run method

Implementation

@override
Future<AuditResult> run(TelnetTransport transport) async {
  final completer = Completer<AuditResult>();
  bool willReceived = false;

  final stateManager = NegotiationStateManager(
    onSend: (bytes) => transport.write(bytes),
  );

  final subscription = transport.events.listen(
    (event) {
      if (completer.isCompleted) return;

      if (event.type == TelnetEventType.iac) {
        final bytes = event.bytes;
        stateManager.handleCommand(bytes);

        // Check for WILL GMCP
        if (bytes.length == 3 &&
            bytes[0] == NegotiationStateManager.iac &&
            bytes[1] == NegotiationStateManager.will &&
            bytes[2] == gmcp) {
          willReceived = true;
        }

        // Check for WONT GMCP
        if (bytes.length == 3 &&
            bytes[0] == NegotiationStateManager.iac &&
            bytes[1] == NegotiationStateManager.wont &&
            bytes[2] == gmcp) {
          completer.complete(
            AuditResult(
              name,
              AuditStatus.fail,
              'Server refused GMCP (sent WONT GMCP).',
            ),
          );
        }

        // Check for IAC SB GMCP ... IAC SE
        if (bytes.length >= 5 &&
            bytes[0] == NegotiationStateManager.iac &&
            bytes[1] == NegotiationStateManager.sb &&
            bytes[2] == gmcp) {
          final gmcpEvent = GmcpParser.parse(bytes);
          if (gmcpEvent != null) {
            completer.complete(
              AuditResult(
                name,
                AuditStatus.pass,
                'GMCP negotiation successful and valid GMCP message received: ${gmcpEvent.package}.${gmcpEvent.message}',
              ),
            );
          } else {
            completer.complete(
              AuditResult(
                name,
                AuditStatus.fail,
                'Received malformed GMCP message.',
              ),
            );
          }
        }
      }
    },
    onError: (error) {
      if (!completer.isCompleted) {
        completer.complete(
          AuditResult(
            name,
            AuditStatus.fail,
            'Error during GMCP probe: $error',
          ),
        );
      }
    },
  );

  try {
    // Request GMCP
    stateManager.requestDo(gmcp);

    return await completer.future.timeout(
      const Duration(seconds: 5),
      onTimeout: () {
        String reason = 'Timeout waiting for GMCP response.';
        if (willReceived) {
          reason =
              'Server sent WILL GMCP but did not send any GMCP subnegotiation messages.';
        }
        return AuditResult(name, AuditStatus.fail, reason);
      },
    );
  } catch (e) {
    if (e is TimeoutException) {
      String reason = 'Timeout waiting for GMCP response.';
      if (willReceived) {
        reason =
            'Server sent WILL GMCP but did not send any GMCP subnegotiation messages.';
      }
      return AuditResult(name, AuditStatus.fail, reason);
    }
    return AuditResult(
      name,
      AuditStatus.fail,
      'Exception during GMCP probe: $e',
    );
  } finally {
    await subscription.cancel();
  }
}