package org.litesoft.sandbox.csapp.client.widgets;

import com.google.gwt.dom.client.*;
import com.google.gwt.user.client.Element;
import com.google.gwt.user.client.*;
import com.google.gwt.user.client.ui.*;

public class UploadWidget extends Composite implements IsWidget
{
    public interface Callback
    {
        public Image createBusyImage();

        public Widget createWaitingMessageWidget( Widget secondsRemaining );

        public void requestingUpload( String filename );

        public void timeout( String filename );

        public void parseResponse( String fileName, String pHtmlResponse );
    }

    private static int instance = 1;

    private final FileUpload upload = createFileUploadWidget();
    private final FormPanel formPanel = createFormPanel( upload );
    private final SimplePanel viewPort = createViewPort( createFormFloater( formPanel ) );
    private final ButtonBase illusionaryClickWidget;
    private final Widget sizingWidget;

    private final int secondsToWait;
    private final Callback callback;

    private boolean externallyEnabled;
    private String lastSubmittedFileName;

    private String servletPath;
    private Timer timer;
    private boolean sized = false;

    public UploadWidget( ButtonBase illusionaryClickWidget, int secondsToWait, Callback callback )
    {
        this.secondsToWait = secondsToWait;
        this.callback = callback;
        externallyEnabled = illusionaryClickWidget.isEnabled();
        sizingWidget = createConstrainer( this.illusionaryClickWidget = illusionaryClickWidget );
        initWidget( createStylingDiv( "UploadWidget", createConstrainer( createFlowPanel( sizingWidget, viewPort ) ) ) );

        //<div style="display: block; width: 100px; height: 20px; overflow: hidden;">
        //<button style="width: 110px; height: 30px; position: relative; top: -5px; left: -5px;"><a href="javascript: void(0)">Upload File</a></button>
        //<input type="file" id="upload_input" name="upload" style="font-size: 50px; width: 120px; opacity: 0; filter:alpha(opacity: 0);  position: relative; top: -40px;; left: -20px" />
        //</div>

        formPanel.addSubmitCompleteHandler( new FormPanel.SubmitCompleteHandler()
        {
            @Override
            public void onSubmitComplete( FormPanel.SubmitCompleteEvent event )
            {
                submitResponse( event.getResults() );
            }
        } );
    }

    public void setServletPath( String url )
    {
        servletPath = noEmpty( url );
    }

    public void setEnabled( boolean enable )
    {
        enableWidgets( externallyEnabled = enable );
    }

    private void enableWidgets( boolean enable )
    {
        enable &= externallyEnabled;
        illusionaryClickWidget.setEnabled( enable );
        upload.setEnabled( enable );
    }

    @Override
    protected void onAttach()
    {
        super.onAttach();
        startTimer();
    }

    @Override
    protected void onDetach()
    {
        stopTimer();
        super.onDetach();
    }

    private void stopTimer()
    {
        if ( timer != null )
        {
            timer.cancel();
            timer = null;
        }
    }

    private void startTimer()
    {
        stopTimer();
        (timer = new Timer()
        {
            @Override
            public void run()
            {
                sized = sized || size();
                String filename = noEmpty( upload.getFilename() );
                if ( filename != null )
                {
                    stopTimer();
                    submitForm( lastSubmittedFileName = filename );
                }
            }
        }).scheduleRepeating( 250 );
    }

    private boolean size()
    {
        int width = sizingWidget.getOffsetWidth();
        int height = sizingWidget.getOffsetHeight();
        if ( (width < 16) || (height < 16) )
        {
            return false;
        }
        viewPort.setSize( width + "px", height + "px" );
        return true;
    }

    private void resetUploadWidget()
    {
        enableWidgets( true );
        formPanel.reset();
        startTimer();
    }

    private String noEmpty( String string )
    {
        if ( string != null )
        {
            if ( (string = string.trim()).length() != 0 )
            {
                return string;
            }
        }
        return null;
    }

    private void submitForm( String filename )
    {
        System.out.println( "UploadWidget.submitForm: " + filename + " to " + servletPath );
        if ( servletPath == null )
        {
            Window.alert( "No Servlet Path Set" );
            return;
        }
        callback.requestingUpload( filename );
        formPanel.setAction( servletPath );
        formPanel.submit();
        enableWidgets( false );
        showBusy();
    }

    private void timeout()
    {
        hideBusy();
        resetUploadWidget();
        callback.timeout( lastSubmittedFileName );
    }

    private void submitResponse( String htmlResponse )
    {
        hideBusy();
        resetUploadWidget();
        callback.parseResponse( lastSubmittedFileName, htmlResponse );
    }

    private static Widget createConstrainer( Widget widget )
    {
        HorizontalPanel constrainer = new HorizontalPanel();
        constrainer.add( widget );
        return constrainer;
    }

    private static Widget createStylingDiv( String styleName, Widget widget )
    {
        SimplePanel divBasePanel = new SimplePanel();
        divBasePanel.addStyleName( styleName );
        divBasePanel.setWidget( widget );
        return divBasePanel;
    }

    private static Widget createFlowPanel( Widget widget1, Widget widget2 )
    {
        FlowPanel panel = new FlowPanel();
        panel.getElement().getStyle().setPosition( Style.Position.RELATIVE );
        panel.add( widget1 );
        panel.add( widget2 );
        return panel;
    }

    private static SimplePanel createViewPort( Widget widget )
    {
        SimplePanel viewPort = new SimplePanel();
        Element element = viewPort.getElement();
        Style style = element.getStyle();
        style.setPosition( Style.Position.ABSOLUTE );
        style.setLeft( 0, Style.Unit.PX );
        style.setTop( 0, Style.Unit.PX );
        style.setOverflow( Style.Overflow.HIDDEN );
        viewPort.setWidget( widget );
        viewPort.setSize( "1px", "1px" );
        return viewPort;
    }

    private static SimplePanel createFormFloater( Widget widget )
    {
        SimplePanel panel = new SimplePanel();
        panel.setSize( "1000px", "400px" );
        Style style = panel.getElement().getStyle();
        style.setPosition( Style.Position.RELATIVE );
        style.setLeft( -600, Style.Unit.PX );
        style.setTop( -5, Style.Unit.PX );
        panel.setWidget( createConstrainer( widget ) );
        return panel;
    }

    private static FormPanel createFormPanel( FileUpload upload )
    {
        FormPanel form = new FormPanel();
        form.add( upload );
        Style style = form.getElement().getStyle();
        style.setMargin( 0, Style.Unit.PX );
        style.setPadding( 0, Style.Unit.PX );
        // Because we're going to add a FileUpload widget, we'll need to set the
        // form to use the POST method, and multipart MIME encoding.
        form.setEncoding( FormPanel.ENCODING_MULTIPART );
        form.setMethod( FormPanel.METHOD_POST );
        return form;
    }

    private static FileUpload createFileUploadWidget()
    {
        FileUpload upload = new FileUpload();
        upload.setName( "UploadWidget" + instance++ );
        upload.getElement().setAttribute( "size", "1" );
        upload.setSize( "1000px", "400px" );
        Style style = upload.getElement().getStyle();
        style.setMargin( 0, Style.Unit.PX );
        style.setPadding( 0, Style.Unit.PX );
        style.setBorderWidth( 0, Style.Unit.PX );
        style.setFontSize( 200, Style.Unit.PX );
        style.setOpacity( 0 ); // Tested w/ FireFox & IE8!
        return upload;
    }

    protected void hideBusy()
    {
        if ( busyPopup != null )
        {
            busyPopup.hide();
            busyPopup = null;
        }
    }

    protected void showBusy()
    {
        hideBusy();
        (busyPopup = new OurBusyPopup()).setPopupPositionAndShow( new PopupPanel.PositionCallback()
        {
            @Override
            public void setPosition( int offsetWidth, int offsetHeight )
            {
                int left = (Window.getClientWidth() - offsetWidth) / 2;
                int top = (Window.getClientHeight() - offsetHeight) / 2;
                busyPopup.setPopupPosition( left, top );
            }
        } );
    }

    private OurBusyPopup busyPopup;

    private class OurBusyPopup extends PopupPanel
    {
        private Widget messageWidget;
        private boolean messageShowing = false;
        private int secondsRemaining = secondsToWait;
        private Label secondsRemainingLabel = new Label( "" + secondsRemaining );
        private long started = System.currentTimeMillis();
        private float currentOpacity = 0;
        private Timer timer;

        private OurBusyPopup()
        {
            setModal( true );
            setGlassEnabled( true );
            getGlassElement().getStyle().setBackgroundColor( "#fff" );
            getGlassElement().getStyle().setCursor( Style.Cursor.WAIT );
            getGlassElement().getStyle().setOpacity( currentOpacity );

            VerticalPanel outerpanel = new VerticalPanel();
            outerpanel.setStyleName( "UploadWidgetBusyContainer" );
            outerpanel.setHorizontalAlignment( HasHorizontalAlignment.ALIGN_CENTER );
            Image busyImage = callback.createBusyImage();
            if ( busyImage != null )
            {
                outerpanel.add( busyImage );
            }
            outerpanel.add( createStylingDiv( "UploadWidgetBusyMessage", callback.createWaitingMessageWidget( secondsRemainingLabel ) ) );
            outerpanel.getElement().getStyle().setVisibility( Style.Visibility.HIDDEN );
            setWidget( messageWidget = outerpanel );
            startTimer();
        }

        @Override
        public void hide()
        {
            stopTimer();
            super.hide();
        }

        private void stopTimer()
        {
            if ( timer != null )
            {
                timer.cancel();
                timer = null;
            }
        }

        private void startTimer()
        {
            stopTimer();
            (timer = new Timer()
            {
                @Override
                public void run()
                {
                    if ( currentOpacity < 0.75 )
                    {
                        getGlassElement().getStyle().setOpacity( currentOpacity += 0.025 );
                    }
                    int secondsPassed = (int) ((System.currentTimeMillis() - started) / 1000);
                    if ( (secondsPassed > 1) && !messageShowing )
                    {
                        messageShowing = true;
                        messageWidget.getElement().getStyle().setVisibility( Style.Visibility.VISIBLE );
                    }
                    int calcSecondsRemaining = secondsToWait - secondsPassed;
                    if ( calcSecondsRemaining < 1 )
                    {
                        stopTimer();
                        timeout();
                        return;
                    }
                    if ( calcSecondsRemaining != secondsRemaining )
                    {
                        secondsRemainingLabel.setText( (secondsRemaining = calcSecondsRemaining) + "" );
                    }
                }
            }).scheduleRepeating( 100 );
        }
    }
}