/**

* hoverIntent is similar to jQuery's built-in "hover" function except that

* instead of firing the onMouseOver event immediately, hoverIntent checks

* to see if the user's mouse has slowed down (beneath the sensitivity

* threshold) before firing the onMouseOver event.

* 

* hoverIntent r6 // 2011.02.26 // jQuery 1.5.1+

* <http://cherne.net/brian/resources/jquery.hoverIntent.html>

* 

* hoverIntent is currently available for use in all personal or commercial 

* projects under both MIT and GPL licenses. This means that you can choose 

* the license that best suits your project, and use it accordingly.

* 

* // basic usage (just like .hover) receives onMouseOver and onMouseOut functions

* $("ul li").hoverIntent( showNav , hideNav );

* 

* // advanced usage receives configuration object only

* $("ul li").hoverIntent({

*	sensitivity: 7, // number = sensitivity threshold (must be 1 or higher)

*	interval: 100,   // number = milliseconds of polling interval

*	over: showNav,  // function = onMouseOver callback (required)

*	timeout: 0,   // number = milliseconds delay before onMouseOut function call

*	out: hideNav    // function = onMouseOut callback (required)

* });

* 

* @param  f  onMouseOver function || An object with configuration options

* @param  g  onMouseOut function  || Nothing (use configuration options object)

* @author    Brian Cherne brian(at)cherne(dot)net

*/

(function($) {

	$.fn.hoverIntent = function(f,g) {

		// default configuration options

		var cfg = {

			sensitivity: 7,

			interval: 100,

			timeout: 0

		};

		// override configuration options with user supplied object

		cfg = $.extend(cfg, g ? { over: f, out: g } : f );

		// instantiate variables

		// cX, cY = current X and Y position of mouse, updated by mousemove event

		// pX, pY = previous X and Y position of mouse, set by mouseover and polling interval

		var cX, cY, pX, pY;

		// A private function for getting mouse position

		var track = function(ev) {

			cX = ev.pageX;

			cY = ev.pageY;

		};

		// A private function for comparing current and previous mouse position

		var compare = function(ev,ob) {

			ob.hoverIntent_t = clearTimeout(ob.hoverIntent_t);

			// compare mouse positions to see if they've crossed the threshold

			if ( ( Math.abs(pX-cX) + Math.abs(pY-cY) ) < cfg.sensitivity ) {

				$(ob).unbind("mousemove",track);

				// set hoverIntent state to true (so mouseOut can be called)

				ob.hoverIntent_s = 1;

				return cfg.over.apply(ob,[ev]);

			} else {

				// set previous coordinates for next time

				pX = cX; pY = cY;

				// use self-calling timeout, guarantees intervals are spaced out properly (avoids JavaScript timer bugs)

				ob.hoverIntent_t = setTimeout( function(){compare(ev, ob);} , cfg.interval );

			}

		};

		// A private function for delaying the mouseOut function

		var delay = function(ev,ob) {

			ob.hoverIntent_t = clearTimeout(ob.hoverIntent_t);

			ob.hoverIntent_s = 0;

			return cfg.out.apply(ob,[ev]);

		};

		// A private function for handling mouse 'hovering'

		var handleHover = function(e) {

			// copy objects to be passed into t (required for event object to be passed in IE)

			var ev = jQuery.extend({},e);

			var ob = this;

			// cancel hoverIntent timer if it exists

			if (ob.hoverIntent_t) { ob.hoverIntent_t = clearTimeout(ob.hoverIntent_t); }

			// if e.type == "mouseenter"

			if (e.type == "mouseenter") {

				// set "previous" X and Y position based on initial entry point

				pX = ev.pageX; pY = ev.pageY;

				// update "current" X and Y position based on mousemove

				$(ob).bind("mousemove",track);

				// start polling interval (self-calling timeout) to compare mouse coordinates over time

				if (ob.hoverIntent_s != 1) { ob.hoverIntent_t = setTimeout( function(){compare(ev,ob);} , cfg.interval );}

			// else e.type == "mouseleave"

			} else {

				// unbind expensive mousemove event

				$(ob).unbind("mousemove",track);

				// if hoverIntent state is true, then call the mouseOut function after the specified delay

				if (ob.hoverIntent_s == 1) { ob.hoverIntent_t = setTimeout( function(){delay(ev,ob);} , cfg.timeout );}

			}

		};

		// bind the function to the two event listeners

		return this.bind('mouseenter',handleHover).bind('mouseleave',handleHover);

	};

})(jQuery);