/**********************************************
    * Copyright (C) 2011 Lukas Laag
    * This file is part of svgreal.
    * 
    * svgreal is free software: you can redistribute it and/or modify
    * it under the terms of the GNU General Public License as published by
    * the Free Software Foundation, either version 3 of the License, or
    * (at your option) any later version.
    * 
   * svgreal is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   * 
   * You should have received a copy of the GNU General Public License
   * along with svgreal.  If not, see http://www.gnu.org/licenses/
   **********************************************/
  package org.vectomatic.svg.edit.client.gxt.widget;
  
  import org.vectomatic.svg.edit.client.SvgrealApp;
  import org.vectomatic.svg.edit.client.load.DndHandler;
  
  import com.extjs.gxt.ui.client.widget.Viewport;
  import com.google.gwt.dom.client.NativeEvent;
  import com.google.gwt.event.dom.client.DomEvent;
  import com.google.gwt.event.dom.client.DragEnterEvent;
  import com.google.gwt.event.dom.client.DragEnterHandler;
  import com.google.gwt.event.dom.client.DragLeaveEvent;
  import com.google.gwt.event.dom.client.DragLeaveHandler;
  import com.google.gwt.event.dom.client.DragOverEvent;
  import com.google.gwt.event.dom.client.DragOverHandler;
  import com.google.gwt.event.dom.client.DropEvent;
  import com.google.gwt.event.dom.client.DropHandler;
  import com.google.gwt.event.dom.client.HasDragEnterHandlers;
  import com.google.gwt.event.dom.client.HasDragLeaveHandlers;
  import com.google.gwt.event.dom.client.HasDragOverHandlers;
  import com.google.gwt.event.dom.client.HasDropHandlers;
  import com.google.gwt.event.shared.GwtEvent;
  import com.google.gwt.event.shared.HandlerRegistration;
  import com.google.gwt.user.client.Element;
  
  /**
   * A viewport class with support for drag and drop of external files.
   * @author laaglu
   */
  public class ViewportExt extends Viewport implements HasDropHandlers, HasDragEnterHandlers, HasDragLeaveHandlers, HasDragOverHandlers {
  	public ViewportExt() {
  		new DndHandler(this);
  	}
  	public void setElement(Element elem) {
  		super.setElement(elem);
  		setup(elem);
  	}
  	
  	private final native void setup(Element elem) /*-{
  	    var x = this;
  		var handler = function(evt) {
  	        x.@org.vectomatic.svg.edit.client.gxt.widget.ViewportExt::dispatch(Lcom/google/gwt/dom/client/NativeEvent;)(evt);
  		};
  		elem.addEventListener("dragenter", handler, false);
  		elem.addEventListener("dragleave", handler, false);
  		elem.addEventListener("dragover", handler, false);
  		elem.addEventListener("drop", handler, false);
  	}-*/;
  	
  	public void fireEvent(GwtEvent<?> event) {
  		revive(event);
  		SvgrealApp.getApp().getEventBus().fireEventFromSource(event, this);
  	}
  	/**
  	 * Revive the event. GWT does it by taking advantage of the
  	 * fact that HandlerManager has package access to GwtEvent.
  	 * Here we use a JSNI call to bypass scope restrictions
  	 */
  	private static final native void revive(GwtEvent<?> event) /*-{
  	  event.@com.google.gwt.event.shared.GwtEvent::revive()();
  	}-*/;
  	
  	/**
  	 * Dispatches the specified event to this node
  	 * event handlers
  	 * @param event The event to dispatch
  	 */
  	public void dispatch(NativeEvent event) {
  		// This call wraps the native event into a DomEvent
  		// and invokes fireEvent
  	    DomEvent.fireNativeEvent(event, this, (Element)event.getCurrentEventTarget().cast());
  	}
  
  	@Override
  	public HandlerRegistration addDropHandler(DropHandler handler) {
  		return SvgrealApp.getApp().getEventBus().addHandlerToSource(DropEvent.getType(), this, handler);
  	}
  
  	@Override
  	public HandlerRegistration addDragLeaveHandler(DragLeaveHandler handler) {
  		return SvgrealApp.getApp().getEventBus().addHandlerToSource(DragLeaveEvent.getType(), this, handler);
  	}
  
 	@Override
 	public HandlerRegistration addDragEnterHandler(DragEnterHandler handler) {
 		return SvgrealApp.getApp().getEventBus().addHandlerToSource(DragEnterEvent.getType(), this, handler);
 	}
 
 	@Override
 	public HandlerRegistration addDragOverHandler(DragOverHandler handler) {
 		return SvgrealApp.getApp().getEventBus().addHandlerToSource(DragOverEvent.getType(), this, handler);
 	}
 
 }