feat(config): gate Firebase behind WEBTRIT_APP_FIREBASE_ENABLED

dart_define.json

@@ -1,4 +1,6 @@
 {
+  "WEBTRIT_APP_FIREBASE_ENABLED": true,
+  "__WEBTRIT_APP_FIREBASE_ENABLED_DESCRIPTION": "Whether Firebase (app, messaging, local push, Remote Config, Installations, Analytics) is initialised. Default true. Disable when the app is embedded in a host that owns the default Firebase app (e.g. the theme configurator's realtime preview) so the embedded app runs Firebase-free.",
   "WEBTRIT_APP_DATABASE_LOG_STATEMENTS": false,
   "_WEBTRIT_APP_CORE_URL": "",
   "WEBTRIT_APP_DEMO_CORE_URL": "http://192.168.10.100:4000",

docs/environment.md

@@ -36,6 +36,8 @@ maintainability and enabling tools to parse configuration reliably.
 - `WEBTRIT_APP_DEMO_CORE_URL` – Demo core URL (_default: **http://localhost:4000**_).
 - `WEBTRIT_APP_DATABASE_LOG_STATEMENTS` – Enables logging of database queries (
   _default: **false**_).
+- `WEBTRIT_APP_FIREBASE_ENABLED` – Whether Firebase is initialised (_default: **true**_). Set to
+  `false` to run embedded in a host that owns the default Firebase app (configurator realtime preview).
 - `_WEBTRIT_APP_CORE_URL` – Custom core URL (optional override).
 - `_WEBTRIT_APP_CORE_VERSION_CONSTRAINT` – Core compatibility range.
 - `_WEBTRIT_APP_ABOUT_URL` – URL for "About" screen content.

lib/app/view/app.dart

@@ -147,7 +147,7 @@ class _AppState extends State<App> {
                   deepLinkBuilder: isDeepLinkEnabled ? appRouter.deepLinkBuilder : null,
                   navigatorObservers: () => [
                     AppRouterObserver(),
-                    context.read<AppAnalyticsRepository>().createObserver(),
+                    if (EnvironmentConfig.FIREBASE_ENABLED) context.read<AppAnalyticsRepository>().createObserver(),
                     AutoRouteObserver(),
                   ],
                   reevaluateListenable: ReevaluateListenable.stream(

lib/bootstrap.dart

@@ -42,17 +42,27 @@ IsolateContext? _isolateContext;
 Future<InstanceRegistry> bootstrap() async {
   final registry = InstanceRegistry();
 
-  // External SDKs (Side effects only, don't need registration)
-  await _initFirebaseApp();
-  await _initFirebaseMessaging();
-  await _initLocalPushs();
+  // External SDKs (Side effects only, don't need registration). Gated by the
+  // WEBTRIT_APP_FIREBASE_ENABLED config so a host that owns the default Firebase
+  // app (e.g. the theme configurator's realtime preview) can run this app
+  // Firebase-free by configuring that flag off.
+  final firebaseEnabled = EnvironmentConfig.FIREBASE_ENABLED;
+  if (firebaseEnabled) {
+    await _initFirebaseApp();
+    await _initFirebaseMessaging();
+    await _initLocalPushs();
+  }
 
   // Initialize Components
 
   // App Info & Device Data
 
   final packageInfo = await PackageInfoFactory.init();
-  final appInfo = await AppInfo.init(FirebaseAppIdProvider());
+  // FirebaseAppIdProvider uses Firebase Installations; without Firebase use the
+  // local shared-preferences id provider instead.
+  final appInfo = await AppInfo.init(
+    firebaseEnabled ? FirebaseAppIdProvider() : const SharedPreferencesAppIdProvider(),
+  );
   final deviceInfo = await DeviceInfoFactory.init();
 
   // Storages
@@ -97,9 +107,21 @@ Future<InstanceRegistry> bootstrap() async {
     apiClientFactory: apiClientFactory,
   );
 
-  // Remote configuration
+  // Remote configuration. Firebase Remote Config needs the Firebase app, so when
+  // Firebase is disabled fall back to the local shared-preferences cache
+  // (DefaultRemoteCacheConfigService also implements RemoteConfigService).
   final remoteCacheConfigService = await DefaultRemoteCacheConfigService.init();
-  final cachedRemoteConfigService = await CachedRemoteConfigService.init(remoteCacheConfigService);
+  RemoteConfigService cachedRemoteConfigService;
+  if (firebaseEnabled) {
+    try {
+      cachedRemoteConfigService = await CachedRemoteConfigService.init(remoteCacheConfigService);
+    } catch (e, s) {
+      Logger('bootstrap').warning('Firebase Remote Config init failed; using local cache fallback', e, s);
+      cachedRemoteConfigService = remoteCacheConfigService;
+    }
+  } else {
+    cachedRemoteConfigService = remoteCacheConfigService;
+  }
 
   final featureAccessStreamFactory = FeatureAccessStreamFactory(
     appThemes: appThemes,

lib/environment_config.dart

@@ -47,6 +47,14 @@ class EnvironmentConfig {
     return seconds > 0 ? seconds : compileTime;
   }
 
+  // Whether Firebase (app, messaging, local push, Remote Config, Installations,
+  // Analytics) is initialised. Disable it when this app is embedded in a host
+  // that owns the default Firebase app (the theme configurator's realtime
+  // preview), so the embedded app runs Firebase-free.
+  static const FIREBASE_ENABLED__NAME = 'WEBTRIT_APP_FIREBASE_ENABLED';
+  static bool get FIREBASE_ENABLED =>
+      _env.boolean(FIREBASE_ENABLED__NAME, const bool.fromEnvironment(FIREBASE_ENABLED__NAME, defaultValue: true));
+
   static const DATABASE_LOG_STATEMENTS__NAME = 'WEBTRIT_APP_DATABASE_LOG_STATEMENTS';
   static bool get DATABASE_LOG_STATEMENTS => _env.boolean(
     DATABASE_LOG_STATEMENTS__NAME,

lib/main.dart

@@ -147,7 +147,13 @@ class RootApp extends StatelessWidget {
                 create: (_) => instanceRegistry.get(),
                 dispose: disposeIfDisposable,
               ),
-              RepositoryProvider.value(value: AppAnalyticsRepository(instance: FirebaseAnalytics.instance)),
+              // Lazy so the FirebaseAnalytics.instance handle is created only when the
+              // analytics observer is actually attached. With WEBTRIT_APP_FIREBASE_ENABLED
+              // false the observer is skipped (see App), so this provider is never read and
+              // the embedded app stays Firebase-free.
+              RepositoryProvider<AppAnalyticsRepository>(
+                create: (_) => AppAnalyticsRepository(instance: FirebaseAnalytics.instance),
+              ),
               RepositoryProvider<RegisterStatusRepository>.value(value: registerStatusRepository),
               RepositoryProvider<PresenceSettingsRepository>.value(value: presenceSettingsRepository),
               RepositoryProvider<QueuedTerminationRequestsRepository>.value(value: queuedTerminationRequestsRepository),

test/environment_config_test.dart

@@ -91,5 +91,15 @@ void main() {
       EnvironmentConfig.applyOverrides({name: '30'});
       expect(EnvironmentConfig.USER_REPOSITORY_POLLING_INTERVAL_SECONDS, 30);
     });
+
+    test('FIREBASE_ENABLED defaults to true and reflects a false override', () {
+      expect(EnvironmentConfig.FIREBASE_ENABLED, isTrue);
+
+      EnvironmentConfig.applyOverrides({EnvironmentConfig.FIREBASE_ENABLED__NAME: 'false'});
+      expect(EnvironmentConfig.FIREBASE_ENABLED, isFalse);
+
+      EnvironmentConfig.clearOverrides();
+      expect(EnvironmentConfig.FIREBASE_ENABLED, isTrue);
+    });
   });
 }