/* Copyright (c) 2006 Brandon Aaron (brandon.aaron@gmail.com || http://brandonaaron.net)
* Dual licensed under the MIT (http://www.opensource.org/licenses/mit-license.php)
* and GPL (http://www.opensource.org/licenses/gpl-license.php) licenses.
* Thanks to: http://adomas.org/javascript-mouse-wheel/ for some pointers.
* Thanks to: Mathias Bank(http://www.mathias-bank.de) for a scope bug fix.
*
* $LastChangedDate: 2007-12-20 09:02:08 -0600 (Thu, 20 Dec 2007) $
* $Rev: 4265 $
*
* Version: 3.0
* 
* Requires: $ 1.2.2+
*/

(function($) {

  $.event.special.mousewheel = {
    setup: function() {
      var handler = $.event.special.mousewheel.handler;

      // Fix pageX, pageY, clientX and clientY for mozilla
      if ($.browser.mozilla)
        $(this).bind('mousemove.mousewheel', function(event) {
          $.data(this, 'mwcursorposdata', {
            pageX: event.pageX,
            pageY: event.pageY,
            clientX: event.clientX,
            clientY: event.clientY
          });
        });

      if (this.addEventListener)
        this.addEventListener(($.browser.mozilla ? 'DOMMouseScroll' : 'mousewheel'), handler, false);
      else
        this.onmousewheel = handler;
    },

    teardown: function() {
      var handler = $.event.special.mousewheel.handler;

      $(this).unbind('mousemove.mousewheel');

      if (this.removeEventListener)
        this.removeEventListener(($.browser.mozilla ? 'DOMMouseScroll' : 'mousewheel'), handler, false);
      else
        this.onmousewheel = function() { };

      $.removeData(this, 'mwcursorposdata');
    },

    handler: function(event) {
      var args = Array.prototype.slice.call(arguments, 1);

      event = $.event.fix(event || window.event);
      // Get correct pageX, pageY, clientX and clientY for mozilla
      $.extend(event, $.data(this, 'mwcursorposdata') || {});
      var delta = 0, returnValue = true;

      if (event.wheelDelta) delta = event.wheelDelta / 120;
      if (event.detail) delta = -event.detail / 3;
      //		if ( $.browser.opera  ) delta = -event.wheelDelta;

      event.data = event.data || {};
      event.type = "mousewheel";

      // Add delta to the front of the arguments
      args.unshift(delta);
      // Add event to the front of the arguments
      args.unshift(event);

      return $.event.handle.apply(this, args);
    }
  };

  $.fn.extend({
    mousewheel: function(fn) {
      return fn ? this.bind("mousewheel", fn) : this.trigger("mousewheel");
    },

    unmousewheel: function(fn) {
      return this.unbind("mousewheel", fn);
    }
  });

})(jQuery);