var Event = Y.Event,

Lang = Y.Lang,

plugins = Y.Env.evt.plugins,

isString = Lang.isString,

listeners = {},

getRelatedTarget = function (e) {

var target = e.relatedTarget;

if (!target) {

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

target = e.toElement;

} else if (e.type == "mouseover") {

target = e.fromElement;

}

}

return target;

},

eventConfig = {

on: function(type, fn, el) {

var args = Y.Array(arguments, 0, true),

element = el,

handles;

if (Lang.isString(el)) {

// Need to use Y.all because if el is a string it could be a

// selector that returns a NodeList

element = Y.all(el);

if (element.size() === 0) { // Not found, check using onAvailable

return Event.onAvailable(el, function() {

Y.on.apply(Y, args);

}, Event, true, false);

}

}

if (element instanceof Y.NodeList || Event._isValidCollection(element)) { // Array or NodeList

handles = [];

Y.each(element, function(v, k) {

args[2] = v;

handles.push(Y.on.apply(Y, args));

});

return (handles.length === 1) ? handles[0] : handles;

}

// At this point el will always be a Node instance

element = Y.Node.getDOMNode(el);

var sDOMEvent = (type === "mouseenter") ? "mouseover" : "mouseout",

// The name of the custom event

sEventName = type + ":" + Y.stamp(element) + sDOMEvent,

listener = listeners[sEventName],

domEventHandle,

ceHandle,

nListeners;

// Bind an actual DOM event listener that will call the

// the custom event

if (!listener) {

domEventHandle = Event._attach([sDOMEvent, Y.rbind(Event._fireMouseEnter, Y, element, sEventName), element], { facade: false });

// Hook into the _delete method for the Custom Event wrapper of this

// DOM Event in order to clean up the 'listeners' map and unsubscribe

// the associated Custom Event listeners fired by this DOM event

// listener if/when the user calls "purgeElement" OR removes all

// listeners of the Custom Event.

Y.after(function (sub) {

if (domEventHandle.sub == sub) {

// Delete this event from the map of known mouseenter

// and mouseleave listeners

delete listeners[sEventName];

Y.log("DOM event listener associated with the " + sEventName + " Custom Event removed. Removing all " + sEventName + " listeners.", "info", "Event");

// Unsubscribe all listeners of the Custom Event fired

// by this DOM event.

Y.detachAll(sEventName);

}

}, domEventHandle.evt, "_delete");

listener = {};

listener.handle = domEventHandle;

listeners[sEventName] = listener;

}

nListeners = listener.count;

listener.count = nListeners ? (nListeners + 1) : 1;

args[0] = sEventName;

// Remove the element from the args

args.splice(2, 1);

// Subscribe to the custom event

ceHandle = Y.on.apply(Y, args);

// Hook into the detach method of the handle in order to clean up the

// 'listeners' map and remove the associated DOM event handler

// responsible for firing this Custom Event if all listener for this

// event have been removed.

Y.after(function () {

listener.count = (listener.count - 1);

if (listener.count === 0) {

Y.log("No more listeners for the " + sEventName + " Custom Event. Removing its associated DOM event listener.", "info", "Event");

listener.handle.detach();

}

}, ceHandle, "detach");

return ceHandle;

}

};

Event._fireMouseEnter = function (e, currentTarget, eventName) {

var relatedTarget = getRelatedTarget(e),

eventFacade;

if (currentTarget !== relatedTarget &&

!Y.DOM.contains(currentTarget, relatedTarget)) {

eventFacade = new Y.DOMEventFacade(e, currentTarget);

Y.publish(eventName, {

contextFn: function() {

return eventFacade.currentTarget;

}

});

Y.fire(eventName, eventFacade);

}

};

plugins.mouseenter = eventConfig;

plugins.mouseleave = eventConfig;