var Class = require('../utils/Class'); 
var PluginCache = require('../plugins/PluginCache'); 
var UpdateList = new Class({ 
initialize: function UpdateList(scene){ 
this.scene = scene; 
this.systems = scene.sys; 
this._list = [] ; 
this._pendingInsertion = [] ; 
this._pendingRemoval = [] ; 
scene.sys.events.once('boot', this.boot, this); 
scene.sys.events.on('start', this.start, this); 
} 
,
boot: function (){ 
this.systems.events.once('destroy', this.destroy, this); 
} 
,
start: function (){ 
var eventEmitter = this.systems.events; 
eventEmitter.on('preupdate', this.preUpdate, this); 
eventEmitter.on('update', this.update, this); 
eventEmitter.once('shutdown', this.shutdown, this); 
} 
,
add: function (child){ 
if (this._list.indexOf(child) === -1 && this._pendingInsertion.indexOf(child) === -1) { 
this._pendingInsertion.push(child); 
} 
return child; 
} 
,
preUpdate: function (){ 
var toRemove = _AN_Read_length('length', this._pendingRemoval); 
var toInsert = _AN_Read_length('length', this._pendingInsertion); 
if (toRemove === 0 && toInsert === 0) { 
return ; 
} 
var i; 
var gameObject; 
for (i = 0; i < toRemove; i++ ){ 
gameObject = this._pendingRemoval[i]; 
var index = this._list.indexOf(gameObject); 
if (index > -1) { 
this._list.splice(index, 1); 
} 
} 
this._list = this._list.concat(this._pendingInsertion.splice(0)); 
this._pendingRemoval.length = 0; 
this._pendingInsertion.length = 0; 
} 
,
update: function (time, delta){ 
for (var i = 0; 
i < (_AN_Read_length('length', this._list)); i++ ){ 
var gameObject = this._list[i]; 
if (gameObject.active) { 
gameObject.preUpdate.call(gameObject, time, delta); 
} 
} 
} 
,
remove: function (child){ 
var index = this._list.indexOf(child); 
if (index !== -1) { 
this._list.splice(index, 1); 
} 
return child; 
} 
,
removeAll: function (){ 
var i = _AN_Read_length('length', this._list); 
while (i-- ){ 
this.remove(this._list[i]); 
} 
return this; 
} 
,
shutdown: function (){ 
this.removeAll(); 
this._list.length = 0; 
this._pendingRemoval.length = 0; 
this._pendingInsertion.length = 0; 
var eventEmitter = this.systems.events; 
eventEmitter.off('preupdate', this.preUpdate, this); 
eventEmitter.off('update', this.update, this); 
eventEmitter.off('shutdown', this.shutdown, this); 
} 
,
destroy: function (){ 
this.shutdown(); 
this.scene.sys.events.off('start', this.start, this); 
this.scene = null ; 
this.systems = null ; 
} 
,
length: { 
get: function (){ 
return (_AN_Read_length('length', this._list)); 
} 
}
}
); 
PluginCache.register('UpdateList', UpdateList, 'updateList'); 
module.exports = UpdateList;