refactor: Only initialize FlutterLocalNotificationsPlugin once

lib/utils/background_push.dart

@@ -71,7 +71,7 @@ class BackgroundPush {
 
   BackgroundPush._(this.client) {
     firebase?.setListeners(
-      onMessage: (message) => pushHelper(
+      onMessage: (message) => PushHelper.processNotification(
         PushNotification.fromJson(
           Map<String, dynamic>.from(message['data'] ?? message),
         ),
@@ -393,7 +393,7 @@ class BackgroundPush {
     );
     // UP may strip the devices list
     data['devices'] ??= [];
-    await pushHelper(
+    await PushHelper.processNotification(
       PushNotification.fromJson(data),
       client: client,
       l10n: l10n,

lib/utils/push_helper.dart

@@ -18,13 +18,37 @@ import 'package:fluffychat/utils/matrix_sdk_extensions/matrix_locals.dart';
 import 'package:fluffychat/utils/platform_infos.dart';
 import 'package:fluffychat/utils/voip/callkeep_manager.dart';
 
-Future<void> pushHelper(
+abstract class PushHelper {
+  static FlutterLocalNotificationsPlugin? _flutterLocalNotificationsPlugin;
+
+  static Future<FlutterLocalNotificationsPlugin> _getLocalNotificationsPlugin({
+    void Function(NotificationResponse?)? onSelectNotification,
+  }) async {
+    var flutterlocalNotifcationsPlugin = _flutterLocalNotificationsPlugin;
+    if (flutterlocalNotifcationsPlugin != null) {
+      return flutterlocalNotifcationsPlugin;
+    }
+
+    flutterlocalNotifcationsPlugin =
+        _flutterLocalNotificationsPlugin = FlutterLocalNotificationsPlugin();
+    await flutterlocalNotifcationsPlugin.initialize(
+      const InitializationSettings(
+        android: AndroidInitializationSettings('notifications_icon'),
+        iOS: DarwinInitializationSettings(),
+      ),
+      onDidReceiveNotificationResponse: onSelectNotification,
+      onDidReceiveBackgroundNotificationResponse: onSelectNotification,
+    );
+    return flutterlocalNotifcationsPlugin;
+  }
+
+  static Future<void> processNotification(
     PushNotification notification, {
     Client? client,
     L10n? l10n,
     String? activeRoomId,
     void Function(NotificationResponse?)? onSelectNotification,
-}) async {
+  }) async {
     try {
       await _tryPushHelper(
         notification,
@@ -36,15 +60,9 @@ Future<void> pushHelper(
     } catch (e, s) {
       Logs().v('Push Helper has crashed!', e, s);
 
-    // Initialise the plugin. app_icon needs to be a added as a drawable resource to the Android head project
-    final flutterLocalNotificationsPlugin = FlutterLocalNotificationsPlugin();
-    await flutterLocalNotificationsPlugin.initialize(
-      const InitializationSettings(
-        android: AndroidInitializationSettings('notifications_icon'),
-        iOS: DarwinInitializationSettings(),
-      ),
-      onDidReceiveNotificationResponse: onSelectNotification,
-      onDidReceiveBackgroundNotificationResponse: onSelectNotification,
+      final flutterLocalNotificationsPlugin =
+          await _getLocalNotificationsPlugin(
+        onSelectNotification: onSelectNotification,
       );
 
       l10n ??= lookupL10n(const Locale('en'));
@@ -70,15 +88,15 @@ Future<void> pushHelper(
       );
       rethrow;
     }
-}
+  }
 
-Future<void> _tryPushHelper(
+  static Future<void> _tryPushHelper(
     PushNotification notification, {
     Client? client,
     L10n? l10n,
     String? activeRoomId,
     void Function(NotificationResponse?)? onSelectNotification,
-}) async {
+  }) async {
     final isBackgroundMessage = client == null;
     Logs().v(
       'Push helper has been started (background=$isBackgroundMessage).',
@@ -92,15 +110,8 @@ Future<void> _tryPushHelper(
       return;
     }
 
-  // Initialise the plugin. app_icon needs to be a added as a drawable resource to the Android head project
-  final flutterLocalNotificationsPlugin = FlutterLocalNotificationsPlugin();
-  await flutterLocalNotificationsPlugin.initialize(
-    const InitializationSettings(
-      android: AndroidInitializationSettings('notifications_icon'),
-      iOS: DarwinInitializationSettings(),
-    ),
-    onDidReceiveNotificationResponse: onSelectNotification,
-    //onDidReceiveBackgroundNotificationResponse: onSelectNotification,
+    final flutterLocalNotificationsPlugin = await _getLocalNotificationsPlugin(
+      onSelectNotification: onSelectNotification,
     );
 
     client ??= (await ClientManager.getClients(
@@ -149,7 +160,8 @@ Future<void> _tryPushHelper(
       client.backgroundSync = false;
     }
 
-  if (event.type.startsWith('m.call') && event.type != EventTypes.CallInvite) {
+    if (event.type.startsWith('m.call') &&
+        event.type != EventTypes.CallInvite) {
       Logs().v('Push message is a m.call but not invite. Do not display.');
       return;
     }
@@ -312,17 +324,17 @@ Future<void> _tryPushHelper(
       payload: event.roomId,
     );
     Logs().v('Push helper has been completed!');
-}
+  }
 
-/// Creates a shortcut for Android platform but does not block displaying the
-/// notification. This is optional but provides a nicer view of the
-/// notification popup.
-Future<void> _setShortcut(
+  /// Creates a shortcut for Android platform but does not block displaying the
+  /// notification. This is optional but provides a nicer view of the
+  /// notification popup.
+  static Future<void> _setShortcut(
     Event event,
     L10n l10n,
     String title,
     File? avatarFile,
-) async {
+  ) async {
     final flutterShortcuts = FlutterShortcuts();
     await flutterShortcuts.initialize(debug: !kReleaseMode);
     await flutterShortcuts.pushShortcutItem(
@@ -341,4 +353,5 @@ Future<void> _setShortcut(
         isImportant: event.room.isFavourite,
       ),
     );
+  }
 }