/**
 *
 * Use :
 * $(selector).hoverintent(myEnterFunction, myLeaveFunction [, options]);
 * $(selector).mouseenterintent(myFunction [, options]);
 * $(selector).mouseleaveintent(myFunction [, options]);
 * $(selector).bind('mouseenterintent' [, options], myFunction);
 * $(selector).bind('mouseleaveintent' [, options], myFunction);
 *
 * Options :
 *   maxSpeed           : (default: 150) mouse cursor must go slower than this maximum mouse speed (pixels/s)
 *   enterTimeout       : (default: 500) if mouse cursor stay this time (ms) inside the element the enter event is triggered
 *   leaveTimeout       : (default: 300) if mouse cursor go out of the element more than this time (ms) the leave event is triggered
 *   checkSpeedInterval : (default: 40) interval for mouse speed checks (can't be lower than 10)
 *
 *
 * This script was inspired by a script written by : Brian Cherne <brian@cherne.net>
 *
 * Free to use, free to study, free to change, free to redistibute
 *
 * @author  : Nicolas Deveaud <nicolas@deveaud.fr>
 * @version : 1.1 (realease date: jan 02 2010)
 */

(function(window, $, undef) {
	if($ === undef) {
		throw 'Dépendence non satisfaite : jQuery';
	}

	var HoverIntent = function(elem, options) {
		var $this = $(elem).data('hoverintent'),
		timeoutEnter,
		timeoutLeave,
		checkSpeedInterval,

		inside,

		event,

		cur = {},
		prv = {},

		// Triggers the event
		triggerEvent = function() {
			inside = !inside;
			event.type = inside ? 'mouseenterintent' : 'mouseleaveintent';
			$.event.handle.call(elem, event);
		},

		// for mouseEnter, we have some things to do before throwing the event
		triggerMouseEnter = function() {
			stopEnterEngine();
			triggerEvent();
		},

		// Some things to be done before throwing the mouse enter event, or when mouse enter is aborted :
		//		Stop cheking speed every [options.checkSpeedInterval]ms
		//		Abort enter timeout
		//		Stop mousemove event handling
		stopEnterEngine = function() {
			window.clearInterval(checkSpeedInterval);
			window.clearTimeout(timeoutEnter);
			$(elem).unbind('mousemove', mousemove);
			prv = {};
		},

		// Every [options.checkSpeedInterval]ms, wee check mouse speed. If it's lower than [options.maxSpeed]px/s the event is thrown
		checkSpeed = function() {
			if(prv.X !== undef && prv.Y !== undef) {
				var speed = (Math.sqrt( Math.pow(prv.X-cur.X, 2) + Math.pow(prv.Y-cur.Y, 2) ) / options.checkSpeedInterval) * 1000;
				if(speed <= options.maxSpeed) {
					triggerMouseEnter();
				}
			}
			prv.X = cur.X;
			prv.Y = cur.Y;
		},

		// When the "enter engine" is started, on every mouse move, the cursor location is register to be able to get the mouse speed
		mousemove = function(e) {
			cur.X = e.pageX;
			cur.Y = e.pageY;
		},

		// What to do when mouse cursor enters or leaves the HTML object (real event, not intent)
		hoverHandler = function(e) {
			// Register the event to be thrown
			event = e;

			// Abort entering
			stopEnterEngine();
			// Stops the leave timeout if it has been started
			window.clearTimeout(timeoutLeave);

			if(e.type === 'mouseenter' && !inside) {
				// start the enter engine :
				//		start handling mousemove event
				//		each [options.checkSpeedInterval]ms => check speed
				//		after [options.enterTimeout]ms without leaving => trigger the enter event

				// If maxSpeed is set to negative, no speed check, only timeout will work
				if(options.maxSpeed >= 0) {
					$(elem).mousemove(mousemove);
					checkSpeedInterval = window.setInterval(checkSpeed, options.checkSpeedInterval);
				}
				timeoutEnter = window.setTimeout(triggerMouseEnter, options.enterTimeout);
			}
			else if(e.type === 'mouseleave' && inside) {
				// Start leave timeout that will throw the event, unless mouse enters before timeout ends
				timeoutLeave = window.setTimeout(triggerEvent, options.leaveTimeout);
			}
		},

		init = function() {
			options = $.extend({
				maxSpeed		: -1,
				enterTimeout	: 0,
				leaveTimeout	: 0
			}, options);

			// It's useless, and probably bad for perfs to have a value under 10 for speed check interval. So bad values are not used
			if(!options.checkSpeedInterval || options.checkSpeedInterval < 10) {
				options.checkSpeedInterval = 10;
			}

			// Start handling mouseenter and mouseleave events
			$(elem)
				.bind('mouseenter mouseleave', hoverHandler)
				// register instance for later use (options change, unbinding)
				.data('hoverintent', this);
		};

		this.changeOptions = function(opt) {
			for(var i in opt) {
				if(typeof opt[i] === 'number') {
					options[i] = opt[i];
				}
			}
		};

		this.unbind = function(eventName) {
			if(eventName === 'enter') {
				options.enterTimeout = 0;
				options.maxSpeed = -1; // no need to check speed => better for perfs
			}
			else if(eventName === 'leave') {
				options.leaveTimeout = 0;
			}
			// Il n'est peut-être pas bond  de couper  les captures d'événements.
			// Si j'ai des timeout à 0, cela revient à un hover simple. Et si j'unbind le
			// enterintent seulement par exemple, avec les unbind je vais me retrouver sans
			// leaveintent non plus... Alors que je voudrait qu'il se comporte toujours comme
			// un leave normal.
/*			if(options.enterTimeout === 0 && options.leaveTimeout === 0) {
				$(elem)
					.unbind('mousemove', mousemove)
					.unbind('mouseleave mouseenter', hoverHandler)
					.removeData('hoverintent');
			}
*/		};

		// If an instance already exists for this element, we don't create a new one, we just adapt options if needed
		if($this && typeof $this.changeOptions === 'function') {
			$this.changeOptions(options);
			return $this;
		}

		init.call(this);
	};

	// Shortcut function to declare both enter and leave special events
	var specialEventSetter = function(eventName, defaultValues) {
		return {
			setup: function(data, namespaces) {
				data = $.extend({}, defaultValues, data);
				$(this)
					.each(function() {
						new HoverIntent(this, data);
					});
			},

			teardown: function(namespaces) {
				$(this).data('hoverintent').unbind(eventName);
			}
		};
	};

	// Declaring special events
	$.event.special.mouseenterintent = specialEventSetter('enter', {
															maxSpeed			: 150,
															enterTimeout		: 500,
															checkSpeedInterval	: 40
														});
	$.event.special.mouseleaveintent = specialEventSetter('leave', {leaveTimeout	: 300});

	$.fn.mouseenterintent = function(fn, options) {
		if(typeof options === 'number') {
			options = {maxSpeed	: options};
			if(typeof arguments[2] === 'number') {
				options.enterTimeout = arguments[2];
			}
			if(typeof arguments[3] === 'number') {
				options.checkSpeedInterval = arguments[3];
			}
		}
		return this.bind('mouseenterintent', options, fn);
	};

	$.fn.mouseleaveintent = function(fn, options) {
		if(typeof options === 'number') {
			options = {leaveTimeout	: options};
		}
		return this.bind('mouseleaveintent', options, fn);
	};

	$.fn.hoverintent = function(fnin, fnout, options) {
		// Both events will be manage with the same HoverIntent instance, so we can set options just on the secon one, it will impact the first event too.
		return this
			.bind('mouseenterintent', fnin)
			.bind('mouseleaveintent', options, fnout);
	};

})(this, this.jQuery);