/*! Copyright (c) 2008 Brandon Aaron (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.
*
* Version: 3.0.1-pre
*
* Requires: 1.2.2+
*
* zyt: modified the delta for safari and removed Opera delta inversion. See:
* http://plugins.jquery.com/node/4413
*/

(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) {
        // safari has a wierd delta it seems
        delta = event.wheelDelta / ($.browser.safari ? 720 : 120);
    }
    if (event.detail) { delta = -event.detail / 2; }

    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);