// This Source Code is in the Public Domain per: http://unlicense.org
package org.litesoft.GWT.client.ui.inspection;

import org.litesoft.GWT.client.*;
import org.litesoft.GWT.client.widgets.*;
import org.litesoft.GWT.client.widgets.nonpublic.*;

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

public class WidgetFinder {
    private WidgetSelector mSelector;

    private WidgetFinder( WidgetSelector pSelector ) {
        mSelector = pSelector;
    }

    /**
     * @throws ClassCastException if the returned object is incompatible with <code>T</code>
     */
    @SuppressWarnings("unchecked")
    public static <T extends Widget> T findRequired( Object pWhat, WidgetSelector pSelector ) {
        T zWidget = (T) find( pSelector );
        if ( zWidget == null ) {
            AlertManager.alert( "WidgetFinder", "Not Found", "No Widget Found for: \n" + pWhat );
        }
        return zWidget;
    }

    public static Widget find( WidgetSelector pSelector ) {
        return (pSelector != null) ? new WidgetFinder( pSelector ).check( RootPanel.get(), WindowSizingPanel.get() ) : null;
    }

    private Widget check( Widget pWidget1, Widget pWidget2 ) {
        Widget zWidget = check( pWidget1 );
        return (zWidget != null) ? zWidget : check( pWidget2 );
    }

    private Widget check( Widget pWidget ) {
        if ( pWidget != null ) {
            if ( mSelector.isAcceptable( pWidget ) ) {
                return pWidget;
            }
            if ( pWidget instanceof HasWidgets ) {
                for ( Widget zWidget : (HasWidgets) pWidget ) {
                    if ( null != (zWidget = check( zWidget )) ) {
                        return zWidget;
                    }
                }
            } else if ( pWidget instanceof WidgetCompositor ) {
                for ( Widget zWidget : ((WidgetCompositor) pWidget).getCompositedWidgets() ) {
                    if ( null != (zWidget = check( zWidget )) ) {
                        return zWidget;
                    }
                }
            }
        }
        return null;
    }
}