/**
 * 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 r5 // 2007.03.27 // jQuery 1.1.2+
 * <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
 * $("ul li").hoverIntent({
 *sensitivity: 7, // number = sensitivity threshold (must be 1 or higher)
 *interval: 100,   // number = milliseconds of polling interval
 *over: showNav,  // function = onMouseOver callback (required)
 *timeout: 0,   // number = milliseconds delay before onMouseOut function call
 *out: hideNav    // function = onMouseOut callback (required)
 * });
 * 
 * @param  f  onMouseOver function || An object with configuration options
 * @param  g  onMouseOut function  || Nothing (use configuration options object)
 * @author    Brian Cherne <brian@cherne.net>
 */
(function($) {
    $.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) {
	    // next three lines copied from jQuery.hover, ignore children onMouseOver/onMouseOut
	    var p = (e.type == "mouseover" ? e.fromElement : e.toElement) || e.relatedTarget;
	    while ( p && p != this ) { try { p = p.parentNode; } catch(e) { p = this; } }
	    if ( p == this ) { return false; }

	    // 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); }

	    // else e.type == "onmouseover"
	    if (e.type == "mouseover") {
		// 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 == "onmouseout"
	    } 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.mouseover(handleHover).mouseout(handleHover);
    };
})(jQuery);