Enhance USB serial services with debug logging and reset functionality

- Introduced debug logging in USB serial services for better traceability.
- Added reset method to UsbSerialFrameDecoder to clear buffered data.
- Updated tests to verify the reset functionality of the decoder.

lib/connector/meshcore_connector.dart

@@ -350,11 +350,38 @@ class MeshCoreConnector extends ChangeNotifier {
           ? allMessages.sublist(allMessages.length - _messageWindowSize)
           : allMessages;
 
-      _conversations[contactKeyHex] = windowedMessages;
+      final currentMessages =
+          _conversations[contactKeyHex] ?? const <Message>[];
+      final mergedMessages = <Message>[...windowedMessages];
+      final existingKeys = <String>{
+        for (final message in windowedMessages) _messageMergeKey(message),
+      };
+
+      for (final message in currentMessages) {
+        final key = _messageMergeKey(message);
+        if (existingKeys.add(key)) {
+          mergedMessages.add(message);
+        }
+      }
+
+      mergedMessages.sort((a, b) => a.timestamp.compareTo(b.timestamp));
+      final windowedMergedMessages = mergedMessages.length > _messageWindowSize
+          ? mergedMessages.sublist(mergedMessages.length - _messageWindowSize)
+          : mergedMessages;
+
+      _conversations[contactKeyHex] = windowedMergedMessages;
       notifyListeners();
     }
   }
 
+  String _messageMergeKey(Message message) {
+    final messageId = message.messageId;
+    if (messageId != null && messageId.isNotEmpty) {
+      return 'id:$messageId';
+    }
+    return 'fallback:${message.isOutgoing}:${message.timestamp.millisecondsSinceEpoch}:${message.text}';
+  }
+
   /// Load older messages for a contact (pagination)
   Future<List<Message>> loadOlderMessages(
     String contactKeyHex, {
@@ -590,6 +617,7 @@ class MeshCoreConnector extends ChangeNotifier {
     _bleDebugLogService = bleDebugLogService;
     _appDebugLogService = appDebugLogService;
     _backgroundService = backgroundService;
+    _usbSerialService.setDebugLogService(_appDebugLogService);
 
     // Initialize notification service
     _notificationService.initialize();
@@ -749,7 +777,7 @@ class MeshCoreConnector extends ChangeNotifier {
         androidScanMode: AndroidScanMode.lowLatency,
       );
     } catch (error) {
-      debugPrint('[BLE Scan] Scan/picker failure: $error');
+      _appDebugLogService?.warn('Scan/picker failure: $error', tag: 'BLE Scan');
       _setState(MeshCoreConnectionState.disconnected);
       rethrow;
     }
@@ -806,7 +834,10 @@ class MeshCoreConnector extends ChangeNotifier {
 
     try {
       final connectLabel = _deviceDisplayName ?? _deviceId;
-      debugPrint('[BLE Connect] Starting connect to $connectLabel');
+      _appDebugLogService?.info(
+        'Starting connect to $connectLabel',
+        tag: 'BLE Connect',
+      );
       _connectionSubscription = device.connectionState.listen((state) {
         if (state == BluetoothConnectionState.disconnected && isConnected) {
           _handleDisconnection();
@@ -820,7 +851,10 @@ class MeshCoreConnector extends ChangeNotifier {
           license: License.free,
         );
       } catch (error) {
-        debugPrint('[BLE Connect] device.connect() failure: $error');
+        _appDebugLogService?.error(
+          'device.connect() failure: $error',
+          tag: 'BLE Connect',
+        );
         rethrow;
       }
 
@@ -828,9 +862,12 @@ class MeshCoreConnector extends ChangeNotifier {
       if (!PlatformInfo.isWeb) {
         try {
           final mtu = await device.requestMtu(185);
-          debugPrint('MTU set to: $mtu');
+          _appDebugLogService?.info('MTU set to: $mtu', tag: 'BLE Connect');
         } catch (e) {
-          debugPrint('MTU request failed: $e, using default');
+          _appDebugLogService?.warn(
+            'MTU request failed: $e, using default',
+            tag: 'BLE Connect',
+          );
         }
       }
 
@@ -838,11 +875,15 @@ class MeshCoreConnector extends ChangeNotifier {
       try {
         services = await device.discoverServices();
       } catch (error) {
-        debugPrint('[BLE Connect] service discovery failure: $error');
+        _appDebugLogService?.error(
+          'service discovery failure: $error',
+          tag: 'BLE Connect',
+        );
         if (PlatformInfo.isWeb &&
             error.toString().contains('GATT Server is disconnected')) {
-          debugPrint(
-            '[BLE Connect] retrying service discovery after transient web disconnect',
+          _appDebugLogService?.warn(
+            'retrying service discovery after transient web disconnect',
+            tag: 'BLE Connect',
           );
           await Future<void>.delayed(const Duration(milliseconds: 300));
           await device.connect(
@@ -882,17 +923,32 @@ class MeshCoreConnector extends ChangeNotifier {
       }
 
       if (PlatformInfo.isWeb) {
-        debugPrint('Starting setNotifyValue(true)');
-        debugPrint('Web: Calling setNotifyValue(true) without awaiting');
+        _appDebugLogService?.info(
+          'Starting setNotifyValue(true)',
+          tag: 'BLE Connect',
+        );
+        _appDebugLogService?.info(
+          'Web: Calling setNotifyValue(true) without awaiting',
+          tag: 'BLE Connect',
+        );
         unawaited(() async {
           try {
             await _txCharacteristic!.setNotifyValue(true);
           } catch (error) {
-            debugPrint('[BLE Connect] notify failure (web, ignored): $error');
-            debugPrint('Web setNotifyValue error (ignoring): $error');
+            _appDebugLogService?.warn(
+              'notify failure (web, ignored): $error',
+              tag: 'BLE Connect',
+            );
+            _appDebugLogService?.warn(
+              'Web setNotifyValue error (ignoring): $error',
+              tag: 'BLE Connect',
+            );
           }
         }());
-        debugPrint('setNotifyValue(true) configuration completed');
+        _appDebugLogService?.info(
+          'setNotifyValue(true) configuration completed',
+          tag: 'BLE Connect',
+        );
       } else {
         bool notifySet = false;
         for (int attempt = 0; attempt < 3 && !notifySet; attempt++) {
@@ -903,8 +959,11 @@ class MeshCoreConnector extends ChangeNotifier {
             await _txCharacteristic!.setNotifyValue(true);
             notifySet = true;
           } catch (e) {
-            debugPrint('[BLE Connect] notify failure: $e');
-            debugPrint('setNotifyValue attempt ${attempt + 1}/3 failed: $e');
+            _appDebugLogService?.warn('notify failure: $e', tag: 'BLE Connect');
+            _appDebugLogService?.warn(
+              'setNotifyValue attempt ${attempt + 1}/3 failed: $e',
+              tag: 'BLE Connect',
+            );
             if (attempt == 2) rethrow;
           }
         }
@@ -925,7 +984,19 @@ class MeshCoreConnector extends ChangeNotifier {
           _activeTransport == MeshCoreTransportType.bluetooth) {
         // Chrome's Web Bluetooth stack commonly delays incoming notifications
         // until the non-blocking notify setup settles. Avoid stacking extra
-        // startup writes while that is happening.
+        // startup writes while that is happening. Defer the clock sync until
+        // the connection has had time to settle.
+        unawaited(
+          Future<void>(() async {
+            await Future<void>.delayed(const Duration(seconds: 5));
+            if (!isConnected ||
+                !PlatformInfo.isWeb ||
+                _activeTransport != MeshCoreTransportType.bluetooth) {
+              return;
+            }
+            await syncTime();
+          }),
+        );
       } else {
         final gotSelfInfo = await _waitForSelfInfo(
           timeout: const Duration(seconds: 3),
@@ -943,7 +1014,7 @@ class MeshCoreConnector extends ChangeNotifier {
         unawaited(getChannels());
       }
     } catch (e) {
-      debugPrint("Connection error: $e");
+      _appDebugLogService?.error('Connection error: $e', tag: 'BLE Connect');
       await disconnect(manual: false);
       rethrow;
     }
@@ -986,7 +1057,7 @@ class MeshCoreConnector extends ChangeNotifier {
       _usbFrameSubscription = _usbSerialService.frameStream.listen(
         _handleFrame,
         onError: (error, stackTrace) {
-          debugPrint('USB transport error: $error');
+          _appDebugLogService?.error('USB transport error: $error', tag: 'USB');
           unawaited(disconnect(manual: false));
         },
         onDone: () {
@@ -1013,7 +1084,7 @@ class MeshCoreConnector extends ChangeNotifier {
 
       await syncTime();
     } catch (error) {
-      debugPrint('USB connection error: $error');
+      _appDebugLogService?.error('USB connection error: $error', tag: 'USB');
       await disconnect(manual: false);
       rethrow;
     }
@@ -1149,7 +1220,7 @@ class MeshCoreConnector extends ChangeNotifier {
       // Skip queued BLE operations so disconnect doesn't get stuck behind them.
       await _device?.disconnect(queue: false);
     } catch (e) {
-      debugPrint("Disconnect error: $e");
+      _appDebugLogService?.warn('Disconnect error: $e', tag: 'BLE Connect');
     }
 
     _device = null;

lib/services/usb_serial_frame_codec.dart

@@ -37,6 +37,11 @@ class UsbSerialFrameDecoder {
   final List<int> _rxBuffer = <int>[];
   int _startIndex = 0;
 
+  void reset() {
+    _rxBuffer.clear();
+    _startIndex = 0;
+  }
+
   List<UsbSerialDecodedPacket> ingest(Uint8List bytes) {
     if (bytes.isEmpty) {
       return const <UsbSerialDecodedPacket>[];

lib/services/usb_serial_service_native.dart

@@ -5,6 +5,7 @@ import 'package:flserial/flserial_exception.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 
+import 'app_debug_log_service.dart';
 import '../utils/platform_info.dart';
 import '../utils/usb_port_labels.dart';
 import 'usb_serial_frame_codec.dart';
@@ -29,6 +30,7 @@ class UsbSerialService {
   String? _connectedPortKey;
   String? _connectedPortLabel;
   FlSerial? _serial;
+  AppDebugLogService? _debugLogService;
 
   UsbSerialStatus get status => _status;
   String? get activePortKey => _connectedPortKey;
@@ -66,6 +68,10 @@ class UsbSerialService {
     return Future.value(FlSerial.listPorts());
   }
 
+  void setDebugLogService(AppDebugLogService? service) {
+    _debugLogService = service;
+  }
+
   Future<void> connect({
     required String portName,
     int baudRate = 115200,
@@ -80,6 +86,7 @@ class UsbSerialService {
 
     _status = UsbSerialStatus.connecting;
     final normalizedPortName = normalizeUsbPortName(portName);
+    _frameDecoder.reset();
 
     if (_useAndroidUsbHost) {
       try {
@@ -87,8 +94,9 @@ class UsbSerialService {
           'portName': normalizedPortName,
           'baudRate': baudRate,
         });
-        debugPrint(
+        _debugLogService?.info(
           'USB serial opened port=$normalizedPortName on Android via USB host bridge',
+          tag: 'USB Serial',
         );
       } on PlatformException catch (error) {
         _status = UsbSerialStatus.disconnected;
@@ -111,8 +119,9 @@ class UsbSerialService {
         serial.setFlowControlNone();
         serial.setRTS(false);
         serial.setDTR(true);
-        debugPrint(
+        _debugLogService?.info(
           'USB serial opened port=$normalizedPortName cts=${serial.getCTS()} dsr=${serial.getDSR()} dtr=true rts=false',
+          tag: 'USB Serial',
         );
       } on FlSerialException catch (error) {
         _serial?.free();
@@ -174,6 +183,7 @@ class UsbSerialService {
     _status = UsbSerialStatus.disconnecting;
     _connectedPortKey = null;
     _connectedPortLabel = null;
+    _frameDecoder.reset();
     await _androidDataSubscription?.cancel();
     _androidDataSubscription = null;
     await _dataSubscription?.cancel();
@@ -255,8 +265,9 @@ class UsbSerialService {
   void _ingestRawBytes(Uint8List bytes) {
     for (final packet in _frameDecoder.ingest(bytes)) {
       if (!packet.isRxFrame) {
-        debugPrint(
+        _debugLogService?.info(
           'USB ignored packet start=0x${packet.frameStart.toRadixString(16).padLeft(2, '0')} len=${packet.payload.length}',
+          tag: 'USB Serial',
         );
         continue;
       }
@@ -287,10 +298,13 @@ class UsbSerialService {
 
   void _logFrameSummary(String prefix, Uint8List bytes) {
     if (bytes.isEmpty) {
-      debugPrint('$prefix len=0');
+      _debugLogService?.info('$prefix len=0', tag: 'USB Serial');
       return;
     }
-    debugPrint('$prefix code=${bytes[0]} len=${bytes.length}');
+    _debugLogService?.info(
+      '$prefix code=${bytes[0]} len=${bytes.length}',
+      tag: 'USB Serial',
+    );
   }
 }
 

lib/services/usb_serial_service_web.dart

@@ -5,6 +5,7 @@ import 'dart:js_interop_unsafe';
 import 'package:flutter/foundation.dart';
 import 'package:web/web.dart' as web;
 
+import 'app_debug_log_service.dart';
 import '../utils/usb_port_labels.dart';
 import 'usb_serial_frame_codec.dart';
 
@@ -27,6 +28,7 @@ class UsbSerialService {
   String? _connectedPortName;
   String? _connectedPortKey;
   String _requestPortLabel = 'Choose USB Device';
+  AppDebugLogService? _debugLogService;
 
   UsbSerialStatus get status => _status;
   String? get activePortKey => _connectedPortKey;
@@ -69,6 +71,7 @@ class UsbSerialService {
     }
 
     _status = UsbSerialStatus.connecting;
+    _frameDecoder.reset();
 
     try {
       final requestedPortName = normalizeUsbPortName(portName);
@@ -88,7 +91,10 @@ class UsbSerialService {
       _status = UsbSerialStatus.connected;
       unawaited(_pumpReads());
 
-      debugPrint('USB serial opened port=$_connectedPortName via Web Serial');
+      _debugLogService?.info(
+        'USB serial opened port=$_connectedPortName via Web Serial',
+        tag: 'USB Serial',
+      );
     } catch (error) {
       await _cleanupFailedConnect();
       _status = UsbSerialStatus.disconnected;
@@ -126,6 +132,7 @@ class UsbSerialService {
     _port = null;
     _connectedPortName = null;
     _connectedPortKey = null;
+    _frameDecoder.reset();
 
     if (reader != null) {
       try {
@@ -169,6 +176,10 @@ class UsbSerialService {
     _requestPortLabel = trimmed;
   }
 
+  void setDebugLogService(AppDebugLogService? service) {
+    _debugLogService = service;
+  }
+
   void dispose() {
     unawaited(disconnect().whenComplete(_closeFrameController));
   }
@@ -407,8 +418,9 @@ class UsbSerialService {
   void _ingestRawBytes(Uint8List bytes) {
     for (final packet in _frameDecoder.ingest(bytes)) {
       if (!packet.isRxFrame) {
-        debugPrint(
+        _debugLogService?.info(
           'USB ignored packet start=0x${packet.frameStart.toRadixString(16).padLeft(2, '0')} len=${packet.payload.length}',
+          tag: 'USB Serial',
         );
         continue;
       }
@@ -439,10 +451,13 @@ class UsbSerialService {
 
   void _logFrameSummary(String prefix, Uint8List bytes) {
     if (bytes.isEmpty) {
-      debugPrint('$prefix len=0');
+      _debugLogService?.info('$prefix len=0', tag: 'USB Serial');
       return;
     }
-    debugPrint('$prefix code=${bytes[0]} len=${bytes.length}');
+    _debugLogService?.info(
+      '$prefix code=${bytes[0]} len=${bytes.length}',
+      tag: 'USB Serial',
+    );
   }
 }
 

test/services/usb_serial_frame_codec_test.dart

@@ -120,4 +120,22 @@ void main() {
       expect(packets.single.payload, orderedEquals(<int>[0x44]));
     },
   );
+
+  test('UsbSerialFrameDecoder reset clears buffered partial data', () {
+    final decoder = UsbSerialFrameDecoder();
+
+    expect(
+      decoder.ingest(Uint8List.fromList(<int>[usbSerialRxFrameStart, 0x02])),
+      isEmpty,
+    );
+
+    decoder.reset();
+
+    final packets = decoder.ingest(
+      Uint8List.fromList(<int>[usbSerialRxFrameStart, 0x01, 0x00, 0x55]),
+    );
+
+    expect(packets, hasLength(1));
+    expect(packets.single.payload, orderedEquals(<int>[0x55]));
+  });
 }