/**
 * 
 * credits for this plugin go to brandonaaron.net
 * 	
 * unfortunately his site is down
 * 
 * @param {Object} up
 * @param {Object} down
 * @param {Object} preventDefault
 */
 /** 
 * Apply the mousewheel event to the elements in the jQuery object. 
 * The handler function should be prepared to take the event object 
 * and a param called 'delta'. The 'delta' param is a number 
 * either > 0 or < 0. > 0 = up and < 0 = down. 
 * 
 * The pageX, pageY, clientX and clientY event properties 
 * are fixed in Firefox. 
 * 
 * @example $("p").mousewheel(function(event, delta){ 
 *   if (delta > 0) 
 *     // do something on mousewheel scroll up 
 *   else if (delta < 0) 
 *     //do something on mousewheel scroll down 
 * }); 
 * 
 * @name mousewheel 
 * @type jQuery 
 * @param Function handler A function to call when onmousewheel fires. Should take two params: event and delta. 
 * @cat Plugins/Mousewheel 
 * @author Brandon Aaron (brandon.aaron@gmail.com || http://brandonaaron.net) 
*/ 
 
jQuery.fn.extend({
	mousewheel: function(up, down, preventDefault) {
		return this.hover(
			function() {
				jQuery.event.mousewheel.giveFocus(this, up, down, preventDefault);
			},
			function() {
				jQuery.event.mousewheel.removeFocus(this);
			}
		);
	},
	mousewheeldown: function(fn, preventDefault) {
		return this.mousewheel(function(){}, fn, preventDefault);
	},
	mousewheelup: function(fn, preventDefault) {
		return this.mousewheel(fn, function(){}, preventDefault);
	},
	unmousewheel: function() {
		return this.each(function() {
			jQuery(this).unmouseover().unmouseout();
			jQuery.event.mousewheel.removeFocus(this);
		});
	},
	unmousewheeldown: jQuery.fn.unmousewheel,
	unmousewheelup: jQuery.fn.unmousewheel
});
 
 
jQuery.event.mousewheel = {
	giveFocus: function(el, up, down, preventDefault) {
		if (el._handleMousewheel) jQuery(el).unmousewheel();
		
		if (preventDefault == window.undefined && down && down.constructor != Function) {
			preventDefault = down;
			down = null;
		}
		
		el._handleMousewheel = function(event) {
			if (!event) event = window.event;
			if (preventDefault)
				if (event.preventDefault) event.preventDefault();
				else event.returnValue = false;
			var delta = 0;
			if (event.wheelDelta) {
				delta = event.wheelDelta/120;
				if (window.opera) delta = -delta;
			} else if (event.detail) {
				delta = -event.detail/3;
			}
			if (up && (delta > 0 || !down))
				up.apply(el, [event, delta]);
			else if (down && delta < 0)
				down.apply(el, [event, delta]);
		};
		
		if (window.addEventListener)
			window.addEventListener('DOMMouseScroll', el._handleMousewheel, false);
		window.onmousewheel = document.onmousewheel = el._handleMousewheel;
	},
	
	removeFocus: function(el) {
		if (!el._handleMousewheel) return;
		
		if (window.removeEventListener)
			window.removeEventListener('DOMMouseScroll', el._handleMousewheel, false);
		window.onmousewheel = document.onmousewheel = null;
		el._handleMousewheel = null;
	}
};