feat: harden geofence and distance diagnostics

lib/features/homes/providers/location_providers.dart

@@ -5,15 +5,28 @@ import 'package:flutter/foundation.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:geolocator/geolocator.dart';
 
+enum UserLocationIssue {
+  servicesDisabled,
+  permissionDenied,
+  permissionDeniedForever,
+  unavailable,
+}
+
 /// Состояние геолокации: позиция или причина отсутствия.
 /// Запрашивается один раз, кешируется до перезапуска провайдера.
 class UserLocation {
   final Position? position;
   final String? error; // null -- всё ок, иначе причина
+  final UserLocationIssue? issue;
+  final DateTime? updatedAt;
 
-  const UserLocation({this.position, this.error});
+  const UserLocation({this.position, this.error, this.issue, this.updatedAt});
 
   bool get hasPosition => position != null;
+  bool get needsAppSettings =>
+      issue == UserLocationIssue.permissionDeniedForever;
+  bool get needsLocationSettings => issue == UserLocationIssue.servicesDisabled;
+  bool get canRequestPermission => issue == UserLocationIssue.permissionDenied;
 
   /// Расстояние в км до точки. Возвращает null если нет позиции
   /// или у цели нет координат.
@@ -50,30 +63,7 @@ class UserLocationNotifier extends Notifier<UserLocation> {
   /// и отдаёт lastKnown мгновенно (если есть).
   Future<void> fetch() async {
     if (state.hasPosition) return;
-
-    final err = await _ensurePermission();
-    if (err != null) {
-      state = UserLocation(error: err);
-      return;
-    }
-
-    try {
-      final last = await Geolocator.getLastKnownPosition();
-      if (last != null) {
-        state = UserLocation(position: last);
-        return;
-      }
-
-      final pos = await Geolocator.getCurrentPosition(
-        locationSettings: const LocationSettings(
-          accuracy: LocationAccuracy.low,
-          timeLimit: Duration(seconds: 10),
-        ),
-      );
-      state = UserLocation(position: pos);
-    } catch (e) {
-      state = UserLocation(error: 'Ошибка: $e');
-    }
+    await refresh();
   }
 
   /// Начать непрерывное отслеживание. Вызывать из initState экрана.
@@ -83,9 +73,9 @@ class UserLocationNotifier extends Notifier<UserLocation> {
     _watchers++;
     if (_sub != null) return;
 
-    final err = await _ensurePermission();
-    if (err != null) {
-      state = UserLocation(error: err);
+    final permissionState = await _ensurePermission();
+    if (!permissionState.isGranted) {
+      state = permissionState.toLocation();
       return;
     }
 
@@ -93,7 +83,7 @@ class UserLocationNotifier extends Notifier<UserLocation> {
       try {
         final last = await Geolocator.getLastKnownPosition();
         if (last != null) {
-          state = UserLocation(position: last);
+          state = _fromPosition(last);
         }
       } catch (_) {}
     }
@@ -104,9 +94,14 @@ class UserLocationNotifier extends Notifier<UserLocation> {
     );
 
     _sub = Geolocator.getPositionStream(locationSettings: settings).listen(
-      (pos) => state = UserLocation(position: pos),
+      (pos) => state = _fromPosition(pos),
       onError: (e) {
         debugPrint('Ошибка стрима геолокации: $e');
+        state = UserLocation(
+          error: 'Не удалось отслеживать позицию: $e',
+          issue: UserLocationIssue.unavailable,
+          updatedAt: state.updatedAt,
+        );
       },
     );
   }
@@ -120,11 +115,61 @@ class UserLocationNotifier extends Notifier<UserLocation> {
     }
   }
 
+  Future<void> refresh() async {
+    final permissionState = await _ensurePermission();
+    if (!permissionState.isGranted) {
+      state = permissionState.toLocation();
+      return;
+    }
+
+    try {
+      final last = await Geolocator.getLastKnownPosition();
+      if (last != null) {
+        state = _fromPosition(last);
+        return;
+      }
+
+      final pos = await Geolocator.getCurrentPosition(
+        locationSettings: const LocationSettings(
+          accuracy: LocationAccuracy.low,
+          timeLimit: Duration(seconds: 10),
+        ),
+      );
+      state = _fromPosition(pos);
+    } catch (e) {
+      state = UserLocation(
+        error: 'Не удалось получить позицию: $e',
+        issue: UserLocationIssue.unavailable,
+        updatedAt: state.updatedAt,
+      );
+    }
+  }
+
+  Future<void> requestPermission() async {
+    await Geolocator.requestPermission();
+    if (_watchers > 0 && _sub == null) {
+      await startWatching();
+      return;
+    }
+    await refresh();
+  }
+
+  Future<void> openAppSettings() async {
+    await Geolocator.openAppSettings();
+  }
+
+  Future<void> openLocationSettings() async {
+    await Geolocator.openLocationSettings();
+  }
+
   /// Проверить сервис и пермишены. Возвращает null если всё ок,
   /// иначе строку с причиной ошибки.
-  Future<String?> _ensurePermission() async {
+  Future<_LocationPermissionState> _ensurePermission() async {
     if (!await Geolocator.isLocationServiceEnabled()) {
-      return 'Геолокация выключена';
+      return const _LocationPermissionState(
+        issue: UserLocationIssue.servicesDisabled,
+        message: 'Геолокация выключена',
+      );
     }
 
     var perm = await Geolocator.checkPermission();
@@ -132,12 +177,35 @@ class UserLocationNotifier extends Notifier<UserLocation> {
       perm = await Geolocator.requestPermission();
     }
     if (perm == LocationPermission.denied) {
-      return 'Нет разрешения';
+      return const _LocationPermissionState(
+        issue: UserLocationIssue.permissionDenied,
+        message: 'Нет разрешения на геолокацию',
+      );
     }
     if (perm == LocationPermission.deniedForever) {
-      return 'Разрешение запрещено навсегда';
+      return const _LocationPermissionState(
+        issue: UserLocationIssue.permissionDeniedForever,
+        message: 'Доступ к геолокации запрещён навсегда',
+      );
     }
-    return null;
+    return const _LocationPermissionState();
+  }
+
+  UserLocation _fromPosition(Position position) {
+    return UserLocation(position: position, updatedAt: position.timestamp);
+  }
+}
+
+class _LocationPermissionState {
+  final UserLocationIssue? issue;
+  final String? message;
+
+  const _LocationPermissionState({this.issue, this.message});
+
+  bool get isGranted => issue == null;
+
+  UserLocation toLocation() {
+    return UserLocation(error: message, issue: issue);
   }
 }