(function(exp, $) {

	var 
		config = {},
		default_lifetime = 3600,
		options = {
			"debug": false
		},

		api_redirect,
		Api_default_storage,
		api_storage,

		internalStates = [];

	/*
	 * ------ SECTION: Utilities
	 */

	/*
	 * Returns a random string used for state
	 */
	var uuid = function() {
		return 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, function(c) {
			var r = Math.random()*16|0, v = c == 'x' ? r : (r&0x3|0x8);
			return v.toString(16);
		});
	}

	/**
	 * A log wrapper, that only logs if logging is turned on in the config
	 * @param  {string} msg Log message
	 */
	var log = function(msg) {
		if (!options.debug) return;
		if (!console) return;
		if (!console.log) return;

		// console.log("LOG(), Arguments", arguments, msg)
		if (arguments.length > 1) {
			console.log(arguments);	
		} else {
			console.log(msg);
		}
		
	}

	/**
	 * Set the global options.
	 */
	var setOptions = function(opts) {
		if (!opts) return;
		for(var k in opts) {
			if (opts.hasOwnProperty(k)) {
				options[k] = opts[k];
			}
		}
		log("Options is set to ", options);
	}


	/* 
	 * Takes an URL as input and a params object.
	 * Each property in the params is added to the url as query string parameters
	 */
	var encodeURL = function(url, params) {
		var res = url;
		var k, i = 0;
		var firstSeparator = (url.indexOf("?") === -1) ? '?' : '&';
		for(k in params) {
		  document
			//res += (i++ === 0 ? firstSeparator : '&') + encodeURIComponent(k) + '=' + encodeURIComponent(params[k]);
			res += (i++ === 0 ? firstSeparator : '&') + encodeURIComponent(k) + '=' + params[k];
		}
		return res;
	}
	

	/*
	 * Returns epoch, seconds since 1970.
	 * Used for calculation of expire times.
	 */
	var epoch = function() {
		return Math.round(new Date().getTime()/1000.0);
	}



	var parseQueryString = function (qs) {
		var e,
			a = /\+/g,  // Regex for replacing addition symbol with a space
			r = /([^&;=]+)=?([^&;]*)/g,
			d = function (s) { return decodeURIComponent(s.replace(a, " ")); },
			q = qs,
			urlParams = {};

		while (e = r.exec(q))
		   urlParams[d(e[1])] = d(e[2]);

		return urlParams;
	}
	/*
	 * ------ / SECTION: Utilities
	 */






	/* 
	 * Redirects the user to a specific URL
	 */
	api_redirect = function(url) {
		window.location = url;
	};

	Api_default_storage = function() {
		log("Constructor");
	};

	/**
		saveState stores an object with an Identifier.
		TODO: Ensure that both localstorage and JSON encoding has fallbacks for ancient browsers.
		In the state object, we put the request object, plus these parameters:
		  * restoreHash
		  * providerID
		  * scopes

	 */
	Api_default_storage.prototype.saveState =  function (state, obj) {
		localStorage.setItem("state-" + state, JSON.stringify(obj));
	}


	/**
	 * getStage()  returns the state object, but also removes it.
	 * @type {Object}
	 */
	Api_default_storage.prototype.getState = function(state) {
		// log("getState (" + state+ ")");
		var obj = JSON.parse(localStorage.getItem("state-" + state));
		localStorage.removeItem("state-" + state)
		return obj;
	};


	/*
	 * Checks if a token, has includes a specific scope.
	 * If token has no scope at all, false is returned.
	 */
	Api_default_storage.prototype.hasScope = function(token, scope) {
		var i;
		if (!token.scopes) return false;
		for(i = 0; i < token.scopes.length; i++) {
			if (token.scopes[i] === scope) return true;
		}
		return false;
	};

	/*
	 * Takes an array of tokens, and removes the ones that
	 * are expired, and the ones that do not meet a scopes requirement.
	 */
	Api_default_storage.prototype.filterTokens = function(tokens, scopes) {
		var i, j, 
			result = [],
			now = epoch(),
			usethis;

		if (!scopes) scopes = [];

		for(i = 0; i < tokens.length; i++) {
			usethis = true;

			// Filter out expired tokens. Tokens that is expired in 1 second from now.
			if (tokens[i].expires && tokens[i].expires < (now+1)) usethis = false;

			// Filter out this token if not all scope requirements are met
			for(j = 0; j < scopes.length; j++) {
				if (!api_storage.hasScope(tokens[i], scopes[j])) usethis = false;
			}

			if (usethis) result.push(tokens[i]);
		}
		return result;
	};


	/*
	 * saveTokens() stores a list of tokens for a provider.

		Usually the tokens stored are a plain Access token plus:
		  * expires : time that the token expires
		  * providerID: the provider of the access token?
		  * scopes: an array with the scopes (not string)
	 */
	Api_default_storage.prototype.saveTokens = function(provider, tokens) {
		// log("Save Tokens (" + provider+ ")");
		localStorage.setItem("tokens-" + provider, JSON.stringify(tokens));
	};

	Api_default_storage.prototype.getTokens = function(provider) {
		// log("Get Tokens (" + provider+ ")");
		var tokens = JSON.parse(localStorage.getItem("tokens-" + provider));
		if (!tokens) tokens = [];

		log("Token received", tokens)
		return tokens;
	};
	Api_default_storage.prototype.wipeTokens = function(provider) {
		localStorage.removeItem("tokens-" + provider);
	};
	
	/*
	 * Save a single token for a provider.
	 * This also cleans up expired tokens for the same provider.
	 */
	Api_default_storage.prototype.saveToken = function(provider, token) {
		var tokens = this.getTokens(provider);
		tokens = api_storage.filterTokens(tokens);
		tokens.push(token);
		this.saveTokens(provider, tokens);
	};

	/*
	 * Get a token if exists for a provider with a set of scopes.
	 * The scopes parameter is OPTIONAL.
	 */
	Api_default_storage.prototype.getToken = function(provider, scopes) {
		var tokens = this.getTokens(provider);
		tokens = api_storage.filterTokens(tokens, scopes);
		if (tokens.length < 1) return null;
		return tokens[0];
	};

	api_storage = new Api_default_storage();
	/**
	 * Check if the hash contains an access token. 
	 * And if it do, extract the state, compare with
	 * config, and store the access token for later use.
	 *
	 * The url parameter is optional. Used with phonegap and
	 * childbrowser when the jso context is not receiving the response,
	 * instead the response is received on a child browser.
	 */
	exp.jso_checkfortoken = function(providerID, url, callback) {
		var 
			atoken,
			h = window.location.hash,
			now = epoch(),
			state,
			co;

		log("jso_checkfortoken(" + providerID + ")");

		// If a url is provided 
		if (url) {
			// log('Hah, I got the url and it ' + url);
			if(url.indexOf('#') === -1) return;
			h = url.substring(url.indexOf('#'));
			// log('Hah, I got the hash and it is ' +  h);
		}

		/*
		 * Start with checking if there is a token in the hash
		 */
		if (h.length < 2) return;
		if (h.indexOf("access_token") === -1) return;
		h = h.substring(1);
		atoken = parseQueryString(h);

		if (atoken.state) {
			state = api_storage.getState(atoken.state);
		} else {
			if (!providerID) {throw "Could not get [state] and no default providerid is provided.";}
			state = {providerID: providerID};
		}

		
		if (!state) throw "Could not retrieve state";
		if (!state.providerID) throw "Could not get providerid from state";
		if (!config[state.providerID]) throw "Could not retrieve config for this provider.";
		co = config[state.providerID];

		/**
		 * If state was not provided, and default provider contains a scope parameter
		 * we assume this is the one requested...
		 */
		if (!atoken.state && co.scope) {
			state.scopes = co.scope;
			log("Setting state: ", state);
		}
		log("Checking atoken ", atoken, " and co ", co);

		/*
		 * Decide when this token should expire.
		 * Priority fallback:
		 * 1. Access token expires_in
		 * 2. Life time in config (may be false = permanent...)
		 * 3. Specific permanent scope.
		 * 4. Default library lifetime:
		 */
		if (atoken["expires_in"]) {
			atoken["expires"] = now + parseInt(atoken["expires_in"], 10);
		} else if (co["default_lifetime"] === false) {
			// Token is permanent.
		} else if (co["default_lifetime"]) {
			atoken["expires"] = now + co["default_lifetime"];
		} else if (co["permanent_scope"]) {
			if (!api_storage.hasScope(atoken, co["permanent_scope"])) {
				atoken["expires"] = now + default_lifetime;
			}
		} else {
			atoken["expires"] = now + default_lifetime;
		}

		/*
		 * Handle scopes for this token
		 */
		if (atoken["scope"]) {
			atoken["scopes"] = atoken["scope"].split(" ");
		} else if (state["scopes"]) {
			atoken["scopes"] = state["scopes"];
		}



		api_storage.saveToken(state.providerID, atoken);

		if (state.restoreHash) {
			window.location.hash = state.restoreHash;
		} else {
			window.location.hash = '';
		}


		log(atoken);

		if (internalStates[atoken.state] && typeof internalStates[atoken.state] === 'function') {
			// log("InternalState is set, calling it now!");
			internalStates[atoken.state]();
			delete internalStates[atoken.state];
		}


		if (typeof callback === 'function') {
			callback();
		}

		// log(atoken);

	}

	/*
	 * A config object contains:
	 */
	var jso_authrequest = function(scopes, callback) {

		var 
			state,
			request,
			authurl,
			co;

    providerid = "oanda";
		if (!config[providerid]) throw "Could not find configuration for provider " + providerid;
		co = config[providerid];

		log("About to send an authorization request to [" + providerid + "]. Config:")
		log(co);

		state = uuid();
		request = {
			"response_type": "token"
		};
		request.state = state;

		if (callback && typeof callback === 'function') {
			internalStates[state] = callback;
		}


		if (co["redirect_uri"]) {
			request["redirect_uri"] = co["redirect_uri"];
		}
		if (co["client_id"]) {
		  document.write(scopes);
			request["client_id"] = co["client_id"];
		}
		
		if (scopes) {
		  document.write(scopes.join("+"));
			request["scope"] = scopes.join("+");
		}

		authurl = encodeURL(co.authorization, request);

		// We'd like to cache the hash for not loosing Application state. 
		// With the implciit grant flow, the hash will be replaced with the access
		// token when we return after authorization.
		if (window.location.hash) {
			request["restoreHash"] = window.location.hash;
		}
		request["providerID"] = providerid;
		if (scopes) {
			request["scopes"] = scopes;
		}


		log("Saving state [" + state+ "]");
		log(JSON.parse(JSON.stringify(request)));

		api_storage.saveState(state, request);
		api_redirect(authurl);

	};

	exp.jso_ensureTokens = function (parameters) {
		var providerid, scopes, token;
                        scopes = parameters['oanda'];
			//scopes = ["read","trade","marketdata","stream"];
			token = api_storage.getToken("oanda", scopes);

			log("Ensure token for provider [oanda] ");
			log(token);

			if (token === null) {
				jso_authrequest(scopes);
			}
		return true;
	}; 

	exp.jso_findDefaultEntry = function(c) {
		var 
			k,
			i = 0;

		if (!c) return;
		log("c", c);
		for(k in c) {
			i++;
			if (c[k].isDefault && c[k].isDefault === true) {
				return k;
			}
		}
		if (i === 1) return k;
	};

	exp.jso_configure = function(c, opts) {
		config = c;
		setOptions(opts);
		try {

			var def = exp.jso_findDefaultEntry(c);
			log("jso_configure() about to check for token for this entry", def);
			exp.jso_checkfortoken(def);	

		} catch(e) {
			log("Error when retrieving token from hash: " + e);
			window.location.hash = "";
		}
		
	}

	exp.jso_dump = function() {
		var key;
		for(key in config) {

			log("=====> Processing provider [" + key + "]");
			log("=] Config");
			log(config[key]);
			log("=] Tokens")
			log(api_storage.getTokens(key));

		}
	}

	exp.jso_wipe = function() {
		var key;
		log("jso_wipe()");
		for(key in config) {
			log("Wipping tokens for " + key);
			api_storage.wipeTokens(key);
		}
	}

	exp.jso_getToken = function(providerid, scopes) {
		var token = api_storage.getToken(providerid, scopes);
		if (!token) return null;
		if (!token["access_token"]) return null;
		return token["access_token"];
	}


       // Add configuration for one or more providers.
       // jso_configure({
       //  "oanda": {
       //         client_id: "abcdefg",
       //         redirect_uri: "https://alchan-ud.dev.oanda.com/index.html",
       //         authorization: "https://oanda-cs-dev:1342/v1/oauth2/authorize",
       //	}
       //});


	exp.jso_registerRedirectHandler = function(callback) {
		api_redirect = callback;
	};

	exp.jso_registerStorageHandler = function(object) {
		api_storage = object;
	};


	/*
	 * From now on, we only perform tasks that require jQuery.
	 * Like adding the $.oajax function.
	 */
	if (typeof $ === 'undefined') return;

	$.oajax = function(settings) {
		var 
			allowia,
			scopes,
			token,
			providerid,
			co;
		
		providerid = settings.jso_provider;
		allowia = settings.jso_allowia || false;
		scopes = settings.jso_scopes;
		token = api_storage.getToken(providerid, scopes);
		co = config[providerid];

		// var successOverridden = settings.success;
		// settings.success = function(response) {
		// }

		var errorOverridden = settings.error || null;

		var performAjax = function() {
			 log("Perform ajax!");

			if (!token) throw "Could not perform AJAX call because no valid tokens was found.";	

			if (co["presenttoken"] && co["presenttoken"] === "qs") {
				 settings.url += ((h.indexOf("?") === -1) ? '?' : '&') + "access_token=" + encodeURIComponent(token["access_token"]);
				if (!settings.data) settings.data = {};
				settings.data["access_token"] = token["access_token"];
			} else {
				if (!settings.headers) settings.headers = {};
				settings.headers["Authorization"] = "Bearer " + token["access_token"];
			}
			return $.ajax(settings);
		};

		settings.error = function(jqXHR, textStatus, errorThrown) {
			log('error(jqXHR, textStatus, errorThrown)');
			log(jqXHR);
			log(textStatus);
			log(errorThrown);

			if (jqXHR.status === 401) {

				log("Token expired. About to delete this token");
				log(token);
				api_storage.wipeTokens(providerid);

			}
			if (errorOverridden && typeof errorOverridden === 'function') {
				errorOverridden(jqXHR, textStatus, errorThrown);
			}
		}


		if (!token) {
			if (allowia) {
				log("Perform authrequest");
				jso_authrequest(scopes, function() {
					token = api_storage.getToken(providerid, scopes);
					performAjax();
				});
				return;
			} else {
				throw "Could not perform AJAX call because no valid tokens was found.";	
			}
		}


		return performAjax();
	};


})(window, window.jQuery);