class Validator {
    public static function isValidTokenFormat($token) {
        return preg_match('/^[A-Za-z0-9\-_]{32,}$/', $token);
    }

    public static function isTokenExpired($expirationDate) {
        return strtotime($expirationDate) < time();
    }

    public static function isValidScope($scope, $allowedScopes) {
        return in_array($scope, $allowedScopes);
    }

    public static function isValidWhitelabelId($whitelabelId) {
        return is_numeric($whitelabelId) && $whitelabelId > 0;
    }
}