Vn.HashParam = new Class
({
	Extends: Vn.Object
	,Tag: 'vn-hash-param'
	,Child: 'param'
	,Properties:
	{
		param:
		{
			type: Vn.Param
			,set: function (x)
			{
				this.link ({_param: x}, {'changed': this._onParamChange});
				this._refreshParam ();
			}
			,get: function ()
			{
				return this._param;
			}
		},
		key:
		{
			type: String
			,set: function (x)
			{
				this._key = x;
				this._onHashChange ();
			}
			,get: function ()
			{
				return this._key;
			}
		}
	}
	
	,lock: false
	,value: undefined
	,_key: null
	
	,initialize: function (props)
	{
		this.parent (props);
		var listener = Vn.Hash.getListener ();
		this.link ({_listener: listener}, {'changed': this._onHashChange});
		this._onHashChange ();
	}

	,_onHashChange: function ()
	{	
		if (!this._key || !this._listener)
			return;

		var newValue = Vn.Hash.get (this._key);

		if (this.value != newValue)
		{
			this.value = newValue;
			this.signalEmit ('changed');
			this._refreshParam ();
		}
	}
	
	,_refreshParam: function ()
	{
		if (this._param && !this.lock)
		{
			this.lock = true;
			this._param.value = this.value;
			this.lock = false;
		}
	}
	
	,_onParamChange: function ()
	{
		if (this.lock)
			return;

		var map = {};
		map[this.key] = this._param.value;

		this.lock = true;
		Vn.Hash.add (map);
		this.lock = false;
	}
});