public static function parse_host($name, $host = '')
    {
        if (!is_string($name)) {
            return $name;
        }

        // %n - host
        $n = preg_replace('/:\d+$/', '', $_SERVER['SERVER_NAME']);
        // %t - host name without first part, e.g. %n=mail.domain.tld, %t=domain.tld
        $t = preg_replace('/^[^\.]+\./', '', $n);
        // %d - domain name without first part
        $d = preg_replace('/^[^\.]+\./', '', $_SERVER['HTTP_HOST']);
        // %h - IMAP host
        $h = $_SESSION['storage_host'] ?: $host;
        // %z - IMAP domain without first part, e.g. %h=imap.domain.tld, %z=domain.tld
        $z = preg_replace('/^[^\.]+\./', '', $h);
        // %s - domain name after the '@' from e-mail address provided at login screen.
        //      Returns FALSE if an invalid email is provided
        if (strpos($name, '%s') !== false) {
            $user_email = self::get_input_value('_user', self::INPUT_POST);
            $user_email = self::idn_convert($user_email, true);
            $matches    = preg_match('/(.*)@([a-z0-9\.\-\[\]\:]+)/i', $user_email, $s);
            if ($matches < 1 || filter_var($s[1]."@".$s[2], FILTER_VALIDATE_EMAIL) === false) {
                return false;
            }
        }

        return str_replace(array('%n', '%t', '%d', '%h', '%z', '%s'), array($n, $t, $d, $h, $z, $s[2]), $name);
    }