var VnObject = require('./object');
var LotIface = require('./lot-iface');
var Value = require('./value');

module.exports = new Class({
	Extends: VnObject
	,Implements: LotIface
	,Tag: 'vn-lot'
	,Properties: {
		params: {
			type: Object
			,set: function(x) {
				this.setAll(x);
			}
			,get: function() {
				return this._params;
			}
		}
		,$: {
			type: Object
			,set: function(x) {
				this.setAll(x);
			}
			,get: function() {
				return this._params;
			}
		}
	}

	,initialize: function(props) {
		this._params = {};
		this.parent(props);
	}
	
	,keys: function() {
		return Object.keys(this._params);
	}

	,assign: function(params) {
		var diff = Value.partialDiff(this._params, params);
		this._assign(diff);
	}

	,setAll: function(params) {
		var diff = Value.diff(this._params, params);
		this._assign(diff);
	}

	,_assign: function(diff) {
		if (diff) {
			Object.assign(this._params, diff);
			this._paramsChanged(diff);
			this.changed(diff);
		}
	}

	/**
	 * Called when lot params changes, can be implemented by child classes to be
	 * notified about changes.
	 * 
	 * @param {Object} diff Changed parameters and its new values
	 */
	,_paramsChanged: function() {}
});