/* 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);