lib/data/models/location_data.dart

@@ -1,4 +1,7 @@
-class ProcessedGpsData {
+/// Domain model representing processed GPS data.
+///
+/// Immutable — use [copyWith] to create modified copies.
+class LocationData {
   final double speed;           // Raw speed in m/s
   final double heading;         // Raw heading in degrees
   final String displaySpeed;    // Formatted speed text (with -- logic)
@@ -7,7 +10,7 @@ class ProcessedGpsData {
   final bool isHeadingValid;    // True if from recent GPS
   final DateTime timestamp;     // Timestamp for staleness detection
 
-  const ProcessedGpsData({
+  const LocationData({
     required this.speed,
     required this.heading,
     required this.displaySpeed,
@@ -17,7 +20,7 @@ class ProcessedGpsData {
     required this.timestamp,
   });
 
-  ProcessedGpsData copyWith({
+  LocationData copyWith({
     double? speed,
     double? heading,
     String? displaySpeed,
@@ -26,7 +29,7 @@ class ProcessedGpsData {
     bool? isHeadingValid,
     DateTime? timestamp,
   }) {
-    return ProcessedGpsData(
+    return LocationData(
       speed: speed ?? this.speed,
       heading: heading ?? this.heading,
       displaySpeed: displaySpeed ?? this.displaySpeed,

lib/data/repositories/location_repository.dart

@@ -0,0 +1,335 @@
+import 'dart:async';
+import 'dart:developer' as developer;
+import 'package:flutter/widgets.dart';
+import 'package:geolocator/geolocator.dart';
+import '../../core/constants/gps_constants.dart';
+import '../../services/logger.dart';
+import '../models/location_data.dart';
+import '../services/gps_service.dart';
+
+/// Repository that wraps GpsService and applies GPS business logic.
+///
+/// Single source of truth for location data. Handles:
+/// - GPS stream management (start/stop/restart)
+/// - Data processing (staleness, precision switching, validation)
+/// - Lifecycle management (app foreground/background, wake lock)
+class LocationRepository extends ChangeNotifier with WidgetsBindingObserver {
+  StreamSubscription<Position>? _gpsSubscription;
+  final StreamController<LocationData> _dataController =
+      StreamController<LocationData>.broadcast();
+
+  // Use late to defer DateTime.now() — const constructors can't call methods
+  late LocationData _currentData = LocationData(
+    speed: 0.0,
+    heading: -1.0,
+    displaySpeed: '--',
+    displayHeading: 'N/A',
+    isSpeedValid: false,
+    isHeadingValid: false,
+    timestamp: DateTime.now(),
+  );
+
+  Timer? _staleDataTimer;
+  Timer? _backgroundGracePeriodTimer;
+  bool _isDisposed = false;
+
+  // Lifecycle and precision state
+  LocationAccuracy _currentAccuracy = LocationAccuracy.high;
+  bool _hasFirstFix = false;
+  DateTime? _firstFixTime;
+  bool _isAppInForeground = true;
+  bool _isGpsActive = false;
+
+  // Public stream for UI components to subscribe to
+  Stream<LocationData> get locationStream => _dataController.stream;
+
+  // Get current data synchronously
+  LocationData get currentData => _currentData;
+
+  bool get isInitialized => _isInitialized;
+  bool get isGpsActive => _isGpsActive;
+
+  bool _isInitialized = false;
+
+  /// Initialize GPS: check permissions, get first fix, start stream.
+  Future<void> initialize() async {
+    if (_isInitialized) {
+      Logger.warn('Already initialized, skipping...', 'LocationRepository');
+      return;
+    }
+
+    Logger.info('Starting location repository initialization...', 'LocationRepository');
+    WidgetsBinding.instance.addObserver(this);
+
+    // Check GPS permissions and services first
+    final serviceEnabled = await GpsService.isLocationServiceEnabled();
+    Logger.debug('Location service enabled: $serviceEnabled', 'LocationRepository');
+    if (!serviceEnabled) {
+      Logger.error('GPS service disabled', 'LocationRepository');
+      _updateData(_currentData.copyWith(
+        displaySpeed: 'GPS OFF',
+        displayHeading: 'GPS OFF',
+      ));
+      _isInitialized = true;
+      return;
+    }
+
+    final permissionGranted = await GpsService.requestPermissions();
+    Logger.debug('GPS permission granted: $permissionGranted', 'LocationRepository');
+    if (!permissionGranted) {
+      Logger.error('GPS permission denied', 'LocationRepository');
+      _updateData(_currentData.copyWith(
+        displaySpeed: 'NO PERM',
+        displayHeading: 'NO PERM',
+      ));
+      _isInitialized = true;
+      return;
+    }
+
+    try {
+      // Get initial position with long timeout for cold start
+      final initialPosition = await GpsService.getCurrentPosition(
+        accuracy: LocationAccuracy.bestForNavigation,
+        timeLimit: GpsConfig.INITIAL_FIX_TIMEOUT,
+      );
+
+      if (initialPosition == null) {
+        Logger.error('Initial GPS fix failed — null position', 'LocationRepository');
+        _updateData(_currentData.copyWith(
+          displaySpeed: 'GPS ERR',
+          displayHeading: 'GPS ERR',
+        ));
+        _isInitialized = true;
+        return;
+      }
+
+      Logger.info('Initial GPS fix obtained', 'LocationRepository');
+      _hasFirstFix = true;
+      _firstFixTime = DateTime.now();
+      _onPositionUpdate(initialPosition);
+
+      // Start position stream
+      Logger.debug('Starting GPS stream with accuracy: $_currentAccuracy', 'LocationRepository');
+      _startPositionStream(_currentAccuracy);
+
+      _isGpsActive = true;
+      await GpsService.setWakeLock(true);
+      _isInitialized = true;
+    } catch (e, stackTrace) {
+      developer.log('GPS subscription creation failed: $e',
+          error: e, stackTrace: stackTrace, name: 'LocationRepository');
+      _updateData(_currentData.copyWith(
+        displaySpeed: 'GPS ERR',
+        displayHeading: 'GPS ERR',
+      ));
+      _isInitialized = true;
+    }
+
+    Logger.info('Location repository initialized successfully', 'LocationRepository');
+  }
+
+  void _startPositionStream(LocationAccuracy accuracy) {
+    _gpsSubscription = GpsService.createPositionStream(accuracy: accuracy).listen(
+      (Position position) {
+        Logger.debug('GPS callback triggered', 'LocationRepository');
+        _onPositionUpdate(position);
+      },
+      onError: (error) {
+        Logger.error('GPS stream error callback: $error', 'LocationRepository');
+        _onGpsError(error);
+      },
+      onDone: () {
+        Logger.warn('GPS stream done callback - stream ended', 'LocationRepository');
+      },
+      cancelOnError: false,
+    );
+  }
+
+  void _onPositionUpdate(Position position) {
+    Logger.debug('Raw GPS update: speed=${position.speed.toStringAsFixed(2)} m/s, heading=${position.heading.toStringAsFixed(1)}°', 'LocationRepository');
+
+    _scheduleStaleDataTimer();
+
+    // Validate speed
+    final rawSpeed = position.speed;
+    final bool speedValid = rawSpeed.isFinite && rawSpeed >= 0;
+    final double speed = speedValid ? rawSpeed : 0.0;
+
+    // Validate heading
+    final rawHeading = position.heading;
+    final bool headingValid = rawHeading.isFinite &&
+        rawHeading >= GpsConfig.VALID_HEADING_MIN &&
+        rawHeading < GpsConfig.VALID_HEADING_MAX;
+    final double heading = headingValid ? rawHeading : _currentData.heading;
+
+    // Format display
+    final displaySpeed = speed.toStringAsFixed(1);
+    final displayHeading = headingValid
+        ? GpsService.formatHeading(heading)
+        : _currentData.displayHeading;
+
+    Logger.debug('Processed: displaySpeed="$displaySpeed", displayHeading="$displayHeading"', 'LocationRepository');
+
+    final locationData = LocationData(
+      speed: speed,
+      heading: heading,
+      displaySpeed: displaySpeed,
+      displayHeading: displayHeading,
+      isSpeedValid: speedValid,
+      isHeadingValid: headingValid,
+      timestamp: DateTime.now(),
+    );
+
+    _updateData(locationData);
+
+    // Check precision switching after first-fix gate
+    if (_hasFirstFix && _firstFixTime != null) {
+      final timeSinceFirstFix = DateTime.now().difference(_firstFixTime!);
+      if (timeSinceFirstFix >= GpsConfig.PRECISION_SWITCH_FIRST_FIX_DELAY) {
+        _checkPrecisionSwitch(position.speed);
+      }
+    }
+  }
+
+  void _onGpsError(dynamic error) {
+    if (_isDisposed) return;
+    final errorString = error.toString().toLowerCase();
+    if (!errorString.contains('timeout') && !errorString.contains('temporarily')) {
+      _updateData(_currentData.copyWith(
+        displaySpeed: 'GPS ERR',
+        displayHeading: 'GPS ERR',
+        isSpeedValid: false,
+        isHeadingValid: false,
+      ));
+    }
+  }
+
+  void _scheduleStaleDataTimer() {
+    _staleDataTimer?.cancel();
+    _staleDataTimer = Timer(GpsConfig.STALE_DATA_THRESHOLD, _handleStaleDataTimeout);
+  }
+
+  void _handleStaleDataTimeout() {
+    if (_isDisposed) return;
+    final displayText = _currentData.displaySpeed;
+    if (displayText == '--' || displayText.startsWith('GPS') || displayText == 'NO PERM') {
+      return;
+    }
+
+    final headingStillValid = _currentData.isHeadingValid &&
+        _currentData.heading >= GpsConfig.VALID_HEADING_MIN &&
+        _currentData.heading < GpsConfig.VALID_HEADING_MAX;
+    final displayHeading = headingStillValid ? _currentData.displayHeading : '--';
+
+    Logger.warn('No GPS updates within ${GpsConfig.STALE_DATA_THRESHOLD.inSeconds}s - marking data as stale', 'LocationRepository');
+
+    final staleData = _currentData.copyWith(
+      displaySpeed: '--',
+      displayHeading: displayHeading,
+      isSpeedValid: false,
+      isHeadingValid: headingStillValid,
+    );
+
+    _staleDataTimer = null;
+    _updateData(staleData);
+  }
+
+  void _updateData(LocationData newData) {
+    if (_isDisposed) return;
+    _currentData = newData;
+    _dataController.add(newData);
+    notifyListeners();
+    Logger.debug('Broadcasting data: ${newData.displaySpeed} ${newData.displayHeading}', 'LocationRepository');
+  }
+
+  /// Check if GPS precision should be switched based on speed.
+  void _checkPrecisionSwitch(double speedMps) {
+    if (_currentAccuracy == LocationAccuracy.high) {
+      if (speedMps < GpsConfig.PRECISION_DOWN_THRESHOLD_MPS) {
+        _switchPrecision(LocationAccuracy.medium);
+      }
+    } else if (_currentAccuracy == LocationAccuracy.medium) {
+      if (speedMps > GpsConfig.PRECISION_UP_THRESHOLD_MPS) {
+        _switchPrecision(LocationAccuracy.high);
+      }
+    }
+  }
+
+  /// Switch GPS precision and restart stream with new accuracy.
+  void _switchPrecision(LocationAccuracy newAccuracy) {
+    if (_currentAccuracy == newAccuracy) return;
+
+    final speedKmh = _currentData.speed * 3.6;
+    Logger.debug('Precision switched to $newAccuracy at ${speedKmh.toStringAsFixed(1)} km/h', 'LocationRepository');
+
+    _currentAccuracy = newAccuracy;
+    _gpsSubscription?.cancel();
+    _startPositionStream(newAccuracy);
+  }
+
+  /// Handle app lifecycle state changes.
+  @override
+  void didChangeAppLifecycleState(AppLifecycleState state) {
+    if (state == AppLifecycleState.paused) {
+      _isAppInForeground = false;
+      // No overlay logic here — overlay is deferred
+      _updateWakeLock();
+    } else if (state == AppLifecycleState.resumed) {
+      _isAppInForeground = true;
+      _backgroundGracePeriodTimer?.cancel();
+      _backgroundGracePeriodTimer = null;
+
+      // Restart GPS if it was stopped
+      if (_gpsSubscription == null && _isInitialized) {
+        restartGps();
+      }
+
+      _updateWakeLock();
+    }
+  }
+
+  /// Stop GPS tracking.
+  void stopGps() {
+    _gpsSubscription?.cancel();
+    _gpsSubscription = null;
+    _isGpsActive = false;
+    _staleDataTimer?.cancel();
+    _updateWakeLock();
+    Logger.info('GPS stopped', 'LocationRepository');
+  }
+
+  /// Restart GPS tracking.
+  void restartGps() {
+    Logger.info('Restarting GPS', 'LocationRepository');
+    _startPositionStream(_currentAccuracy);
+    _isGpsActive = true;
+    _updateWakeLock();
+  }
+
+  /// Update wake lock based on GPS state and app visibility.
+  Future<void> _updateWakeLock() async {
+    final shouldKeepAwake = _isGpsActive && _isAppInForeground;
+    await GpsService.setWakeLock(shouldKeepAwake);
+    Logger.debug(
+      'Wake lock ${shouldKeepAwake ? "enabled" : "disabled"} (GPS: $_isGpsActive, foreground: $_isAppInForeground)',
+      'LocationRepository',
+    );
+  }
+
+  @override
+  void dispose() {
+    super.dispose();
+    _isDisposed = true;
+    Logger.info('Disposing location repository...', 'LocationRepository');
+    WidgetsBinding.instance.removeObserver(this);
+    _backgroundGracePeriodTimer?.cancel();
+    _backgroundGracePeriodTimer = null;
+    _gpsSubscription?.cancel();
+    _gpsSubscription = null;
+    _staleDataTimer?.cancel();
+    _staleDataTimer = null;
+    _dataController.close();
+    GpsService.setWakeLock(false);
+    Logger.info('Location repository disposed', 'LocationRepository');
+  }
+}

lib/data/services/gps_service.dart

@@ -1,12 +1,16 @@
 import 'dart:async';
 import 'package:geolocator/geolocator.dart';
 import 'package:permission_handler/permission_handler.dart';
-import 'config/gps_constants.dart';
+import 'package:wakelock_plus/wakelock_plus.dart';
+import '../../core/constants/gps_constants.dart';
 
+/// Lightweight stateless wrapper around Geolocator.
+///
+/// Only handles platform I/O — no business logic.
 class GpsService {
   static double? _lastValidHeading;
 
-  /// Create a position stream with dynamic accuracy setting
+  /// Create a position stream with dynamic accuracy setting.
   static Stream<Position> createPositionStream({
     LocationAccuracy accuracy = LocationAccuracy.high,
   }) {
@@ -18,12 +22,6 @@ class GpsService {
     );
   }
 
-  /// Deprecated: Use createPositionStream() instead
-  @Deprecated('Use createPositionStream(accuracy: LocationAccuracy.bestForNavigation) instead')
-  static Stream<Position> get positionStream {
-    return createPositionStream(accuracy: LocationAccuracy.bestForNavigation);
-  }
-
   static Future<bool> requestPermissions() async {
     final permission = await Permission.locationWhenInUse.request();
     return permission.isGranted;
@@ -33,6 +31,22 @@ class GpsService {
     return await Geolocator.isLocationServiceEnabled();
   }
 
+  static Future<Position?> getCurrentPosition({
+    LocationAccuracy accuracy = LocationAccuracy.bestForNavigation,
+    Duration timeLimit = const Duration(seconds: 60),
+  }) async {
+    try {
+      return await Geolocator.getCurrentPosition(
+        locationSettings: LocationSettings(
+          accuracy: accuracy,
+          timeLimit: timeLimit,
+        ),
+      );
+    } catch (_) {
+      return null;
+    }
+  }
+
   static double getCachedHeading(double heading) {
     if (heading >= GpsConfig.VALID_HEADING_MIN && heading <= GpsConfig.VALID_HEADING_MAX) {
       _lastValidHeading = heading;
@@ -43,7 +57,6 @@ class GpsService {
 
   static String getCompassDirection(double heading) {
     final cachedHeading = getCachedHeading(heading);
-    
     const directions = ['N', 'NE', 'E', 'SE', 'S', 'SW', 'W', 'NW'];
     final index = ((cachedHeading + 22.5) / 45).floor() % 8;
     return directions[index];
@@ -51,6 +64,10 @@ class GpsService {
 
   static String formatHeading(double heading) {
     final cachedHeading = getCachedHeading(heading);
-    return '${cachedHeading.round()} ${getCompassDirection(heading)}'; // don't add that degree symbol, this is cooler
+    return '${cachedHeading.round()} ${getCompassDirection(heading)}';
+  }
+
+  static Future<void> setWakeLock(bool enable) async {
+    await WakelockPlus.toggle(enable: enable);
   }
 }

lib/data/services/overlay_service.dart

@@ -1,7 +1,7 @@
 import 'package:flutter_overlay_window/flutter_overlay_window.dart';
 import 'package:permission_handler/permission_handler.dart';
 import 'package:retry/retry.dart';
-import 'logger.dart';
+import '../../services/logger.dart';
 
 /// Service wrapper for FlutterOverlayWindow platform calls with retry logic
 /// Encapsulates all overlay operations with error handling and verification

lib/main.dart

@@ -1,13 +1,19 @@
 import 'package:flutter/material.dart';
 import 'package:provider/provider.dart';
 import 'package:shared_preferences/shared_preferences.dart';
-import 'screens/speedometer_screen.dart';
-import 'screens/overlay_screen.dart';
-import 'services/gps_data_manager.dart';
-import 'services/overlay_service.dart';
+import 'ui/features/speedometer/speedometer_view.dart';
+import 'ui/features/speedometer/speedometer_view_model.dart';
 import 'providers/settings_provider.dart';
-import 'providers/overlay_provider.dart';
-import 'services/logger.dart';
+import 'data/repositories/location_repository.dart';
+
+/// Stub ViewModel for the overlay feature.
+///
+/// [Overlay] has been deferred — see ui/features/overlay/ for details.
+class OverlayViewModel extends ChangeNotifier {
+  bool get isOverlayActive => false;
+  void toggleOverlay() {}
+  void closeOverlay() {}
+}
 
 void main() async {
   WidgetsFlutterBinding.ensureInitialized();
@@ -16,22 +22,29 @@ void main() async {
   runApp(
     MultiProvider(
       providers: [
+        // Shared
         Provider<SharedPreferences>.value(value: prefs),
-        Provider<OverlayService>(create: (_) => OverlayService()),
-        ChangeNotifierProvider(
-          create: (context) => SettingsProvider(context.read<SharedPreferences>()),
+        // Data layer
+        ChangeNotifierProvider<LocationRepository>(
+          create: (_) {
+            final repo = LocationRepository();
+            repo.initialize();
+            return repo;
+          },
         ),
-        ChangeNotifierProvider(
-          create: (_) => GpsDataManager(),
+        // UI layer — ViewModels subscribe to repositories
+        ChangeNotifierProvider<SpeedometerViewModel>(
+          create: (context) => SpeedometerViewModel(
+            context.read<LocationRepository>(),
+          ),
         ),
-        ChangeNotifierProxyProvider2<GpsDataManager, SettingsProvider, OverlayProvider>(
-          create: (context) => OverlayProvider(context.read<OverlayService>()),
-          update: (_, gpsManager, settings, overlay) => overlay!
-            ..updateDependencies(
-              gpsManager: gpsManager,
-              currentUnit: settings.currentUnit,
-              currentThemeIndex: settings.currentThemeIndex,
-            ),
+        ChangeNotifierProvider<OverlayViewModel>(
+          create: (_) => OverlayViewModel(),
+        ),
+        ChangeNotifierProvider<SettingsProvider>(
+          create: (context) => SettingsProvider(
+            context.read<SharedPreferences>(),
+          ),
         ),
       ],
       child: const SpeedoApp(),
@@ -39,15 +52,6 @@ void main() async {
   );
 }
 
-@pragma("vm:entry-point")
-void overlayMain() {
-  Logger.info('overlayMain() called', 'Overlay');
-  runApp(const MaterialApp(
-    debugShowCheckedModeBanner: false,
-    home: OverlaySpeedometer(),
-  ));
-}
-
 class SpeedoApp extends StatelessWidget {
   const SpeedoApp({super.key});
 
@@ -61,7 +65,7 @@ class SpeedoApp extends StatelessWidget {
         brightness: Brightness.dark,
         colorSchemeSeed: Colors.green,
       ),
-      home: const SpeedometerScreen(),
+      home: const SpeedometerView(),
     );
   }
 }

lib/models/overlay_message.dart

@@ -1,128 +0,0 @@
-/// Typed message class for overlay IPC communication
-/// Replaces unvalidated Map data with type-safe serialization
-class OverlayMessage {
-  final String action;
-  final String? speedText;
-  final String? unitText;
-  final String? headingText;
-  final double? heading;
-  final int? unitIndex;
-  final int? themeIndex;
-  final double? overlayWidth;
-  final double? overlayHeight;
-  final DateTime timestamp;
-
-  OverlayMessage({
-    required this.action,
-    this.speedText,
-    this.unitText,
-    this.headingText,
-    this.heading,
-    this.unitIndex,
-    this.themeIndex,
-    this.overlayWidth,
-    this.overlayHeight,
-    required this.timestamp,
-  });
-
-  /// Factory constructor for display update messages
-  factory OverlayMessage.updateDisplay({
-    required String speedText,
-    required String unitText,
-    required String headingText,
-    required double heading,
-    required int unitIndex,
-    required int themeIndex,
-    double? overlayWidth,
-    double? overlayHeight,
-  }) {
-    return OverlayMessage(
-      action: 'updateDisplay',
-      speedText: speedText,
-      unitText: unitText,
-      headingText: headingText,
-      heading: heading,
-      unitIndex: unitIndex,
-      themeIndex: themeIndex,
-      overlayWidth: overlayWidth,
-      overlayHeight: overlayHeight,
-      timestamp: DateTime.now(),
-    );
-  }
-
-  /// Factory constructor for long press close signal
-  factory OverlayMessage.longPressClose() {
-    return OverlayMessage(
-      action: 'longPressClose',
-      timestamp: DateTime.now(),
-    );
-  }
-
-  /// Factory constructor for overlay closed notification
-  factory OverlayMessage.overlayClosed() {
-    return OverlayMessage(
-      action: 'overlayClosed',
-      timestamp: DateTime.now(),
-    );
-  }
-
-  /// Serialize to Map for overlay IPC
-  Map<String, dynamic> toMap() {
-    final map = <String, dynamic>{'action': action};
-    if (speedText != null) map['speedText'] = speedText;
-    if (unitText != null) map['unitText'] = unitText;
-    if (headingText != null) map['headingText'] = headingText;
-    if (heading != null) map['heading'] = heading;
-    if (unitIndex != null) map['unitIndex'] = unitIndex;
-    if (themeIndex != null) map['themeIndex'] = themeIndex;
-    if (overlayWidth != null) map['overlayWidth'] = overlayWidth;
-    if (overlayHeight != null) map['overlayHeight'] = overlayHeight;
-    map['timestamp'] = timestamp.millisecondsSinceEpoch;
-    return map;
-  }
-
-  /// Deserialize from Map received via overlay IPC
-  factory OverlayMessage.fromMap(Map<dynamic, dynamic> map) {
-    return OverlayMessage(
-      action: map['action'] as String? ?? 'unknown',
-      speedText: map['speedText'] as String?,
-      unitText: map['unitText'] as String?,
-      headingText: map['headingText'] as String?,
-      heading: (map['heading'] as num?)?.toDouble(),
-      unitIndex: map['unitIndex'] as int?,
-      themeIndex: map['themeIndex'] as int?,
-      overlayWidth: (map['overlayWidth'] as num?)?.toDouble(),
-      overlayHeight: (map['overlayHeight'] as num?)?.toDouble(),
-      timestamp: DateTime.fromMillisecondsSinceEpoch(
-        map['timestamp'] as int? ?? DateTime.now().millisecondsSinceEpoch,
-      ),
-    );
-  }
-
-  /// Create a copy with updated fields
-  OverlayMessage copyWith({
-    String? action,
-    String? speedText,
-    String? unitText,
-    String? headingText,
-    double? heading,
-    int? unitIndex,
-    int? themeIndex,
-    double? overlayWidth,
-    double? overlayHeight,
-    DateTime? timestamp,
-  }) {
-    return OverlayMessage(
-      action: action ?? this.action,
-      speedText: speedText ?? this.speedText,
-      unitText: unitText ?? this.unitText,
-      headingText: headingText ?? this.headingText,
-      heading: heading ?? this.heading,
-      unitIndex: unitIndex ?? this.unitIndex,
-      themeIndex: themeIndex ?? this.themeIndex,
-      overlayWidth: overlayWidth ?? this.overlayWidth,
-      overlayHeight: overlayHeight ?? this.overlayHeight,
-      timestamp: timestamp ?? this.timestamp,
-    );
-  }
-}

lib/models/theme_model.dart

@@ -1,32 +0,0 @@
-import '../config/color_themes.dart';
-
-/// Theme model that wraps ColorThemes with rotation and state management.
-/// Holds all possible color palettes via delegation, exposing only the current set.
-class ThemeModel {
-  final int _currentIndex;
-
-  const ThemeModel({int currentIndex = 0}) : _currentIndex = currentIndex;
-
-  /// Get the current active color theme
-  ColorTheme get current => ColorThemes.getTheme(_currentIndex);
-
-  /// Get the name of the current theme
-  String get currentSetName => current.name;
-
-  /// Get the current theme index
-  int get currentIndex => _currentIndex;
-
-  /// Rotate to the next theme (circular)
-  ThemeModel rotate() {
-    return ThemeModel(
-      currentIndex: ColorThemes.getNextThemeIndex(_currentIndex),
-    );
-  }
-
-  /// Create a copy with an updated theme index
-  ThemeModel copyWith({int? currentIndex}) {
-    return ThemeModel(
-      currentIndex: currentIndex ?? _currentIndex,
-    );
-  }
-}

lib/providers/overlay_provider.dart

@@ -1,274 +0,0 @@
-import 'dart:async';
-import 'package:flutter/widgets.dart';
-import 'package:bg_launcher/bg_launcher.dart';
-import '../config/overlay_constants.dart';
-import '../config/timing_constants.dart';
-import '../config/speed_unit.dart';
-import '../models/overlay_message.dart';
-import '../models/processed_gps_data.dart';
-import '../services/gps_data_manager.dart';
-import '../services/logger.dart';
-import '../services/overlay_service.dart';
-
-enum OverlayError { permission, creationFailed, communicationDegraded }
-
-class OverlayProvider extends ChangeNotifier {
-  final OverlayService _overlayService;
-
-  bool _isOverlayActive = false;
-  bool _isDisposed = false;
-  bool _tapCloseRequested = false;
-
-  StreamSubscription<ProcessedGpsData>? _gpsSubscription;
-  StreamSubscription<dynamic>? _overlayMessageSubscription;
-  Timer? _overlayStatusCheckTimer;
-  Timer? _tapCloseTimer;
-
-  // Dependencies — set via update() from ProxyProvider
-  GpsDataManager? _gpsManager;
-  SpeedUnit _currentUnit = SpeedUnit.kmh;
-  int _currentThemeIndex = 0;
-
-  // Error callback — set by SpeedometerScreen after provider is available
-  void Function(OverlayError)? onError;
-
-  OverlayProvider(this._overlayService);
-
-  bool get isOverlayActive => _isOverlayActive;
-
-  /// Called by ChangeNotifierProxyProvider2 when GpsDataManager or SettingsProvider changes.
-  /// Sets up GPS stream subscription on first call, updates settings references on subsequent calls.
-  void updateDependencies({
-    required GpsDataManager gpsManager,
-    required SpeedUnit currentUnit,
-    required int currentThemeIndex,
-  }) {
-    if (_isDisposed) return;
-
-    _currentUnit = currentUnit;
-    _currentThemeIndex = currentThemeIndex;
-
-    // Subscribe to GPS stream on first update (only once)
-    if (_gpsManager == null) {
-      _gpsManager = gpsManager;
-      _gpsSubscription = gpsManager.dataStream.listen((data) {
-        if (_isOverlayActive && !_isDisposed) {
-          _pushDataToOverlay(data);
-        }
-      });
-      Logger.debug('GPS stream subscription created for overlay', 'OverlayProvider');
-    }
-
-    // Push updated settings to overlay if active
-    if (_isOverlayActive && _gpsManager != null) {
-      _pushDataToOverlay(_gpsManager!.currentData);
-    }
-  }
-
-  /// Show the floating overlay window
-  Future<void> showOverlay() async {
-    if (_isDisposed) return;
-
-    try {
-      // Check permission before attempting to show overlay
-      final hasPermission = await _overlayService.checkPermission();
-      if (!hasPermission) {
-        Logger.warn('Overlay permission denied', 'OverlayProvider');
-        onError?.call(OverlayError.permission);
-        return;
-      }
-
-      final overlaySize = _getOverlaySize();
-      final gpsData = _gpsManager?.currentData;
-
-      // Send initial display data WITH size info
-      final speedText = _gpsManager?.getFormattedSpeed(_currentUnit) ?? '--';
-      final headingText = gpsData?.displayHeading ?? 'N/A';
-      final unitText = _currentUnit.label;
-
-      await _overlayService.shareData(OverlayMessage.updateDisplay(
-        speedText: speedText,
-        unitText: unitText,
-        headingText: headingText,
-        heading: gpsData?.heading ?? -1.0,
-        unitIndex: _currentUnit.index,
-        themeIndex: _currentThemeIndex,
-        overlayWidth: overlaySize['width']!.toDouble(),
-        overlayHeight: overlaySize['height']!.toDouble(),
-      ).toMap());
-
-      final success = await _overlayService.showOverlay(
-        width: overlaySize['width']!,
-        height: overlaySize['height']!,
-      );
-
-      if (!success) {
-        Logger.error('Overlay creation failed or verification failed', 'OverlayProvider');
-        onError?.call(OverlayError.creationFailed);
-        return;
-      }
-
-      Logger.info('OVERLAY LAUNCHED - Size: ${overlaySize['width']}x${overlaySize['height']}', 'OverlayProvider');
-
-      _isOverlayActive = true;
-      _startListeningToOverlayMessages();
-      _startOverlayStatusCheck();
-      notifyListeners();
-    } catch (e) {
-      Logger.error('Failed to show overlay: $e', 'OverlayProvider');
-      onError?.call(OverlayError.creationFailed);
-    }
-  }
-
-  /// Close the floating overlay window
-  Future<void> closeOverlay() async {
-    if (!_isOverlayActive || _isDisposed) return;
-
-    try {
-      await _overlayService.closeOverlay();
-      Logger.info('OVERLAY CLOSED - Requested from main app', 'OverlayProvider');
-      _handleOverlayClose();
-    } catch (e) {
-      Logger.error('Error closing overlay: $e', 'OverlayProvider');
-    }
-  }
-
-  /// Toggle overlay state (show if hidden, close if active)
-  Future<void> toggleOverlay() async {
-    if (_isOverlayActive) {
-      await closeOverlay();
-    } else {
-      await showOverlay();
-    }
-  }
-
-  Map<String, int> _getOverlaySize() {
-    final window = WidgetsBinding.instance.platformDispatcher.views.first;
-    final physicalSize = window.physicalSize;
-    final overlayWidth = (physicalSize.width * OverlayConfig.WIDTH_PERCENTAGE).round();
-    final overlayHeight = (overlayWidth * OverlayConfig.ASPECT_RATIO).round();
-    return {'width': overlayWidth, 'height': overlayHeight};
-  }
-
-  void _pushDataToOverlay(ProcessedGpsData gpsData) {
-    if (!_isOverlayActive || _isDisposed) return;
-
-    final speedText = _gpsManager?.getFormattedSpeed(_currentUnit) ?? '--';
-    final unitText = _currentUnit.label;
-    final headingText = gpsData.displayHeading;
-
-    Logger.debug('Pushing to overlay: speed="$speedText", heading="$headingText"', 'OverlayProvider');
-
-    _overlayService.shareData(OverlayMessage.updateDisplay(
-      speedText: speedText,
-      unitText: unitText,
-      headingText: headingText,
-      heading: gpsData.heading,
-      unitIndex: _currentUnit.index,
-      themeIndex: _currentThemeIndex,
-    ).toMap());
-  }
-
-  void _startListeningToOverlayMessages() {
-    if (_overlayMessageSubscription != null) return;
-
-    _overlayMessageSubscription = _overlayService.overlayListener.listen(
-      (data) {
-        try {
-          if (data is Map) {
-            final action = data['action'];
-            switch (action) {
-              case 'overlayClosed':
-                _handleOverlayClose();
-                break;
-              case 'longPressClose':
-                _tapCloseRequested = true;
-                _tapCloseTimer?.cancel();
-                _tapCloseTimer = Timer(TimingConfig.TAP_CLOSE_DELAY, () {
-                  _tapCloseRequested = false;
-                });
-                break;
-              default:
-                Logger.warn('Unknown overlay action: "$action"', 'OverlayProvider');
-            }
-          }
-        } catch (e) {
-          Logger.error('Error processing overlay message: $e', 'OverlayProvider');
-        }
-      },
-      onError: (error) {
-        Logger.error('Overlay listener error: $error', 'OverlayProvider');
-      },
-    );
-  }
-
-  void _stopListeningToOverlayMessages() {
-    _overlayMessageSubscription?.cancel();
-    _overlayMessageSubscription = null;
-  }
-
-  void _startOverlayStatusCheck() {
-    _overlayStatusCheckTimer?.cancel();
-
-    _overlayStatusCheckTimer = Timer.periodic(TimingConfig.OVERLAY_STATUS_CHECK_INTERVAL, (timer) async {
-      if (_isOverlayActive && !_isDisposed) {
-        try {
-          final isActive = await _overlayService.isActive();
-          if (!isActive) {
-            timer.cancel();
-            _handleOverlayClose();
-          }
-        } catch (e) {
-          Logger.error('Overlay status check failed: $e', 'OverlayProvider');
-        }
-      } else {
-        timer.cancel();
-      }
-    });
-    Logger.debug('Started overlay status monitoring', 'OverlayProvider');
-  }
-
-  void _handleOverlayClose({bool bringToForeground = false}) {
-    if (_isDisposed) return;
-
-    final shouldBringToFront = bringToForeground || _tapCloseRequested;
-
-    _tapCloseTimer?.cancel();
-    _overlayStatusCheckTimer?.cancel();
-    _tapCloseRequested = false;
-
-    _isOverlayActive = false;
-    _stopListeningToOverlayMessages();
-    notifyListeners();
-
-    if (shouldBringToFront) {
-      _bringAppToFront();
-    }
-  }
-
-  void _bringAppToFront() {
-    try {
-      BgLauncher.bringAppToForeground();
-    } catch (e) {
-      Logger.error('BgLauncher failed to bring app to front: $e', 'OverlayProvider');
-    }
-  }
-
-  /// Push current data to overlay — used by background heartbeat
-  void pushCurrentData() {
-    if (_isOverlayActive && _gpsManager != null && !_isDisposed) {
-      _pushDataToOverlay(_gpsManager!.currentData);
-    }
-  }
-
-  @override
-  void dispose() {
-    _isDisposed = true;
-    _gpsSubscription?.cancel();
-    _overlayMessageSubscription?.cancel();
-    _overlayStatusCheckTimer?.cancel();
-    _tapCloseTimer?.cancel();
-    Logger.info('OverlayProvider disposed', 'OverlayProvider');
-    super.dispose();
-  }
-}

lib/providers/settings_provider.dart

@@ -1,8 +1,8 @@
 import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 import 'package:shared_preferences/shared_preferences.dart';
-import '../config/speed_unit.dart';
-import '../config/color_themes.dart';
+import '../core/constants/speed_unit.dart';
+import '../core/theme/color_themes.dart';
 import '../services/logger.dart';
 
 class SettingsProvider extends ChangeNotifier {

lib/screens/overlay_screen.dart

@@ -1,326 +0,0 @@
-import 'package:flutter/material.dart';
-import 'dart:async';
-import 'dart:math' as math;
-import 'package:flutter_overlay_window/flutter_overlay_window.dart';
-import '../config/color_themes.dart';
-import '../config/overlay_constants.dart';
-import '../models/overlay_message.dart';
-import '../services/logger.dart';
-
-class OverlaySpeedometer extends StatefulWidget {
-  const OverlaySpeedometer({super.key});
-
-  @override
-  State<OverlaySpeedometer> createState() => _OverlaySpeedometerState();
-}
-
-class _OverlaySpeedometerState extends State<OverlaySpeedometer> {
-  String _speedText = '--';
-  String _unitText = 'km/h';
-  String _headingText = 'N/A';
-  double _heading = -1.0;
-  int _currentThemeIndex = 0;
-  double _systemScreenWidth = 400;
-  double _overlayWidth = 280;
-  double _overlayHeight = 140;
-  DateTime _lastUpdateTime = DateTime.now();
-  Timer? _stalenessCheckTimer;
-
-  @override
-  void initState() {
-    super.initState();
-    Logger.info('CREATED - Floating window initialized (${DateTime.now().millisecondsSinceEpoch})', 'Overlay');
-    _getSystemScreenSize();
-    _listenToMainAppMessages();
-    _startStalenessMonitoring();
-  }
-
-  @override
-  void dispose() {
-    _stalenessCheckTimer?.cancel();
-    Logger.info('DISPOSING - Overlay widget disposed (${DateTime.now().millisecondsSinceEpoch})', 'Overlay');
-    super.dispose();
-  }
-
-  void _getSystemScreenSize() {
-    try {
-      // Get actual system screen resolution, not just app window size
-      final window = WidgetsBinding.instance.platformDispatcher.views.first;
-      final physicalSize = window.physicalSize;
-      final devicePixelRatio = window.devicePixelRatio;
-      final systemSize = physicalSize / devicePixelRatio;
-
-      Logger.debug('Screen detection:', 'Overlay');
-      Logger.debug('  physicalSize: ${physicalSize.width.round()}x${physicalSize.height.round()}', 'Overlay');
-      Logger.debug('  devicePixelRatio: $devicePixelRatio', 'Overlay');
-      Logger.debug('  calculated systemSize: ${systemSize.width.round()}x${systemSize.height.round()}', 'Overlay');
-
-      setState(() {
-        _systemScreenWidth = systemSize.width;
-      });
-
-      Logger.debug('_systemScreenWidth set to: ${_systemScreenWidth.round()}', 'Overlay');
-    } catch (e) {
-      Logger.error('Error getting system screen size: $e', 'Overlay');
-      // Fallback to reasonable default
-      setState(() {
-        _systemScreenWidth = OverlayConfig.DEFAULT_SCREEN_WIDTH;
-      });
-    }
-  }
-
-  void _listenToMainAppMessages() {
-    FlutterOverlayWindow.overlayListener.listen((data) {
-      if (data is Map) {
-        final message = OverlayMessage.fromMap(data);
-        if (message.action == 'updateDisplay') {
-          setState(() {
-            _speedText = message.speedText ?? '--';
-            _unitText = message.unitText ?? '';
-            _headingText = message.headingText ?? 'N/A';
-            _heading = message.heading ?? -1.0;
-            _currentThemeIndex = message.themeIndex ?? 0;
-            _lastUpdateTime = message.timestamp;
-            // Update overlay dimensions if provided by main app
-            if (message.overlayWidth != null) {
-              _overlayWidth = message.overlayWidth!;
-            }
-            if (message.overlayHeight != null) {
-              _overlayHeight = message.overlayHeight!;
-            }
-          });
-
-          Logger.debug('UPDATE received:', 'Overlay');
-          Logger.debug('  speedText: "$_speedText"', 'Overlay');
-          Logger.debug('  headingText: "$_headingText"', 'Overlay');
-          Logger.debug('  direction: ${_heading.toStringAsFixed(1)}°', 'Overlay');
-          Logger.debug('  themeIndex: $_currentThemeIndex', 'Overlay');
-          Logger.debug('  systemScreenWidth: ${_systemScreenWidth.round()}', 'Overlay');
-          Logger.debug('  overlaySize from main: ${_overlayWidth.round()}x${_overlayHeight.round()}', 'Overlay');
-        }
-      }
-    });
-  }
-
-  void _startStalenessMonitoring() {
-    _stalenessCheckTimer = Timer.periodic(OverlayConfig.STALENESS_CHECK_INTERVAL, (timer) {
-      if (!mounted) return;
-
-      final age = DateTime.now().difference(_lastUpdateTime);
-      if (age >= OverlayConfig.STALENESS_DASH_THRESHOLD && _speedText != '--') {
-        setState(() {
-          _speedText = '--';
-        });
-      }
-    });
-  }
-
-
-  @override
-  Widget build(BuildContext context) {
-    final buildTimestamp = DateTime.now().millisecondsSinceEpoch;
-    final currentTheme = ColorThemes.getTheme(_currentThemeIndex);
-
-    // Calculate staleness opacity
-    final age = DateTime.now().difference(_lastUpdateTime);
-    final isStale = age >= OverlayConfig.STALENESS_DIM_THRESHOLD;
-    final staleOpacity = isStale ? OverlayConfig.STALENESS_DIM_OPACITY : 1.0;
-
-    // Use overlay dimensions provided by main app (not calculated locally)
-    final fontSize = (_overlayWidth * OverlayConfig.FONT_SIZE_RATIO);
-
-    Logger.debug('Building overlay widget ($buildTimestamp)', 'Overlay');
-    Logger.debug('Window size: ${_overlayWidth.round()}x${_overlayHeight.round()}, fontSize: ${fontSize.round()}', 'Overlay');
-
-    return Material(
-      color: Colors.transparent,
-      child: SizedBox(
-        // Use SizedBox to fill the overlay window completely
-        width: double.infinity,
-        height: double.infinity,
-        child: Container(
-          decoration: BoxDecoration(
-            color: currentTheme.background.withValues(alpha: OverlayConfig.BACKGROUND_OPACITY),
-            borderRadius: BorderRadius.circular(12),
-            border: Border.all(
-              color: currentTheme.speedText.withValues(alpha: OverlayConfig.BORDER_OPACITY),
-              width: 1
-            ),
-          ),
-          child: Stack(
-            children: [
-              // Main content - landscape layout (1:1 flex as per NOTES.txt)
-              Row(
-                children: [
-                  // Speed section - left half
-                  Expanded(
-                    flex: 55,
-                    child: Container(
-                      padding: const EdgeInsets.all(6),
-                      child: Center(
-                        child: Column(
-                          mainAxisAlignment: MainAxisAlignment.center,
-                          children: [
-                            Flexible(
-                              flex: 3,
-                              child: FittedBox(
-                                fit: BoxFit.contain,
-                                child: Text(
-                                  (_speedText),
-                                  style: TextStyle(
-                                    fontSize: fontSize,
-                                    fontWeight: FontWeight.w300,
-                                    color: currentTheme.speedText.withValues(alpha: staleOpacity),
-                                    fontFamily: 'DIN1451Alt',
-                                  ),
-                                ),
-                              ),
-                            ),
-                            Flexible(
-                              flex: 1,
-                              child: FittedBox(
-                                fit: BoxFit.contain,
-                                child: Text(
-                                  _unitText,
-                                  style: TextStyle(
-                                    fontSize: fontSize * OverlayConfig.UNIT_FONT_RATIO,
-                                    fontWeight: FontWeight.w300,
-                                    color: currentTheme.unitText.withValues(alpha: staleOpacity),
-                                    fontFamily: 'DIN1451Alt',
-                                  ),
-                                ),
-                              ),
-                            ),
-                          ],
-                        ),
-                      ),
-                    ),
-                  ),
-                  // Direction section - right half (same as full-screen behavior)
-                  Expanded(
-                    flex: 45,
-                    child: Container(
-                      padding: const EdgeInsets.all(8),
-                      child: Column(
-                        mainAxisAlignment: MainAxisAlignment.center,
-                        children: [
-                          Flexible(
-                            flex: 5,
-                            child: Transform.rotate(
-                              angle: (_heading >= 0 && _heading < 360) ? (_heading * math.pi / 180.0) : 0,
-                              child: FittedBox(
-                                fit: BoxFit.contain,
-                                child: Icon(
-                                  Icons.navigation,
-                                  size: fontSize * OverlayConfig.ICON_SIZE_RATIO,
-                                  color: currentTheme.headingText.withValues(alpha: staleOpacity),
-                                ),
-                              ),
-                            ),
-                          ),
-                          Flexible(
-                            flex: 2,
-                            child: FittedBox(
-                              fit: BoxFit.contain,
-                              child: Text(
-                                _headingText,
-                                style: TextStyle(
-                                  fontSize: fontSize * OverlayConfig.HEADING_FONT_RATIO,
-                                  color: currentTheme.headingText.withValues(alpha: staleOpacity),
-                                  fontFamily: 'DIN1451Alt',
-                                ),
-                              ),
-                            ),
-                          ),
-                        ],
-                      ),
-                    ),
-                  ),
-                ],
-              ),
-              // Transparent full-overlay gesture detection layer
-              Positioned.fill(
-                child: GestureDetector(
-                  behavior: HitTestBehavior.translucent, // Ensure gestures are captured
-                  onPanStart: (details) {
-                    Logger.debug('Pan start detected - gestures are working!', 'Overlay');
-                  },
-                  onLongPress: () async {
-                    final timestamp = DateTime.now().millisecondsSinceEpoch;
-                    Logger.info('Long press detected - closing overlay and bringing main app to front ($timestamp)', 'Overlay');
-                    try {
-                      // Skip haptic feedback in overlay - platform services not available
-                      Logger.debug('Skipping haptic feedback (overlay context limitation)', 'Overlay');
-
-                      // Signal main app to bring to foreground when overlay closes (non-blocking)
-                      Logger.debug('Sending bring-to-front close signal...', 'Overlay');
-                      FlutterOverlayWindow.shareData(OverlayMessage.longPressClose().toMap()).then((_) {
-                        Logger.debug('Long press close signal sent successfully', 'Overlay');
-                      }).catchError((error) {
-                        Logger.warn('Long press close signal failed (expected): $error', 'Overlay');
-                      });
-
-                      // Small delay to give signal a chance
-                      await Future.delayed(const Duration(milliseconds: 50));
-
-                      // Close the overlay
-                      Logger.info('Attempting to close overlay...', 'Overlay');
-                      await FlutterOverlayWindow.closeOverlay();
-                      Logger.info('Overlay closed successfully via long press', 'Overlay');
-
-                    } catch (e, stackTrace) {
-                      Logger.error('Long press close failed: $e', 'Overlay');
-                      Logger.error('Stack trace: $stackTrace', 'Overlay');
-                      // Fallback: try to close anyway
-                      try {
-                        Logger.debug('Attempting fallback close...', 'Overlay');
-                        await FlutterOverlayWindow.closeOverlay();
-                        Logger.info('Fallback close succeeded', 'Overlay');
-                      } catch (fallbackError) {
-                        Logger.error('Fallback close also failed: $fallbackError', 'Overlay');
-                      }
-                    }
-                  },
-                  // Tap to bring main app to front functionality removed per NOTES.txt
-                  // onTap: () async {
-                  //   final timestamp = DateTime.now().millisecondsSinceEpoch;
-                  //   customDebugPrint('[Overlay] 👆 Tap detected - bringing main app to foreground ($timestamp)');
-                  //   try {
-                  //     // Try to signal main app to come to foreground (non-blocking)
-                  //     customDebugPrint('[Overlay] 📤 Attempting to signal bring-to-front...');
-                  //     FlutterOverlayWindow.shareData({
-                  //       'action': 'bringToFront',
-                  //     }).catchError((error) {
-                  //       customDebugPrint('[Overlay] ❌ Bring-to-front signal failed (expected): $error');
-                  //     });
-                  //
-                  //     customDebugPrint('[Overlay] ✅ Tap gesture completed (overlay stays open)');
-                  //
-                  //   } catch (e, stackTrace) {
-                  //     customDebugPrint('[Overlay] ❌ Tap gesture failed: $e');
-                  //     customDebugPrint('[Overlay] 📚 Stack trace: $stackTrace');
-                  //   }
-                  // },
-                  child: Container(
-                    width: double.infinity,
-                    height: double.infinity,
-                    color: Colors.transparent,
-                    child: Center(
-                      child: Text(
-                        'GESTURE',
-                        style: TextStyle(
-                          color: Colors.transparent,
-                          fontSize: 1,
-                        ),
-                      ),
-                    ),
-                  ),
-                ),
-              ),
-            ],
-          ),
-        ),
-      ),
-    );
-  }
-}

lib/screens/speedometer_screen.dart

@@ -1,516 +0,0 @@
-import 'package:flutter/material.dart';
-import 'package:flutter/services.dart';
-import 'package:provider/provider.dart';
-import 'package:permission_handler/permission_handler.dart';
-import 'dart:async';
-import 'dart:math' as math;
-import '../config/timing_constants.dart';
-import '../config/overlay_constants.dart';
-import '../config/color_themes.dart';
-import '../services/gps_data_manager.dart';
-import '../models/processed_gps_data.dart';
-import '../providers/settings_provider.dart';
-import '../providers/overlay_provider.dart';
-import '../services/logger.dart';
-
-class SpeedometerScreen extends StatefulWidget {
-  const SpeedometerScreen({super.key});
-
-  @override
-  State<SpeedometerScreen> createState() => _SpeedometerScreenState();
-}
-
-class _SpeedometerScreenState extends State<SpeedometerScreen> {
-  // Local widget state only (not shared app state)
-  String _errorMessage = '';
-  Timer? _backgroundHeartbeatTimer;
-  Timer? _stalenessCheckTimer;
-
-  @override
-  void initState() {
-    super.initState();
-    // Delay GPS init and error callback setup to after first frame so context is available
-    WidgetsBinding.instance.addPostFrameCallback((_) {
-      _initializeGpsManager();
-      context.read<OverlayProvider>().onError = _handleOverlayError;
-      // Wire overlay provider into GPS manager for lifecycle decisions
-      context.read<GpsDataManager>().setOverlayProvider(context.read<OverlayProvider>());
-    });
-    _ensureOverlayPermission();
-    _startBackgroundHeartbeat();
-    _stalenessCheckTimer = Timer.periodic(OverlayConfig.STALENESS_CHECK_INTERVAL, (_) {
-      if (mounted) setState(() {}); // Trigger rebuild to re-evaluate staleness
-    });
-  }
-
-  @override
-  void dispose() {
-    _backgroundHeartbeatTimer?.cancel();
-    _stalenessCheckTimer?.cancel();
-    try {
-      context.read<OverlayProvider>().onError = null;
-    } catch (e) {
-      // Provider might already be disposed
-    }
-    Logger.info('SpeedometerScreen disposed', 'Main');
-    super.dispose();
-  }
-
-  Future<void> _initializeGpsManager() async {
-    Logger.info('Starting GPS manager initialization...', 'Main');
-    try {
-      await context.read<GpsDataManager>().initialize();
-      Logger.info('GPS manager initialized', 'Main');
-    } catch (e) {
-      Logger.error('GPS manager initialization failed: $e', 'Main');
-      if (mounted) {
-        setState(() => _errorMessage = 'Failed to initialize GPS manager');
-      }
-    }
-  }
-
-  void _handleOverlayError(OverlayError error) {
-    if (!mounted) return;
-
-    String message;
-    SnackBarAction? action;
-
-    switch (error) {
-      case OverlayError.permission:
-        message = 'Overlay permission required';
-        action = SnackBarAction(
-          label: 'Settings',
-          onPressed: () => openAppSettings(),
-        );
-        break;
-      case OverlayError.creationFailed:
-        message = 'Failed to create overlay window';
-        break;
-      case OverlayError.communicationDegraded:
-        message = 'Overlay communication degraded';
-        break;
-    }
-
-    ScaffoldMessenger.of(context).showSnackBar(
-      SnackBar(
-        content: Text(message),
-        action: action,
-        duration: const Duration(seconds: 4),
-      ),
-    );
-  }
-
-  Future<void> _ensureOverlayPermission() async {
-    try {
-      // Note: Overlay permission request is handled by OverlayProvider,
-      // but we check here to avoid issues at app startup
-    } catch (e) {
-      Logger.error('Error checking overlay permission: $e', 'Main');
-    }
-  }
-
-  void _startBackgroundHeartbeat() {
-    _backgroundHeartbeatTimer = Timer.periodic(TimingConfig.HEARTBEAT_INTERVAL, (timer) {
-      if (!mounted) return;
-      final overlay = context.read<OverlayProvider>();
-      if (overlay.isOverlayActive) {
-        overlay.pushCurrentData();
-      }
-    });
-  }
-
-  Widget _buildSpeedDisplay(String speedText, ColorTheme currentTheme, double fontSize, double opacity) {
-    if (speedText == '--') {
-      return Text(
-        speedText,
-        style: TextStyle(
-          fontSize: fontSize,
-          fontWeight: FontWeight.w300,
-          color: currentTheme.speedText.withValues(alpha: opacity),
-          fontFamily: 'DIN1451Alt',
-        ),
-      );
-    }
-
-    // Split speed into integral and decimal parts
-    final parts = speedText.split('.');
-    final integralPart = parts[0];
-    final decimalPart = parts.length > 1 ? '.${parts[1]}' : '.0';
-
-    return Row(
-      mainAxisAlignment: MainAxisAlignment.center,
-      crossAxisAlignment: CrossAxisAlignment.baseline,
-      textBaseline: TextBaseline.alphabetic,
-      children: [
-        Text(
-          integralPart,
-          style: TextStyle(
-            fontSize: fontSize,
-            fontWeight: FontWeight.w300,
-            color: currentTheme.speedText.withValues(alpha: opacity),
-            fontFamily: 'DIN1451Alt',
-          ),
-        ),
-        Text(
-          decimalPart,
-          style: TextStyle(
-            fontSize: fontSize * 0.5,
-            fontWeight: FontWeight.w300,
-            color: currentTheme.speedTextSub.withValues(alpha: opacity),
-            fontFamily: 'DIN1451Alt',
-          ),
-        ),
-      ],
-    );
-  }
-
-  @override
-  Widget build(BuildContext context) {
-    return Selector<SettingsProvider, ColorTheme>(
-      selector: (_, settings) => settings.currentTheme,
-      builder: (context, currentTheme, _) {
-        return Scaffold(
-          backgroundColor: currentTheme.background,
-          body: SafeArea(
-            child: LayoutBuilder(
-              builder: (context, constraints) {
-                final isLandscape = constraints.maxWidth > constraints.maxHeight;
-                if (isLandscape) {
-                  return _buildLandscapeLayout(currentTheme);
-                } else {
-                  return _buildPortraitLayout(currentTheme);
-                }
-              },
-            ),
-          ),
-        );
-      },
-    );
-  }
-
-  Widget _buildPortraitLayout(ColorTheme currentTheme) {
-    return Column(
-      children: [
-        // Speed area - takes most space, precise tap targets on text only
-        Expanded(
-          flex: 65,
-          child: Container(
-            width: double.infinity,
-            color: Colors.transparent,
-            padding: const EdgeInsets.all(4),
-            child: Column(
-              mainAxisAlignment: MainAxisAlignment.center,
-              children: [
-                if (_errorMessage.isNotEmpty)
-                  Flexible(
-                    child: Text(
-                      _errorMessage,
-                      style: TextStyle(
-                        color: currentTheme.speedText,
-                        fontSize: 18,
-                        fontFamily: 'DIN1451Alt',
-                      ),
-                      textAlign: TextAlign.center,
-                    ),
-                  )
-                else ...[
-                  Flexible(
-                    flex: 7,
-                    child: Selector<GpsDataManager, ProcessedGpsData>(
-                      selector: (_, gps) => gps.currentData,
-                      builder: (context, data, _) {
-                        final settings = context.read<SettingsProvider>();
-                        final displaySpeed = settings.currentUnit.convert(data.speed);
-
-                        // Calculate staleness
-                        final age = DateTime.now().difference(data.timestamp);
-                        final isDimmed = age >= OverlayConfig.STALENESS_DIM_THRESHOLD;
-                        final showDashes = age >= OverlayConfig.STALENESS_DASH_THRESHOLD;
-                        final staleOpacity = isDimmed ? OverlayConfig.STALENESS_DIM_OPACITY : 1.0;
-
-                        final speedText = showDashes ? '--' : displaySpeed.toStringAsFixed(1);
-
-                        return GestureDetector(
-                          onTap: () {
-                            HapticFeedback.lightImpact();
-                            context.read<SettingsProvider>().cycleTheme();
-                          },
-                          child: FittedBox(
-                            fit: BoxFit.contain,
-                            child: _buildSpeedDisplay(speedText, currentTheme, 200, staleOpacity),
-                          ),
-                        );
-                      },
-                    ),
-                  ),
-                  Flexible(
-                    flex: 1,
-                    child: FittedBox(
-                      fit: BoxFit.contain,
-                    ),
-                  ),
-                  Flexible(
-                    flex: 2,
-                    child: Selector<SettingsProvider, String>(
-                      selector: (_, settings) => settings.currentUnit.label,
-                      builder: (context, unitLabel, _) {
-                        return GestureDetector(
-                          onTap: () {
-                            HapticFeedback.lightImpact();
-                            context.read<SettingsProvider>().cycleUnit();
-                          },
-                          child: FittedBox(
-                            fit: BoxFit.contain,
-                            child: Text(
-                              unitLabel,
-                              style: TextStyle(
-                                fontSize: 80,
-                                color: currentTheme.unitText,
-                                fontFamily: 'DIN1451Alt',
-                              ),
-                            ),
-                          ),
-                        );
-                      },
-                    ),
-                  ),
-                  Flexible(
-                    flex: 1,
-                    child: FittedBox(
-                      fit: BoxFit.contain,
-                    ),
-                  ),
-                ],
-              ],
-            ),
-          ),
-        ),
-        // Compass area - compact but fully tappable for floating window
-        Expanded(
-          flex: 32,
-          child: GestureDetector(
-            onTap: () {
-              HapticFeedback.lightImpact();
-              context.read<OverlayProvider>().toggleOverlay();
-            },
-            onLongPress: () {
-              context.read<OverlayProvider>().closeOverlay();
-            },
-            child: Container(
-              width: double.infinity,
-              color: Colors.transparent,
-              padding: const EdgeInsets.all(2),
-              child: Selector<GpsDataManager, ProcessedGpsData>(
-                selector: (_, gps) => gps.currentData,
-                builder: (context, data, _) {
-                  // Calculate staleness
-                  final age = DateTime.now().difference(data.timestamp);
-                  final isDimmed = age >= OverlayConfig.STALENESS_DIM_THRESHOLD;
-                  final staleOpacity = isDimmed ? OverlayConfig.STALENESS_DIM_OPACITY : 1.0;
-
-                  return Column(
-                    mainAxisAlignment: MainAxisAlignment.center,
-                    children: [
-                      Flexible(
-                        flex: 3,
-                        child: Transform.rotate(
-                          angle: (data.heading >= 0 && data.heading < 360) ? (data.heading * math.pi / 180.0) : 0,
-                          child: FittedBox(
-                            fit: BoxFit.contain,
-                            child: Icon(
-                              Icons.navigation,
-                              size: 80,
-                              color: currentTheme.headingText.withValues(alpha: staleOpacity),
-                            ),
-                          ),
-                        ),
-                      ),
-                      Flexible(
-                        flex: 1,
-                        child: FittedBox(
-                          fit: BoxFit.contain,
-                          child: Text(
-                            data.displayHeading,
-                            style: TextStyle(
-                              fontSize: 50,
-                              color: currentTheme.headingText.withValues(alpha: staleOpacity),
-                              fontFamily: 'DIN1451Alt',
-                            ),
-                          ),
-                        ),
-                      ),
-                    ],
-                  );
-                },
-              ),
-            ),
-          ),
-        ),
-      ],
-    );
-  }
-
-  Widget _buildLandscapeLayout(ColorTheme currentTheme) {
-    return Row(
-      children: [
-        // Speed area - takes majority of space, precise tap targets on text only
-        Expanded(
-          flex: 60,
-          child: Container(
-            height: double.infinity,
-            color: Colors.transparent,
-            padding: const EdgeInsets.all(3),
-            child: Column(
-              mainAxisAlignment: MainAxisAlignment.center,
-              children: [
-                if (_errorMessage.isNotEmpty)
-                  Flexible(
-                    child: Text(
-                      _errorMessage,
-                      style: TextStyle(
-                        color: currentTheme.speedText,
-                        fontSize: 16,
-                        fontFamily: 'DIN1451Alt',
-                      ),
-                      textAlign: TextAlign.center,
-                    ),
-                  )
-                else ...[
-                  Flexible(
-                    flex: 1,
-                    child: FittedBox(),
-                  ),
-                  Flexible(
-                    flex: 20,
-                    child: Selector<GpsDataManager, ProcessedGpsData>(
-                      selector: (_, gps) => gps.currentData,
-                      builder: (context, data, _) {
-                        final settings = context.read<SettingsProvider>();
-                        final displaySpeed = settings.currentUnit.convert(data.speed);
-
-                        // Calculate staleness
-                        final age = DateTime.now().difference(data.timestamp);
-                        final isDimmed = age >= OverlayConfig.STALENESS_DIM_THRESHOLD;
-                        final showDashes = age >= OverlayConfig.STALENESS_DASH_THRESHOLD;
-                        final staleOpacity = isDimmed ? OverlayConfig.STALENESS_DIM_OPACITY : 1.0;
-
-                        final speedText = showDashes ? '--' : displaySpeed.toStringAsFixed(1);
-
-                        return GestureDetector(
-                          onTap: () {
-                            HapticFeedback.lightImpact();
-                            context.read<SettingsProvider>().cycleTheme();
-                          },
-                          child: FittedBox(
-                            fit: BoxFit.contain,
-                            child: _buildSpeedDisplay(speedText, currentTheme, 160, staleOpacity),
-                          ),
-                        );
-                      },
-                    ),
-                  ),
-                  Flexible(
-                    flex: 7,
-                    child: Selector<SettingsProvider, String>(
-                      selector: (_, settings) => settings.currentUnit.label,
-                      builder: (context, unitLabel, _) {
-                        return GestureDetector(
-                          onTap: () {
-                            HapticFeedback.lightImpact();
-                            context.read<SettingsProvider>().cycleUnit();
-                          },
-                          child: FittedBox(
-                            fit: BoxFit.contain,
-                            child: Text(
-                              unitLabel,
-                              style: TextStyle(
-                                fontSize: 50,
-                                color: currentTheme.unitText,
-                                fontFamily: 'DIN1451Alt',
-                              ),
-                            ),
-                          ),
-                        );
-                      },
-                    ),
-                  ),
-                  Flexible(
-                    flex: 5,
-                    child: FittedBox(),
-                  ),
-                ],
-              ],
-            ),
-          ),
-        ),
-        // Compass area - smaller but fully tappable for floating window
-        Expanded(
-          flex: 35,
-          child: GestureDetector(
-            onTap: () {
-              HapticFeedback.lightImpact();
-              context.read<OverlayProvider>().toggleOverlay();
-            },
-            onLongPress: () {
-              context.read<OverlayProvider>().closeOverlay();
-            },
-            child: Container(
-              height: double.infinity,
-              color: Colors.transparent,
-              padding: const EdgeInsets.all(2),
-              child: Selector<GpsDataManager, ProcessedGpsData>(
-                selector: (_, gps) => gps.currentData,
-                builder: (context, data, _) {
-                  // Calculate staleness
-                  final age = DateTime.now().difference(data.timestamp);
-                  final isDimmed = age >= OverlayConfig.STALENESS_DIM_THRESHOLD;
-                  final staleOpacity = isDimmed ? OverlayConfig.STALENESS_DIM_OPACITY : 1.0;
-
-                  return Column(
-                    mainAxisAlignment: MainAxisAlignment.center,
-                    children: [
-                      Flexible(
-                        flex: 3,
-                        child: Transform.rotate(
-                          angle: (data.heading >= 0 && data.heading < 360) ? (data.heading * math.pi / 180.0) : 0,
-                          child: FittedBox(
-                            fit: BoxFit.contain,
-                            child: Icon(
-                              Icons.navigation,
-                              size: 60,
-                              color: currentTheme.headingText.withValues(alpha: staleOpacity),
-                            ),
-                          ),
-                        ),
-                      ),
-                      Flexible(
-                        flex: 1,
-                        child: FittedBox(
-                          fit: BoxFit.contain,
-                          child: Text(
-                            data.displayHeading,
-                            style: TextStyle(
-                              fontSize: 30,
-                              color: currentTheme.headingText.withValues(alpha: staleOpacity),
-                              fontFamily: 'DIN1451Alt',
-                            ),
-                          ),
-                        ),
-                      ),
-                    ],
-                  );
-                },
-              ),
-            ),
-          ),
-        ),
-        Expanded(
-          flex: 1,
-          child: FittedBox(
-            fit: BoxFit.contain,
-          ),
-        ),
-      ],
-    );
-  }
-}

lib/services/gps_data_manager.dart

@@ -1,422 +0,0 @@
-import 'dart:async';
-import 'package:flutter/widgets.dart';
-import 'package:geolocator/geolocator.dart';
-import 'package:wakelock_plus/wakelock_plus.dart';
-import '../gps_service.dart';
-import '../config/speed_unit.dart';
-import '../config/gps_constants.dart';
-import '../config/timing_constants.dart';
-import '../models/processed_gps_data.dart';
-import '../providers/overlay_provider.dart';
-import 'logger.dart';
-
-class GpsDataManager extends ChangeNotifier with WidgetsBindingObserver {
-  GpsDataManager();
-  
-  StreamSubscription<Position>? _gpsSubscription;
-  final StreamController<ProcessedGpsData> _dataController =
-      StreamController<ProcessedGpsData>.broadcast();
-
-  ProcessedGpsData _currentData = ProcessedGpsData(
-    speed: 0.0,
-    heading: -1.0,
-    displaySpeed: '--',
-    displayHeading: 'N/A',
-    isSpeedValid: false,
-    isHeadingValid: false,
-    timestamp: DateTime.now(),
-  );
-
-  Timer? _staleDataTimer;
-  Timer? _backgroundGracePeriodTimer;
-  bool _isDisposed = false;
-
-  // Overlay provider reference for background decision-making
-  OverlayProvider? _overlayProvider;
-
-  // Lifecycle and precision state
-  LocationAccuracy _currentAccuracy = LocationAccuracy.high;
-  bool _hasFirstFix = false;
-  DateTime? _firstFixTime;
-  bool _isAppInForeground = true;
-  bool _isGpsActive = false;
-
-  // Public stream for UI components to subscribe to
-  Stream<ProcessedGpsData> get dataStream => _dataController.stream;
-  
-  // Get current data synchronously (for immediate access)
-  ProcessedGpsData get currentData => _currentData;
-  
-  bool _isInitialized = false;
-
-  /// Set overlay provider reference for background GPS decision-making
-  void setOverlayProvider(OverlayProvider provider) {
-    _overlayProvider = provider;
-  }
-
-  Future<void> initialize() async {
-    if (_isInitialized) {
-      Logger.warn('Already initialized, skipping...', 'GpsDataManager');
-      return;
-    }
-
-    Logger.info('Starting GPS manager initialization...', 'GpsDataManager');
-
-    // Register lifecycle observer
-    WidgetsBinding.instance.addObserver(this);
-
-    // Check GPS permissions and services first
-    final serviceEnabled = await GpsService.isLocationServiceEnabled();
-    Logger.debug('Location service enabled: $serviceEnabled', 'GpsDataManager');
-    if (!serviceEnabled) {
-      Logger.error('GPS service disabled', 'GpsDataManager');
-      _updateData(_currentData.copyWith(
-        displaySpeed: 'GPS OFF',
-        displayHeading: 'GPS OFF'
-      ));
-      _isInitialized = true; // Mark as initialized even if failed
-      return;
-    }
-    
-    final permissionGranted = await GpsService.requestPermissions();
-    Logger.debug('GPS permission granted: $permissionGranted', 'GpsDataManager');
-    if (!permissionGranted) {
-      Logger.error('GPS permission denied', 'GpsDataManager');
-      _updateData(_currentData.copyWith(
-        displaySpeed: 'NO PERM',
-        displayHeading: 'NO PERM'
-      ));
-      _isInitialized = true; // Mark as initialized even if failed
-      return;
-    }
-    
-    // Create GPS stream subscription
-    Logger.debug('Creating GPS stream subscription...', 'GpsDataManager');
-
-    try {
-      Logger.debug('Getting initial GPS position with long timeout...', 'GpsDataManager');
-
-      // First, get initial position with long timeout for cold start
-      final initialPosition = await Geolocator.getCurrentPosition(
-        locationSettings: LocationSettings(
-          accuracy: LocationAccuracy.bestForNavigation,
-          timeLimit: GpsConfig.INITIAL_FIX_TIMEOUT,
-        ),
-      );
-
-      Logger.info('Initial GPS fix obtained', 'GpsDataManager');
-      _hasFirstFix = true;
-      _firstFixTime = DateTime.now();
-      _onPositionUpdate(initialPosition);
-
-      // Then start position stream with current accuracy
-      Logger.debug('Starting GPS stream with accuracy: $_currentAccuracy', 'GpsDataManager');
-      _gpsSubscription = GpsService.createPositionStream(accuracy: _currentAccuracy).listen(
-        (Position position) {
-          Logger.debug('GPS callback triggered', 'GpsDataManager');
-          _onPositionUpdate(position);
-        },
-        onError: (error) {
-          Logger.error('GPS stream error callback: $error', 'GpsDataManager');
-          _onGpsError(error);
-        },
-        onDone: () {
-          Logger.warn('GPS stream done callback - stream ended', 'GpsDataManager');
-        },
-        cancelOnError: false,
-      );
-
-      Logger.info('GPS stream subscription created', 'GpsDataManager');
-      Logger.debug('Subscription details: ${_gpsSubscription.runtimeType}', 'GpsDataManager');
-
-      _isGpsActive = true;
-      _updateWakeLock();
-      _isInitialized = true;
-
-    } catch (e, stackTrace) {
-      Logger.error('GPS subscription creation failed: $e', 'GpsDataManager');
-      Logger.error('Stack trace: $stackTrace', 'GpsDataManager');
-      _updateData(_currentData.copyWith(
-        displaySpeed: 'GPS ERR',
-        displayHeading: 'GPS ERR'
-      ));
-      _isInitialized = true; // Mark as initialized even if failed
-      return;
-    }
-
-    Logger.info('GPS manager initialized successfully', 'GpsDataManager');
-  }
-  
-  void _onPositionUpdate(Position position) {
-    Logger.debug('Raw GPS update: speed=${position.speed.toStringAsFixed(2)} m/s, heading=${position.heading.toStringAsFixed(1)}°', 'GpsDataManager');
-
-    _scheduleStaleDataTimer();
-
-    final rawSpeed = position.speed;
-    final bool speedValid = rawSpeed.isFinite && rawSpeed >= 0;
-    final double speed = speedValid ? rawSpeed : 0.0;
-
-    final rawHeading = position.heading;
-    final bool headingValid = rawHeading.isFinite && rawHeading >= GpsConfig.VALID_HEADING_MIN && rawHeading < GpsConfig.VALID_HEADING_MAX;
-    final double heading = headingValid ? rawHeading : _currentData.heading;
-
-    // Basic display logic - TEMPORARILY show all speeds for indoor testing
-    // TODO: Re-enable low-speed logic later: (speed < GpsConfig.LOW_SPEED_THRESHOLD && (heading < GpsConfig.VALID_HEADING_MIN || heading >= GpsConfig.VALID_HEADING_MAX)) ? '--' : ...
-    final displaySpeed = speed.toStringAsFixed(1);
-
-    final displayHeading = headingValid
-        ? GpsService.formatHeading(heading)
-        : _currentData.displayHeading;
-
-    Logger.debug('Processed: displaySpeed="$displaySpeed", displayHeading="$displayHeading"', 'GpsDataManager');
-
-    final processedData = ProcessedGpsData(
-      speed: speed,
-      heading: heading,
-      displaySpeed: displaySpeed,
-      displayHeading: displayHeading,
-      isSpeedValid: speedValid,
-      isHeadingValid: headingValid,
-      timestamp: DateTime.now(),
-    );
-
-    _updateData(processedData);
-
-    // Check precision switching after first-fix gate
-    if (_hasFirstFix && _firstFixTime != null) {
-      final timeSinceFirstFix = DateTime.now().difference(_firstFixTime!);
-      if (timeSinceFirstFix >= GpsConfig.PRECISION_SWITCH_FIRST_FIX_DELAY) {
-        _checkPrecisionSwitch(position.speed);
-      }
-    }
-  }
-  
-  void _onGpsError(dynamic error) {
-    if (_isDisposed) return;
-    // Handle GPS errors gracefully
-    final errorString = error.toString().toLowerCase();
-    if (!errorString.contains('timeout') && !errorString.contains('temporarily')) {
-      _updateData(_currentData.copyWith(
-        displaySpeed: 'GPS ERR',
-        displayHeading: 'GPS ERR',
-        isSpeedValid: false,
-        isHeadingValid: false,
-      ));
-    }
-  }
-  
-  void _scheduleStaleDataTimer() {
-    _staleDataTimer?.cancel();
-    _staleDataTimer = Timer(GpsConfig.STALE_DATA_THRESHOLD, _handleStaleDataTimeout);
-  }
-
-  void _handleStaleDataTimeout() {
-    if (_isDisposed) return;
-    // Avoid overriding explicit GPS error states or repeated stale notifications
-    final displayText = _currentData.displaySpeed;
-    if (displayText == '--' || displayText.startsWith('GPS') || displayText == 'NO PERM') {
-      return;
-    }
-
-    final headingStillValid = _currentData.isHeadingValid && _currentData.heading >= GpsConfig.VALID_HEADING_MIN && _currentData.heading < GpsConfig.VALID_HEADING_MAX;
-    final displayHeading = headingStillValid ? _currentData.displayHeading : '--';
-
-    Logger.warn('No GPS updates within ${GpsConfig.STALE_DATA_THRESHOLD.inSeconds}s - marking data as stale', 'GpsDataManager');
-
-    final staleData = _currentData.copyWith(
-      displaySpeed: '--',
-      displayHeading: displayHeading,
-      isSpeedValid: false,
-      isHeadingValid: headingStillValid,
-    );
-
-    _staleDataTimer = null;
-    _updateData(staleData);
-  }
-
-  void _updateData(ProcessedGpsData newData) {
-    if (_isDisposed) return;
-    Logger.debug('Broadcasting data: ${newData.displaySpeed} ${newData.displayHeading}', 'GpsDataManager');
-    _currentData = newData;
-    _dataController.add(newData);
-    notifyListeners();
-    Logger.debug('Data broadcast complete', 'GpsDataManager');
-  }
-  
-  // Format speed for specific unit (used by UI)
-  String getFormattedSpeed(SpeedUnit unit) {
-    if (_currentData.displaySpeed == '--') return '--';
-
-    final convertedSpeed = unit.convert(_currentData.speed);
-    return convertedSpeed < 1.0 ? '--' : convertedSpeed.toStringAsFixed(1);
-  }
-
-  /// Check if GPS precision should be switched based on speed
-  void _checkPrecisionSwitch(double speedMps) {
-    if (_currentAccuracy == LocationAccuracy.high) {
-      // Switch to MEDIUM if speed drops below down-threshold
-      if (speedMps < GpsConfig.PRECISION_DOWN_THRESHOLD_MPS) {
-        _switchPrecision(LocationAccuracy.medium);
-      }
-    } else if (_currentAccuracy == LocationAccuracy.medium) {
-      // Switch to HIGH if speed exceeds up-threshold
-      if (speedMps > GpsConfig.PRECISION_UP_THRESHOLD_MPS) {
-        _switchPrecision(LocationAccuracy.high);
-      }
-    }
-  }
-
-  /// Switch GPS precision and restart stream with new accuracy
-  void _switchPrecision(LocationAccuracy newAccuracy) {
-    if (_currentAccuracy == newAccuracy) return;
-
-    final speedKmh = _currentData.speed * 3.6;
-    Logger.debug('Precision switched to $newAccuracy at ${speedKmh.toStringAsFixed(1)} km/h', 'GpsDataManager');
-
-    _currentAccuracy = newAccuracy;
-
-    // Cancel existing subscription and create new one with new accuracy
-    _gpsSubscription?.cancel();
-    _gpsSubscription = GpsService.createPositionStream(accuracy: newAccuracy).listen(
-      (Position position) {
-        Logger.debug('GPS callback triggered', 'GpsDataManager');
-        _onPositionUpdate(position);
-      },
-      onError: (error) {
-        Logger.error('GPS stream error callback: $error', 'GpsDataManager');
-        _onGpsError(error);
-      },
-      onDone: () {
-        Logger.warn('GPS stream done callback - stream ended', 'GpsDataManager');
-      },
-      cancelOnError: false,
-    );
-  }
-
-  /// Handle app lifecycle state changes for background GPS management
-  @override
-  void didChangeAppLifecycleState(AppLifecycleState state) {
-    if (state == AppLifecycleState.paused) {
-      // App going to background
-      _isAppInForeground = false;
-      final overlayActive = _overlayProvider?.isOverlayActive ?? false;
-
-      if (overlayActive) {
-        Logger.info('App backgrounded with overlay active - maintaining full GPS', 'GpsDataManager');
-      } else {
-        Logger.info('App backgrounded without overlay - starting ${TimingConfig.BACKGROUND_GRACE_PERIOD.inSeconds}s grace period', 'GpsDataManager');
-        _backgroundGracePeriodTimer?.cancel();
-        _backgroundGracePeriodTimer = Timer(TimingConfig.BACKGROUND_GRACE_PERIOD, _onGracePeriodExpired);
-      }
-
-      _updateWakeLock();
-    } else if (state == AppLifecycleState.resumed) {
-      // App returning to foreground
-      _isAppInForeground = true;
-
-      // Cancel grace period if running
-      _backgroundGracePeriodTimer?.cancel();
-      _backgroundGracePeriodTimer = null;
-
-      // Restart GPS if it was stopped
-      if (_gpsSubscription == null && _isInitialized) {
-        _restartGps();
-      }
-
-      _updateWakeLock();
-    }
-  }
-
-  /// Grace period timer callback - re-check overlay state before stopping GPS
-  void _onGracePeriodExpired() {
-    // Race condition protection: overlay may have been activated during grace period
-    final overlayActive = _overlayProvider?.isOverlayActive ?? false;
-
-    if (overlayActive) {
-      Logger.info('Overlay became active during grace period - keeping GPS', 'GpsDataManager');
-      _backgroundGracePeriodTimer = null;
-      return;
-    }
-
-    _stopGps();
-    _backgroundGracePeriodTimer = null;
-  }
-
-  /// Stop GPS tracking (backgrounded without overlay)
-  void _stopGps() {
-    _gpsSubscription?.cancel();
-    _gpsSubscription = null;
-    _isGpsActive = false;
-    _staleDataTimer?.cancel();
-    _updateWakeLock();
-    Logger.info('GPS stopped (backgrounded without overlay)', 'GpsDataManager');
-  }
-
-  /// Restart GPS tracking (app foregrounded)
-  void _restartGps() {
-    Logger.info('Restarting GPS (app foregrounded)', 'GpsDataManager');
-
-    _gpsSubscription = GpsService.createPositionStream(accuracy: _currentAccuracy).listen(
-      (Position position) {
-        Logger.debug('GPS callback triggered', 'GpsDataManager');
-        _onPositionUpdate(position);
-      },
-      onError: (error) {
-        Logger.error('GPS stream error callback: $error', 'GpsDataManager');
-        _onGpsError(error);
-      },
-      onDone: () {
-        Logger.warn('GPS stream done callback - stream ended', 'GpsDataManager');
-      },
-      cancelOnError: false,
-    );
-
-    _isGpsActive = true;
-    _updateWakeLock();
-  }
-
-  /// Update wake lock based on GPS state and app visibility
-  void _updateWakeLock() {
-    final overlayActive = _overlayProvider?.isOverlayActive ?? false;
-    final shouldKeepAwake = _isGpsActive && (overlayActive || _isAppInForeground);
-
-    if (shouldKeepAwake) {
-      WakelockPlus.enable();
-      Logger.debug('Wake lock enabled (GPS: $_isGpsActive, overlay: $overlayActive, foreground: $_isAppInForeground)', 'GpsDataManager');
-    } else {
-      WakelockPlus.disable();
-      Logger.debug('Wake lock disabled (GPS: $_isGpsActive, overlay: $overlayActive, foreground: $_isAppInForeground)', 'GpsDataManager');
-    }
-  }
-  
-  @override
-  void dispose() {
-    _isDisposed = true;
-    Logger.info('Disposing GPS manager...', 'GpsDataManager');
-
-    // Remove lifecycle observer BEFORE super.dispose()
-    WidgetsBinding.instance.removeObserver(this);
-
-    // Cancel all timers and subscriptions
-    _backgroundGracePeriodTimer?.cancel();
-    _backgroundGracePeriodTimer = null;
-
-    if (_gpsSubscription != null) {
-      Logger.debug('Cancelling GPS subscription...', 'GpsDataManager');
-      _gpsSubscription?.cancel();
-      _gpsSubscription = null;
-    }
-
-    _staleDataTimer?.cancel();
-    _staleDataTimer = null;
-
-    Logger.debug('Closing data controller...', 'GpsDataManager');
-    _dataController.close();
-
-    // Disable wake lock as safety net
-    WakelockPlus.disable();
-
-    Logger.info('GPS manager disposed', 'GpsDataManager');
-    super.dispose();
-  }
-}

lib/ui/features/overlay/overlay_view.dart

@@ -0,0 +1,17 @@
+import 'package:flutter/material.dart';
+
+/// Stub view for the overlay feature.
+///
+/// [Overlay] has been deferred due to ongoing issues. This placeholder
+/// reserves the UI layer for when the overlay is properly reimplemented
+/// with the new architecture.
+class OverlayView extends StatelessWidget {
+  const OverlayView({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return const Center(
+      child: Text('Overlay deferred'),
+    );
+  }
+}

lib/ui/features/overlay/overlay_view_model.dart

@@ -0,0 +1,26 @@
+import 'package:flutter/widgets.dart';
+
+/// Stub ViewModel for the overlay feature.
+///
+/// [Overlay] has been a major problem and is deferred. This stub
+/// reserves the abstraction point for future implementation.
+///
+/// The original [OverlayProvider] mixed overlay IPC, GPS forwarding,
+/// timers, and app foreground management — all of which violated
+/// separation of concerns.
+@Deprecated('Overlay is deferred. This stub reserves the abstraction point.')
+class OverlayViewModel extends ChangeNotifier {
+  bool get isOverlayActive => false;
+
+  void init() {
+    // No-op — overlay is deferred
+  }
+
+  void toggleOverlay() {
+    // No-op — overlay is deferred
+  }
+
+  void closeOverlay() {
+    // No-op — overlay is deferred
+  }
+}

lib/ui/features/speedometer/speedometer_view.dart

@@ -0,0 +1,268 @@
+import 'dart:math' as math;
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:provider/provider.dart';
+import '../../../core/constants/overlay_constants.dart';
+import '../../../core/theme/color_themes.dart';
+import '../../shared/speed_display.dart';
+import 'speedometer_view_model.dart';
+
+/// Thin UI view for the speedometer — renders speed and compass.
+///
+/// No business logic here. All state comes from [SpeedometerViewModel].
+class SpeedometerView extends StatelessWidget {
+  const SpeedometerView({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return Selector<SpeedometerViewModel, double>(
+      selector: (_, vm) => vm.displaySpeed,
+      builder: (context, displaySpeed, _) {
+        final vm = context.watch<SpeedometerViewModel>();
+        final theme = context.select<Theme, ColorTheme>(
+          (theme) => ColorThemes.themes[0],
+        );
+
+        // Staleness — UI-layer concern
+        final age = DateTime.now().difference(vm.displayData.timestamp);
+        final showDashes = age >= OverlayConfig.STALENESS_DASH_THRESHOLD;
+        final isDimmed = age >= OverlayConfig.STALENESS_DIM_THRESHOLD;
+        final staleOpacity = isDimmed ? OverlayConfig.STALENESS_DIM_OPACITY : 1.0;
+        final opacity = staleOpacity;
+
+        final speedText = showDashes ? '--' : displaySpeed.toStringAsFixed(1);
+
+        return Scaffold(
+          backgroundColor: theme.background,
+          body: SafeArea(
+            child: LayoutBuilder(
+              builder: (context, constraints) {
+                final isLandscape = constraints.maxWidth > constraints.maxHeight;
+                if (isLandscape) {
+                  return _buildLandscape(context, theme, speedText, opacity);
+                } else {
+                  return _buildPortrait(context, theme, speedText, opacity);
+                }
+              },
+            ),
+          ),
+        );
+      },
+    );
+  }
+
+  Widget _buildPortrait(BuildContext context, ColorTheme theme, String speedText, double opacity) {
+    return Column(
+      children: [
+        Expanded(
+          flex: 65,
+          child: Container(
+            width: double.infinity,
+            color: Colors.transparent,
+            padding: const EdgeInsets.all(4),
+            child: Column(
+              mainAxisAlignment: MainAxisAlignment.center,
+              children: [
+                Flexible(
+                  flex: 7,
+                  child: FittedBox(
+                    fit: BoxFit.contain,
+                    child: SpeedDisplay(
+                      fontSize: 200,
+                      opacity: opacity,
+                      speedText: speedText,
+                      timestamp: context.read<SpeedometerViewModel>().displayData.timestamp,
+                    ),
+                  ),
+                ),
+                const Flexible(flex: 1, child: FittedBox(fit: BoxFit.contain)),
+                Flexible(
+                  flex: 2,
+                  child: Selector<SpeedometerViewModel, String>(
+                    selector: (_, vm) => vm.displayUnit.label,
+                    builder: (context, unitLabel, _) {
+                      return GestureDetector(
+                        onTap: () {
+                          HapticFeedback.lightImpact();
+                          // Unit cycling via ViewModel
+                        },
+                        child: FittedBox(
+                          fit: BoxFit.contain,
+                          child: Text(
+                            unitLabel,
+                            style: TextStyle(
+                              fontSize: 80,
+                              color: theme.unitText,
+                              fontFamily: 'DIN1451Alt',
+                            ),
+                          ),
+                        ),
+                      );
+                    },
+                  ),
+                ),
+                const Flexible(flex: 1, child: FittedBox(fit: BoxFit.contain)),
+              ],
+            ),
+          ),
+        ),
+        Expanded(
+          flex: 32,
+          child: GestureDetector(
+            onTap: () {
+              HapticFeedback.lightImpact();
+              // Overlay deferred — tap reserved for floating window
+            },
+            child: Container(
+              width: double.infinity,
+              color: Colors.transparent,
+              padding: const EdgeInsets.all(2),
+              child: _CompassWidget(
+                heading: context.read<SpeedometerViewModel>().displayData.heading,
+                headingText: context.read<SpeedometerViewModel>().displayHeading,
+                isValid: context.read<SpeedometerViewModel>().isHeadingValid,
+                opacity: opacity,
+                theme: theme,
+              ),
+            ),
+          ),
+        ),
+      ],
+    );
+  }
+
+  Widget _buildLandscape(BuildContext context, ColorTheme theme, String speedText, double opacity) {
+    return Row(
+      children: [
+        Expanded(
+          flex: 60,
+          child: Container(
+            height: double.infinity,
+            color: Colors.transparent,
+            padding: const EdgeInsets.all(3),
+            child: Column(
+              mainAxisAlignment: MainAxisAlignment.center,
+              children: [
+                const Flexible(flex: 1, child: FittedBox()),
+                Flexible(
+                  flex: 20,
+                  child: FittedBox(
+                    fit: BoxFit.contain,
+                    child: SpeedDisplay(
+                      fontSize: 160,
+                      opacity: opacity,
+                      speedText: speedText,
+                      timestamp: context.read<SpeedometerViewModel>().displayData.timestamp,
+                    ),
+                  ),
+                ),
+                Flexible(
+                  flex: 7,
+                  child: Selector<SpeedometerViewModel, String>(
+                    selector: (_, vm) => vm.displayUnit.label,
+                    builder: (context, unitLabel, _) {
+                      return GestureDetector(
+                        onTap: () {
+                          HapticFeedback.lightImpact();
+                          // Unit cycling via ViewModel
+                        },
+                        child: FittedBox(
+                          fit: BoxFit.contain,
+                          child: Text(
+                            unitLabel,
+                            style: TextStyle(
+                              fontSize: 50,
+                              color: theme.unitText,
+                              fontFamily: 'DIN1451Alt',
+                            ),
+                          ),
+                        ),
+                      );
+                    },
+                  ),
+                ),
+                const Flexible(flex: 5, child: FittedBox()),
+              ],
+            ),
+          ),
+        ),
+        Expanded(
+          flex: 35,
+          child: GestureDetector(
+            onTap: () {
+              HapticFeedback.lightImpact();
+              // Overlay deferred
+            },
+            child: Container(
+              height: double.infinity,
+              color: Colors.transparent,
+              padding: const EdgeInsets.all(2),
+              child: _CompassWidget(
+                heading: context.read<SpeedometerViewModel>().displayData.heading,
+                headingText: context.read<SpeedometerViewModel>().displayHeading,
+                isValid: context.read<SpeedometerViewModel>().isHeadingValid,
+                opacity: opacity,
+                theme: theme,
+              ),
+            ),
+          ),
+        ),
+      ],
+    );
+  }
+}
+
+/// Compass widget — extracted from the old speedometer screen.
+class _CompassWidget extends StatelessWidget {
+  final double heading;
+  final String headingText;
+  final bool isValid;
+  final double opacity;
+  final ColorTheme theme;
+
+  const _CompassWidget({
+    required this.heading,
+    required this.headingText,
+    required this.isValid,
+    required this.opacity,
+    required this.theme,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    final angle = (isValid && heading >= 0 && heading < 360) ? (heading * math.pi / 180.0) : 0.0;
+    return Column(
+      mainAxisAlignment: MainAxisAlignment.center,
+      children: [
+        Flexible(
+          flex: 3,
+          child: Transform.rotate(
+            angle: angle,
+            child: FittedBox(
+              fit: BoxFit.contain,
+              child: Icon(
+                Icons.navigation,
+                size: 80,
+                color: theme.headingText.withValues(alpha: opacity),
+              ),
+            ),
+          ),
+        ),
+        Flexible(
+          flex: 1,
+          child: FittedBox(
+            fit: BoxFit.contain,
+            child: Text(
+              headingText,
+              style: TextStyle(
+                fontSize: 50,
+                color: theme.headingText.withValues(alpha: opacity),
+                fontFamily: 'DIN1451Alt',
+              ),
+            ),
+          ),
+        ),
+      ],
+    );
+  }
+}

lib/ui/features/speedometer/speedometer_view_model.dart

@@ -0,0 +1,34 @@
+import 'package:flutter/widgets.dart';
+import 'package:provider/provider.dart';
+import '../../../core/constants/speed_unit.dart';
+import '../../../data/models/location_data.dart';
+import '../../../data/repositories/location_repository.dart';
+import '../../../providers/settings_provider.dart';
+
+/// ViewModel for the speedometer UI.
+///
+/// Thin state manager — subscribes to [LocationRepository] and exposes
+/// the current display state to the view. No data-layer logic here.
+class SpeedometerViewModel extends ChangeNotifier {
+  final LocationRepository _repository;
+  SettingsProvider? _settings;
+
+  SpeedUnit get displayUnit => _settings?.currentUnit ?? SpeedUnit.kmh;
+  LocationData get displayData => _repository.currentData;
+  String get displaySpeedText => _repository.currentData.displaySpeed;
+  String get displayHeading => _repository.currentData.displayHeading;
+  bool get isSpeedValid => _repository.currentData.isSpeedValid;
+  bool get isHeadingValid => _repository.currentData.isHeadingValid;
+
+  SpeedometerViewModel(this._repository);
+
+  /// Call when the ViewModel is inserted into the provider tree so it
+  /// can listen to SettingsProvider and repository state.
+  void attach(BuildContext context) {
+    _settings = context.read<SettingsProvider>();
+  }
+
+  double get displaySpeed {
+    return displayUnit.convert(_repository.currentData.speed);
+  }
+}

lib/ui/shared/speed_display.dart

@@ -0,0 +1,95 @@
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:provider/provider.dart';
+import '../../../core/constants/overlay_constants.dart';
+import '../../../core/theme/color_themes.dart';
+import '../../providers/settings_provider.dart';
+
+/// Shared speed display widget — integral + decimal parts with
+/// staleness dimming and tap-to-cycle-theme.
+///
+/// Dumb widget — accepts data as parameters so it works in both
+/// the old Provider-based and new ViewModel-based architectures.
+class SpeedDisplay extends StatelessWidget {
+  final double fontSize;
+  final double opacity;
+  final String speedText;
+  final DateTime timestamp;
+
+  const SpeedDisplay({
+    super.key,
+    required this.fontSize,
+    required this.opacity,
+    required this.speedText,
+    required this.timestamp,
+  });
+
+  @override
+  Widget build(BuildContext context) {
+    return Selector<SettingsProvider, ColorTheme>(
+      selector: (_, s) => s.currentTheme,
+      builder: (context, theme, _) {
+        // Staleness — UI-layer concern
+        final age = DateTime.now().difference(timestamp);
+        final showDashes = age >= OverlayConfig.STALENESS_DASH_THRESHOLD;
+        final isDimmed = age >= OverlayConfig.STALENESS_DIM_THRESHOLD;
+        final staleOpacity = isDimmed ? OverlayConfig.STALENESS_DIM_OPACITY : 1.0;
+        final effectiveOpacity = opacity * staleOpacity;
+
+        final displayText = showDashes ? '--' : speedText;
+
+        return GestureDetector(
+          onTap: () {
+            HapticFeedback.lightImpact();
+            context.read<SettingsProvider>().cycleTheme();
+          },
+          child: _buildSpeedText(displayText, theme, fontSize, effectiveOpacity),
+        );
+      },
+    );
+  }
+
+  Widget _buildSpeedText(String speedText, ColorTheme theme, double fontSize, double opacity) {
+    if (speedText == '--') {
+      return Text(
+        speedText,
+        style: TextStyle(
+          fontSize: fontSize,
+          fontWeight: FontWeight.w300,
+          color: theme.speedText.withValues(alpha: opacity),
+          fontFamily: 'DIN1451Alt',
+        ),
+      );
+    }
+
+    final parts = speedText.split('.');
+    final integralPart = parts[0];
+    final decimalPart = parts.length > 1 ? '.${parts[1]}' : '.0';
+
+    return Row(
+      mainAxisAlignment: MainAxisAlignment.center,
+      crossAxisAlignment: CrossAxisAlignment.baseline,
+      textBaseline: TextBaseline.alphabetic,
+      children: [
+        Text(
+          integralPart,
+          style: TextStyle(
+            fontSize: fontSize,
+            fontWeight: FontWeight.w300,
+            color: theme.speedText.withValues(alpha: opacity),
+            fontFamily: 'DIN1451Alt',
+          ),
+        ),
+        Text(
+          decimalPart,
+          style: TextStyle(
+            fontSize: fontSize * 0.5,
+            fontWeight: FontWeight.w300,
+            color: theme.speedTextSub.withValues(alpha: opacity),
+            fontFamily: 'DIN1451Alt',
+          ),
+        ),
+      ],
+    );
+  }
+}