private async Task ConnectAsync()

in iothub/device/src/Transport/Mqtt/MqttIotHubAdapter.cs [326:404]
67 lines of code
11 McCabe index (conditional complexity)

        private async Task ConnectAsync(IChannelHandlerContext context)
        {
            if (Logging.IsEnabled)
                Logging.Enter(this, context.Name, nameof(ConnectAsync));

            try
            {
                string id = string.IsNullOrWhiteSpace(_moduleId) ? _deviceId : $"{_deviceId}/{_moduleId}";
                string password = null;
                if (_passwordProvider != null)
                {
                    password = await _passwordProvider.GetPasswordAsync().ConfigureAwait(true);
                }
                else
                {
                    Debug.Assert(_mqttTransportSettings.ClientCertificate != null);
                }

                string usernameString = $"{_iotHubHostName}/{id}/?{ClientApiVersionHelper.ApiVersionQueryStringLatest}&{DeviceClientTypeParam}={Uri.EscapeDataString(_productInfo.ToString())}";

                if (!string.IsNullOrWhiteSpace(_mqttTransportSettings.AuthenticationChain))
                {
                    usernameString += $"&{AuthChainParam}={Uri.EscapeDataString(_mqttTransportSettings.AuthenticationChain)}";
                }

                // This check is added to enable the device or module client to available plug and play features. For devices or modules that pass in the model Id,
                // the SDK will enable plug and play features by appending the model Id to the MQTT CONNECT packet (in the username).
                if (!string.IsNullOrWhiteSpace(_options?.ModelId))
                {
                    usernameString += $"&{ModelIdParam}={Uri.EscapeDataString(_options.ModelId)}";
                }

                if (Logging.IsEnabled)
                    Logging.Info(this, $"{nameof(usernameString)}={usernameString}", nameof(ConnectAsync));

                var connectPacket = new ConnectPacket
                {
                    ClientId = id,
                    HasUsername = true,
                    Username = usernameString,
                    HasPassword = !string.IsNullOrEmpty(password),
                    Password = password,
                    KeepAliveInSeconds = _mqttTransportSettings.KeepAliveInSeconds,
                    CleanSession = _mqttTransportSettings.CleanSession,
                    HasWill = _mqttTransportSettings.HasWill
                };

                if (connectPacket.HasWill)
                {
                    Message message = _willMessage.Message;
                    QualityOfService publishToServerQoS = _mqttTransportSettings.PublishToServerQoS;
                    string topicName = GetTelemetryTopicName();
                    PublishPacket will = await ComposePublishPacketAsync(context, message, publishToServerQoS, topicName).ConfigureAwait(true);

                    connectPacket.WillMessage = will.Payload;
                    connectPacket.WillQualityOfService = _willMessage.QoS;
                    connectPacket.WillRetain = false;
                    connectPacket.WillTopicName = will.TopicName;
                }
                _stateFlags = StateFlags.Connecting;

                ScheduleCheckConnectTimeoutAsync(context);
                await WriteMessageAsync(context, connectPacket, s_shutdownOnWriteErrorHandler).ConfigureAwait(true);
                _lastChannelActivityTime = DateTime.UtcNow;
                ScheduleKeepConnectionAliveAsync(context);
            }
            catch (Exception ex) when (!ex.IsFatal())
            {
                if (Logging.IsEnabled)
                    Logging.Error(this, $"A non-fatal exception occurred while opening the MQTT connection, will shut down: {ex}", nameof(ConnectAsync));

                ShutdownOnErrorAsync(context, ex);
            }
            finally
            {
                if (Logging.IsEnabled)
                    Logging.Exit(this, context.Name, nameof(ConnectAsync));
            }
        }