App\Http\Controllers\BotController::base64_url_decode PHP Method

    private function base64_url_decode($arg)
    {
        $res = $arg;
        $res = str_replace('-', '+', $res);
        $res = str_replace('_', '/', $res);
        switch (strlen($res) % 4) {
            case 0:
                break;
            case 2:
                $res .= "==";
                break;
            case 3:
                $res .= "=";
                break;
            default:
                break;
        }
        $res = base64_decode($res);
        return $res;
    }