feat(dfu): add firmware update controls to device page

lib/pages/device_details_page.dart

@@ -1,6 +1,9 @@
 import 'dart:async';
 
+import 'package:abawo_bt_app/model/firmware_file_selection.dart';
 import 'package:abawo_bt_app/model/shifter_types.dart';
+import 'package:abawo_bt_app/service/firmware_file_selection_service.dart';
+import 'package:abawo_bt_app/service/firmware_update_service.dart';
 import 'package:abawo_bt_app/service/shifter_service.dart';
 import 'package:abawo_bt_app/widgets/bike_scan_dialog.dart';
 import 'package:abawo_bt_app/widgets/gear_ratio_editor_card.dart';
@@ -64,9 +67,46 @@ class _DeviceDetailsPageState extends ConsumerState<DeviceDetailsPage> {
   List<double> _gearRatios = const [];
   int _defaultGearIndex = 0;
 
+  late final FirmwareFileSelectionService _firmwareFileSelectionService;
+  FirmwareUpdateService? _firmwareUpdateService;
+  StreamSubscription<DfuUpdateProgress>? _firmwareProgressSubscription;
+  DfuV1PreparedFirmware? _selectedFirmware;
+  DfuUpdateProgress _dfuProgress = const DfuUpdateProgress(
+    state: DfuUpdateState.idle,
+    totalBytes: 0,
+    sentBytes: 0,
+    lastAckedSequence: 0xFF,
+    sessionId: 0,
+    flags: DfuUpdateFlags(),
+  );
+  bool _isSelectingFirmware = false;
+  bool _isStartingFirmwareUpdate = false;
+  String? _firmwareUserMessage;
+
+  bool get _isFirmwareUpdateBusy {
+    if (_isStartingFirmwareUpdate) {
+      return true;
+    }
+    switch (_dfuProgress.state) {
+      case DfuUpdateState.starting:
+      case DfuUpdateState.waitingForAck:
+      case DfuUpdateState.transferring:
+      case DfuUpdateState.finishing:
+        return true;
+      case DfuUpdateState.idle:
+      case DfuUpdateState.completed:
+      case DfuUpdateState.aborted:
+      case DfuUpdateState.failed:
+        return false;
+    }
+  }
+
   @override
   void initState() {
     super.initState();
+    _firmwareFileSelectionService = FirmwareFileSelectionService(
+      filePicker: LocalFirmwareFilePicker(),
+    );
     _connectionStatusSubscription =
         ref.listenManual<AsyncValue<(ConnectionStatus, String?)>>(
       connectionStatusProvider,
@@ -88,6 +128,8 @@ class _DeviceDetailsPageState extends ConsumerState<DeviceDetailsPage> {
     _connectionStatusSubscription?.close();
     _statusSubscription?.cancel();
     _shifterService?.dispose();
+    _firmwareProgressSubscription?.cancel();
+    unawaited(_firmwareUpdateService?.dispose() ?? Future<void>.value());
     super.dispose();
   }
 
@@ -100,6 +142,9 @@ class _DeviceDetailsPageState extends ConsumerState<DeviceDetailsPage> {
     _isExitingPage = true;
     _reconnectTimeoutTimer?.cancel();
 
+    await _firmwareUpdateService?.cancelUpdate();
+    await _disposeFirmwareUpdateService();
+
     final bluetooth = ref.read(bluetoothProvider).value;
     await bluetooth?.disconnect();
     await _stopStatusStreaming();
@@ -127,11 +172,13 @@ class _DeviceDetailsPageState extends ConsumerState<DeviceDetailsPage> {
 
     if (_wasConnectedToCurrentDevice &&
         !_isReconnecting &&
-        status == ConnectionStatus.disconnected) {
+        status == ConnectionStatus.disconnected &&
+        !_isFirmwareUpdateBusy) {
       _startReconnect();
     }
 
-    if (!isCurrentDevice || status == ConnectionStatus.disconnected) {
+    if ((!isCurrentDevice || status == ConnectionStatus.disconnected) &&
+        !_isFirmwareUpdateBusy) {
       _stopStatusStreaming();
     }
   }
@@ -161,6 +208,13 @@ class _DeviceDetailsPageState extends ConsumerState<DeviceDetailsPage> {
 
   Future<void> _startStatusStreamingIfNeeded() async {
     if (_shifterService != null) {
+      _statusSubscription ??= _shifterService!.statusStream.listen((status) {
+        if (!mounted) {
+          return;
+        }
+        _recordStatus(status);
+      });
+      _shifterService!.startStatusNotifications();
       if (!_hasLoadedGearRatios && !_isGearRatiosLoading) {
         unawaited(_loadGearRatios());
       }
@@ -216,13 +270,26 @@ class _DeviceDetailsPageState extends ConsumerState<DeviceDetailsPage> {
   Future<void> _stopStatusStreaming() async {
     await _statusSubscription?.cancel();
     _statusSubscription = null;
+
+    if (_isFirmwareUpdateBusy) {
+      return;
+    }
+
+    await _disposeFirmwareUpdateService();
     await _shifterService?.dispose();
     _shifterService = null;
   }
 
+  Future<void> _disposeFirmwareUpdateService() async {
+    await _firmwareProgressSubscription?.cancel();
+    _firmwareProgressSubscription = null;
+    await _firmwareUpdateService?.dispose();
+    _firmwareUpdateService = null;
+  }
+
   Future<void> _loadGearRatios() async {
     final shifter = _shifterService;
-    if (shifter == null || _isGearRatiosLoading) {
+    if (shifter == null || _isGearRatiosLoading || _isFirmwareUpdateBusy) {
       return;
     }
 
@@ -257,6 +324,10 @@ class _DeviceDetailsPageState extends ConsumerState<DeviceDetailsPage> {
 
   Future<String?> _saveGearRatios(
       List<double> ratios, int defaultGearIndex) async {
+    if (_isFirmwareUpdateBusy) {
+      return 'Gear ratio changes are disabled during firmware update.';
+    }
+
     final shifter = _shifterService;
     if (shifter == null) {
       return 'Status channel is not ready yet.';
@@ -289,6 +360,15 @@ class _DeviceDetailsPageState extends ConsumerState<DeviceDetailsPage> {
   }
 
   Future<void> _connectButtonToBike() async {
+    if (_isFirmwareUpdateBusy) {
+      ScaffoldMessenger.of(context).showSnackBar(
+        const SnackBar(
+          content: Text('Connect to bike is disabled during firmware updates.'),
+        ),
+      );
+      return;
+    }
+
     final selectedBike = await BikeScanDialog.show(
       context,
       excludedDeviceId: widget.deviceAddress,
@@ -328,6 +408,177 @@ class _DeviceDetailsPageState extends ConsumerState<DeviceDetailsPage> {
     );
   }
 
+  Future<FirmwareUpdateService?> _ensureFirmwareUpdateService() async {
+    final shifter = _shifterService;
+    if (shifter == null) {
+      return null;
+    }
+    if (_firmwareUpdateService != null) {
+      return _firmwareUpdateService;
+    }
+
+    final asyncBluetooth = ref.read(bluetoothProvider);
+    final bluetooth = asyncBluetooth.valueOrNull;
+    if (bluetooth == null) {
+      return null;
+    }
+
+    final service = FirmwareUpdateService(
+      transport: ShifterFirmwareUpdateTransport(
+        shifterService: shifter,
+        bluetoothController: bluetooth,
+        buttonDeviceId: widget.deviceAddress,
+      ),
+    );
+
+    _firmwareProgressSubscription = service.progressStream.listen((progress) {
+      if (!mounted) {
+        return;
+      }
+      setState(() {
+        _dfuProgress = progress;
+        if (progress.state == DfuUpdateState.failed &&
+            progress.errorMessage != null) {
+          _firmwareUserMessage = progress.errorMessage;
+        }
+        if (progress.state == DfuUpdateState.completed) {
+          _firmwareUserMessage =
+              'Firmware update completed. The button rebooted and reconnected.';
+        }
+        if (progress.state == DfuUpdateState.aborted) {
+          _firmwareUserMessage = 'Firmware update canceled.';
+        }
+      });
+    });
+
+    _firmwareUpdateService = service;
+    return service;
+  }
+
+  Future<void> _selectFirmwareFile() async {
+    if (_isFirmwareUpdateBusy || _isSelectingFirmware) {
+      return;
+    }
+
+    setState(() {
+      _isSelectingFirmware = true;
+      _firmwareUserMessage = null;
+    });
+
+    final result = await _firmwareFileSelectionService.selectAndPrepareDfuV1();
+    if (!mounted) {
+      return;
+    }
+
+    setState(() {
+      _isSelectingFirmware = false;
+      if (result.isSuccess) {
+        _selectedFirmware = result.firmware;
+        _firmwareUserMessage =
+            'Selected ${result.firmware!.fileName}. Ready to start update.';
+      } else if (!result.isCanceled) {
+        _firmwareUserMessage = result.failure?.message;
+      }
+    });
+  }
+
+  Future<void> _startFirmwareUpdate() async {
+    if (_isFirmwareUpdateBusy || _isSelectingFirmware) {
+      return;
+    }
+
+    final firmware = _selectedFirmware;
+    if (firmware == null) {
+      setState(() {
+        _firmwareUserMessage =
+            'Select a firmware .bin file before starting the update.';
+      });
+      return;
+    }
+
+    await _startStatusStreamingIfNeeded();
+    final updater = await _ensureFirmwareUpdateService();
+    if (!mounted) {
+      return;
+    }
+    if (updater == null) {
+      setState(() {
+        _firmwareUserMessage =
+            'Firmware updater is not ready. Ensure the button is connected.';
+      });
+      return;
+    }
+
+    setState(() {
+      _isStartingFirmwareUpdate = true;
+      _firmwareUserMessage =
+          'Starting update. Keep this screen open and stay near the button.';
+    });
+
+    final result = await updater.startUpdate(
+      imageBytes: firmware.fileBytes,
+      sessionId: firmware.metadata.sessionId,
+      flags: DfuUpdateFlags.fromRaw(firmware.metadata.flags),
+    );
+
+    if (!mounted) {
+      return;
+    }
+
+    setState(() {
+      _isStartingFirmwareUpdate = false;
+      if (result.isErr()) {
+        _firmwareUserMessage = result.unwrapErr().toString();
+      }
+    });
+  }
+
+  Future<void> _cancelFirmwareUpdate() async {
+    final updater = _firmwareUpdateService;
+    if (updater == null || !_isFirmwareUpdateBusy) {
+      return;
+    }
+    setState(() {
+      _firmwareUserMessage = 'Canceling firmware update...';
+    });
+    await updater.cancelUpdate();
+  }
+
+  String _dfuPhaseText(DfuUpdateState state) {
+    switch (state) {
+      case DfuUpdateState.idle:
+        return 'Idle';
+      case DfuUpdateState.starting:
+        return 'Sending START command';
+      case DfuUpdateState.waitingForAck:
+        return 'Waiting for ACK from button';
+      case DfuUpdateState.transferring:
+        return 'Transferring firmware frames';
+      case DfuUpdateState.finishing:
+        return 'Finalizing update and waiting for reboot/reconnect';
+      case DfuUpdateState.completed:
+        return 'Update completed';
+      case DfuUpdateState.aborted:
+        return 'Update canceled';
+      case DfuUpdateState.failed:
+        return 'Update failed';
+    }
+  }
+
+  String _formatBytes(int bytes) {
+    if (bytes < 1024) {
+      return '$bytes B';
+    }
+    if (bytes < 1024 * 1024) {
+      return '${(bytes / 1024).toStringAsFixed(1)} KB';
+    }
+    return '${(bytes / (1024 * 1024)).toStringAsFixed(2)} MB';
+  }
+
+  String _hexByte(int value) {
+    return '0x${(value & 0xFF).toRadixString(16).padLeft(2, '0').toUpperCase()}';
+  }
+
   Future<void> _terminateConnectionAndGoHome(String toastMessage) async {
     await _disconnectOnClose();
 
@@ -465,6 +716,13 @@ class _DeviceDetailsPageState extends ConsumerState<DeviceDetailsPage> {
     final isCurrentConnected = connectionData != null &&
         connectionData.$1 == ConnectionStatus.connected &&
         connectionData.$2 == widget.deviceAddress;
+    final canSelectFirmware =
+        isCurrentConnected && !_isSelectingFirmware && !_isFirmwareUpdateBusy;
+    final canStartFirmware = isCurrentConnected &&
+        !_isSelectingFirmware &&
+        !_isFirmwareUpdateBusy &&
+        _selectedFirmware != null;
+    final canCancelFirmware = _isFirmwareUpdateBusy;
 
     return PopScope(
       canPop: false,
@@ -508,18 +766,42 @@ class _DeviceDetailsPageState extends ConsumerState<DeviceDetailsPage> {
                     SizedBox(
                       width: double.infinity,
                       child: FilledButton.icon(
-                        onPressed: _connectButtonToBike,
+                        onPressed:
+                            _isFirmwareUpdateBusy ? null : _connectButtonToBike,
                         icon: const Icon(Icons.link),
                         label: const Text('Connect Button to Bike'),
                       ),
                     ),
                     const SizedBox(height: 16),
-                    GearRatioEditorCard(
+                    _FirmwareUpdateCard(
+                      selectedFirmware: _selectedFirmware,
+                      progress: _dfuProgress,
+                      isSelecting: _isSelectingFirmware,
+                      isStarting: _isStartingFirmwareUpdate,
+                      canSelect: canSelectFirmware,
+                      canStart: canStartFirmware,
+                      canCancel: canCancelFirmware,
+                      phaseText: _dfuPhaseText(_dfuProgress.state),
+                      statusText: _firmwareUserMessage,
+                      formattedProgressBytes:
+                          '${_formatBytes(_dfuProgress.sentBytes)} / ${_formatBytes(_dfuProgress.totalBytes)}',
+                      onSelectFirmware: _selectFirmwareFile,
+                      onStartUpdate: _startFirmwareUpdate,
+                      onCancelUpdate: _cancelFirmwareUpdate,
+                      ackSequenceHex: _hexByte(_dfuProgress.lastAckedSequence),
+                    ),
+                    const SizedBox(height: 16),
+                    Opacity(
+                      opacity: _isFirmwareUpdateBusy ? 0.6 : 1,
+                      child: AbsorbPointer(
+                        absorbing: _isFirmwareUpdateBusy,
+                        child: GearRatioEditorCard(
                           ratios: _gearRatios,
                           defaultGearIndex: _defaultGearIndex,
                           isLoading: _isGearRatiosLoading,
                           errorText: _gearRatiosError,
-                      onRetry: _loadGearRatios,
+                          onRetry:
+                              _isFirmwareUpdateBusy ? null : _loadGearRatios,
                           onSave: _saveGearRatios,
                           presets: const [
                             GearRatioPreset(
@@ -530,6 +812,8 @@ class _DeviceDetailsPageState extends ConsumerState<DeviceDetailsPage> {
                             ),
                           ],
                         ),
+                      ),
+                    ),
                   ],
                 ],
               ),
@@ -583,6 +867,159 @@ class _StatusHistoryEntry {
   final CentralStatus status;
 }
 
+class _FirmwareUpdateCard extends StatelessWidget {
+  const _FirmwareUpdateCard({
+    required this.selectedFirmware,
+    required this.progress,
+    required this.isSelecting,
+    required this.isStarting,
+    required this.canSelect,
+    required this.canStart,
+    required this.canCancel,
+    required this.phaseText,
+    required this.statusText,
+    required this.formattedProgressBytes,
+    required this.ackSequenceHex,
+    required this.onSelectFirmware,
+    required this.onStartUpdate,
+    required this.onCancelUpdate,
+  });
+
+  final DfuV1PreparedFirmware? selectedFirmware;
+  final DfuUpdateProgress progress;
+  final bool isSelecting;
+  final bool isStarting;
+  final bool canSelect;
+  final bool canStart;
+  final bool canCancel;
+  final String phaseText;
+  final String? statusText;
+  final String formattedProgressBytes;
+  final String ackSequenceHex;
+  final Future<void> Function() onSelectFirmware;
+  final Future<void> Function() onStartUpdate;
+  final Future<void> Function() onCancelUpdate;
+
+  bool get _showProgress {
+    return progress.totalBytes > 0 ||
+        progress.sentBytes > 0 ||
+        progress.state != DfuUpdateState.idle;
+  }
+
+  bool get _showRebootExpectation {
+    return progress.state == DfuUpdateState.finishing ||
+        progress.state == DfuUpdateState.completed;
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+    final colorScheme = theme.colorScheme;
+
+    return Container(
+      decoration: BoxDecoration(
+        borderRadius: BorderRadius.circular(16),
+        color: colorScheme.surfaceContainerHighest.withValues(alpha: 0.55),
+        border: Border.all(
+          color: colorScheme.outlineVariant.withValues(alpha: 0.6),
+        ),
+      ),
+      padding: const EdgeInsets.fromLTRB(14, 12, 14, 14),
+      child: Column(
+        crossAxisAlignment: CrossAxisAlignment.start,
+        children: [
+          const Text(
+            'Firmware Update',
+            style: TextStyle(fontSize: 17, fontWeight: FontWeight.w700),
+          ),
+          const SizedBox(height: 10),
+          Wrap(
+            spacing: 8,
+            runSpacing: 8,
+            children: [
+              OutlinedButton.icon(
+                onPressed: canSelect ? onSelectFirmware : null,
+                icon: isSelecting
+                    ? const SizedBox(
+                        width: 16,
+                        height: 16,
+                        child: CircularProgressIndicator(strokeWidth: 2),
+                      )
+                    : const Icon(Icons.upload_file),
+                label: const Text('Select Firmware'),
+              ),
+              FilledButton.icon(
+                onPressed: canStart ? onStartUpdate : null,
+                icon: isStarting
+                    ? const SizedBox(
+                        width: 16,
+                        height: 16,
+                        child: CircularProgressIndicator(strokeWidth: 2),
+                      )
+                    : const Icon(Icons.system_update_alt),
+                label: const Text('Start Update'),
+              ),
+              TextButton.icon(
+                onPressed: canCancel ? onCancelUpdate : null,
+                icon: const Icon(Icons.stop_circle_outlined),
+                label: const Text('Cancel Update'),
+              ),
+            ],
+          ),
+          const SizedBox(height: 10),
+          Text(
+            selectedFirmware == null
+                ? 'Selected file: none'
+                : 'Selected file: ${selectedFirmware!.fileName}',
+            style: theme.textTheme.bodyMedium,
+          ),
+          if (selectedFirmware != null) ...[
+            const SizedBox(height: 4),
+            Text(
+              'Size: ${selectedFirmware!.fileBytes.length} bytes  |  Session: ${selectedFirmware!.metadata.sessionId}  |  CRC32: 0x${selectedFirmware!.metadata.crc32.toRadixString(16).padLeft(8, '0').toUpperCase()}',
+              style: theme.textTheme.bodySmall,
+            ),
+          ],
+          const SizedBox(height: 10),
+          Text('Phase: $phaseText', style: theme.textTheme.bodyMedium),
+          if (_showProgress) ...[
+            const SizedBox(height: 8),
+            LinearProgressIndicator(
+              value: progress.totalBytes > 0 ? progress.fractionComplete : 0,
+            ),
+            const SizedBox(height: 6),
+            Text(
+              '${progress.percentComplete}%  •  $formattedProgressBytes  •  Last ACK $ackSequenceHex',
+              style: theme.textTheme.bodySmall,
+            ),
+          ],
+          if (_showRebootExpectation) ...[
+            const SizedBox(height: 8),
+            Text(
+              'Expected behavior: the button reboots after FINISH, disconnects briefly, then reconnects.',
+              style: theme.textTheme.bodySmall?.copyWith(
+                color: colorScheme.primary,
+                fontWeight: FontWeight.w600,
+              ),
+            ),
+          ],
+          if (statusText != null && statusText!.trim().isNotEmpty) ...[
+            const SizedBox(height: 8),
+            Text(
+              statusText!,
+              style: theme.textTheme.bodySmall?.copyWith(
+                color: progress.state == DfuUpdateState.failed
+                    ? colorScheme.error
+                    : theme.textTheme.bodySmall?.color,
+              ),
+            ),
+          ],
+        ],
+      ),
+    );
+  }
+}
+
 class _StatusBanner extends StatelessWidget {
   const _StatusBanner({
     required this.status,