/* 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 / 1220;
		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);