/**
* 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);