/* 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);