class Users {
    private static $key, $table, $logtable;

    public static function init($key) {
        self::$key = $key;
        self::$table = DBPREFIX.$key.'s';
        self::$logtable = self::$table.'_access_log';
    }

    public static function isLogged() {
        if(isset($_SESSION[self::$key])) {
            if(isset($_SESSION[self::$key]['uid'])) {
                $uid = intval($_SESSION[self::$key]['uid']);
                $user = DB::select()->from(self::$table)->where('id', '=', $uid)->execute()->object();
                if(count($user) > 0) {
                    return true;
                }
                else {
                    return false;
                }

            }
            else {
                return false;
            }
        }
        else {
            return false;
        }
    }

    public static function userExist($login) {
        $user = DB::select()->from(self::$table)->where('login', '=', $login)->execute()->object();
        if(count($user) > 0) {
            return true;
        }
        else {
            return false;
        }
    }

    public static function getUser($login) {
        $user = DB::select()->from(self::$table)->where('login', '=', $login)->execute()->object();
        if(count($user) > 0) {
            return $user[0];
        }
        else {
            return false;
        }
    }

    public static function generateHash($password) {
        $salt = self::generateSalt();
        $hashedPassword = crypt($password, $salt);
        return array('hashed_password' => $hashedPassword, 'salt' => $salt);
    }

    private static function generateSalt() {
        $blowfishPre = '$2y$10$';
        $blowfishEnd = '$';
        $allowedChars ='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789./';
        $charsLength = strlen($allowedChars);
        $saltLength = 20;
        $salt = "";
        for($i=0; $i < $saltLength; $i++)
        {
            $salt .= $allowedChars[mt_rand(0,$charsLength)];
        }
        $bcrypt_salt = $blowfishPre . $salt . $blowfishEnd;
        return $bcrypt_salt;
    }

    public static function comparePasswords($input, $uid) {
        $user = DB::select()->from(self::$table)->where('id', '=', $uid)->execute()->object();
        if(count($user) > 0) {
            $user = $user[0];
            $password = $user->password;
            return crypt($input, $password) === $password;
        }
        else {
            return false;
        }
    }

    public static function userExit() {
        if(isset($_SESSION[self::$key])) {
            unset($_SESSION[self::$key]);
        }
    }

    public static function changePassword($password, $uid) {
        $newPassword = self::generateHash($password);
        if(isset($newPassword['hashed_password']) && isset($newPassword['salt'])) {
            DB::update(self::$table)->set(array('password' => $newPassword['hashed_password'], 'salt' => $newPassword['salt']))->where('id', '=', $uid)->execute();
        }
    }

    public static function updateTime($uid) {
        DB::update(self::$table)->set(array('last_login' => time()))->where('id', '=', $uid)->execute();
    }

    public static function writeAccessLog($uid, $success) {
        if($success) {
            DB::insert(self::$logtable)->set(array('admin_id' => $uid, 'date' => time(), 'success' => '1'))->execute();
        }
        else if(!$success) {
            DB::insert(self::$logtable)->set(array('admin_id' => $uid, 'date' => time(), 'success' => '0'))->execute();
        }
    }
}