/* 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);