/* 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: 2007-06-20 16:25:35 -0500 (Wed, 20 Jun 2007) $
 * $Rev: 2125 $
 *
 * Version: 2.2
 */
(function($){
    $.fn.extend({
        mousewheel: function(f){
            if (!f.guid) 
                f.guid = $.event.guid++;
            if (!$.event._mwCache) 
                $.event._mwCache = [];
            return this.each(function(){
                if (this._mwHandlers) 
                    return this._mwHandlers.push(f);
                else 
                    this._mwHandlers = [];
                this._mwHandlers.push(f);
                var s = this;
                this._mwHandler = function(e){
                    e = $.event.fix(e || window.event);
                    $.extend(e, this._mwCursorPos ||
                    {});
                    var delta = 0, returnValue = true;
                    if (e.wheelDelta) 
                        delta = e.wheelDelta / 120;
                    if (e.detail) 
                        delta = -e.detail / 3;
                    if (window.opera) 
                        delta = -e.wheelDelta;
                    for (var i = 0; i < s._mwHandlers.length; i++) 
                        if (s._mwHandlers[i]) 
                            if (s._mwHandlers[i].call(s, e, delta) === false) {
                                returnValue = false;
                                e.preventDefault();
                                e.stopPropagation();
                            }
                    return returnValue;
                };
                if ($.browser.mozilla && !this._mwFixCursorPos) {
                    this._mwFixCursorPos = function(e){
                        this._mwCursorPos = {
                            pageX: e.pageX,
                            pageY: e.pageY,
                            clientX: e.clientX,
                            clientY: e.clientY
                        };
                    };
                    $(this).bind('mousemove', this._mwFixCursorPos);
                }
                if (this.addEventListener) 
                    if ($.browser.mozilla) 
                        this.addEventListener('DOMMouseScroll', this._mwHandler, false);
                    else 
                        this.addEventListener('mousewheel', this._mwHandler, false);
                else 
                    this.onmousewheel = this._mwHandler;
                $.event._mwCache.push($(this));
            });
        },
        unmousewheel: function(f){
            return this.each(function(){
                if (f && this._mwHandlers) {
                    for (var i = 0; i < this._mwHandlers.length; i++) 
                        if (this._mwHandlers[i] && this._mwHandlers[i].guid == f.guid) 
                            delete this._mwHandlers[i];
                }
                else {
                    if ($.browser.mozilla && !this._mwFixCursorPos) 
                        $(this).unbind('mousemove', this._mwFixCursorPos);
                    if (this.addEventListener) 
                        if ($.browser.mozilla) 
                            this.removeEventListener('DOMMouseScroll', this._mwHandler, false);
                        else 
                            this.removeEventListener('mousewheel', this._mwHandler, false);
                    else 
                        this.onmousewheel = null;
                    this._mwHandlers = this._mwHandler = this._mwFixCursorPos = this._mwCursorPos = null;
                }
            });
        }
    });
    $(window).one('unload', function(){
        var els = $.event._mwCache || [];
        for (var i = 0; i < els.length; i++) 
            els[i].unmousewheel();
    });
})(jQuery);