/**
    * This file Copyright (c) 2012-2013 Magnolia International
    * Ltd.  (http://www.magnolia-cms.com). All rights reserved.
    *
    *
    * This file is dual-licensed under both the Magnolia
    * Network Agreement and the GNU General Public License.
    * You may elect to use one or the other of these licenses.
    *
   * This file is distributed in the hope that it will be
   * useful, but AS-IS and WITHOUT ANY WARRANTY; without even the
   * implied warranty of MERCHANTABILITY or FITNESS FOR A
   * PARTICULAR PURPOSE, TITLE, or NONINFRINGEMENT.
   * Redistribution, except as permitted by whichever of the GPL
   * or MNA you select, is prohibited.
   *
   * 1. For the GPL license (GPL), you can redistribute and/or
   * modify this file under the terms of the GNU General
   * Public License, Version 3, as published by the Free Software
   * Foundation.  You should have received a copy of the GNU
   * General Public License, Version 3 along with this program;
   * if not, write to the Free Software Foundation, Inc., 51
   * Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
   *
   * 2. For the Magnolia Network Agreement (MNA), this file
   * and the accompanying materials are made available under the
   * terms of the MNA which accompanies this distribution, and
   * is available at http://www.magnolia-cms.com/mna.html
   *
   * Any modifications to this file must keep this entire header
   * intact.
   *
   */
  package info.magnolia.ui.vaadin.gwt.client.editor.jsni;
  
  import info.magnolia.ui.vaadin.gwt.client.widget.PageEditorView;
  
  import com.google.gwt.core.client.GWT;
  import com.google.gwt.dom.client.Document;
  import com.google.gwt.dom.client.Element;
  import com.google.gwt.dom.client.NativeEvent;
  import com.google.gwt.event.dom.client.DomEvent;
  import com.google.gwt.event.dom.client.LoadEvent;
  import com.google.gwt.event.dom.client.LoadHandler;
  import com.google.gwt.user.client.Timer;
  import com.google.gwt.user.client.ui.Frame;
  
  /**
   * WebkitFrameEventHandler. Provides separated implementations to overcome different bugs in the
   * handling of iframes on webkit browsers including the iPad.
   * See SCRUM-1593 for details.
   */
  public class WebkitFrameEventHandler extends AbstractFrameEventHandler {
  
      private MyTimer timer = new MyTimer();
      private boolean loaded = false;
      private int touchStartY = 0;
  
      @Override
      public void init() {
          registerLoadHandler();
      }
  
      @Override
      public void onFrameReady() {
          super.onFrameReady();
          timer.cancel();
          registerUnloadHandler(getView().getFrame().getElement(), timer);
      }
  
      /**
       * Registers two separated implementations of an onload event.
       * In case the onload is not triggered it's supposed to fallback on a readystate poller.
       * We have to make sure, that they don't interfere by using a loaded boolean.
       */
      public void registerLoadHandler() {
          Frame frame = getView().getFrame();
  
          frame.addLoadHandler(new LoadHandler() {
              @Override
              public void onLoad(LoadEvent event) {
                  if (loaded) {
                      return;
                  }
                  loaded = true;
                  onFrameReady();
              }
          });
          timer.setIframe(frame);
          timer.scheduleRepeating(100);
  
      }
  
      @Override
      public void notifyUrlChange() {
          loaded = false;
          timer.scheduleRepeating(100);
      }
  
     /**
      * This function is supposed to trigger an unload event, when the page inside the Iframe is changed.
      * Doesn't work, that's why browsing inside the iframe is broken for webkit.
      */
     public native void registerUnloadHandler(Element element, Timer timer) /*-{
         var that = timer;
         var poll = function(){
             that.@com.google.gwt.user.client.Timer::scheduleRepeating(I)(100);
         };
 
         element.contentWindow.addEventListener('unload', poll, false);
 
     }-*/;
 
     /**
      * Custom implementation for iPads of the touch end handling. Suppresses the selection, when scrolling.
      */
     @Override
     public native void initNativeTouchSelectionListener(Element element, PageEditorView.Listener listener) /*-{
         if (element != 'undefined') {
             var ref = this;
             var that = listener;
             var wndRef = $wnd;
             element.ontouchend = function(event) {
                 var touchEndY = event.changedTouches[0].pageY;
                 var touchStartY = ref.@info.magnolia.ui.vaadin.gwt.client.editor.jsni.WebkitFrameEventHandler::touchStartY;
                 if (Math.abs(touchEndY - touchStartY) < 5) {
                     that.@info.magnolia.ui.vaadin.gwt.client.widget.PageEditorView.Listener::selectElement(Lcom/google/gwt/dom/client/Element;)(event.target);
                 }
             }
 
             element.ontouchstart = function(event) {
                 ref.@info.magnolia.ui.vaadin.gwt.client.editor.jsni.WebkitFrameEventHandler::touchStartY = event.targetTouches[0].pageY;
             }
 
         }
     }-*/;
 
     @Override
     public native void initNativeKeyListener(Element element) /*-{
         if (element != 'undefined') {
             element.onkeydown = function(event) {
                 var eventObj = document.createEventObject ?
                     document.createEventObject() : document.createEvent("Events");
 
                 if(eventObj.initEvent){
                     eventObj.initEvent("keydown", true, true);
                 }
 
                 eventObj.keyCode = event.keyCode;
                 eventObj.which = event.keyCode;
 
                 element.dispatchEvent ? element.dispatchEvent(eventObj) : element.fireEvent("onkeydown", eventObj);
 
                 element.dispatchEvent(event);
             }
         }
     }-*/;
 
     /**
      * Poller to check the readystate of the contentdocument in the iframe.
      */
     private class MyTimer extends Timer {
 
         Frame iframe;
 
         @Override
         public void run() {
             GWT.log("timer started");
             String readyState = getReadyState(iframe.getElement());
 
             if (readyState != null && !readyState.isEmpty()) {
                 GWT.log("doc.readyState" + readyState);
             }
 
             if ("interactive".equals(readyState)) {
                 NativeEvent event = Document.get().createLoadEvent();
                 DomEvent.fireNativeEvent(event, iframe);
             }
         }
 
         public void setIframe(Frame iframe) {
             this.iframe = iframe;
         }
 
         public final native String getReadyState(Element element) /*-{
             if (element.contentWindow != null) {
                 return element.contentWindow.document.readyState;
             }
             return '';
         }-*/;
     }
 }