run method

Implementation

@override
Future<AuditResult> run(TelnetTransport transport) async {
  final completer = Completer<AuditResult>();
  bool willReceived = false;
  bool sbReceived = 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 MCCP2
        if (bytes.length == 3 &&
            bytes[0] == NegotiationStateManager.iac &&
            bytes[1] == NegotiationStateManager.will &&
            bytes[2] == mccp2) {
          willReceived = true;
        }

        // Check for WONT MCCP2
        if (bytes.length == 3 &&
            bytes[0] == NegotiationStateManager.iac &&
            bytes[1] == NegotiationStateManager.wont &&
            bytes[2] == mccp2) {
          completer.complete(
            AuditResult(
              name,
              AuditStatus.fail,
              'Server refused MCCP2 (sent WONT MCCP2).',
            ),
          );
        }

        // Check for IAC SB MCCP2 IAC SE
        if (bytes.length == 5 &&
            bytes[0] == NegotiationStateManager.iac &&
            bytes[1] == NegotiationStateManager.sb &&
            bytes[2] == mccp2 &&
            bytes[3] == NegotiationStateManager.iac &&
            bytes[4] == NegotiationStateManager.se) {
          sbReceived = true;
        }
      } else if (event.type == TelnetEventType.data) {
        if (sbReceived) {
          completer.complete(
            AuditResult(
              name,
              AuditStatus.pass,
              'MCCP2 negotiation successful and compressed data received.',
            ),
          );
        }
      }
    },
    onError: (error) {
      if (!completer.isCompleted) {
        completer.complete(
          AuditResult(
            name,
            AuditStatus.fail,
            'Error during MCCP2 probe: $error',
          ),
        );
      }
    },
  );

  try {
    // Request MCCP2
    stateManager.requestDo(mccp2);

    return await completer.future.timeout(
      const Duration(seconds: 5),
      onTimeout: () {
        String reason = 'Timeout waiting for MCCP2 response.';
        if (willReceived && !sbReceived) {
          reason =
              'Server sent WILL MCCP2 but did not start compression (no SB MCCP2).';
        }
        return AuditResult(name, AuditStatus.fail, reason);
      },
    );
  } catch (e) {
    if (e is TimeoutException) {
      String reason = 'Timeout waiting for MCCP2 response.';
      if (willReceived && !sbReceived) {
        reason =
            'Server sent WILL MCCP2 but did not start compression (no SB MCCP2).';
      }
      return AuditResult(name, AuditStatus.fail, reason);
    }
    return AuditResult(
      name,
      AuditStatus.fail,
      'Exception during MCCP2 probe: $e',
    );
  } finally {
    await subscription.cancel();
  }
}