improve notifications

android/app/build.gradle

@@ -31,7 +31,7 @@ if (keystorePropertiesFile.exists()) {
 
 android {
     namespace "de.nucleus.foss_warn"
-    compileSdk 35
+    compileSdk 36
 
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_17

android/settings.gradle

@@ -19,7 +19,7 @@ pluginManagement {
 plugins {
     id "dev.flutter.flutter-plugin-loader" version "1.0.0"
     id "com.android.application" version "8.8.0" apply false
-    id "org.jetbrains.kotlin.android" version "2.0.21" apply false
+    id "org.jetbrains.kotlin.android" version "2.2.0" apply false
 }
 
 include ":app"

lib/class/class_app_state.dart

@@ -1,6 +1,20 @@
 class AppState {
-  bool error = false; // true if API call and parsing was not successful
+  /// Flag that indicates that there was an error
+  bool error = false;
+
+  /// Flag to indicate that the displayed alerts are just from the cache and could
+  /// be out-dated. This should only happen, if the user does not have an internet connection
   bool areWarningsFromCache = false;
-  bool isFirstFetch =
-      true; // used to display a text that the app is fetching new alerts if the app is freshly started
+
+  /// used to display a text that the app is fetching new alerts if the app is freshly started
+  bool isFirstFetch = true;
+
+  /// Flag to indicate an error with the push notification setup
+  bool pushNotificationSetupError = false;
+
+  /// Flag that is set to true when we are resubscribing places.
+  /// This is to avoid race conditions with the update loop, which could mark the
+  /// place as expired if it tries to fetch alerts just between we unsubscribed
+  /// the old subscriptions and not yet have resubscribed.
+  bool reSubscriptionInProgress = false;
 }

lib/class/class_area.dart

@@ -6,7 +6,6 @@ import 'package:latlong2/latlong.dart';
 import 'package:flutter/material.dart';
 import 'package:foss_warn/class/class_error_logger.dart';
 import '../main.dart';
-import 'class_douglas_peucker.dart';
 
 class Area {
   String description; // general description of the area
@@ -52,9 +51,9 @@ class Area {
     if (data != null) {
       // there a multiple entries => multiple areas
       for (int i = 0; i < data.length; i++) {
-        Map<String, dynamic> capToGeoJson =
-            _convertCAPGeoInfoToGeoJson(data[i]);
-
+        Map<String, dynamic> capToGeoJson = _convertCAPGeoInfoToGeoJson(
+          data[i],
+        );
         data[i].putIfAbsent("geoJson", () => jsonEncode(capToGeoJson));
         result.add(Area.fromJson(data[i]));
       }
@@ -88,7 +87,6 @@ class Area {
   static Map<String, dynamic> _convertCAPGeoInfoToGeoJson(
     Map<String, dynamic> data,
   ) {
-    const double polygonSimplificationTolerance = 0.001;
     Map<String, dynamic> featureCollection = {};
     featureCollection.putIfAbsent("type", () => "FeatureCollection");
 
@@ -138,12 +136,6 @@ class Area {
             oneRowCoordinates.add(onePairOfCoordinatesList);
           }
 
-          // apply douglas peucker to reduce number of polygons
-          oneRowCoordinates = DouglasPeucker.simplify(
-            coordinates: oneRowCoordinates,
-            tolerance: polygonSimplificationTolerance,
-          );
-
           oneRowCoordinatesOuterList.clear();
           oneRowCoordinatesOuterList.add(oneRowCoordinates);
 
@@ -191,12 +183,6 @@ class Area {
           oneRowCoordinates.add(onePairOfCoordinatesList);
         }
 
-        // apply douglas peucker to reduce number of polygons
-        oneRowCoordinates = DouglasPeucker.simplify(
-          coordinates: oneRowCoordinates,
-          tolerance: polygonSimplificationTolerance,
-        );
-
         // add the row to the List
         coordinatesList.add(oneRowCoordinates);
 

lib/class/class_bounding_box.dart

@@ -21,19 +21,20 @@ class BoundingBox {
     /// create new warnMessage objects from saved data
     return BoundingBox(
       minLatLng: LatLng(
-        minLatLng['coordinates']![0],
         minLatLng['coordinates']![1],
+        minLatLng['coordinates']![0],
       ), //@todo
       maxLatLng: LatLng(
-        maxLatLng['coordinates']![0],
         maxLatLng['coordinates']![1],
+        maxLatLng['coordinates']![0],
       ),
     );
   }
 
   Map<String, dynamic> toJson() {
     try {
       return {
+        // LatLng.toJson returns [longitude, latitude]
         'min_latLng': minLatLng,
         'max_latLng': maxLatLng,
       };

lib/class/class_info.dart

@@ -95,6 +95,8 @@ class Info {
     if (json['category'] is List) {
       categories =
           Category.categoryListFromJson(List<String>.from(json['category']));
+    } else if (json["category"] == null) {
+      categories = [Category.other];
     } else {
       categories = [Category.fromString(json['category'])];
     }

lib/class/class_notification_service.dart

@@ -307,4 +307,13 @@ class NotificationService {
   static Future<void> cancelAllNotification() async {
     await _flutterLocalNotificationsPlugin.cancelAll();
   }
+
+  /// Check if a notification with the given id is currently active
+  static Future<bool> isNotificationActive(int id) async {
+    List<ActiveNotification> activeNotification =
+        await _flutterLocalNotificationsPlugin.getActiveNotifications();
+    return activeNotification.any(
+      (notification) => notification.id != null && notification.id == id,
+    );
+  }
 }

lib/class/class_unified_push_handler.dart

@@ -1,21 +1,23 @@
 import 'dart:convert';
-import 'dart:math';
 
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:foss_warn/class/class_error_logger.dart';
 import 'package:foss_warn/class/class_user_preferences.dart';
-import 'package:foss_warn/class/class_warn_message.dart';
 import 'package:foss_warn/services/api_handler.dart';
 import 'package:foss_warn/services/list_handler.dart';
 import 'package:foss_warn/services/warnings.dart';
 
 import 'package:unifiedpush/unifiedpush.dart';
+import '../main.dart';
 import '../services/alert_api/fpas.dart';
+import '../services/notification_handler.dart';
 import '../widgets/dialogs/no_up_distributor_found_dialog.dart';
 import '../widgets/dialogs/select_unified_push_distributor_dialog.dart';
-import 'class_notification_service.dart';
+
+/// Thrown when a UnifiedPush registration failed with a timeout
+class UnifiedPushRegistrationTimeoutError implements Exception {}
 
 final unifiedPushHandlerProvider = Provider(
   (ref) => UnifiedPushHandler(
@@ -34,12 +36,13 @@ class UnifiedPushHandler {
   final UserPreferencesService _preferencesService;
   final UserPreferences _userPreferences;
 
+  /// Callback function for the UnifiedPush  plugin
+  /// this method gets called when a new endpoint is selected
   void onNewEndpoint(PushEndpoint endpoint, String instance) {
     debugPrint("new Endpoint:${endpoint.url}");
-    if (instance != UserPreferences.unifiedPushInstance) {
-      return;
-    }
+    if (instance != UserPreferences.unifiedPushInstance) return;
 
+    // update preferences with the new URL and Keys
     _preferencesService.setUnifiedpushEndpoint(endpoint.url);
     if (endpoint.pubKeySet != null) {
       _preferencesService.setWebPushPublicKey(endpoint.pubKeySet!.pubKey);
@@ -49,7 +52,11 @@ class UnifiedPushHandler {
     //@TODO(Nucleus): we need to update the subscriptions and send the new endpoint to the server
   }
 
+  /// Callback for the UnfiedPush plugin
+  /// This method gets called with the registration failed
+  /// For now we are just logging that error
   void onRegistrationFailed(FailedReason failedReason, String instance) {
+    if (instance != UserPreferences.unifiedPushInstance) return;
     // @todo error handling
     ErrorLogger.writeErrorLog(
       "class_unifiedPushHandler",
@@ -59,7 +66,13 @@ class UnifiedPushHandler {
     debugPrint("Registration failed: ${failedReason.name}");
   }
 
+  /// Callback for the UnifiedPush plugin
+  /// This method gets called when the client unregisters from the distributor
+  /// This updates the state in the preferences
   void onUnregistered(String instance) {
+    debugPrint("onUnregistered called");
+    if (instance != UserPreferences.unifiedPushInstance) return;
+
     debugPrint("onUnregistered called");
     _preferencesService.setUnifiedpushEndpoint("");
     _preferencesService.setUnifiedPushRegistered(false);
@@ -68,7 +81,8 @@ class UnifiedPushHandler {
     _preferencesService.setWebPushPublicKey("");
   }
 
-  /// callback function to handle notification from unifiedPush
+  /// callback for the UnifiedPush plugin
+  /// This method handles incoming notification from unifiedPush
   Future<void> onMessage({
     required AlertAPI alertApi,
     required MyPlacesService myPlacesService,
@@ -82,60 +96,13 @@ class UnifiedPushHandler {
 
     var payload = utf8.decode(message.content);
     debugPrint("Received a notification. Message: $payload");
-    var userPreferences = ref.read(userPreferencesProvider);
-
-    if (userPreferences.showDebugNotification) {
-      NotificationService.showNotification(
-        id: Random().nextInt(100),
-        title: "DEBUG Notification",
-        body:
-            "FOSSWarn has received a push notification with content: $payload",
-        payload: "",
-        channelId: "de.nucleus.foss_warn.notifications_other",
-        channelName: "Debug notifications",
-      );
-    }
-
-    String? addedAlertId;
 
-    try {
-      var payloadAsJson = jsonDecode(payload) as Map<String, dynamic>;
-      addedAlertId = payloadAsJson["alert_id"];
-      if (addedAlertId != null) {
-        WarnMessage alert = await ref.read(alertApiProvider).getAlertDetail(
-              alertId: addedAlertId,
-              placeSubscriptionId: "Not used",
-            );
-        if (checkIfEventShouldBeNotified(
-          alert.info[0].severity,
-          userPreferences,
-        )) {
-          NotificationService.showNotification(
-            id: alert.identifier.hashCode,
-            title: "New alert",
-            body: alert.info.first.headline,
-            payload: "",
-            channelId:
-                "de.nucleus.foss_warn.notifications_${alert.info[0].severity.name}",
-            channelName: "",
-          );
-        }
-      }
-    } on FormatException catch (e) {
-      debugPrint("Payload is not a json: $e");
-    } on AlertUnavailableError catch (e) {
-      debugPrint("Alert is not available anymore: $e");
-      ErrorLogger.writeErrorLog(
-        "class_unified_push_handler.dart",
-        "onMessage",
-        "Alert $addedAlertId is not available anymore",
-      );
-    }
-    // @TODO(Nucleus): This is not the perfect solution as we can not check for already read alerts or if the alert is just an update. It would be preferable if we could fetch all alerts like we did before. Currently, this results in a "concurrent modification during iteration" error if the app is launched by a notification.
+    handleIncomingNotification(payload, ref);
   }
 
   /// register for push notifications and keep registration up to date
   /// This method needs to called at every app startup
+  /// @TODO Nucleus: refactor this and use more smaller methods
   Future<void> setupUnifiedPush(
     BuildContext context,
     WidgetRef ref,
@@ -216,4 +183,96 @@ class UnifiedPushHandler {
       return;
     }
   }
+
+  /// Change the current distributor to the new selected distributor
+  /// This method first unregisters the old distributor and then registers
+  /// again with the new selected Distributor
+  /// The selected distributor has to be the [String] id of the distributor
+  ///
+  /// Throws an [UnifiedPushRegistrationTimeoutError] when the registration failed
+  /// with en timeout error
+  Future<void> changeDistributor(
+    String selectedDistributor,
+    WidgetRef ref,
+  ) async {
+    appState.reSubscriptionInProgress = true;
+    await unregisterDistributor(ref);
+    await registerDistributor(selectedDistributor, ref);
+    // wait until the registration is finished we have a new endpoint
+    await Future.doWhile(() async {
+      await Future.delayed(const Duration(microseconds: 1));
+      UserPreferences userPreferences = ref.read(userPreferencesProvider);
+      return !userPreferences.unifiedPushRegistered;
+    }).timeout(
+      const Duration(seconds: 20),
+      onTimeout: () {
+        debugPrint(
+          "Timeout waiting for unifiedPushRegistered to be set to true.",
+        );
+        throw UnifiedPushRegistrationTimeoutError();
+      },
+    );
+  }
+
+  /// unregisters the current distributor and sets the unifiedPush
+  /// registered flag in the setting to false
+  Future<void> unregisterDistributor(WidgetRef ref) async {
+    UnifiedPush.unregister(UserPreferences.unifiedPushInstance);
+    await _preferencesService.setUnifiedPushRegistered(false);
+  }
+
+  /// Register for notifications with the given distributor
+  Future<void> registerDistributor(
+    String selectedDistributor,
+    WidgetRef ref,
+  ) async {
+    debugPrint(
+      "[unifiedPushHandler] register new distributor $selectedDistributor",
+    );
+    await UnifiedPush.saveDistributor(selectedDistributor);
+    String? tempVapidKey;
+    if (_userPreferences.webPushVapidKey == "") {
+      // if server supports WebPush, try to fetch the vapid key
+      if (_userPreferences.webPushVapidKey == "") {
+        try {
+          AlertAPI alertAPI = ref.read(alertApiProvider);
+          tempVapidKey = await alertAPI.fetchVapidKeyForWebPush();
+          _preferencesService.setWebPushVapidKey(tempVapidKey);
+        } on VapidKeyException {
+          ErrorLogger.writeErrorLog(
+            "class_unified_push_handler.dart",
+            "setup unifiedPush",
+            "Failed to fetch VAPID key for webpush",
+          );
+        }
+      }
+    }
+
+    // register your app to the distributor
+    try {
+      await UnifiedPush.register(
+        instance: UserPreferences.unifiedPushInstance,
+        vapid: tempVapidKey ?? _userPreferences.webPushVapidKey,
+      );
+    } on MissingPluginException catch (e) {
+      //@TODO (Nucleus) do not catch this exception here
+      debugPrint("error while registering UnifiedPush: $e");
+      return;
+    }
+  }
+
+  Future<List<Map<String, String>>> getListOfDistributors() async {
+    List<Map<String, String>> result = [];
+    List<String> distributors = await UnifiedPush.getDistributors();
+    for (String distributor in distributors) {
+      var split = distributor.split(".");
+      String name = split.last;
+      result.add({"name": name, "distributor": distributor});
+    }
+    return result;
+  }
+
+  Future<String?> getDistributor() async {
+    return await UnifiedPush.getDistributor();
+  }
 }