var Lot = require ('./lot');
var LotIface = require ('./lot-iface');

var Klass = new Class ();
module.exports = Klass;

var Type =
{
	INCLUDE: 1,
	EXCLUDE: 2
};

Klass.extend
({
	Type: Type
});

Klass.implement
({
	Extends: Lot
	,Tag: 'vn-lot-query'
	,Properties:
	{
		fields:
		{ 
			type: Array
			,set: function (x)
			{
				this._fields = x;
				this._onSourceChange ();
			}
			,get: function ()
			{
				return this._fields;
			}
		},
		source:
		{ 
			type: LotIface
			,set: function (x)
			{
				this.link ({_source: x}, {change: this._onSourceChange});
				this._onSourceChange ();
			}
			,get: function ()
			{
				return this._source;
			}
		},
		type:
		{
			enumType: Type
			,set: function (x)
			{
				this._type = x;
				this._onSourceChange ();
			}
			,get: function ()
			{
				return this._type;
			}
		}
	}

	,_fields: null
	,_source: null
	,_type: Type.INCLUDE
	,_sourceFields: null

	,_onSourceChange: function ()
	{
		var changed = false;
		var params = this._source ? this._source.params : {};

		if (this._fields)
		switch (this._type)
		{
			case Type.EXCLUDE:
				changed = this.typeExclude (params);
				break;
			default:
				changed = this.typeInclude (params);
		}
		else
			changed = true;

		if (changed)
			this.changed ();
	}

	,typeInclude: function (params)
	{
		var changed = false;
		var fields = this._fields;

		for (var i = fields.length; i--;)
		{
			var field = fields[i];

			if (this._params[field] !== params[field])
			{
				this._params[field] = params[field];
				changed = true;
			}
		}

		return changed;
	}

	,typeExclude: function (params)
	{
		var changed = false;
		var sourceFields = [];

		for (var field in params)
		if (this._fields.indexOf (field) === -1
		&& this._params[field] !== params[field])
		{
			this._params[field] = params[field];
			sourceFields.push (field);
			changed = true;
		}

		return changed;
	}
});