Added Cyton Status check

mobile/lib/src/application/device/device_selector_cubit.dart

@@ -36,7 +36,7 @@ class DeviceSelectorCubit extends Cubit<DeviceState> {
     _deviceRepository.connect(device, connectionCallback);
   }
 
-  void connectionCallback(bool connected, Exception e) {
+  void connectionCallback(bool connected, [Exception e]) {
     if (e != null) {
       emit(DeviceConnectionFailure(e));
       resetSearch();

mobile/lib/src/domain/acquisition_device/i_acquisition_device_repository.dart

@@ -3,7 +3,7 @@ import 'acquisition_device.dart';
 abstract class IAcquisitionDeviceRepository {
   void initializeRepository();
 
-  void connect(AcquisitionDevice device, Function(bool, Exception) callback);
+  void connect(AcquisitionDevice device, Function(bool, [Exception]) callback);
   void disconnect();
 
   Future<Stream<List<int>>> startDataStream();

mobile/lib/src/infrastructure/connection_repositories/bluetooth_repository.dart

@@ -49,7 +49,7 @@ class BluetoothRepository implements IAcquisitionDeviceRepository {
   }
 
   void connect(
-      AcquisitionDevice device, Function(bool, Exception) callback) async {
+      AcquisitionDevice device, Function(bool, [Exception]) callback) async {
     _selectedDevice = device;
     _acquisitionDevicePersistency.clear();
     _bluetoothScanSubscription.pause();
@@ -61,7 +61,7 @@ class BluetoothRepository implements IAcquisitionDeviceRepository {
         .listen((event) {
       if (event.connectionState == DeviceConnectionState.connected) {
         setupCharacteristics();
-        callback(true, null);
+        callback(true);
       } else if (event.connectionState == DeviceConnectionState.disconnected) {
         disconnect();
         callback(false, Exception("Failed to connect to device"));

mobile/lib/src/infrastructure/connection_repositories/serial_repository.dart

@@ -12,6 +12,7 @@ class SerialRepository implements IAcquisitionDeviceRepository {
   UsbPort _serialPort;
   List<AcquisitionDevice> _acquisitionDevicePersistency = [];
   List<UsbDevice> _serialDevices = [];
+  StreamSubscription _inputStreamSubscription;
   final streamController = StreamController<List<AcquisitionDevice>>();
 
   void initializeRepository() {
@@ -46,11 +47,40 @@ class SerialRepository implements IAcquisitionDeviceRepository {
     _serialPort.setPortParameters(
         115200, UsbPort.DATABITS_8, UsbPort.STOPBITS_1, UsbPort.PARITY_NONE);
 
-    callback(true, null);
+    _checkCytonConnection(callback);
+  }
+
+  Future<void> _checkCytonConnection(
+      Function(bool, [Exception]) callback) async {
+    var status = "";
+
+    _inputStreamSubscription = _serialPort.inputStream.listen((event) {
+      status += String.fromCharCodes(event);
+
+      if (isFullMessage(status)) {
+        _inputStreamSubscription.cancel();
+
+        if (status == CYTON_SYSTEM_UP)
+          callback(true);
+        else {
+          disconnect();
+          callback(false, Exception(status));
+        }
+      }
+    });
+
+    await _serialPort.write(Uint8List.fromList(CYTON_GET_STATUS));
+  }
+
+  bool isFullMessage(String message) {
+    return message.length > CYTON_MESSAGE_FOOTER.length &&
+        message.substring(message.length - CYTON_MESSAGE_FOOTER.length) ==
+            CYTON_MESSAGE_FOOTER;
   }
 
   Future<void> disconnect() async {
     await _serialPort?.close();
+    _inputStreamSubscription?.cancel();
     _selectedDevice = null;
     _serialPort = null;
   }

mobile/lib/src/infrastructure/constants.dart

@@ -29,6 +29,9 @@ const OPEN_BCI_GANGLION_HEADER = [
   ]
 ];
 
+const CYTON_MESSAGE_FOOTER = "\$\$\$";
+const CYTON_GET_STATUS = [0xF0, 0x07];
+const CYTON_SYSTEM_UP = "Success: System is Up\$\$\$";
 const CYTON_NUMBER_CHANNELS = 8;
 const CYTON_PACKET_SIZE = 33;
 const CYTON_NUMBER_COLUMNS = 24;