type = this.name = type; // .name is deprecated
            this.options = options;
            this.intervalDuration = intervalDuration || moment.duration(1, 'day');

            this.nextDayThreshold = moment.duration(this.opt('nextDayThreshold'));
            this.initThemingProps();
            this.initHiddenDays();

            this.documentMousedownProxy = proxy(this, 'documentMousedown');

            this.initialize();
        },


        // A good place for subclasses to initialize member variables
        initialize: function() {
            // subclasses can implement
        },


        // Retrieves an option with the given name
        opt: function(name) {
            return this.options[name];
        },


        // Triggers handlers that are view-related. Modifies args before passing to calendar.
        trigger: function(name, thisObj) { // arguments beyond thisObj are passed along
            var calendar = this.calendar;

            return calendar.trigger.apply(
                calendar,
                [name, thisObj || this].concat(
                    Array.prototype.slice.call(arguments, 2), // arguments beyond thisObj
                    [ this ] // always make the last argument a reference to the view. TODO: deprecate
                )
            );
        },


        /* Dates
         ------------------------------------------------------------------------------------------------------------------*/


        // Updates all internal dates to center around the given current date
        setDate: function(date) {
            this.setRange(this.computeRange(date));
        },


        // Updates all internal dates for displaying the given range.
        // Expects all values to be normalized (like what computeRange does).
        setRange: function(range) {
            $.extend(this, range);
            this.updateTitle();
        },


        // Given a single current date, produce information about what range to display.
        // Subclasses can override. Must return all properties.
        computeRange: function(date) {
            var intervalUnit = computeIntervalUnit(this.intervalDuration);
            var intervalStart = date.clone().startOf(intervalUnit);
            var intervalEnd = intervalStart.clone().add(this.intervalDuration);
            var start, end;

            // normalize the range's time-ambiguity
            if (/year|month|week|day/.test(intervalUnit)) { // whole-days?
                intervalStart.stripTime();
                intervalEnd.stripTime();
            }
            else { // needs to have a time?
                if (!intervalStart.hasTime()) {
                    intervalStart = this.calendar.rezoneDate(intervalStart); // convert to current timezone, with 00:00
                }
                if (!intervalEnd.hasTime()) {
                    intervalEnd = this.calendar.rezoneDate(intervalEnd); // convert to current timezone, with 00:00
                }
            }

            start = intervalStart.clone();
            start = this.skipHiddenDays(start);
            end = intervalEnd.clone();
            end = this.skipHiddenDays(end, -1, true); // exclusively move backwards

            return {
                intervalUnit: intervalUnit,
                intervalStart: intervalStart,
                intervalEnd: intervalEnd,
                start: start,
                end: end
            };
        },


        // Computes the new date when the user hits the prev button, given the current date
        computePrevDate: function(date) {
            return this.massageCurrentDate(
                date.clone().startOf(this.intervalUnit).subtract(this.intervalDuration), -1
            );
        },


        // Computes the new date when the user hits the next button, given the current date
        computeNextDate: function(date) {
            return this.massageCurrentDate(
                date.clone().startOf(this.intervalUnit).add(this.intervalDuration)
            );
        },


        // Given an arbitrarily calculated current date of the calendar, returns a date that is ensured to be completely
        // visible. `direction` is optional and indicates which direction the current date was being
        // incremented or decremented (1 or -1).
        massageCurrentDate: function(date, direction) {
            if (this.intervalDuration.as('days') <= 1) { // if the view displays a single day or smaller
                if (this.isHiddenDay(date)) {
                    date = this.skipHiddenDays(date, direction);
                    date.startOf('day');
                }
            }

            return date;
        },


        /* Title and Date Formatting
         ------------------------------------------------------------------------------------------------------------------*/


        // Sets the view's title property to the most updated computed value
        updateTitle: function() {
            this.title = this.computeTitle();
        },


        // Computes what the title at the top of the calendar should be for this view
        computeTitle: function() {
            return this.formatRange(
                { start: this.intervalStart, end: this.intervalEnd },
                this.opt('titleFormat') || this.computeTitleFormat(),
                this.opt('titleRangeSeparator')
            );
        },


        // Generates the format string that should be used to generate the title for the current date range.
        // Attempts to compute the most appropriate format if not explicitly specified with `titleFormat`.
        computeTitleFormat: function() {
            if (this.intervalUnit == 'year') {
                return 'YYYY';
            }
            else if (this.intervalUnit == 'month') {
                return this.opt('monthYearFormat'); // like "September 2014"
            }
            else if (this.intervalDuration.as('days') > 1) {
                return 'll'; // multi-day range. shorter, like "Sep 9 - 10 2014"
            }
            else {
                return 'LL'; // one day. longer, like "September 9 2014"
            }
        },


        // Utility for formatting a range. Accepts a range object, formatting string, and optional separator.
        // Displays all-day ranges naturally, with an inclusive end. Takes the current isRTL into account.
        formatRange: function(range, formatStr, separator) {
            var end = range.end;

            if (!end.hasTime()) { // all-day?
                end = end.clone().subtract(1); // convert to inclusive. last ms of previous day
            }

            return formatRange(range.start, end, formatStr, separator, this.opt('isRTL'));
        },


        /* Rendering
         ------------------------------------------------------------------------------------------------------------------*/


        // Sets the container element that the view should render inside of.
        // Does other DOM-related initializations.
        setElement: function(el) {
            this.el = el;
            this.bindGlobalHandlers();
        },


        // Removes the view's container element from the DOM, clearing any content beforehand.
        // Undoes any other DOM-related attachments.
        removeElement: function() {
            this.clear(); // clears all content

            // clean up the skeleton
            if (this.isSkeletonRendered) {
                this.destroySkeleton();
                this.isSkeletonRendered = false;
            }

            this.unbindGlobalHandlers();

            this.el.remove();

            // NOTE: don't null-out this.el in case the View was destroyed within an API callback.
            // We don't null-out the View's other jQuery element references upon destroy, so why should we kill this.el?
        },


        // Does everything necessary to display the view centered around the given date.
        // Does every type of rendering EXCEPT rendering events.
        display: function(date) {
            var scrollState = null;

            if (this.isDisplayed) {
                scrollState = this.queryScroll();
            }

            this.clear(); // clear the old content
            this.setDate(date);
            this.render();
            this.updateSize();
            this.renderBusinessHours(); // might need coordinates, so should go after updateSize()
            this.isDisplayed = true;

            scrollState = this.computeInitialScroll(scrollState);
            this.forceScroll(scrollState);

            this.triggerRender();
        },


        // Does everything necessary to clear the content of the view.
        // Clears dates and events. Does not clear the skeleton.
        clear: function() { // clears the view of *content* but not the skeleton
            if (this.isDisplayed) {
                this.unselect();
                this.clearEvents();
                this.triggerDestroy();
                this.destroyBusinessHours();
                this.destroy();
                this.isDisplayed = false;
            }
        },


        // Renders the view's date-related content, rendering the view's non-content skeleton if necessary
        render: function() {
            if (!this.isSkeletonRendered) {
                this.renderSkeleton();
                this.isSkeletonRendered = true;
            }
            this.renderDates();
        },


        // Unrenders the view's date-related content.
        // Call this instead of destroyDates directly in case the View subclass wants to use a render/destroy pattern
        // where both the skeleton and the content always get rendered/unrendered together.
        destroy: function() {
            this.destroyDates();
        },


        // Renders the basic structure of the view before any content is rendered
        renderSkeleton: function() {
            // subclasses should implement
        },


        // Unrenders the basic structure of the view
        destroySkeleton: function() {
            // subclasses should implement
        },


        // Renders the view's date-related content (like cells that represent days/times).
        // Assumes setRange has already been called and the skeleton has already been rendered.
        renderDates: function() {
            // subclasses should implement
        },


        // Unrenders the view's date-related content
        destroyDates: function() {
            // subclasses should override
        },


        // Renders business-hours onto the view. Assumes updateSize has already been called.
        renderBusinessHours: function() {
            // subclasses should implement
        },


        // Unrenders previously-rendered business-hours
        destroyBusinessHours: function() {
            // subclasses should implement
        },


        // Signals that the view's content has been rendered
        triggerRender: function() {
            this.trigger('viewRender', this, this, this.el);
        },


        // Signals that the view's content is about to be unrendered
        triggerDestroy: function() {
            this.trigger('viewDestroy', this, this, this.el);
        },


        // Binds DOM handlers to elements that reside outside the view container, such as the document
        bindGlobalHandlers: function() {
            $(document).on('mousedown', this.documentMousedownProxy);
        },


        // Unbinds DOM handlers from elements that reside outside the view container
        unbindGlobalHandlers: function() {
            $(document).off('mousedown', this.documentMousedownProxy);
        },


        // Initializes internal variables related to theming
        initThemingProps: function() {
            var tm = this.opt('theme') ? 'ui' : 'fc';

            this.widgetHeaderClass = tm + '-widget-header';
            this.widgetContentClass = tm + '-widget-content';
            this.highlightStateClass = tm + '-state-highlight';
        },


        /* Dimensions
         ------------------------------------------------------------------------------------------------------------------*/


        // Refreshes anything dependant upon sizing of the container element of the grid
        updateSize: function(isResize) {
            var scrollState;

            if (isResize) {
                scrollState = this.queryScroll();
            }

            this.updateHeight();
            this.updateWidth();

            if (isResize) {
                this.setScroll(scrollState);
            }
        },


        // Refreshes the horizontal dimensions of the calendar
        updateWidth: function() {
            // subclasses should implement
        },


        // Refreshes the vertical dimensions of the calendar
        updateHeight: function() {
            var calendar = this.calendar; // we poll the calendar for height information

            this.setHeight(
                calendar.getSuggestedViewHeight(),
                calendar.isHeightAuto()
            );
        },


        // Updates the vertical dimensions of the calendar to the specified height.
        // if `isAuto` is set to true, height becomes merely a suggestion and the view should use its "natural" height.
        setHeight: function(height, isAuto) {
            // subclasses should implement
        },


        /* Scroller
         ------------------------------------------------------------------------------------------------------------------*/


        // Given the total height of the view, return the number of pixels that should be used for the scroller.
        // Utility for subclasses.
        computeScrollerHeight: function(totalHeight) {
            var scrollerEl = this.scrollerEl;
            var both;
            var otherHeight; // cumulative height of everything that is not the scrollerEl in the view (header+borders)

            both = this.el.add(scrollerEl);

            // fuckin IE8/9/10/11 sometimes returns 0 for dimensions. this weird hack was the only thing that worked
            both.css({
                position: 'relative', // cause a reflow, which will force fresh dimension recalculation
                left: -1 // ensure reflow in case the el was already relative. negative is less likely to cause new scroll
            });
            otherHeight = this.el.outerHeight() - scrollerEl.height(); // grab the dimensions
            both.css({ position: '', left: '' }); // undo hack

            return totalHeight - otherHeight;
        },


        // Computes the initial pre-configured scroll state prior to allowing the user to change it.
        // Given the scroll state from the previous rendering. If first time rendering, given null.
        computeInitialScroll: function(previousScrollState) {
            return 0;
        },


        // Retrieves the view's current natural scroll state. Can return an arbitrary format.
        queryScroll: function() {
            if (this.scrollerEl) {
                return this.scrollerEl.scrollTop(); // operates on scrollerEl by default
            }
        },


        // Sets the view's scroll state. Will accept the same format computeInitialScroll and queryScroll produce.
        setScroll: function(scrollState) {
            if (this.scrollerEl) {
                return this.scrollerEl.scrollTop(scrollState); // operates on scrollerEl by default
            }
        },


        // Sets the scroll state, making sure to overcome any predefined scroll value the browser has in mind
        forceScroll: function(scrollState) {
            var _this = this;

            this.setScroll(scrollState);
            setTimeout(function() {
                _this.setScroll(scrollState);
            }, 0);
        },


        /* Event Elements / Segments
         ------------------------------------------------------------------------------------------------------------------*/


        // Does everything necessary to display the given events onto the current view
        displayEvents: function(events) {
            var scrollState = this.queryScroll();

            this.clearEvents();
            this.renderEvents(events);
            this.isEventsRendered = true;
            this.setScroll(scrollState);
            this.triggerEventRender();
        },


        // Does everything necessary to clear the view's currently-rendered events
        clearEvents: function() {
            if (this.isEventsRendered) {
                this.triggerEventDestroy();
                this.destroyEvents();
                this.isEventsRendered = false;
            }
        },


        // Renders the events onto the view.
        renderEvents: function(events) {
            // subclasses should implement
        },


        // Removes event elements from the view.
        destroyEvents: function() {
            // subclasses should implement
        },


        // Signals that all events have been rendered
        triggerEventRender: function() {
            this.renderedEventSegEach(function(seg) {
                this.trigger('eventAfterRender', seg.event, seg.event, seg.el);
            });
            this.trigger('eventAfterAllRender');
        },


        // Signals that all event elements are about to be removed
        triggerEventDestroy: function() {
            this.renderedEventSegEach(function(seg) {
                this.trigger('eventDestroy', seg.event, seg.event, seg.el);
            });
        },


        // Given an event and the default element used for rendering, returns the element that should actually be used.
        // Basically runs events and elements through the eventRender hook.
        resolveEventEl: function(event, el) {
            var custom = this.trigger('eventRender', event, event, el);

            if (custom === false) { // means don't render at all
                el = null;
            }
            else if (custom && custom !== true) {
                el = $(custom);
            }

            return el;
        },


        // Hides all rendered event segments linked to the given event
        showEvent: function(event) {
            this.renderedEventSegEach(function(seg) {
                seg.el.css('visibility', '');
            }, event);
        },


        // Shows all rendered event segments linked to the given event
        hideEvent: function(event) {
            this.renderedEventSegEach(function(seg) {
                seg.el.css('visibility', 'hidden');
            }, event);
        },


        // Iterates through event segments that have been rendered (have an el). Goes through all by default.
        // If the optional `event` argument is specified, only iterates through segments linked to that event.
        // The `this` value of the callback function will be the view.
        renderedEventSegEach: function(func, event) {
            var segs = this.getEventSegs();
            var i;

            for (i = 0; i < segs.length; i++) {
                if (!event || segs[i].event._id === event._id) {
                    if (segs[i].el) {
                        func.call(this, segs[i]);
                    }
                }
            }
        },


        // Retrieves all the rendered segment objects for the view
        getEventSegs: function() {
            // subclasses must implement
            return [];
        },


        /* Event Drag-n-Drop
         ------------------------------------------------------------------------------------------------------------------*/


        // Computes if the given event is allowed to be dragged by the user
        isEventDraggable: function(event) {
            var source = event.source || {};

            return firstDefined(
                event.startEditable,
                source.startEditable,
                this.opt('eventStartEditable'),
                event.editable,
                source.editable,
                this.opt('editable')
            );
        },


        // Must be called when an event in the view is dropped onto new location.
        // `dropLocation` is an object that contains the new start/end/allDay values for the event.
        reportEventDrop: function(event, dropLocation, largeUnit, el, ev) {
            var calendar = this.calendar;
            var mutateResult = calendar.mutateEvent(event, dropLocation, largeUnit);
            var undoFunc = function() {
                mutateResult.undo();
                calendar.reportEventChange();
            };

            this.triggerEventDrop(event, mutateResult.dateDelta, undoFunc, el, ev);
            calendar.reportEventChange(); // will rerender events
        },


        // Triggers event-drop handlers that have subscribed via the API
        triggerEventDrop: function(event, dateDelta, undoFunc, el, ev) {
            this.trigger('eventDrop', el[0], event, dateDelta, undoFunc, ev, {}); // {} = jqui dummy
        },


        /* External Element Drag-n-Drop
         ------------------------------------------------------------------------------------------------------------------*/


        // Must be called when an external element, via jQuery UI, has been dropped onto the calendar.
        // `meta` is the parsed data that has been embedded into the dragging event.
        // `dropLocation` is an object that contains the new start/end/allDay values for the event.
        reportExternalDrop: function(meta, dropLocation, el, ev, ui) {
            var eventProps = meta.eventProps;
            var eventInput;
            var event;

            // Try to build an event object and render it. TODO: decouple the two
            if (eventProps) {
                eventInput = $.extend({}, eventProps, dropLocation);
                event = this.calendar.renderEvent(eventInput, meta.stick)[0]; // renderEvent returns an array
            }

            this.triggerExternalDrop(event, dropLocation, el, ev, ui);
        },


        // Triggers external-drop handlers that have subscribed via the API
        triggerExternalDrop: function(event, dropLocation, el, ev, ui) {

            // trigger 'drop' regardless of whether element represents an event
            this.trigger('drop', el[0], dropLocation.start, ev, ui);

            if (event) {
                this.trigger('eventReceive', null, event); // signal an external event landed
            }
        },


        /* Drag-n-Drop Rendering (for both events and external elements)
         ------------------------------------------------------------------------------------------------------------------*/


        // Renders a visual indication of a event or external-element drag over the given drop zone.
        // If an external-element, seg will be `null`
        renderDrag: function(dropLocation, seg) {
            // subclasses must implement
        },


        // Unrenders a visual indication of an event or external-element being dragged.
        destroyDrag: function() {
            // subclasses must implement
        },


        /* Event Resizing
         ------------------------------------------------------------------------------------------------------------------*/


        // Computes if the given event is allowed to be resized from its starting edge
        isEventResizableFromStart: function(event) {
            return this.opt('eventResizableFromStart') && this.isEventResizable(event);
        },


        // Computes if the given event is allowed to be resized from its ending edge
        isEventResizableFromEnd: function(event) {
            return this.isEventResizable(event);
        },


        // Computes if the given event is allowed to be resized by the user at all
        isEventResizable: function(event) {
            var source = event.source || {};

            return firstDefined(
                event.durationEditable,
                source.durationEditable,
                this.opt('eventDurationEditable'),
                event.editable,
                source.editable,
                this.opt('editable')
            );
        },


        // Must be called when an event in the view has been resized to a new length
        reportEventResize: function(event, resizeLocation, largeUnit, el, ev) {
            var calendar = this.calendar;
            var mutateResult = calendar.mutateEvent(event, resizeLocation, largeUnit);
            var undoFunc = function() {
                mutateResult.undo();
                calendar.reportEventChange();
            };

            this.triggerEventResize(event, mutateResult.durationDelta, undoFunc, el, ev);
            calendar.reportEventChange(); // will rerender events
        },


        // Triggers event-resize handlers that have subscribed via the API
        triggerEventResize: function(event, durationDelta, undoFunc, el, ev) {
            this.trigger('eventResize', el[0], event, durationDelta, undoFunc, ev, {}); // {} = jqui dummy
        },


        /* Selection
         ------------------------------------------------------------------------------------------------------------------*/


        // Selects a date range on the view. `start` and `end` are both Moments.
        // `ev` is the native mouse event that begin the interaction.
        select: function(range, ev) {
            this.unselect(ev);
            this.renderSelection(range);
            this.reportSelection(range, ev);
        },


        // Renders a visual indication of the selection
        renderSelection: function(range) {
            // subclasses should implement
        },


        // Called when a new selection is made. Updates internal state and triggers handlers.
        reportSelection: function(range, ev) {
            this.isSelected = true;
            this.trigger('select', null, range.start, range.end, ev);
        },


        // Undoes a selection. updates in the internal state and triggers handlers.
        // `ev` is the native mouse event that began the interaction.
        unselect: function(ev) {
            if (this.isSelected) {
                this.isSelected = false;
                this.destroySelection();
                this.trigger('unselect', null, ev);
            }
        },


        // Unrenders a visual indication of selection
        destroySelection: function() {
            // subclasses should implement
        },


        // Handler for unselecting when the user clicks something and the 'unselectAuto' setting is on
        documentMousedown: function(ev) {
            var ignore;

            // is there a selection, and has the user made a proper left click?
            if (this.isSelected && this.opt('unselectAuto') && isPrimaryMouseButton(ev)) {

                // only unselect if the clicked element is not identical to or inside of an 'unselectCancel' element
                ignore = this.opt('unselectCancel');
                if (!ignore || !$(ev.target).closest(ignore).length) {
                    this.unselect(ev);
                }
            }
        },


        /* Date Utils
         ------------------------------------------------------------------------------------------------------------------*/


        // Initializes internal variables related to calculating hidden days-of-week
        initHiddenDays: function() {
            var hiddenDays = this.opt('hiddenDays') || []; // array of day-of-week indices that are hidden
            var isHiddenDayHash = []; // is the day-of-week hidden? (hash with day-of-week-index -> bool)
            var dayCnt = 0;
            var i;

            if (this.opt('weekends') === false) {
                hiddenDays.push(0, 6); // 0=sunday, 6=saturday
            }

            for (i = 0; i < 7; i++) {
                if (
                    !(isHiddenDayHash[i] = $.inArray(i, hiddenDays) !== -1)
                ) {
                    dayCnt++;
                }
            }

            if (!dayCnt) {
                throw 'invalid hiddenDays'; // all days were hidden? bad.
            }

            this.isHiddenDayHash = isHiddenDayHash;
        },


        // Is the current day hidden?
        // `day` is a day-of-week index (0-6), or a Moment
        isHiddenDay: function(day) {
            if (moment.isMoment(day)) {
                day = day.day();
            }
            return this.isHiddenDayHash[day];
        },


        // Incrementing the current day until it is no longer a hidden day, returning a copy.
        // If the initial value of `date` is not a hidden day, don't do anything.
        // Pass `isExclusive` as `true` if you are dealing with an end date.
        // `inc` defaults to `1` (increment one day forward each time)
        skipHiddenDays: function(date, inc, isExclusive) {
            var out = date.clone();
            inc = inc || 1;
            while (
                this.isHiddenDayHash[(out.day() + (isExclusive ? inc : 0) + 7) % 7]
                ) {
                out.add(inc, 'days');
            }
            return out;
        },


        // Returns the date range of the full days the given range visually appears to occupy.
        // Returns a new range object.
        computeDayRange: function(range) {
            var startDay = range.start.clone().stripTime(); // the beginning of the day the range starts
            var end = range.end;
            var endDay = null;
            var endTimeMS;

            if (end) {
                endDay = end.clone().stripTime(); // the beginning of the day the range exclusively ends
                endTimeMS = +end.time(); // # of milliseconds into `endDay`

                // If the end time is actually inclusively part of the next day and is equal to or
                // beyond the next day threshold, adjust the end to be the exclusive end of `endDay`.
                // Otherwise, leaving it as inclusive will cause it to exclude `endDay`.
                if (endTimeMS && endTimeMS >= this.nextDayThreshold) {
                    endDay.add(1, 'days');
                }
            }

            // If no end was specified, or if it is within `startDay` but not past nextDayThreshold,
            // assign the default duration of one day.
            if (!end || endDay <= startDay) {
                endDay = startDay.clone().add(1, 'days');
            }

            return { start: startDay, end: endDay };
        },


        // Does the given event visually appear to occupy more than one day?
        isMultiDayEvent: function(event) {
            var range = this.computeDayRange(event); // event is range-ish

            return range.end.diff(range.start, 'days') > 1;
        }

    });

    ;;

    var Calendar = fc.Calendar = fc.CalendarBase = Class.extend({

        dirDefaults: null, // option defaults related to LTR or RTL
        langDefaults: null, // option defaults related to current locale
        overrides: null, // option overrides given to the fullCalendar constructor
        options: null, // all defaults combined with overrides
        viewSpecCache: null, // cache of view definitions
        view: null, // current View object
        header: null,


        // a lot of this class' OOP logic is scoped within this constructor function,
        // but in the future, write individual methods on the prototype.
        constructor: Calendar_constructor,


        // Initializes `this.options` and other important options-related objects
        initOptions: function(overrides) {
            var lang, langDefaults;
            var isRTL, dirDefaults;

            // converts legacy options into non-legacy ones.
            // in the future, when this is removed, don't use `overrides` reference. make a copy.
            overrides = massageOverrides(overrides);

            lang = overrides.lang;
            langDefaults = langOptionHash[lang];
            if (!langDefaults) {
                lang = Calendar.defaults.lang;
                langDefaults = langOptionHash[lang] || {};
            }

            isRTL = firstDefined(
                overrides.isRTL,
                langDefaults.isRTL,
                Calendar.defaults.isRTL
            );
            dirDefaults = isRTL ? Calendar.rtlDefaults : {};

            this.dirDefaults = dirDefaults;
            this.langDefaults = langDefaults;
            this.overrides = overrides;
            this.options = mergeOptions( // merge defaults and overrides. lowest to highest precedence
                Calendar.defaults, // global defaults
                dirDefaults,
                langDefaults,
                overrides
            );
            populateInstanceComputableOptions(this.options);

            this.viewSpecCache = {}; // somewhat unrelated
        },


        // Gets information about how to create a view. Will use a cache.
        getViewSpec: function(viewType) {
            var cache = this.viewSpecCache;

            return cache[viewType] || (cache[viewType] = this.buildViewSpec(viewType));
        },


        // Given a duration singular unit, like "week" or "day", finds a matching view spec.
        // Preference is given to views that have corresponding buttons.
        getUnitViewSpec: function(unit) {
            var viewTypes;
            var i;
            var spec;

            if ($.inArray(unit, intervalUnits) != -1) {

                // put views that have buttons first. there will be duplicates, but oh well
                viewTypes = this.header.getViewsWithButtons();
                $.each(fc.views, function(viewType) { // all views
                    viewTypes.push(viewType);
                });

                for (i = 0; i < viewTypes.length; i++) {
                    spec = this.getViewSpec(viewTypes[i]);
                    if (spec) {
                        if (spec.singleUnit == unit) {
                            return spec;
                        }
                    }
                }
            }
        },


        // Builds an object with information on how to create a given view
        buildViewSpec: function(requestedViewType) {
            var viewOverrides = this.overrides.views || {};
            var defaultsChain = []; // for the view. lowest to highest priority
            var overridesChain = []; // for the view. lowest to highest priority
            var viewType = requestedViewType;
            var viewClass;
            var defaults; // for the view
            var overrides; // for the view
            var duration;
            var unit;
            var spec;

            // iterate from the specific view definition to a more general one until we hit an actual View class
            while (viewType && !viewClass) {
                defaults = fcViews[viewType] || {};
                overrides = viewOverrides[viewType] || {};
                duration = duration || overrides.duration || defaults.duration;
                viewType = overrides.type || defaults.type; // for next iteration

                if (typeof defaults === 'function') { // a class
                    viewClass = defaults;
                    defaultsChain.unshift(viewClass.defaults || {});
                }
                else { // an options object
                    defaultsChain.unshift(defaults);
                }
                overridesChain.unshift(overrides);
            }

            if (viewClass) {
                spec = { 'class': viewClass, type: requestedViewType };

                if (duration) {
                    duration = moment.duration(duration);
                    if (!duration.valueOf()) { // invalid?
                        duration = null;
                    }
                }
                if (duration) {
                    spec.duration = duration;
                    unit = computeIntervalUnit(duration);

                    // view is a single-unit duration, like "week" or "day"
                    // incorporate options for this. lowest priority
                    if (duration.as(unit) === 1) {
                        spec.singleUnit = unit;
                        overridesChain.unshift(viewOverrides[unit] || {});
                    }
                }

                // collapse into single objects
                spec.defaults = mergeOptions.apply(null, defaultsChain);
                spec.overrides = mergeOptions.apply(null, overridesChain);

                this.buildViewSpecOptions(spec);
                this.buildViewSpecButtonText(spec, requestedViewType);

                return spec;
            }
        },


        // Builds and assigns a view spec's options object from its already-assigned defaults and overrides
        buildViewSpecOptions: function(spec) {
            spec.options = mergeOptions( // lowest to highest priority
                Calendar.defaults, // global defaults
                spec.defaults, // view's defaults (from ViewSubclass.defaults)
                this.dirDefaults,
                this.langDefaults, // locale and dir take precedence over view's defaults!
                this.overrides, // calendar's overrides (options given to constructor)
                spec.overrides // view's overrides (view-specific options)
            );
            populateInstanceComputableOptions(spec.options);
        },


        // Computes and assigns a view spec's buttonText-related options
        buildViewSpecButtonText: function(spec, requestedViewType) {

            // given an options object with a possible `buttonText` hash, lookup the buttonText for the
            // requested view, falling back to a generic unit entry like "week" or "day"
            function queryButtonText(options) {
                var buttonText = options.buttonText || {};
                return buttonText[requestedViewType] ||
                    (spec.singleUnit ? buttonText[spec.singleUnit] : null);
            }

            // highest to lowest priority
            spec.buttonTextOverride =
                queryButtonText(this.overrides) || // constructor-specified buttonText lookup hash takes precedence
                spec.overrides.buttonText; // `buttonText` for view-specific options is a string

            // highest to lowest priority. mirrors buildViewSpecOptions
            spec.buttonTextDefault =
                queryButtonText(this.langDefaults) ||
                queryButtonText(this.dirDefaults) ||
                spec.defaults.buttonText || // a single string. from ViewSubclass.defaults
                queryButtonText(Calendar.defaults) ||
                (spec.duration ? this.humanizeDuration(spec.duration) : null) || // like "3 days"
                requestedViewType; // fall back to given view name
        },


        // Given a view name for a custom view or a standard view, creates a ready-to-go View object
        instantiateView: function(viewType) {
            var spec = this.getViewSpec(viewType);

            return new spec['class'](this, viewType, spec.options, spec.duration);
        },


        // Returns a boolean about whether the view is okay to instantiate at some point
        isValidViewType: function(viewType) {
            return Boolean(this.getViewSpec(viewType));
        }

    });


    function Calendar_constructor(element, overrides) {
        var t = this;


        t.initOptions(overrides || {});
        var options = this.options;


        // Exports
        // -----------------------------------------------------------------------------------

        t.render = render;
        t.destroy = destroy;
        t.refetchEvents = refetchEvents;
        t.reportEvents = reportEvents;
        t.reportEventChange = reportEventChange;
        t.rerenderEvents = renderEvents; // `renderEvents` serves as a rerender. an API method
        t.changeView = renderView; // `renderView` will switch to another view
        t.select = select;
        t.unselect = unselect;
        t.prev = prev;
        t.next = next;
        t.prevYear = prevYear;
        t.nextYear = nextYear;
        t.today = today;
        t.gotoDate = gotoDate;
        t.incrementDate = incrementDate;
        t.zoomTo = zoomTo;
        t.getDate = getDate;
        t.getCalendar = getCalendar;
        t.getView = getView;
        t.option = option;
        t.trigger = trigger;



        // Language-data Internals
        // -----------------------------------------------------------------------------------
        // Apply overrides to the current language's data


        var localeData = createObject( // make a cheap copy
            getMomentLocaleData(options.lang) // will fall back to en
        );

        if (options.monthNames) {
            localeData._months = options.monthNames;
        }
        if (options.monthNamesShort) {
            localeData._monthsShort = options.monthNamesShort;
        }
        if (options.dayNames) {
            localeData._weekdays = options.dayNames;
        }
        if (options.dayNamesShort) {
            localeData._weekdaysShort = options.dayNamesShort;
        }
        if (options.firstDay != null) {
            var _week = createObject(localeData._week); // _week: { dow: # }
            _week.dow = options.firstDay;
            localeData._week = _week;
        }

        // assign a normalized value, to be used by our .week() moment extension
        localeData._fullCalendar_weekCalc = (function(weekCalc) {
            if (typeof weekCalc === 'function') {
                return weekCalc;
            }
            else if (weekCalc === 'local') {
                return weekCalc;
            }
            else if (weekCalc === 'iso' || weekCalc === 'ISO') {
                return 'ISO';
            }
        })(options.weekNumberCalculation);



        // Calendar-specific Date Utilities
        // -----------------------------------------------------------------------------------


        t.defaultAllDayEventDuration = moment.duration(options.defaultAllDayEventDuration);
        t.defaultTimedEventDuration = moment.duration(options.defaultTimedEventDuration);


        // Builds a moment using the settings of the current calendar: timezone and language.
        // Accepts anything the vanilla moment() constructor accepts.
        t.moment = function() {
            var mom;

            if (options.timezone === 'local') {
                mom = fc.moment.apply(null, arguments);

                // Force the moment to be local, because fc.moment doesn't guarantee it.
                if (mom.hasTime()) { // don't give ambiguously-timed moments a local zone
                    mom.local();
                }
            }
            else if (options.timezone === 'UTC') {
                mom = fc.moment.utc.apply(null, arguments); // process as UTC
            }
            else {
                mom = fc.moment.parseZone.apply(null, arguments); // let the input decide the zone
            }

            if ('_locale' in mom) { // moment 2.8 and above
                mom._locale = localeData;
            }
            else { // pre-moment-2.8
                mom._lang = localeData;
            }

            return mom;
        };


        // Returns a boolean about whether or not the calendar knows how to calculate
        // the timezone offset of arbitrary dates in the current timezone.
        t.getIsAmbigTimezone = function() {
            return options.timezone !== 'local' && options.timezone !== 'UTC';
        };


        // Returns a copy of the given date in the current timezone of it is ambiguously zoned.
        // This will also give the date an unambiguous time.
        t.rezoneDate = function(date) {
            return t.moment(date.toArray());
        };


        // Returns a moment for the current date, as defined by the client's computer,
        // or overridden by the `now` option.
        t.getNow = function() {
            var now = options.now;
            if (typeof now === 'function') {
                now = now();
            }
            return t.moment(now);
        };


        // Get an event's normalized end date. If not present, calculate it from the defaults.
        t.getEventEnd = function(event) {
            if (event.end) {
                return event.end.clone();
            }
            else {
                return t.getDefaultEventEnd(event.allDay, event.start);
            }
        };


        // Given an event's allDay status and start date, return swhat its fallback end date should be.
        t.getDefaultEventEnd = function(allDay, start) { // TODO: rename to computeDefaultEventEnd
            var end = start.clone();

            if (allDay) {
                end.stripTime().add(t.defaultAllDayEventDuration);
            }
            else {
                end.add(t.defaultTimedEventDuration);
            }

            if (t.getIsAmbigTimezone()) {
                end.stripZone(); // we don't know what the tzo should be
            }

            return end;
        };


        // Produces a human-readable string for the given duration.
        // Side-effect: changes the locale of the given duration.
        t.humanizeDuration = function(duration) {
            return (duration.locale || duration.lang).call(duration, options.lang) // works moment-pre-2.8
                .humanize();
        };



        // Imports
        // -----------------------------------------------------------------------------------


        EventManager.call(t, options);
        var isFetchNeeded = t.isFetchNeeded;
        var fetchEvents = t.fetchEvents;



        // Locals
        // -----------------------------------------------------------------------------------


        var _element = element[0];
        var header;
        var headerElement;
        var content;
        var tm; // for making theme classes
        var currentView; // NOTE: keep this in sync with this.view
        var viewsByType = {}; // holds all instantiated view instances, current or not
        var suggestedViewHeight;
        var windowResizeProxy; // wraps the windowResize function
        var ignoreWindowResize = 0;
        var date;
        var events = [];



        // Main Rendering
        // -----------------------------------------------------------------------------------


        if (options.defaultDate != null) {
            date = t.moment(options.defaultDate);
        }
        else {
            date = t.getNow();
        }


        function render() {
            if (!content) {
                initialRender();
            }
            else if (elementVisible()) {
                // mainly for the public API
                calcSize();
                renderView();
            }
        }


        function initialRender() {
            tm = options.theme ? 'ui' : 'fc';
            element.addClass('fc');

            if (options.isRTL) {
                element.addClass('fc-rtl');
            }
            else {
                element.addClass('fc-ltr');
            }

            if (options.theme) {
                element.addClass('ui-widget');
            }
            else {
                element.addClass('fc-unthemed');
            }

            content = $("<div class='fc-view-container'/>").prependTo(element);

            header = t.header = new Header(t, options);
            headerElement = header.render();
            if (headerElement) {
                element.prepend(headerElement);
            }

            renderView(options.defaultView);

            if (options.handleWindowResize) {
                windowResizeProxy = debounce(windowResize, options.windowResizeDelay); // prevents rapid calls
                $(window).resize(windowResizeProxy);
            }
        }


        function destroy() {

            if (currentView) {
                currentView.removeElement();

                // NOTE: don't null-out currentView/t.view in case API methods are called after destroy.
                // It is still the "current" view, just not rendered.
            }

            header.destroy();
            content.remove();
            element.removeClass('fc fc-ltr fc-rtl fc-unthemed ui-widget');

            if (windowResizeProxy) {
                $(window).unbind('resize', windowResizeProxy);
            }
        }


        function elementVisible() {
            return element.is(':visible');
        }



        // View Rendering
        // -----------------------------------------------------------------------------------


        // Renders a view because of a date change, view-type change, or for the first time.
        // If not given a viewType, keep the current view but render different dates.
        function renderView(viewType) {
            ignoreWindowResize++;

            // if viewType is changing, destroy the old view
            if (currentView && viewType && currentView.type !== viewType) {
                header.deactivateButton(currentView.type);
                freezeContentHeight(); // prevent a scroll jump when view element is removed
                currentView.removeElement();
                currentView = t.view = null;
            }

            // if viewType changed, or the view was never created, create a fresh view
            if (!currentView && viewType) {
                currentView = t.view =
                    viewsByType[viewType] ||
                    (viewsByType[viewType] = t.instantiateView(viewType));

                currentView.setElement(
                    $("<div class='fc-view fc-" + viewType + "-view' />").appendTo(content)
                );
                header.activateButton(viewType);
            }

            if (currentView) {

                // in case the view should render a period of time that is completely hidden
                date = currentView.massageCurrentDate(date);

                // render or rerender the view
                if (
                    !currentView.isDisplayed ||
                    !date.isWithin(currentView.intervalStart, currentView.intervalEnd) // implicit date window change
                ) {
                    if (elementVisible()) {

                        freezeContentHeight();
                        currentView.display(date);
                        unfreezeContentHeight();

                        // need to do this after View::render, so dates are calculated
                        updateHeaderTitle();
                        updateTodayButton();

                        getAndRenderEvents();
                    }
                }
            }

            unfreezeContentHeight(); // undo any lone freezeContentHeight calls
            ignoreWindowResize--;
        }



        // Resizing
        // -----------------------------------------------------------------------------------


        t.getSuggestedViewHeight = function() {
            if (suggestedViewHeight === undefined) {
                calcSize();
            }
            return suggestedViewHeight;
        };


        t.isHeightAuto = function() {
            return options.contentHeight === 'auto' || options.height === 'auto';
        };


        function updateSize(shouldRecalc) {
            if (elementVisible()) {

                if (shouldRecalc) {
                    _calcSize();
                }

                ignoreWindowResize++;
                currentView.updateSize(true); // isResize=true. will poll getSuggestedViewHeight() and isHeightAuto()
                ignoreWindowResize--;

                return true; // signal success
            }
        }


        function calcSize() {
            if (elementVisible()) {
                _calcSize();
            }
        }


        function _calcSize() { // assumes elementVisible
            if (typeof options.contentHeight === 'number') { // exists and not 'auto'
                suggestedViewHeight = options.contentHeight;
            }
            else if (typeof options.height === 'number') { // exists and not 'auto'
                suggestedViewHeight = options.height - (headerElement ? headerElement.outerHeight(true) : 0);
            }
            else {
                suggestedViewHeight = Math.round(content.width() / Math.max(options.aspectRatio, .5));
            }
        }


        function windowResize(ev) {
            if (
                !ignoreWindowResize &&
                ev.target === window && // so we don't process jqui "resize" events that have bubbled up
                currentView.start // view has already been rendered
            ) {
                if (updateSize(true)) {
                    currentView.trigger('windowResize', _element);
                }
            }
        }



        /* Event Fetching/Rendering
         -----------------------------------------------------------------------------*/
        // TODO: going forward, most of this stuff should be directly handled by the view


        function refetchEvents() { // can be called as an API method
            destroyEvents(); // so that events are cleared before user starts waiting for AJAX
            fetchAndRenderEvents();
        }


        function renderEvents() { // destroys old events if previously rendered
            if (elementVisible()) {
                freezeContentHeight();
                currentView.displayEvents(events);
                unfreezeContentHeight();
            }
        }


        function destroyEvents() {
            freezeContentHeight();
            currentView.clearEvents();
            unfreezeContentHeight();
        }


        function getAndRenderEvents() {
            if (!options.lazyFetching || isFetchNeeded(currentView.start, currentView.end)) {
                fetchAndRenderEvents();
            }
            else {
                renderEvents();
            }
        }


        function fetchAndRenderEvents() {
            fetchEvents(currentView.start, currentView.end);
            // ... will call reportEvents
            // ... which will call renderEvents
        }


        // called when event data arrives
        function reportEvents(_events) {
            events = _events;
            renderEvents();
        }


        // called when a single event's data has been changed
        function reportEventChange() {
            renderEvents();
        }



        /* Header Updating
         -----------------------------------------------------------------------------*/


        function updateHeaderTitle() {
            header.updateTitle(currentView.title);
        }


        function updateTodayButton() {
            var now = t.getNow();
            if (now.isWithin(currentView.intervalStart, currentView.intervalEnd)) {
                header.disableButton('today');
            }
            else {
                header.enableButton('today');
            }
        }



        /* Selection
         -----------------------------------------------------------------------------*/


        function select(start, end) {

            start = t.moment(start);
            if (end) {
                end = t.moment(end);
            }
            else if (start.hasTime()) {
                end = start.clone().add(t.defaultTimedEventDuration);
            }
            else {
                end = start.clone().add(t.defaultAllDayEventDuration);
            }

            currentView.select({ start: start, end: end }); // accepts a range
        }


        function unselect() { // safe to be called before renderView
            if (currentView) {
                currentView.unselect();
            }
        }



        /* Date
         -----------------------------------------------------------------------------*/


        function prev() {
            date = currentView.computePrevDate(date);
            renderView();
        }


        function next() {
            date = currentView.computeNextDate(date);
            renderView();
        }


        function prevYear() {
            date.add(-1, 'years');
            renderView();
        }


        function nextYear() {
            date.add(1, 'years');
            renderView();
        }


        function today() {
            date = t.getNow();
            renderView();
        }


        function gotoDate(dateInput) {
            date = t.moment(dateInput);
            renderView();
        }


        function incrementDate(delta) {
            date.add(moment.duration(delta));
            renderView();
        }


        // Forces navigation to a view for the given date.
        // `viewType` can be a specific view name or a generic one like "week" or "day".
        function zoomTo(newDate, viewType) {
            var spec;

            viewType = viewType || 'day'; // day is default zoom
            spec = t.getViewSpec(viewType) || t.getUnitViewSpec(viewType);

            date = newDate;
            renderView(spec ? spec.type : null);
        }


        function getDate() {
            return date.clone();
        }



        /* Height "Freezing"
         -----------------------------------------------------------------------------*/
        // TODO: move this into the view


        function freezeContentHeight() {
            content.css({
                width: '100%',
                height: content.height(),
                overflow: 'hidden'
            });
        }


        function unfreezeContentHeight() {
            content.css({
                width: '',
                height: '',
                overflow: ''
            });
        }



        /* Misc
         -----------------------------------------------------------------------------*/


        function getCalendar() {
            return t;
        }


        function getView() {
            return currentView;
        }


        function option(name, value) {
            if (value === undefined) {
                return options[name];
            }
            if (name == 'height' || name == 'contentHeight' || name == 'aspectRatio') {
                options[name] = value;
                updateSize(true); // true = allow recalculation of height
            }
        }


        function trigger(name, thisObj) {
            if (options[name]) {
                return options[name].apply(
                    thisObj || _element,
                    Array.prototype.slice.call(arguments, 2)
                );
            }
        }

    }

    ;;

    Calendar.defaults = {

        titleRangeSeparator: ' \u2014 ', // emphasized dash
        monthYearFormat: 'MMMM YYYY', // required for en. other languages rely on datepicker computable option

        defaultTimedEventDuration: '02:00:00',
        defaultAllDayEventDuration: { days: 1 },
        forceEventDuration: false,
        nextDayThreshold: '09:00:00', // 9am

        // display
        defaultView: 'month',
        aspectRatio: 1.35,
        header: {
            left: 'title',
            center: '',
            right: 'today prev,next'
        },
        weekends: true,
        weekNumbers: false,

        weekNumberTitle: 'W',
        weekNumberCalculation: 'local',

        //editable: false,

        // event ajax
        lazyFetching: true,
        startParam: 'start',
        endParam: 'end',
        timezoneParam: 'timezone',

        timezone: false,

        //allDayDefault: undefined,

        // locale
        isRTL: false,
        buttonText: {
            prev: "prev",
            next: "next",
            prevYear: "prev year",
            nextYear: "next year",
            year: 'year', // TODO: locale files need to specify this
            today: 'today',
            month: 'month',
            week: 'week',
            day: 'day'
        },

        buttonIcons: {
            prev: 'left-single-arrow',
            next: 'right-single-arrow',
            prevYear: 'left-double-arrow',
            nextYear: 'right-double-arrow'
        },

        // jquery-ui theming
        theme: false,
        themeButtonIcons: {
            prev: 'circle-triangle-w',
            next: 'circle-triangle-e',
            prevYear: 'seek-prev',
            nextYear: 'seek-next'
        },

        //eventResizableFromStart: false,
        dragOpacity: .75,
        dragRevertDuration: 500,
        dragScroll: true,

        //selectable: false,
        unselectAuto: true,

        dropAccept: '*',

        eventLimit: false,
        eventLimitText: 'more',
        eventLimitClick: 'popover',
        dayPopoverFormat: 'LL',

        handleWindowResize: true,
        windowResizeDelay: 200 // milliseconds before an updateSize happens

    };


    Calendar.englishDefaults = { // used by lang.js
        dayPopoverFormat: 'dddd, MMMM D'
    };


    Calendar.rtlDefaults = { // right-to-left defaults
        header: { // TODO: smarter solution (first/center/last ?)
            left: 'next,prev today',
            center: '',
            right: 'title'
        },
        buttonIcons: {
            prev: 'right-single-arrow',
            next: 'left-single-arrow',
            prevYear: 'right-double-arrow',
            nextYear: 'left-double-arrow'
        },
        themeButtonIcons: {
            prev: 'circle-triangle-e',
            next: 'circle-triangle-w',
            nextYear: 'seek-prev',
            prevYear: 'seek-next'
        }
    };

    ;;

    var langOptionHash = fc.langs = {}; // initialize and expose


// TODO: document the structure and ordering of a FullCalendar lang file
// TODO: rename everything "lang" to "locale", like what the moment project did


// Initialize jQuery UI datepicker translations while using some of the translations
// Will set this as the default language for datepicker.
    fc.datepickerLang = function(langCode, dpLangCode, dpOptions) {

        // get the FullCalendar internal option hash for this language. create if necessary
        var fcOptions = langOptionHash[langCode] || (langOptionHash[langCode] = {});

        // transfer some simple options from datepicker to fc
        fcOptions.isRTL = dpOptions.isRTL;
        fcOptions.weekNumberTitle = dpOptions.weekHeader;

        // compute some more complex options from datepicker
        $.each(dpComputableOptions, function(name, func) {
            fcOptions[name] = func(dpOptions);
        });

        // is jQuery UI Datepicker is on the page?
        if ($.datepicker) {

            // Register the language data.
            // FullCalendar and MomentJS use language codes like "pt-br" but Datepicker
            // does it like "pt-BR" or if it doesn't have the language, maybe just "pt".
            // Make an alias so the language can be referenced either way.
            $.datepicker.regional[dpLangCode] =
                $.datepicker.regional[langCode] = // alias
                    dpOptions;

            // Alias 'en' to the default language data. Do this every time.
            $.datepicker.regional.en = $.datepicker.regional[''];

            // Set as Datepicker's global defaults.
            $.datepicker.setDefaults(dpOptions);
        }
    };


// Sets FullCalendar-specific translations. Will set the language as the global default.
    fc.lang = function(langCode, newFcOptions) {
        var fcOptions;
        var momOptions;

        // get the FullCalendar internal option hash for this language. create if necessary
        fcOptions = langOptionHash[langCode] || (langOptionHash[langCode] = {});

        // provided new options for this language? merge them in
        if (newFcOptions) {
            fcOptions = langOptionHash[langCode] = mergeOptions(fcOptions, newFcOptions);
        }

        // compute language options that weren't defined.
        // always do this. newFcOptions can be undefined when initializing from i18n file,
        // so no way to tell if this is an initialization or a default-setting.
        momOptions = getMomentLocaleData(langCode); // will fall back to en
        $.each(momComputableOptions, function(name, func) {
            if (fcOptions[name] == null) {
                fcOptions[name] = func(momOptions, fcOptions);
            }
        });

        // set it as the default language for FullCalendar
        Calendar.defaults.lang = langCode;
    };


// NOTE: can't guarantee any of these computations will run because not every language has datepicker
// configs, so make sure there are English fallbacks for these in the defaults file.
    var dpComputableOptions = {

        buttonText: function(dpOptions) {
            return {
                // the translations sometimes wrongly contain HTML entities
                prev: stripHtmlEntities(dpOptions.prevText),
                next: stripHtmlEntities(dpOptions.nextText),
                today: stripHtmlEntities(dpOptions.currentText)
            };
        },

        // Produces format strings like "MMMM YYYY" -> "September 2014"
        monthYearFormat: function(dpOptions) {
            return dpOptions.showMonthAfterYear ?
            'YYYY[' + dpOptions.yearSuffix + '] MMMM' :
            'MMMM YYYY[' + dpOptions.yearSuffix + ']';
        }

    };

    var momComputableOptions = {

        // Produces format strings like "ddd M/D" -> "Fri 9/15"
        dayOfMonthFormat: function(momOptions, fcOptions) {
            var format = momOptions.longDateFormat('l'); // for the format like "M/D/YYYY"

            // strip the year off the edge, as well as other misc non-whitespace chars
            format = format.replace(/^Y+[^\w\s]*|[^\w\s]*Y+$/g, '');

            if (fcOptions.isRTL) {
                format += ' ddd'; // for RTL, add day-of-week to end
            }
            else {
                format = 'ddd ' + format; // for LTR, add day-of-week to beginning
            }
            return format;
        },

        // Produces format strings like "h:mma" -> "6:00pm"
        mediumTimeFormat: function(momOptions) { // can't be called `timeFormat` because collides with option
            return momOptions.longDateFormat('LT')
                .replace(/\s*a$/i, 'a'); // convert AM/PM/am/pm to lowercase. remove any spaces beforehand
        },

        // Produces format strings like "h(:mm)a" -> "6pm" / "6:30pm"
        smallTimeFormat: function(momOptions) {
            return momOptions.longDateFormat('LT')
                .replace(':mm', '(:mm)')
                .replace(/(\Wmm)$/, '($1)') // like above, but for foreign langs
                .replace(/\s*a$/i, 'a'); // convert AM/PM/am/pm to lowercase. remove any spaces beforehand
        },

        // Produces format strings like "h(:mm)t" -> "6p" / "6:30p"
        extraSmallTimeFormat: function(momOptions) {
            return momOptions.longDateFormat('LT')
                .replace(':mm', '(:mm)')
                .replace(/(\Wmm)$/, '($1)') // like above, but for foreign langs
                .replace(/\s*a$/i, 't'); // convert to AM/PM/am/pm to lowercase one-letter. remove any spaces beforehand
        },

        // Produces format strings like "ha" / "H" -> "6pm" / "18"
        hourFormat: function(momOptions) {
            return momOptions.longDateFormat('LT')
                .replace(':mm', '')
                .replace(/(\Wmm)$/, '') // like above, but for foreign langs
                .replace(/\s*a$/i, 'a'); // convert AM/PM/am/pm to lowercase. remove any spaces beforehand
        },

        // Produces format strings like "h:mm" -> "6:30" (with no AM/PM)
        noMeridiemTimeFormat: function(momOptions) {
            return momOptions.longDateFormat('LT')
                .replace(/\s*a$/i, ''); // remove trailing AM/PM
        }

    };


// options that should be computed off live calendar options (considers override options)
    var instanceComputableOptions = { // TODO: best place for this? related to lang?

        // Produces format strings for results like "Mo 16"
        smallDayDateFormat: function(options) {
            return options.isRTL ?
                'D dd' :
                'dd D';
        },

        // Produces format strings for results like "Wk 5"
        weekFormat: function(options) {
            return options.isRTL ?
            'w[ ' + options.weekNumberTitle + ']' :
            '[' + options.weekNumberTitle + ' ]w';
        },

        // Produces format strings for results like "Wk5"
        smallWeekFormat: function(options) {
            return options.isRTL ?
            'w[' + options.weekNumberTitle + ']' :
            '[' + options.weekNumberTitle + ']w';
        }

    };

    function populateInstanceComputableOptions(options) {
        $.each(instanceComputableOptions, function(name, func) {
            if (options[name] == null) {
                options[name] = func(options);
            }
        });
    }


// Returns moment's internal locale data. If doesn't exist, returns English.
// Works with moment-pre-2.8
    function getMomentLocaleData(langCode) {
        var func = moment.localeData || moment.langData;
        return func.call(moment, langCode) ||
            func.call(moment, 'en'); // the newer localData could return null, so fall back to en
    }


// Initialize English by forcing computation of moment-derived options.
// Also, sets it as the default.
    fc.lang('en', Calendar.englishDefaults);

    ;;

    /* Top toolbar area with buttons and title
     ----------------------------------------------------------------------------------------------------------------------*/
// TODO: rename all header-related things to "toolbar"

    function Header(calendar, options) {
        var t = this;

        // exports
        t.render = render;
        t.destroy = destroy;
        t.updateTitle = updateTitle;
        t.activateButton = activateButton;
        t.deactivateButton = deactivateButton;
        t.disableButton = disableButton;
        t.enableButton = enableButton;
        t.getViewsWithButtons = getViewsWithButtons;

        // locals
        var el = $();
        var viewsWithButtons = [];
        var tm;


        function render() {
            var sections = options.header;

            tm = options.theme ? 'ui' : 'fc';

            if (sections) {
                el = $("<div class='fc-toolbar'/>")
                    .append(renderSection('left'))
                    .append(renderSection('right'))
                    .append(renderSection('center'))
                    .append('<div class="fc-clear"/>');

                return el;
            }
        }


        function destroy() {
            el.remove();
        }


        function renderSection(position) {
            var sectionEl = $('<div class="fc-' + position + '"/>');
            var buttonStr = options.header[position];

            if (buttonStr) {
                $.each(buttonStr.split(' '), function(i) {
                    var groupChildren = $();
                    var isOnlyButtons = true;
                    var groupEl;

                    $.each(this.split(','), function(j, buttonName) {
                        var viewSpec;
                        var buttonClick;
                        var overrideText; // text explicitly set by calendar's constructor options. overcomes icons
                        var defaultText;
                        var themeIcon;
                        var normalIcon;
                        var innerHtml;
                        var classes;
                        var button;

                        if (buttonName == 'title') {
                            groupChildren = groupChildren.add($('<h2>&nbsp;</h2>')); // we always want it to take up height
                            isOnlyButtons = false;
                        }
                        else {
                            viewSpec = calendar.getViewSpec(buttonName);

                            if (viewSpec) {
                                buttonClick = function() {
                                    calendar.changeView(buttonName);
                                };
                                viewsWithButtons.push(buttonName);
                                overrideText = viewSpec.buttonTextOverride;
                                defaultText = viewSpec.buttonTextDefault;
                            }
                            else if (calendar[buttonName]) { // a calendar method
                                buttonClick = function() {
                                    calendar[buttonName]();
                                };
                                overrideText = (calendar.overrides.buttonText || {})[buttonName];
                                defaultText = options.buttonText[buttonName]; // everything else is considered default
                            }

                            if (buttonClick) {

                                themeIcon = options.themeButtonIcons[buttonName];
                                normalIcon = options.buttonIcons[buttonName];

                                if (overrideText) {
                                    innerHtml = htmlEscape(overrideText);
                                }
                                else if (themeIcon && options.theme) {
                                    innerHtml = "<span class='ui-icon ui-icon-" + themeIcon + "'></span>";
                                }
                                else if (normalIcon && !options.theme) {
                                    innerHtml = "<span class='fc-icon fc-icon-" + normalIcon + "'></span>";
                                }
                                else {
                                    innerHtml = htmlEscape(defaultText);
                                }

                                classes = [
                                    'fc-' + buttonName + '-button',
                                    tm + '-button',
                                    tm + '-state-default'
                                ];

                                button = $( // type="button" so that it doesn't submit a form
                                    '<button type="button" class="' + classes.join(' ') + '">' +
                                    innerHtml +
                                    '</button>'
                                )
                                    .click(function() {
                                        // don't process clicks for disabled buttons
                                        if (!button.hasClass(tm + '-state-disabled')) {

                                            buttonClick();

                                            // after the click action, if the button becomes the "active" tab, or disabled,
                                            // it should never have a hover class, so remove it now.
                                            if (
                                                button.hasClass(tm + '-state-active') ||
                                                button.hasClass(tm + '-state-disabled')
                                            ) {
                                                button.removeClass(tm + '-state-hover');
                                            }
                                        }
                                    })
                                    .mousedown(function() {
                                        // the *down* effect (mouse pressed in).
                                        // only on buttons that are not the "active" tab, or disabled
                                        button
                                            .not('.' + tm + '-state-active')
                                            .not('.' + tm + '-state-disabled')
                                            .addClass(tm + '-state-down');
                                    })
                                    .mouseup(function() {
                                        // undo the *down* effect
                                        button.removeClass(tm + '-state-down');
                                    })
                                    .hover(
                                    function() {
                                        // the *hover* effect.
                                        // only on buttons that are not the "active" tab, or disabled
                                        button
                                            .not('.' + tm + '-state-active')
                                            .not('.' + tm + '-state-disabled')
                                            .addClass(tm + '-state-hover');
                                    },
                                    function() {
                                        // undo the *hover* effect
                                        button
                                            .removeClass(tm + '-state-hover')
                                            .removeClass(tm + '-state-down'); // if mouseleave happens before mouseup
                                    }
                                );

                                groupChildren = groupChildren.add(button);
                            }
                        }
                    });

                    if (isOnlyButtons) {
                        groupChildren
                            .first().addClass(tm + '-corner-left').end()
                            .last().addClass(tm + '-corner-right').end();
                    }

                    if (groupChildren.length > 1) {
                        groupEl = $('<div/>');
                        if (isOnlyButtons) {
                            groupEl.addClass('fc-button-group');
                        }
                        groupEl.append(groupChildren);
                        sectionEl.append(groupEl);
                    }
                    else {
                        sectionEl.append(groupChildren); // 1 or 0 children
                    }
                });
            }

            return sectionEl;
        }


        function updateTitle(text) {
            el.find('h2').text(text);
        }


        function activateButton(buttonName) {
            el.find('.fc-' + buttonName + '-button')
                .addClass(tm + '-state-active');
        }


        function deactivateButton(buttonName) {
            el.find('.fc-' + buttonName + '-button')
                .removeClass(tm + '-state-active');
        }


        function disableButton(buttonName) {
            el.find('.fc-' + buttonName + '-button')
                .attr('disabled', 'disabled')
                .addClass(tm + '-state-disabled');
        }


        function enableButton(buttonName) {
            el.find('.fc-' + buttonName + '-button')
                .removeAttr('disabled')
                .removeClass(tm + '-state-disabled');
        }


        function getViewsWithButtons() {
            return viewsWithButtons;
        }

    }

    ;;

    fc.sourceNormalizers = [];
    fc.sourceFetchers = [];

    var ajaxDefaults = {
        dataType: 'json',
        cache: false
    };

    var eventGUID = 1;


    function EventManager(options) { // assumed to be a calendar
        var t = this;


        // exports
        t.isFetchNeeded = isFetchNeeded;
        t.fetchEvents = fetchEvents;
        t.addEventSource = addEventSource;
        t.removeEventSource = removeEventSource;
        t.updateEvent = updateEvent;
        t.renderEvent = renderEvent;
        t.removeEvents = removeEvents;
        t.clientEvents = clientEvents;
        t.mutateEvent = mutateEvent;
        t.normalizeEventRange = normalizeEventRange;
        t.normalizeEventRangeTimes = normalizeEventRangeTimes;
        t.ensureVisibleEventRange = ensureVisibleEventRange;


        // imports
        var trigger = t.trigger;
        var getView = t.getView;
        var reportEvents = t.reportEvents;


        // locals
        var stickySource = { events: [] };
        var sources = [ stickySource ];
        var rangeStart, rangeEnd;
        var currentFetchID = 0;
        var pendingSourceCnt = 0;
        var loadingLevel = 0;
        var cache = []; // holds events that have already been expanded


        $.each(
            (options.events ? [ options.events ] : []).concat(options.eventSources || []),
            function(i, sourceInput) {
                var source = buildEventSource(sourceInput);
                if (source) {
                    sources.push(source);
                }
            }
        );



        /* Fetching
         -----------------------------------------------------------------------------*/


        function isFetchNeeded(start, end) {
            return !rangeStart || // nothing has been fetched yet?
                    // or, a part of the new range is outside of the old range? (after normalizing)
                start.clone().stripZone() < rangeStart.clone().stripZone() ||
                end.clone().stripZone() > rangeEnd.clone().stripZone();
        }


        function fetchEvents(start, end) {
            rangeStart = start;
            rangeEnd = end;
            cache = [];
            var fetchID = ++currentFetchID;
            var len = sources.length;
            pendingSourceCnt = len;
            for (var i=0; i<len; i++) {
                fetchEventSource(sources[i], fetchID);
            }
        }


        function fetchEventSource(source, fetchID) {
            _fetchEventSource(source, function(eventInputs) {
                var isArraySource = $.isArray(source.events);
                var i, eventInput;
                var abstractEvent;

                if (fetchID == currentFetchID) {

                    if (eventInputs) {
                        for (i = 0; i < eventInputs.length; i++) {
                            eventInput = eventInputs[i];

                            if (isArraySource) { // array sources have already been convert to Event Objects
                                abstractEvent = eventInput;
                            }
                            else {
                                abstractEvent = buildEventFromInput(eventInput, source);
                            }

                            if (abstractEvent) { // not false (an invalid event)
                                cache.push.apply(
                                    cache,
                                    expandEvent(abstractEvent) // add individual expanded events to the cache
                                );
                            }
                        }
                    }

                    pendingSourceCnt--;
                    if (!pendingSourceCnt) {
                        reportEvents(cache);
                    }
                }
            });
        }


        function _fetchEventSource(source, callback) {
            var i;
            var fetchers = fc.sourceFetchers;
            var res;

            for (i=0; i<fetchers.length; i++) {
                res = fetchers[i].call(
                    t, // this, the Calendar object
                    source,
                    rangeStart.clone(),
                    rangeEnd.clone(),
                    options.timezone,
                    callback
                );

                if (res === true) {
                    // the fetcher is in charge. made its own async request
                    return;
                }
                else if (typeof res == 'object') {
                    // the fetcher returned a new source. process it
                    _fetchEventSource(res, callback);
                    return;
                }
            }

            var events = source.events;
            if (events) {
                if ($.isFunction(events)) {
                    pushLoading();
                    events.call(
                        t, // this, the Calendar object
                        rangeStart.clone(),
                        rangeEnd.clone(),
                        options.timezone,
                        function(events) {
                            callback(events);
                            popLoading();
                        }
                    );
                }
                else if ($.isArray(events)) {
                    callback(events);
                }
                else {
                    callback();
                }
            }else{
                var url = source.url;
                if (url) {
                    var success = source.success;
                    var error = source.error;
                    var complete = source.complete;

                    // retrieve any outbound GET/POST $.ajax data from the options
                    var customData;
                    if ($.isFunction(source.data)) {
                        // supplied as a function that returns a key/value object
                        customData = source.data();
                    }
                    else {
                        // supplied as a straight key/value object
                        customData = source.data;
                    }

                    // use a copy of the custom data so we can modify the parameters
                    // and not affect the passed-in object.
                    var data = $.extend({}, customData || {});

                    var startParam = firstDefined(source.startParam, options.startParam);
                    var endParam = firstDefined(source.endParam, options.endParam);
                    var timezoneParam = firstDefined(source.timezoneParam, options.timezoneParam);

                    if (startParam) {
                        data[startParam] = rangeStart.format();
                    }
                    if (endParam) {
                        data[endParam] = rangeEnd.format();
                    }
                    if (options.timezone && options.timezone != 'local') {
                        data[timezoneParam] = options.timezone;
                    }

                    pushLoading();
                    $.ajax($.extend({}, ajaxDefaults, source, {
                        data: data,
                        success: function(events) {
                            events = events || [];
                            var res = applyAll(success, this, arguments);
                            if ($.isArray(res)) {
                                events = res;
                            }
                            callback(events);
                        },
                        error: function() {
                            applyAll(error, this, arguments);
                            callback();
                        },
                        complete: function() {
                            applyAll(complete, this, arguments);
                            popLoading();
                        }
                    }));
                }else{
                    callback();
                }
            }
        }



        /* Sources
         -----------------------------------------------------------------------------*/


        function addEventSource(sourceInput) {
            var source = buildEventSource(sourceInput);
            if (source) {
                sources.push(source);
                pendingSourceCnt++;
                fetchEventSource(source, currentFetchID); // will eventually call reportEvents
            }
        }


        function buildEventSource(sourceInput) { // will return undefined if invalid source
            var normalizers = fc.sourceNormalizers;
            var source;
            var i;

            if ($.isFunction(sourceInput) || $.isArray(sourceInput)) {
                source = { events: sourceInput };
            }
            else if (typeof sourceInput === 'string') {
                source = { url: sourceInput };
            }
            else if (typeof sourceInput === 'object') {
                source = $.extend({}, sourceInput); // shallow copy
            }

            if (source) {

                // TODO: repeat code, same code for event classNames
                if (source.className) {
                    if (typeof source.className === 'string') {
                        source.className = source.className.split(/\s+/);
                    }
                    // otherwise, assumed to be an array
                }
                else {
                    source.className = [];
                }

                // for array sources, we convert to standard Event Objects up front
                if ($.isArray(source.events)) {
                    source.origArray = source.events; // for removeEventSource
                    source.events = $.map(source.events, function(eventInput) {
                        return buildEventFromInput(eventInput, source);
                    });
                }

                for (i=0; i<normalizers.length; i++) {
                    normalizers[i].call(t, source);
                }

                return source;
            }
        }


        function removeEventSource(source) {
            sources = $.grep(sources, function(src) {
                return !isSourcesEqual(src, source);
            });
            // remove all client events from that source
            cache = $.grep(cache, function(e) {
                return !isSourcesEqual(e.source, source);
            });
            reportEvents(cache);
        }


        function isSourcesEqual(source1, source2) {
            return source1 && source2 && getSourcePrimitive(source1) == getSourcePrimitive(source2);
        }


        function getSourcePrimitive(source) {
            return (
                    (typeof source === 'object') ? // a normalized event source?
                        (source.origArray || source.googleCalendarId || source.url || source.events) : // get the primitive
                        null
                ) ||
                source; // the given argument *is* the primitive
        }



        /* Manipulation
         -----------------------------------------------------------------------------*/


        // Only ever called from the externally-facing API
        function updateEvent(event) {

            // massage start/end values, even if date string values
            event.start = t.moment(event.start);
            if (event.end) {
                event.end = t.moment(event.end);
            }
            else {
                event.end = null;
            }

            mutateEvent(event, getMiscEventProps(event)); // will handle start/end/allDay normalization
            reportEvents(cache); // reports event modifications (so we can redraw)
        }


        // Returns a hash of misc event properties that should be copied over to related events.
        function getMiscEventProps(event) {
            var props = {};

            $.each(event, function(name, val) {
                if (isMiscEventPropName(name)) {
                    if (val !== undefined && isAtomic(val)) { // a defined non-object
                        props[name] = val;
                    }
                }
            });

            return props;
        }

        // non-date-related, non-id-related, non-secret
        function isMiscEventPropName(name) {
            return !/^_|^(id|allDay|start|end)$/.test(name);
        }


        // returns the expanded events that were created
        function renderEvent(eventInput, stick) {
            var abstractEvent = buildEventFromInput(eventInput);
            var events;
            var i, event;

            if (abstractEvent) { // not false (a valid input)
                events = expandEvent(abstractEvent);

                for (i = 0; i < events.length; i++) {
                    event = events[i];

                    if (!event.source) {
                        if (stick) {
                            stickySource.events.push(event);
                            event.source = stickySource;
                        }
                        cache.push(event);
                    }
                }

                reportEvents(cache);

                return events;
            }

            return [];
        }


        function removeEvents(filter) {
            var eventID;
            var i;

            if (filter == null) { // null or undefined. remove all events
                filter = function() { return true; }; // will always match
            }
            else if (!$.isFunction(filter)) { // an event ID
                eventID = filter + '';
                filter = function(event) {
                    return event._id == eventID;
                };
            }

            // Purge event(s) from our local cache
            cache = $.grep(cache, filter, true); // inverse=true

            // Remove events from array sources.
            // This works because they have been converted to official Event Objects up front.
            // (and as a result, event._id has been calculated).
            for (i=0; i<sources.length; i++) {
                if ($.isArray(sources[i].events)) {
                    sources[i].events = $.grep(sources[i].events, filter, true);
                }
            }

            reportEvents(cache);
        }


        function clientEvents(filter) {
            if ($.isFunction(filter)) {
                return $.grep(cache, filter);
            }
            else if (filter != null) { // not null, not undefined. an event ID
                filter += '';
                return $.grep(cache, function(e) {
                    return e._id == filter;
                });
            }
            return cache; // else, return all
        }



        /* Loading State
         -----------------------------------------------------------------------------*/


        function pushLoading() {
            if (!(loadingLevel++)) {
                trigger('loading', null, true, getView());
            }
        }


        function popLoading() {
            if (!(--loadingLevel)) {
                trigger('loading', null, false, getView());
            }
        }



        /* Event Normalization
         -----------------------------------------------------------------------------*/


        // Given a raw object with key/value properties, returns an "abstract" Event object.
        // An "abstract" event is an event that, if recurring, will not have been expanded yet.
        // Will return `false` when input is invalid.
        // `source` is optional
        function buildEventFromInput(input, source) {
            var out = {};
            var start, end;
            var allDay;

            if (options.eventDataTransform) {
                input = options.eventDataTransform(input);
            }
            if (source && source.eventDataTransform) {
                input = source.eventDataTransform(input);
            }

            // Copy all properties over to the resulting object.
            // The special-case properties will be copied over afterwards.
            $.extend(out, input);

            if (source) {
                out.source = source;
            }

            out._id = input._id || (input.id === undefined ? '_fc' + eventGUID++ : input.id + '');

            if (input.className) {
                if (typeof input.className == 'string') {
                    out.className = input.className.split(/\s+/);
                }
                else { // assumed to be an array
                    out.className = input.className;
                }
            }
            else {
                out.className = [];
            }

            start = input.start || input.date; // "date" is an alias for "start"
            end = input.end;

            // parse as a time (Duration) if applicable
            if (isTimeString(start)) {
                start = moment.duration(start);
            }
            if (isTimeString(end)) {
                end = moment.duration(end);
            }

            if (input.dow || moment.isDuration(start) || moment.isDuration(end)) {

                // the event is "abstract" (recurring) so don't calculate exact start/end dates just yet
                out.start = start ? moment.duration(start) : null; // will be a Duration or null
                out.end = end ? moment.duration(end) : null; // will be a Duration or null
                out._recurring = true; // our internal marker
            }
            else {

                if (start) {
                    start = t.moment(start);
                    if (!start.isValid()) {
                        return false;
                    }
                }

                if (end) {
                    end = t.moment(end);
                    if (!end.isValid()) {
                        end = null; // let defaults take over
                    }
                }

                allDay = input.allDay;
                if (allDay === undefined) { // still undefined? fallback to default
                    allDay = firstDefined(
                        source ? source.allDayDefault : undefined,
                        options.allDayDefault
                    );
                    // still undefined? normalizeEventRange will calculate it
                }

                assignDatesToEvent(start, end, allDay, out);
            }

            return out;
        }


        // Normalizes and assigns the given dates to the given partially-formed event object.
        // NOTE: mutates the given start/end moments. does not make a copy.
        function assignDatesToEvent(start, end, allDay, event) {
            event.start = start;
            event.end = end;
            event.allDay = allDay;
            normalizeEventRange(event);
            backupEventDates(event);
        }


        // Ensures proper values for allDay/start/end. Accepts an Event object, or a plain object with event-ish properties.
        // NOTE: Will modify the given object.
        function normalizeEventRange(props) {

            normalizeEventRangeTimes(props);

            if (props.end && !props.end.isAfter(props.start)) {
                props.end = null;
            }

            if (!props.end) {
                if (options.forceEventDuration) {
                    props.end = t.getDefaultEventEnd(props.allDay, props.start);
                }
                else {
                    props.end = null;
                }
            }
        }


        // Ensures the allDay property exists and the timeliness of the start/end dates are consistent
        function normalizeEventRangeTimes(range) {
            if (range.allDay == null) {
                range.allDay = !(range.start.hasTime() || (range.end && range.end.hasTime()));
            }

            if (range.allDay) {
                range.start.stripTime();
                if (range.end) {
                    // TODO: consider nextDayThreshold here? If so, will require a lot of testing and adjustment
                    range.end.stripTime();
                }
            }
            else {
                if (!range.start.hasTime()) {
                    range.start = t.rezoneDate(range.start); // will assign a 00:00 time
                }
                if (range.end && !range.end.hasTime()) {
                    range.end = t.rezoneDate(range.end); // will assign a 00:00 time
                }
            }
        }


        // If `range` is a proper range with a start and end, returns the original object.
        // If missing an end, computes a new range with an end, computing it as if it were an event.
        // TODO: make this a part of the event -> eventRange system
        function ensureVisibleEventRange(range) {
            var allDay;

            if (!range.end) {

                allDay = range.allDay; // range might be more event-ish than we think
                if (allDay == null) {
                    allDay = !range.start.hasTime();
                }

                range = $.extend({}, range); // make a copy, copying over other misc properties
                range.end = t.getDefaultEventEnd(allDay, range.start);
            }
            return range;
        }


        // If the given event is a recurring event, break it down into an array of individual instances.
        // If not a recurring event, return an array with the single original event.
        // If given a falsy input (probably because of a failed buildEventFromInput call), returns an empty array.
        // HACK: can override the recurring window by providing custom rangeStart/rangeEnd (for businessHours).
        function expandEvent(abstractEvent, _rangeStart, _rangeEnd) {
            var events = [];
            var dowHash;
            var dow;
            var i;
            var date;
            var startTime, endTime;
            var start, end;
            var event;

            _rangeStart = _rangeStart || rangeStart;
            _rangeEnd = _rangeEnd || rangeEnd;

            if (abstractEvent) {
                if (abstractEvent._recurring) {

                    // make a boolean hash as to whether the event occurs on each day-of-week
                    if ((dow = abstractEvent.dow)) {
                        dowHash = {};
                        for (i = 0; i < dow.length; i++) {
                            dowHash[dow[i]] = true;
                        }
                    }

                    // iterate through every day in the current range
                    date = _rangeStart.clone().stripTime(); // holds the date of the current day
                    while (date.isBefore(_rangeEnd)) {

                        if (!dowHash || dowHash[date.day()]) { // if everyday, or this particular day-of-week

                            startTime = abstractEvent.start; // the stored start and end properties are times (Durations)
                            endTime = abstractEvent.end; // "
                            start = date.clone();
                            end = null;

                            if (startTime) {
                                start = start.time(startTime);
                            }
                            if (endTime) {
                                end = date.clone().time(endTime);
                            }

                            event = $.extend({}, abstractEvent); // make a copy of the original
                            assignDatesToEvent(
                                start, end,
                                !startTime && !endTime, // allDay?
                                event
                            );
                            events.push(event);
                        }

                        date.add(1, 'days');
                    }
                }
                else {
                    events.push(abstractEvent); // return the original event. will be a one-item array
                }
            }

            return events;
        }



        /* Event Modification Math
         -----------------------------------------------------------------------------------------*/


        // Modifies an event and all related events by applying the given properties.
        // Special date-diffing logic is used for manipulation of dates.
        // If `props` does not contain start/end dates, the updated values are assumed to be the event's current start/end.
        // All date comparisons are done against the event's pristine _start and _end dates.
        // Returns an object with delta information and a function to undo all operations.
        // For making computations in a granularity greater than day/time, specify largeUnit.
        // NOTE: The given `newProps` might be mutated for normalization purposes.
        function mutateEvent(event, newProps, largeUnit) {
            var miscProps = {};
            var oldProps;
            var clearEnd;
            var startDelta;
            var endDelta;
            var durationDelta;
            var undoFunc;

            // diffs the dates in the appropriate way, returning a duration
            function diffDates(date1, date0) { // date1 - date0
                if (largeUnit) {
                    return diffByUnit(date1, date0, largeUnit);
                }
                else if (newProps.allDay) {
                    return diffDay(date1, date0);
                }
                else {
                    return diffDayTime(date1, date0);
                }
            }

            newProps = newProps || {};

            // normalize new date-related properties
            if (!newProps.start) {
                newProps.start = event.start.clone();
            }
            if (newProps.end === undefined) {
                newProps.end = event.end ? event.end.clone() : null;
            }
            if (newProps.allDay == null) { // is null or undefined?
                newProps.allDay = event.allDay;
            }
            normalizeEventRange(newProps);

            // create normalized versions of the original props to compare against
            // need a real end value, for diffing
            oldProps = {
                start: event._start.clone(),
                end: event._end ? event._end.clone() : t.getDefaultEventEnd(event._allDay, event._start),
                allDay: newProps.allDay // normalize the dates in the same regard as the new properties
            };
            normalizeEventRange(oldProps);

            // need to clear the end date if explicitly changed to null
            clearEnd = event._end !== null && newProps.end === null;

            // compute the delta for moving the start date
            startDelta = diffDates(newProps.start, oldProps.start);

            // compute the delta for moving the end date
            if (newProps.end) {
                endDelta = diffDates(newProps.end, oldProps.end);
                durationDelta = endDelta.subtract(startDelta);
            }
            else {
                durationDelta = null;
            }

            // gather all non-date-related properties
            $.each(newProps, function(name, val) {
                if (isMiscEventPropName(name)) {
                    if (val !== undefined) {
                        miscProps[name] = val;
                    }
                }
            });

            // apply the operations to the event and all related events
            undoFunc = mutateEvents(
                clientEvents(event._id), // get events with this ID
                clearEnd,
                newProps.allDay,
                startDelta,
                durationDelta,
                miscProps
            );

            return {
                dateDelta: startDelta,
                durationDelta: durationDelta,
                undo: undoFunc
            };
        }


        // Modifies an array of events in the following ways (operations are in order):
        // - clear the event's `end`
        // - convert the event to allDay
        // - add `dateDelta` to the start and end
        // - add `durationDelta` to the event's duration
        // - assign `miscProps` to the event
        //
        // Returns a function that can be called to undo all the operations.
        //
        // TODO: don't use so many closures. possible memory issues when lots of events with same ID.
        //
        function mutateEvents(events, clearEnd, allDay, dateDelta, durationDelta, miscProps) {
            var isAmbigTimezone = t.getIsAmbigTimezone();
            var undoFunctions = [];

            // normalize zero-length deltas to be null
            if (dateDelta && !dateDelta.valueOf()) { dateDelta = null; }
            if (durationDelta && !durationDelta.valueOf()) { durationDelta = null; }

            $.each(events, function(i, event) {
                var oldProps;
                var newProps;

                // build an object holding all the old values, both date-related and misc.
                // for the undo function.
                oldProps = {
                    start: event.start.clone(),
                    end: event.end ? event.end.clone() : null,
                    allDay: event.allDay
                };
                $.each(miscProps, function(name) {
                    oldProps[name] = event[name];
                });

                // new date-related properties. work off the original date snapshot.
                // ok to use references because they will be thrown away when backupEventDates is called.
                newProps = {
                    start: event._start,
                    end: event._end,
                    allDay: allDay // normalize the dates in the same regard as the new properties
                };
                normalizeEventRange(newProps); // massages start/end/allDay

                // strip or ensure the end date
                if (clearEnd) {
                    newProps.end = null;
                }
                else if (durationDelta && !newProps.end) { // the duration translation requires an end date
                    newProps.end = t.getDefaultEventEnd(newProps.allDay, newProps.start);
                }

                if (dateDelta) {
                    newProps.start.add(dateDelta);
                    if (newProps.end) {
                        newProps.end.add(dateDelta);
                    }
                }

                if (durationDelta) {
                    newProps.end.add(durationDelta); // end already ensured above
                }

                // if the dates have changed, and we know it is impossible to recompute the
                // timezone offsets, strip the zone.
                if (
                    isAmbigTimezone &&
                    !newProps.allDay &&
                    (dateDelta || durationDelta)
                ) {
                    newProps.start.stripZone();
                    if (newProps.end) {
                        newProps.end.stripZone();
                    }
                }

                $.extend(event, miscProps, newProps); // copy over misc props, then date-related props
                backupEventDates(event); // regenerate internal _start/_end/_allDay

                undoFunctions.push(function() {
                    $.extend(event, oldProps);
                    backupEventDates(event); // regenerate internal _start/_end/_allDay
                });
            });

            return function() {
                for (var i = 0; i < undoFunctions.length; i++) {
                    undoFunctions[i]();
                }
            };
        }


        /* Business Hours
         -----------------------------------------------------------------------------------------*/

        t.getBusinessHoursEvents = getBusinessHoursEvents;


        // Returns an array of events as to when the business hours occur in the given view.
        // Abuse of our event system :(
        function getBusinessHoursEvents(wholeDay) {
            var optionVal = options.businessHours;
            var defaultVal = {
                className: 'fc-nonbusiness',
                start: '09:00',
                end: '17:00',
                dow: [ 1, 2, 3, 4, 5 ], // monday - friday
                rendering: 'inverse-background'
            };
            var view = t.getView();
            var eventInput;

            if (optionVal) { // `true` (which means "use the defaults") or an override object
                eventInput = $.extend(
                    {}, // copy to a new object in either case
                    defaultVal,
                    typeof optionVal === 'object' ? optionVal : {} // override the defaults
                );
            }

            if (eventInput) {

                // if a whole-day series is requested, clear the start/end times
                if (wholeDay) {
                    eventInput.start = null;
                    eventInput.end = null;
                }

                return expandEvent(
                    buildEventFromInput(eventInput),
                    view.start,
                    view.end
                );
            }

            return [];
        }


        /* Overlapping / Constraining
         -----------------------------------------------------------------------------------------*/

        t.isEventRangeAllowed = isEventRangeAllowed;
        t.isSelectionRangeAllowed = isSelectionRangeAllowed;
        t.isExternalDropRangeAllowed = isExternalDropRangeAllowed;


        function isEventRangeAllowed(range, event) {
            var source = event.source || {};
            var constraint = firstDefined(
                event.constraint,
                source.constraint,
                options.eventConstraint
            );
            var overlap = firstDefined(
                event.overlap,
                source.overlap,
                options.eventOverlap
            );

            range = ensureVisibleEventRange(range); // ensure a proper range with an end for isRangeAllowed

            return isRangeAllowed(range, constraint, overlap, event);
        }


        function isSelectionRangeAllowed(range) {
            return isRangeAllowed(range, options.selectConstraint, options.selectOverlap);
        }


        // when `eventProps` is defined, consider this an event.
        // `eventProps` can contain misc non-date-related info about the event.
        function isExternalDropRangeAllowed(range, eventProps) {
            var eventInput;
            var event;

            // note: very similar logic is in View's reportExternalDrop
            if (eventProps) {
                eventInput = $.extend({}, eventProps, range);
                event = expandEvent(buildEventFromInput(eventInput))[0];
            }

            if (event) {
                return isEventRangeAllowed(range, event);
            }
            else { // treat it as a selection

                range = ensureVisibleEventRange(range); // ensure a proper range with an end for isSelectionRangeAllowed

                return isSelectionRangeAllowed(range);
            }
        }


        // Returns true if the given range (caused by an event drop/resize or a selection) is allowed to exist
        // according to the constraint/overlap settings.
        // `event` is not required if checking a selection.
        function isRangeAllowed(range, constraint, overlap, event) {
            var constraintEvents;
            var anyContainment;
            var peerEvents;
            var i, peerEvent;
            var peerOverlap;

            // normalize. fyi, we're normalizing in too many places :(
            range = $.extend({}, range); // copy all properties in case there are misc non-date properties
            range.start = range.start.clone().stripZone();
            range.end = range.end.clone().stripZone();

            // the range must be fully contained by at least one of produced constraint events
            if (constraint != null) {

                // not treated as an event! intermediate data structure
                // TODO: use ranges in the future
                constraintEvents = constraintToEvents(constraint);

                anyContainment = false;
                for (i = 0; i < constraintEvents.length; i++) {
                    if (eventContainsRange(constraintEvents[i], range)) {
                        anyContainment = true;
                        break;
                    }
                }

                if (!anyContainment) {
                    return false;
                }
            }

            peerEvents = t.getPeerEvents(event, range);

            for (i = 0; i < peerEvents.length; i++)  {
                peerEvent = peerEvents[i];

                // there needs to be an actual intersection before disallowing anything
                if (eventIntersectsRange(peerEvent, range)) {

                    // evaluate overlap for the given range and short-circuit if necessary
                    if (overlap === false) {
                        return false;
                    }
                    // if the event's overlap is a test function, pass the peer event in question as the first param
                    else if (typeof overlap === 'function' && !overlap(peerEvent, event)) {
                        return false;
                    }

                    // if we are computing if the given range is allowable for an event, consider the other event's
                    // EventObject-specific or Source-specific `overlap` property
                    if (event) {
                        peerOverlap = firstDefined(
                            peerEvent.overlap,
                            (peerEvent.source || {}).overlap
                            // we already considered the global `eventOverlap`
                        );
                        if (peerOverlap === false) {
                            return false;
                        }
                        // if the peer event's overlap is a test function, pass the subject event as the first param
                        if (typeof peerOverlap === 'function' && !peerOverlap(event, peerEvent)) {
                            return false;
                        }
                    }
                }
            }

            return true;
        }


        // Given an event input from the API, produces an array of event objects. Possible event inputs:
        // 'businessHours'
        // An event ID (number or string)
        // An object with specific start/end dates or a recurring event (like what businessHours accepts)
        function constraintToEvents(constraintInput) {

            if (constraintInput === 'businessHours') {
                return getBusinessHoursEvents();
            }

            if (typeof constraintInput === 'object') {
                return expandEvent(buildEventFromInput(constraintInput));
            }

            return clientEvents(constraintInput); // probably an ID
        }


        // Does the event's date range fully contain the given range?
        // start/end already assumed to have stripped zones :(
        function eventContainsRange(event, range) {
            var eventStart = event.start.clone().stripZone();
            var eventEnd = t.getEventEnd(event).stripZone();

            return range.start >= eventStart && range.end <= eventEnd;
        }


        // Does the event's date range intersect with the given range?
        // start/end already assumed to have stripped zones :(
        function eventIntersectsRange(event, range) {
            var eventStart = event.start.clone().stripZone();
            var eventEnd = t.getEventEnd(event).stripZone();

            return range.start < eventEnd && range.end > eventStart;
        }


        t.getEventCache = function() {
            return cache;
        };

    }


// Returns a list of events that the given event should be compared against when being considered for a move to
// the specified range. Attached to the Calendar's prototype because EventManager is a mixin for a Calendar.
    Calendar.prototype.getPeerEvents = function(event, range) {
        var cache = this.getEventCache();
        var peerEvents = [];
        var i, otherEvent;

        for (i = 0; i < cache.length; i++) {
            otherEvent = cache[i];
            if (
                !event ||
                event._id !== otherEvent._id // don't compare the event to itself or other related [repeating] events
            ) {
                peerEvents.push(otherEvent);
            }
        }

        return peerEvents;
    };


// updates the "backup" properties, which are preserved in order to compute diffs later on.
    function backupEventDates(event) {
        event._allDay = event.allDay;
        event._start = event.start.clone();
        event._end = event.end ? event.end.clone() : null;
    }

    ;;

    /* An abstract class for the "basic" views, as well as month view. Renders one or more rows of day cells.
     ----------------------------------------------------------------------------------------------------------------------*/
// It is a manager for a DayGrid subcomponent, which does most of the heavy lifting.
// It is responsible for managing width/height.

    var BasicView = fcViews.basic = View.extend({

        dayGrid: null, // the main subcomponent that does most of the heavy lifting

        dayNumbersVisible: false, // display day numbers on each day cell?
        weekNumbersVisible: false, // display week numbers along the side?

        weekNumberWidth: null, // width of all the week-number cells running down the side

        headRowEl: null, // the fake row element of the day-of-week header


        initialize: function() {
            this.dayGrid = new DayGrid(this);
            this.coordMap = this.dayGrid.coordMap; // the view's date-to-cell mapping is identical to the subcomponent's
        },


        // Sets the display range and computes all necessary dates
        setRange: function(range) {
            View.prototype.setRange.call(this, range); // call the super-method

            this.dayGrid.breakOnWeeks = /year|month|week/.test(this.intervalUnit); // do before setRange
            this.dayGrid.setRange(range);
        },


        // Compute the value to feed into setRange. Overrides superclass.
        computeRange: function(date) {
            var range = View.prototype.computeRange.call(this, date); // get value from the super-method

            // year and month views should be aligned with weeks. this is already done for week
            if (/year|month/.test(range.intervalUnit)) {
                range.start.startOf('week');
                range.start = this.skipHiddenDays(range.start);

                // make end-of-week if not already
                if (range.end.weekday()) {
                    range.end.add(1, 'week').startOf('week');
                    range.end = this.skipHiddenDays(range.end, -1, true); // exclusively move backwards
                }
            }

            return range;
        },


        // Renders the view into `this.el`, which should already be assigned
        render: function() {

            this.dayNumbersVisible = this.dayGrid.rowCnt > 1; // TODO: make grid responsible
            this.weekNumbersVisible = this.opt('weekNumbers');
            this.dayGrid.numbersVisible = this.dayNumbersVisible || this.weekNumbersVisible;

            this.el.addClass('fc-basic-view').html(this.renderHtml());

            this.headRowEl = this.el.find('thead .fc-row');

            this.scrollerEl = this.el.find('.fc-day-grid-container');
            this.dayGrid.coordMap.containerEl = this.scrollerEl; // constrain clicks/etc to the dimensions of the scroller

            this.dayGrid.setElement(this.el.find('.fc-day-grid'));
            this.dayGrid.renderDates(this.hasRigidRows());
        },


        // Unrenders the content of the view. Since we haven't separated skeleton rendering from date rendering,
        // always completely kill the dayGrid's rendering.
        destroy: function() {
            this.dayGrid.destroyDates();
            this.dayGrid.removeElement();
        },


        renderBusinessHours: function() {
            this.dayGrid.renderBusinessHours();
        },


        // Builds the HTML skeleton for the view.
        // The day-grid component will render inside of a container defined by this HTML.
        renderHtml: function() {
            return '' +
                '<table>' +
                '<thead class="fc-head">' +
                '<tr>' +
                '<td class="' + this.widgetHeaderClass + '">' +
                this.dayGrid.headHtml() + // render the day-of-week headers
                '</td>' +
                '</tr>' +
                '</thead>' +
                '<tbody class="fc-body">' +
                '<tr>' +
                '<td class="' + this.widgetContentClass + '">' +
                '<div class="fc-day-grid-container">' +
                '<div class="fc-day-grid"/>' +
                '</div>' +
                '</td>' +
                '</tr>' +
                '</tbody>' +
                '</table>';
        },


        // Generates the HTML that will go before the day-of week header cells.
        // Queried by the DayGrid subcomponent when generating rows. Ordering depends on isRTL.
        headIntroHtml: function() {
            if (this.weekNumbersVisible) {
                return '' +
                    '<th class="fc-week-number ' + this.widgetHeaderClass + '" ' + this.weekNumberStyleAttr() + '>' +
                    '<span>' + // needed for matchCellWidths
                    htmlEscape(this.opt('weekNumberTitle')) +
                    '</span>' +
                    '</th>';
            }
        },


        // Generates the HTML that will go before content-skeleton cells that display the day/week numbers.
        // Queried by the DayGrid subcomponent. Ordering depends on isRTL.
        numberIntroHtml: function(row) {
            if (this.weekNumbersVisible) {
                return '' +
                    '<td class="fc-week-number" ' + this.weekNumberStyleAttr() + '>' +
                    '<span>' + // needed for matchCellWidths
                    this.dayGrid.getCell(row, 0).start.format('w') +
                    '</span>' +
                    '</td>';
            }
        },


        // Generates the HTML that goes before the day bg cells for each day-row.
        // Queried by the DayGrid subcomponent. Ordering depends on isRTL.
        dayIntroHtml: function() {
            if (this.weekNumbersVisible) {
                return '<td class="fc-week-number ' + this.widgetContentClass + '" ' +
                    this.weekNumberStyleAttr() + '></td>';
            }
        },


        // Generates the HTML that goes before every other type of row generated by DayGrid. Ordering depends on isRTL.
        // Affects helper-skeleton and highlight-skeleton rows.
        introHtml: function() {
            if (this.weekNumbersVisible) {
                return '<td class="fc-week-number" ' + this.weekNumberStyleAttr() + '></td>';
            }
        },


        // Generates the HTML for the <td>s of the "number" row in the DayGrid's content skeleton.
        // The number row will only exist if either day numbers or week numbers are turned on.
        numberCellHtml: function(cell) {
            var date = cell.start;
            var classes;

            if (!this.dayNumbersVisible) { // if there are week numbers but not day numbers
                return '<td/>'; //  will create an empty space above events :(
            }

            classes = this.dayGrid.getDayClasses(date);
            classes.unshift('fc-day-number');

            return '' +
                '<td class="' + classes.join(' ') + '" data-date="' + date.format() + '">' +
                date.date() +
                '</td>';
        },


        // Generates an HTML attribute string for setting the width of the week number column, if it is known
        weekNumberStyleAttr: function() {
            if (this.weekNumberWidth !== null) {
                return 'style="width:' + this.weekNumberWidth + 'px"';
            }
            return '';
        },


        // Determines whether each row should have a constant height
        hasRigidRows: function() {
            var eventLimit = this.opt('eventLimit');
            return eventLimit && typeof eventLimit !== 'number';
        },


        /* Dimensions
         ------------------------------------------------------------------------------------------------------------------*/


        // Refreshes the horizontal dimensions of the view
        updateWidth: function() {
            if (this.weekNumbersVisible) {
                // Make sure all week number cells running down the side have the same width.
                // Record the width for cells created later.
                this.weekNumberWidth = matchCellWidths(
                    this.el.find('.fc-week-number')
                );
            }
        },


        // Adjusts the vertical dimensions of the view to the specified values
        setHeight: function(totalHeight, isAuto) {
            var eventLimit = this.opt('eventLimit');
            var scrollerHeight;

            // reset all heights to be natural
            unsetScroller(this.scrollerEl);
            uncompensateScroll(this.headRowEl);

            this.dayGrid.destroySegPopover(); // kill the "more" popover if displayed

            // is the event limit a constant level number?
            if (eventLimit && typeof eventLimit === 'number') {
                this.dayGrid.limitRows(eventLimit); // limit the levels first so the height can redistribute after
            }

            scrollerHeight = this.computeScrollerHeight(totalHeight);
            this.setGridHeight(scrollerHeight, isAuto);

            // is the event limit dynamically calculated?
            if (eventLimit && typeof eventLimit !== 'number') {
                this.dayGrid.limitRows(eventLimit); // limit the levels after the grid's row heights have been set
            }

            if (!isAuto && setPotentialScroller(this.scrollerEl, scrollerHeight)) { // using scrollbars?

                compensateScroll(this.headRowEl, getScrollbarWidths(this.scrollerEl));

                // doing the scrollbar compensation might have created text overflow which created more height. redo
                scrollerHeight = this.computeScrollerHeight(totalHeight);
                this.scrollerEl.height(scrollerHeight);
            }
        },


        // Sets the height of just the DayGrid component in this view
        setGridHeight: function(height, isAuto) {
            if (isAuto) {
                undistributeHeight(this.dayGrid.rowEls); // let the rows be their natural height with no expanding
            }
            else {
                distributeHeight(this.dayGrid.rowEls, height, true); // true = compensate for height-hogging rows
            }
        },


        /* Events
         ------------------------------------------------------------------------------------------------------------------*/


        // Renders the given events onto the view and populates the segments array
        renderEvents: function(events) {
            this.dayGrid.renderEvents(events);

            this.updateHeight(); // must compensate for events that overflow the row
        },


        // Retrieves all segment objects that are rendered in the view
        getEventSegs: function() {
            return this.dayGrid.getEventSegs();
        },


        // Unrenders all event elements and clears internal segment data
        destroyEvents: function() {
            this.dayGrid.destroyEvents();

            // we DON'T need to call updateHeight() because:
            // A) a renderEvents() call always happens after this, which will eventually call updateHeight()
            // B) in IE8, this causes a flash whenever events are rerendered
        },


        /* Dragging (for both events and external elements)
         ------------------------------------------------------------------------------------------------------------------*/


        // A returned value of `true` signals that a mock "helper" event has been rendered.
        renderDrag: function(dropLocation, seg) {
            return this.dayGrid.renderDrag(dropLocation, seg);
        },


        destroyDrag: function() {
            this.dayGrid.destroyDrag();
        },


        /* Selection
         ------------------------------------------------------------------------------------------------------------------*/


        // Renders a visual indication of a selection
        renderSelection: function(range) {
            this.dayGrid.renderSelection(range);
        },


        // Unrenders a visual indications of a selection
        destroySelection: function() {
            this.dayGrid.destroySelection();
        }

    });

    ;;

    /* A month view with day cells running in rows (one-per-week) and columns
     ----------------------------------------------------------------------------------------------------------------------*/

    var MonthView = fcViews.month = BasicView.extend({

        // Produces information about what range to display
        computeRange: function(date) {
            var range = BasicView.prototype.computeRange.call(this, date); // get value from super-method
            var rowCnt;

            // ensure 6 weeks
            if (this.isFixedWeeks()) {
                rowCnt = Math.ceil(range.end.diff(range.start, 'weeks', true)); // could be partial weeks due to hiddenDays
                range.end.add(6 - rowCnt, 'weeks');
            }

            return range;
        },


        // Overrides the default BasicView behavior to have special multi-week auto-height logic
        setGridHeight: function(height, isAuto) {

            isAuto = isAuto || this.opt('weekMode') === 'variable'; // LEGACY: weekMode is deprecated

            // if auto, make the height of each row the height that it would be if there were 6 weeks
            if (isAuto) {
                height *= this.rowCnt / 6;
            }

            distributeHeight(this.dayGrid.rowEls, height, !isAuto); // if auto, don't compensate for height-hogging rows
        },


        isFixedWeeks: function() {
            var weekMode = this.opt('weekMode'); // LEGACY: weekMode is deprecated
            if (weekMode) {
                return weekMode === 'fixed'; // if any other type of weekMode, assume NOT fixed
            }

            return this.opt('fixedWeekCount');
        }

    });

    MonthView.duration = { months: 1 }; // important for prev/next

    MonthView.defaults = {
        fixedWeekCount: true
    };
    ;;

    /* A week view with simple day cells running horizontally
     ----------------------------------------------------------------------------------------------------------------------*/

    fcViews.basicWeek = {
        type: 'basic',
        duration: { weeks: 1 }
    };
    ;;

    /* A view with a single simple day cell
     ----------------------------------------------------------------------------------------------------------------------*/

    fcViews.basicDay = {
        type: 'basic',
        duration: { days: 1 }
    };
    ;;

    /* An abstract class for all agenda-related views. Displays one more columns with time slots running vertically.
     ----------------------------------------------------------------------------------------------------------------------*/
// Is a manager for the TimeGrid subcomponent and possibly the DayGrid subcomponent (if allDaySlot is on).
// Responsible for managing width/height.

    var AGENDA_DEFAULTS = {
        allDaySlot: true,
        allDayText: 'all-day',
        scrollTime: '06:00:00',
        slotDuration: '00:30:00',
        minTime: '00:00:00',
        maxTime: '24:00:00',
        slotEventOverlap: true // a bad name. confused with overlap/constraint system
    };

    var AGENDA_ALL_DAY_EVENT_LIMIT = 5;

    var AgendaView = fcViews.agenda = View.extend({

        timeGrid: null, // the main time-grid subcomponent of this view
        dayGrid: null, // the "all-day" subcomponent. if all-day is turned off, this will be null

        axisWidth: null, // the width of the time axis running down the side

        noScrollRowEls: null, // set of fake row elements that must compensate when scrollerEl has scrollbars

        // when the time-grid isn't tall enough to occupy the given height, we render an <hr> underneath
        bottomRuleEl: null,
        bottomRuleHeight: null,


        initialize: function() {
            this.timeGrid = new TimeGrid(this);

            if (this.opt('allDaySlot')) { // should we display the "all-day" area?
                this.dayGrid = new DayGrid(this); // the all-day subcomponent of this view

                // the coordinate grid will be a combination of both subcomponents' grids
                this.coordMap = new ComboCoordMap([
                    this.dayGrid.coordMap,
                    this.timeGrid.coordMap
                ]);
            }
            else {
                this.coordMap = this.timeGrid.coordMap;
            }
        },


        /* Rendering
         ------------------------------------------------------------------------------------------------------------------*/


        // Sets the display range and computes all necessary dates
        setRange: function(range) {
            View.prototype.setRange.call(this, range); // call the super-method

            this.timeGrid.setRange(range);
            if (this.dayGrid) {
                this.dayGrid.setRange(range);
            }
        },


        // Renders the view into `this.el`, which has already been assigned
        render: function() {

            this.el.addClass('fc-agenda-view').html(this.renderHtml());

            // the element that wraps the time-grid that will probably scroll
            this.scrollerEl = this.el.find('.fc-time-grid-container');
            this.timeGrid.coordMap.containerEl = this.scrollerEl; // don't accept clicks/etc outside of this

            this.timeGrid.setElement(this.el.find('.fc-time-grid'));
            this.timeGrid.renderDates();

            // the <hr> that sometimes displays under the time-grid
            this.bottomRuleEl = $('<hr class="fc-divider ' + this.widgetHeaderClass + '"/>')
                .appendTo(this.timeGrid.el); // inject it into the time-grid

            if (this.dayGrid) {
                this.dayGrid.setElement(this.el.find('.fc-day-grid'));
                this.dayGrid.renderDates();

                // have the day-grid extend it's coordinate area over the <hr> dividing the two grids
                this.dayGrid.bottomCoordPadding = this.dayGrid.el.next('hr').outerHeight();
            }

            this.noScrollRowEls = this.el.find('.fc-row:not(.fc-scroller *)'); // fake rows not within the scroller
        },


        // Unrenders the content of the view. Since we haven't separated skeleton rendering from date rendering,
        // always completely kill each grid's rendering.
        destroy: function() {
            this.timeGrid.destroyDates();
            this.timeGrid.removeElement();

            if (this.dayGrid) {
                this.dayGrid.destroyDates();
                this.dayGrid.removeElement();
            }
        },


        renderBusinessHours: function() {
            this.timeGrid.renderBusinessHours();

            if (this.dayGrid) {
                this.dayGrid.renderBusinessHours();
            }
        },


        // Builds the HTML skeleton for the view.
        // The day-grid and time-grid components will render inside containers defined by this HTML.
        renderHtml: function() {
            return '' +
                '<table>' +
                '<thead class="fc-head">' +
                '<tr>' +
                '<td class="' + this.widgetHeaderClass + '">' +
                this.timeGrid.headHtml() + // render the day-of-week headers
                '</td>' +
                '</tr>' +
                '</thead>' +
                '<tbody class="fc-body">' +
                '<tr>' +
                '<td class="' + this.widgetContentClass + '">' +
                (this.dayGrid ?
                '<div class="fc-day-grid"/>' +
                '<hr class="fc-divider ' + this.widgetHeaderClass + '"/>' :
                    ''
                ) +
                '<div class="fc-time-grid-container">' +
                '<div class="fc-time-grid"/>' +
                '</div>' +
                '</td>' +
                '</tr>' +
                '</tbody>' +
                '</table>';
        },


        // Generates the HTML that will go before the day-of week header cells.
        // Queried by the TimeGrid subcomponent when generating rows. Ordering depends on isRTL.
        headIntroHtml: function() {
            var date;
            var weekText;

            if (this.opt('weekNumbers')) {
                date = this.timeGrid.getCell(0).start;
                weekText = date.format(this.opt('smallWeekFormat'));

                return '' +
                    '<th class="fc-axis fc-week-number ' + this.widgetHeaderClass + '" ' + this.axisStyleAttr() + '>' +
                    '<span>' + // needed for matchCellWidths
                    htmlEscape(weekText) +
                    '</span>' +
                    '</th>';
            }
            else {
                return '<th class="fc-axis ' + this.widgetHeaderClass + '" ' + this.axisStyleAttr() + '></th>';
            }
        },


        // Generates the HTML that goes before the all-day cells.
        // Queried by the DayGrid subcomponent when generating rows. Ordering depends on isRTL.
        dayIntroHtml: function() {
            return '' +
                '<td class="fc-axis ' + this.widgetContentClass + '" ' + this.axisStyleAttr() + '>' +
                '<span>' + // needed for matchCellWidths
                (this.opt('allDayHtml') || htmlEscape(this.opt('allDayText'))) +
                '</span>' +
                '</td>';
        },


        // Generates the HTML that goes before the bg of the TimeGrid slot area. Long vertical column.
        slotBgIntroHtml: function() {
            return '<td class="fc-axis ' + this.widgetContentClass + '" ' + this.axisStyleAttr() + '></td>';
        },


        // Generates the HTML that goes before all other types of cells.
        // Affects content-skeleton, helper-skeleton, highlight-skeleton for both the time-grid and day-grid.
        // Queried by the TimeGrid and DayGrid subcomponents when generating rows. Ordering depends on isRTL.
        introHtml: function() {
            return '<td class="fc-axis" ' + this.axisStyleAttr() + '></td>';
        },


        // Generates an HTML attribute string for setting the width of the axis, if it is known
        axisStyleAttr: function() {
            if (this.axisWidth !== null) {
                return 'style="width:' + this.axisWidth + 'px"';
            }
            return '';
        },


        /* Dimensions
         ------------------------------------------------------------------------------------------------------------------*/


        updateSize: function(isResize) {
            this.timeGrid.updateSize(isResize);

            View.prototype.updateSize.call(this, isResize); // call the super-method
        },


        // Refreshes the horizontal dimensions of the view
        updateWidth: function() {
            // make all axis cells line up, and record the width so newly created axis cells will have it
            this.axisWidth = matchCellWidths(this.el.find('.fc-axis'));
        },


        // Adjusts the vertical dimensions of the view to the specified values
        setHeight: function(totalHeight, isAuto) {
            var eventLimit;
            var scrollerHeight;

            if (this.bottomRuleHeight === null) {
                // calculate the height of the rule the very first time
                this.bottomRuleHeight = this.bottomRuleEl.outerHeight();
            }
            this.bottomRuleEl.hide(); // .show() will be called later if this <hr> is necessary

            // reset all dimensions back to the original state
            this.scrollerEl.css('overflow', '');
            unsetScroller(this.scrollerEl);
            uncompensateScroll(this.noScrollRowEls);

            // limit number of events in the all-day area
            if (this.dayGrid) {
                this.dayGrid.destroySegPopover(); // kill the "more" popover if displayed

                eventLimit = this.opt('eventLimit');
                if (eventLimit && typeof eventLimit !== 'number') {
                    eventLimit = AGENDA_ALL_DAY_EVENT_LIMIT; // make sure "auto" goes to a real number
                }
                if (eventLimit) {
                    this.dayGrid.limitRows(eventLimit);
                }
            }

            if (!isAuto) { // should we force dimensions of the scroll container, or let the contents be natural height?

                scrollerHeight = this.computeScrollerHeight(totalHeight);
                if (setPotentialScroller(this.scrollerEl, scrollerHeight)) { // using scrollbars?

                    // make the all-day and header rows lines up
                    compensateScroll(this.noScrollRowEls, getScrollbarWidths(this.scrollerEl));

                    // the scrollbar compensation might have changed text flow, which might affect height, so recalculate
                    // and reapply the desired height to the scroller.
                    scrollerHeight = this.computeScrollerHeight(totalHeight);
                    this.scrollerEl.height(scrollerHeight);
                }
                else { // no scrollbars
                    // still, force a height and display the bottom rule (marks the end of day)
                    this.scrollerEl.height('100%').css('overflow', 'hidden'); // in case <hr> goes outside
                    this.bottomRuleEl.show();
                }
            }
        },


        // Computes the initial pre-configured scroll state prior to allowing the user to change it
        computeInitialScroll: function() {
            var scrollTime = moment.duration(this.opt('scrollTime'));
            var top = this.timeGrid.computeTimeTop(scrollTime);

            // zoom can give weird floating-point values. rather scroll a little bit further
            top = Math.ceil(top);

            if (top) {
                top++; // to overcome top border that slots beyond the first have. looks better
            }

            return top;
        },


        /* Events
         ------------------------------------------------------------------------------------------------------------------*/


        // Renders events onto the view and populates the View's segment array
        renderEvents: function(events) {
            var dayEvents = [];
            var timedEvents = [];
            var daySegs = [];
            var timedSegs;
            var i;

            // separate the events into all-day and timed
            for (i = 0; i < events.length; i++) {
                if (events[i].allDay) {
                    dayEvents.push(events[i]);
                }
                else {
                    timedEvents.push(events[i]);
                }
            }

            // render the events in the subcomponents
            timedSegs = this.timeGrid.renderEvents(timedEvents);
            if (this.dayGrid) {
                daySegs = this.dayGrid.renderEvents(dayEvents);
            }

            // the all-day area is flexible and might have a lot of events, so shift the height
            this.updateHeight();
        },


        // Retrieves all segment objects that are rendered in the view
        getEventSegs: function() {
            return this.timeGrid.getEventSegs().concat(
                this.dayGrid ? this.dayGrid.getEventSegs() : []
            );
        },


        // Unrenders all event elements and clears internal segment data
        destroyEvents: function() {

            // destroy the events in the subcomponents
            this.timeGrid.destroyEvents();
            if (this.dayGrid) {
                this.dayGrid.destroyEvents();
            }

            // we DON'T need to call updateHeight() because:
            // A) a renderEvents() call always happens after this, which will eventually call updateHeight()
            // B) in IE8, this causes a flash whenever events are rerendered
        },


        /* Dragging (for events and external elements)
         ------------------------------------------------------------------------------------------------------------------*/


        // A returned value of `true` signals that a mock "helper" event has been rendered.
        renderDrag: function(dropLocation, seg) {
            if (dropLocation.start.hasTime()) {
                return this.timeGrid.renderDrag(dropLocation, seg);
            }
            else if (this.dayGrid) {
                return this.dayGrid.renderDrag(dropLocation, seg);
            }
        },


        destroyDrag: function() {
            this.timeGrid.destroyDrag();
            if (this.dayGrid) {
                this.dayGrid.destroyDrag();
            }
        },


        /* Selection
         ------------------------------------------------------------------------------------------------------------------*/


        // Renders a visual indication of a selection
        renderSelection: function(range) {
            if (range.start.hasTime() || range.end.hasTime()) {
                this.timeGrid.renderSelection(range);
            }
            else if (this.dayGrid) {
                this.dayGrid.renderSelection(range);
            }
        },


        // Unrenders a visual indications of a selection
        destroySelection: function() {
            this.timeGrid.destroySelection();
            if (this.dayGrid) {
                this.dayGrid.destroySelection();
            }
        }

    });

    AgendaView.defaults = AGENDA_DEFAULTS;

    ;;

    /* A week view with an all-day cell area at the top, and a time grid below
     ----------------------------------------------------------------------------------------------------------------------*/

    fcViews.agendaWeek = {
        type: 'agenda',
        duration: { weeks: 1 }
    };
    ;;

    /* A day view with an all-day cell area at the top, and a time grid below
     ----------------------------------------------------------------------------------------------------------------------*/

    fcViews.agendaDay = {
        type: 'agenda',
        duration: { days: 1 }
    };
    ;;

    return fc; // export for Node/CommonJS
});
Commits for namibiapublic/js/vendor/fullcalendar.js

Revision	Author	Commited	Message
df0489 ...	Mark	Fri 14 Oct, 2016 10:01:00 +0000	initial commit
History View complete history Commits RSS feed for public/js/vendor/fullcalendar.js