/* 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);