var VnObject = require ('./object');
var VnDate = require ('./date');
var Lot = require ('./lot');

/**
 * Class to handle the URL.
 */
module.exports = new Class  
({
	Extends: VnObject
	,Implements: Lot
	,Properties: {
		window:
		{
			type: Window
			,set: function (x)
			{
				this._window = x;
				x.addEventListener ('hashchange', this._hashChangedHandler);
				this._hashChanged ();
			}
			,get: function ()
			{
				return this._window;
			}
		},
		params:
		{ 
			type: Object
			,set: function (x)
			{
				this.setAll (x);
			}
			,get: function ()
			{
				return this._hashMap;
			}
		}
	}

	,initialize: function (props)
	{
		this._hash = null;
		this._hashMap = null;
		this._window = null;
		this._hashChangedHandler = this._hashChanged.bind (this);
		this.parent (props);
	}

	,get: function (key, type)
	{
		return this.parseValue (this._hashMap[key], type);
	}

	,set: function (key, value)
	{
		var map = {};
		map[key] = value;
		this.assign (map);
	}
	
	/**
	 * Sets the hash part of the URL, respecting the current hash variables.
	 *
	 * @param {Object} map A key-value map
	 */
	,assign: function (map)
	{
		var newMap = this._hashMap;

		for (var key in map)
			newMap[key] = map[key];
			
		this.setAll (newMap);
	}
	
	/**
	 * Sets the hash part of the URL.
	 *
	 * @param {Object} map A key-value map
	 */
	,setAll: function (map)
	{
		if (map)
		for (var key in map)
		if (map[key] === null || map[key] === undefined)
			delete map[key];

		var newHash = this.make (map);

		if (!map)
			map = {};

		if (newHash !== this._hash)
		{
			this._hashMap = map;
			this._hash = newHash;
			
			this._blockChanged = true;
			location.hash = newHash;
			this._blockChanged = false;

			this.changed ();
		}
	}

	/**
	 * Creates a URL with the given hash data.
	 *
	 * @param {Object} map A key-value map
	 * @param {boolean} add %true to combine with the current map, %false otherwise
	 * @return {String} The URL
	 */
	,make: function (map, add)
	{
		var hash = '#!';
		
		if (add && map)
		for (var key in this._hashMap)
		if (!map[key])
			map[key] = this._hashMap[key];

		for (var key in map)
		{
			if (hash.length > 2)
				hash += '&';

			hash += encodeURIComponent (key) +'='+ this.renderValue (map[key]);
		}
	
		return hash;
	}

	,_hashChanged: function ()
	{
		var newHash = location.hash;

		if (this._blockChanged || newHash === this._hash)
			return;

		var newMap = hashMap = {};
		var kvPairs = newHash.substr(2).split ('&');

		for (var i = 0; i < kvPairs.length; i++)
		{
			var kvPair = kvPairs[i].split ('=', 2);
			
			if (kvPair[0])
				newMap[decodeURIComponent (kvPair[0])] = decodeURIComponent (kvPair[1]);
		}

		this._hashMap = newMap;
		this._hash = newHash;
		this.changed ();
	}

	,renderValue: function (v)
	{
		switch (typeof v)
		{
			case 'number':
				return v;
			case 'boolean':
				return (v) ? 'true' : 'false';
			case 'object':
			if (v instanceof Date)
				return VnDate.strftime (v, '%Y-%m-%d');
		}

		return v;
	}

	,parseValue: function (v, type)
	{
		if (v === '')
			return null;

		if (type && v !== undefined && v !== null)
		switch (type)
		{
			case Boolean:
				return (/^(true|1)$/i).test (v);
			case Number:
				return 0 + new Number (v);
			case Date:
				var date = new Date (v);
				date.setHours (0, 0, 0, 0);
				return date;
		}

		return v;
	}

	,_destroy: function ()
	{
		this._window.removeEventListener ('hashchange', this._hashChangedHandler);
		this._window = null;
		this.parent ();
	}
});