"use strict";

var fs = require("fs");
var crypto = require("crypto");
var md5 = require("md5");

var tokens = {};

exports.TokenManager = function (folder, file) {

	this.path = folder + file;

	var self = this;

	try {
		var fd = fs.openSync(self.path, "wx");
		self.writeTokens();
	} catch (e) {
		self.readTokens();
	}
};

exports.TokenManager.prototype.addToken = function (id, token, pass) {
	tokens[md5(id)] = encrypt(token, pass);
	this.writeTokens();
};

exports.TokenManager.prototype.readTokens = function () {
	tokens = JSON.parse(fs.readFileSync(this.path, "utf8"));
	for (tkn in tokens) {
		tokens[tkn] = decrypt(tokens[tkn], tkn);
	}
};

exports.TokenManager.prototype.writeTokens = function () {
	var tkn = {};
	for (token in tokens) {
		tkn[token] = encrypt(tokens[token], token);
	}
	fs.writeFile(this.path, JSON.stringify(tkn), function (err) {});
};

exports.TokenManager.prototype.exists = function (id) {
	return tokens[md5(id)];
};

exports.TokenManager.prototype.getToken = function (id, pass) {
	try {
		return decrypt(tokens[md5(id)], pass);
	} catch (e) {
		return false;
	}
};

function encrypt(string, password) {
	var cipher = crypto.createCipher("aes-256-ctr", password);
	var crypted = cipher.update(string, 'utf8', 'hex');
	crypted += cipher.final('hex');
	return crypted;
}

function decrypt(string, password) {
	var decipher = crypto.createDecipher("aes-256-ctr", password);
	var dec = decipher.update(string, 'hex', 'utf8');
	dec += decipher.final('utf8');
	return dec;
}