Htk.Select = new Class
({
	Extends: Htk.Field
	,Implements: Db.Iterator
	,Tag: 'htk-combo'
	,Properties:
	{
		/**
		 * The model associated to this form.
		 **/
		model:
		{ 
			type: Db.Model
			,set: function (x)
			{
				this.link ({_model: x}, {'status-changed': this.onModelChange});
				this.onModelChange ();
			}
			,get: function ()
			{
				return this._model;
			}
		},
		/**
		 * The row where the form positioned, has -1 if the row is unselected.
		 **/
		row:
		{ 
			type: Number
			,set: function (x)
			{
				if (!this._model || this._model.numRows <= x || x < -1)
					x = -1;
				if (x == this._row)
					return;

				this._row = x;
				this.iterChanged ();
			}
			,get: function ()
			{
				return this._row;
			}
		},
		/**
		 * The number of rows in the form.
		 **/
		numRows:
		{
			type: Number
			,get: function ()
			{
				if (this._model)
					return this._model.numRows;

				return 0;
			}
		},
		/**
		 * Checks if the form data is ready.
		 **/
		ready:
		{
			type: Boolean
			,get: function ()
			{
				return this._ready;
			}
		},
		/**
		 * Checks if the form data is ready.
		 **/
		placeholder:
		{
			type: String
			,set: function (x)
			{
				this._placeholder = x;
				
				if (this._placeholderNode)
					Vn.Node.setText (this._placeholderNode, x);
			}
			,get: function ()
			{
				return this._placeholder;
			}
		}
	}
	
	,_row: -1
	,_model: null
	,valueColumnIndex: 0
	,valueColumnName: null
	,showColumnIndex: 1
	,showColumnName: null

	,initialize: function (props)
	{
		this.parent (props);
		this.createElement ('select');
		this.node.addEventListener ('change', this.changed.bind (this));
	}

	,on: function (id, callback, instance)
	{
		switch (id)
		{
			case 'click':
				this.node.addEventListener (id,
					callback.bind (instance, this));
				break;
			default:
				this.parent (id, callback, instance);
		}
	}
	
	,setRow: function (row)
	{
		this._row = row;
		this.iterChanged ();
	}
	
	,changed: function (event)
	{
		var value;
		var row = this.node.selectedIndex - 1;

		if (row >= 0)
			value = this._model.getByIndex (row, this.valueColumnIndex);
		else
			value = null;

		this.valueChanged (value);
		this.setRow (row);
	}
	
	,addOption: function (value, text)
	{
		var option = document.createElement ('option');
		option.value = value;
		
		if (text)
			option.appendChild (document.createTextNode (text));

		this.node.appendChild (option);
	}
	
	,addPlaceholder: function (text)
	{
		var option = document.createElement ('option');
		option.disabled = true;
		option.selected = true;
		option.value = null;
		
		if (text)
			option.appendChild (document.createTextNode (text));

		this.node.appendChild (option);
		this._placeholderNode = option;
	}
	
	,onModelChange: function ()
	{
		var placeholder = '';
		var model = this._model;
		this.signalEmit ('status-changed');
	
		Vn.Node.removeChilds (this.node);

		switch (model.status)
		{
			case Db.Model.Status.READY:
			{
				var data = model.data;
				this.addPlaceholder (this._placeholder);
				
				for (var i = 0; i < data.length; i++)
					this.addOption (data[i][this.showColumnIndex], data[i][1]);
				
				this.selectOption ();
				break;
			}
			case Db.Model.Status.ERROR:
				placeholder = 'Error';
				break;
			case Db.Model.Status.LOADING:
				placeholder = 'Loading...';
			default:
				this.addPlaceholder (_(placeholder));
				this.setRow (-1);
		}
	}
	
	,setEditable: function (editable)
	{
		this.node.disabled = !editable;
	}

	,selectOption: function ()
	{
		var row;
	
		if (this._model && this._model.status == Db.Model.Status.READY)
		{
			row = this._model.searchByIndex (this.valueColumnIndex, this._value);

			if (row != -1)
				this.node.selectedIndex = row + 1;
		}
		else
			row = -1;

		this.setRow (row);
	}

	,putValue: function (value)
	{
		this.selectOption ();
	}
});