/// A sign-in link from the guardian login mail
/// (`https://<connect-host>/app/guardian-login?rid=…&lt=…`).
class GuardianLoginLink {
  static const path = '/app/guardian-login';

  final String requestId;
  final String linkToken;

  const GuardianLoginLink({required this.requestId, required this.linkToken});

  /// Parses [uri] if it is a guardian login link for the server at [apiBase].
  /// Links of another server (e.g. live link while the app points at beta)
  /// are rejected: the request only exists on the server that sent the mail.
  static GuardianLoginLink? parse(Uri uri, {required Uri apiBase}) {
    if (uri.scheme != 'https' || uri.host != apiBase.host) return null;
    final basePath = apiBase.path.endsWith('/')
        ? apiBase.path.substring(0, apiBase.path.length - 1)
        : apiBase.path;
    if (uri.path != '$basePath$path') return null;
    final requestId = uri.queryParameters['rid'];
    final linkToken = uri.queryParameters['lt'];
    if (requestId == null || requestId.isEmpty) return null;
    if (linkToken == null || linkToken.isEmpty) return null;
    return GuardianLoginLink(requestId: requestId, linkToken: linkToken);
  }
}