/**
*  @module cloudkid
*/
(function(){
	
	"use strict";
	
	/** 
	*  The SavedData functions use localStorage and sessionStorage, with a cookie fallback. 
	*
	*  @class SavedData
	*/
	var SavedData = {},
	
	/** A constant to determine if we can use localStorage and sessionStorage */
	WEB_STORAGE_SUPPORT = typeof(window.Storage) !== "undefined",
	
	/** A constant for cookie fallback for SavedData.clear() */
	ERASE_COOKIE = -1;

	//in iOS, if the user is in Private Browsing, writing to localStorage throws an error.
	if(WEB_STORAGE_SUPPORT)
	{
		try
		{
			localStorage.setItem("LS_TEST", "test");
			localStorage.removeItem("LS_TEST");
		}
		catch(e)
		{
			WEB_STORAGE_SUPPORT = false;
		}
	}
	
	/** 
	*  Remove a saved variable by name.
	*  @method remove
	*  @static
	*  @param {String} name The name of the value to remove
	*/
	SavedData.remove = function(name)
	{
		if(WEB_STORAGE_SUPPORT)
		{
			localStorage.removeItem(name);
			sessionStorage.removeItem(name);
		}
		else
			SavedData.write(name,"",ERASE_COOKIE);
	};
	
	/**
	*  Save a variable.
	*  @method write
	*  @static
	*  @param {String} name The name of the value to save
	*  @param {mixed} value The value to save. This will be run through JSON.stringify().
	*  @param {Boolean} [tempOnly=false] If the value should be saved only in the current browser session.
	*/
	SavedData.write = function(name, value, tempOnly)
	{
		if(WEB_STORAGE_SUPPORT)
		{
			if(tempOnly)
				sessionStorage.setItem(name, JSON.stringify(value));
			else
				localStorage.setItem(name, JSON.stringify(value));
		}
		else
		{
			var expires;
			if (tempOnly)
			{
				if(tempOnly !== ERASE_COOKIE)
					expires = "";//remove when browser is closed
				else
					expires = "; expires=Thu, 01 Jan 1970 00:00:00 GMT";//save cookie in the past for immediate removal
			}
			else
				expires = "; expires="+new Date(2147483646000).toGMTString();//THE END OF (32bit UNIX) TIME!
				
			document.cookie = name+"="+escape(JSON.stringify(value))+expires+"; path=/";
		}
	};
	
	/**
	*  Read the value of a saved variable
	*  @method read
	*  @static
	*  @param {String} name The name of the variable
	*  @return {mixed} The value (run through `JSON.parse()`) or null if it doesn't exist
	*/
	SavedData.read = function(name)
	{
		if(WEB_STORAGE_SUPPORT)
		{
			var value = localStorage.getItem(name) || sessionStorage.getItem(name);
			if(value)
				return JSON.parse(value);
			else
				return null;
		}
		else
		{
			var nameEQ = name + "=",
				ca = document.cookie.split(';'),
				i = 0, c;
				
			for(i=0;i < ca.length;i++)
			{
				c = ca[i];
				while (c.charAt(0) == ' ') c = c.substring(1,c.length);
				if (c.indexOf(nameEQ) === 0) return JSON.parse(unescape(c.substring(nameEQ.length,c.length)));
			}
			return null;
		}
	};
	
	// Assign to the global space
	namespace('cloudkid').SavedData = SavedData;
	
}());