/* ************************************************************************

   qooxdoo - the new era of web development

   http://qooxdoo.org

   Copyright:
     2007-2008 1&1 Internet AG, Germany, http://www.1und1.de

   License:
     LGPL: http://www.gnu.org/licenses/lgpl.html
     EPL: http://www.eclipse.org/org/documents/epl-v10.php
     See the LICENSE file in the project's top-level directory for details.

   Authors:
     * Sebastian Werner (wpbasti)
     * Fabian Jakobs (fjakobs)
     * Christian Hagendorn (chris_schmidt)

************************************************************************ */

/**
 * This handler provides event for the window object.
 */
qx.Class.define("qx.event.handler.Window",
{
  extend : qx.core.Object,
  implement : qx.event.IEventHandler,




  /*
  *****************************************************************************
     CONSTRUCTOR
  *****************************************************************************
  */

  /**
   * Create a new instance
   *
   * @param manager {qx.event.Manager} Event manager for the window to use
   */
  construct : function(manager)
  {
    this.base(arguments);

    // Define shorthands
    this._manager = manager;
    this._window = manager.getWindow();

    // Initialize observers
    this._initWindowObserver();
  },





  /*
  *****************************************************************************
     STATICS
  *****************************************************************************
  */

  statics :
  {
    /** {Integer} Priority of this handler */
    PRIORITY : qx.event.Registration.PRIORITY_NORMAL,

    /** {Map} Supported event types */
    SUPPORTED_TYPES :
    {
      error : 1,
      load : 1,
      beforeunload : 1,
      unload : 1,
      resize : 1,
      scroll : 1,
      beforeshutdown : 1
    },

    /** {Integer} Which target check to use */
    TARGET_CHECK : qx.event.IEventHandler.TARGET_WINDOW,

    /** {Integer} Whether the method "canHandleEvent" must be called */
    IGNORE_CAN_HANDLE : true
  },





  /*
  *****************************************************************************
     MEMBERS
  *****************************************************************************
  */

  members :
  {
    /*
    ---------------------------------------------------------------------------
      EVENT HANDLER INTERFACE
    ---------------------------------------------------------------------------
    */

    // interface implementation
    canHandleEvent : function(target, type) {},


    // interface implementation
    registerEvent : function(target, type, capture) {
      // Nothing needs to be done here
    },


    // interface implementation
    unregisterEvent : function(target, type, capture) {
      // Nothing needs to be done here
    },




    /*
    ---------------------------------------------------------------------------
      OBSERVER INIT/STOP
    ---------------------------------------------------------------------------
    */

    /**
     * Initializes the native mouse event listeners.
     *
     * @return {void}
     */
    _initWindowObserver : function()
    {
      this._onNativeWrapper = qx.lang.Function.listener(this._onNative, this);
      var types = qx.event.handler.Window.SUPPORTED_TYPES;

      for (var key in types) {
        qx.bom.Event.addNativeListener(this._window, key, this._onNativeWrapper);
      }
    },


    /**
     * Disconnect the native mouse event listeners.
     *
     * @return {void}
     */
    _stopWindowObserver : function()
    {
      var types = qx.event.handler.Window.SUPPORTED_TYPES;

      for (var key in types) {
        qx.bom.Event.removeNativeListener(this._window, key, this._onNativeWrapper);
      }
    },






    /*
    ---------------------------------------------------------------------------
      NATIVE EVENT SUPPORT
    ---------------------------------------------------------------------------
    */

    /**
     * Native listener for all supported events.
     *
     * @signature function(e)
     * @param e {Event} Native event
     */
    _onNative : qx.event.GlobalError.observeMethod(function(e)
    {
      if (this.isDisposed()) {
        return;
      }

      var win = this._window;
      try {
        var doc = win.document;
      } catch (e) {
        // IE7 sometimes dispatches "unload" events on protected windows
        // Ignore these events
        return;
      }

      var html = doc.documentElement;

      // At least Safari 3.1 and Opera 9.2.x have a bubbling scroll event
      // which needs to be ignored here.
      //
      // In recent WebKit nightlies scroll events do no longer bubble
      //
      // Internet Explorer does not have a target in resize events.
      var target = qx.bom.Event.getTarget(e);
      if (target == null || target === win || target === doc || target === html)
      {
        var event = qx.event.Registration.createEvent(e.type, qx.event.type.Native, [e, win]);
        qx.event.Registration.dispatchEvent(win, event);

        var result = event.getReturnValue();
        if (result != null)
        {
          e.returnValue = result;
          return result;
        }
      }
    })
  },





  /*
  *****************************************************************************
     DESTRUCTOR
  *****************************************************************************
  */

  destruct : function()
  {
    this._stopWindowObserver();
    this._manager = this._window = null;
  },






  /*
  *****************************************************************************
     DEFER
  *****************************************************************************
  */

  defer : function(statics) {
    qx.event.Registration.addHandler(statics);
  }
});
