Show ad after adding a homework

app/lib/ads/ads_controller.dart

@@ -2,13 +2,15 @@ import 'dart:async';
 
 import 'package:flutter/foundation.dart';
 import 'package:google_mobile_ads/google_mobile_ads.dart';
+import 'package:key_value_store/key_value_store.dart';
 import 'package:platform_check/platform_check.dart';
 import 'package:remote_configuration/remote_configuration.dart';
 import 'package:sharezone/sharezone_plus/subscription_service/subscription_service.dart';
 
 class AdsController extends ChangeNotifier {
   final SubscriptionService subscriptionService;
   final RemoteConfiguration remoteConfiguration;
+  final KeyValueStore keyValueStore;
 
   /// Defines if ads are visible for the current user.
   bool areAdsVisible = false;
@@ -17,6 +19,7 @@ class AdsController extends ChangeNotifier {
   AdsController({
     required this.subscriptionService,
     required this.remoteConfiguration,
+    required this.keyValueStore,
   }) {
     if (remoteConfiguration.getBool('ads_enabled')) {
       _initializeMobileAdsSDK();
@@ -78,6 +81,57 @@ class AdsController extends ChangeNotifier {
     );
   }
 
+  Future<void> maybeShowFullscreenAd() async {
+    if (areAdsVisible && _shouldShowFullscreenAd()) {
+      await _showFullscreenAd(adUnitId: getAdUnitId());
+    }
+  }
+
+  bool _shouldShowFullscreenAd() {
+    final editingHwCounter =
+        keyValueStore.getInt('homework-editing-counter') ?? 0;
+    final creatingHwCounter =
+        keyValueStore.getInt('homework-creating-counter') ?? 0;
+    final sum = editingHwCounter + creatingHwCounter;
+
+    if (sum == 0) {
+      // For a better user experience, we don't want to show an ad when the user
+      // shows his first homework. Technically, the sum should then be 1, but
+      // since we're not waiting for the counter to increment, we need to check
+      // for 0.
+      return false;
+    }
+
+    return sum % 5 == 0;
+  }
+
+  Future<void> _showFullscreenAd({
+    required String adUnitId,
+  }) async {
+    InterstitialAd.load(
+      adUnitId: adUnitId,
+      request: createAdRequest(),
+      adLoadCallback: InterstitialAdLoadCallback(
+        onAdLoaded: (ad) {
+          ad.fullScreenContentCallback = FullScreenContentCallback(
+            onAdFailedToShowFullScreenContent: (ad, err) {
+              ad.dispose();
+            },
+            onAdDismissedFullScreenContent: (ad) {
+              ad.dispose();
+            },
+          );
+
+          debugPrint('$ad loaded.');
+          ad.show();
+        },
+        onAdFailedToLoad: (LoadAdError error) {
+          debugPrint('InterstitialAd failed to load: $error');
+        },
+      ),
+    );
+  }
+
   @override
   void dispose() {
     _subscription?.cancel();

app/lib/homework/homework_dialog/homework_dialog.dart

@@ -25,6 +25,7 @@ import 'package:flutter/services.dart';
 import 'package:flutter_bloc/flutter_bloc.dart' as bloc_lib show BlocProvider;
 import 'package:flutter_bloc/flutter_bloc.dart' hide BlocProvider;
 import 'package:hausaufgabenheft_logik/hausaufgabenheft_logik.dart' hide Date;
+import 'package:key_value_store/key_value_store.dart';
 import 'package:platform_check/platform_check.dart';
 import 'package:provider/provider.dart';
 import 'package:sharezone/filesharing/dialog/attach_file.dart';
@@ -75,6 +76,7 @@ class _HomeworkDialogState extends State<HomeworkDialog> {
     final szContext = BlocProvider.of<SharezoneContext>(context);
     final analytics = szContext.analytics;
     final holidayManager = BlocProvider.of<HolidayBloc>(context).holidayManager;
+    final keyValueStore = context.read<KeyValueStore>();
 
     late NextLessonCalculator nextLessonCalculator;
     if (widget.nextLessonCalculator != null) {
@@ -108,6 +110,7 @@ class _HomeworkDialogState extends State<HomeworkDialog> {
           nextSchooldayCalculator: nextSchooldayCalculator,
           markdownAnalytics: markdownAnalytics,
           analytics: analytics,
+          keyValueStore: keyValueStore,
         );
         return value;
       });
@@ -119,6 +122,7 @@ class _HomeworkDialogState extends State<HomeworkDialog> {
         nextSchooldayCalculator: nextSchooldayCalculator,
         markdownAnalytics: markdownAnalytics,
         analytics: analytics,
+        keyValueStore: keyValueStore,
       );
     }
   }

app/lib/homework/homework_page.dart

@@ -13,6 +13,7 @@ import 'package:flutter/material.dart';
 import 'package:hausaufgabenheft_logik/hausaufgabenheft_logik.dart'
     hide StudentHomeworkPageBloc;
 import 'package:provider/provider.dart';
+import 'package:sharezone/ads/ads_controller.dart';
 import 'package:sharezone/homework/homework_dialog/homework_dialog.dart';
 import 'package:sharezone_widgets/sharezone_widgets.dart';
 import 'package:user/user.dart';
@@ -41,6 +42,9 @@ Future<void> openHomeworkDialogAndShowConfirmationIfSuccessful(
     ),
   );
   if (successful == true && context.mounted) {
+    final adsController = context.read<AdsController>();
+    adsController.maybeShowFullscreenAd();
+
     await showUserConfirmationOfHomeworkArrival(context: context);
   }
 }

app/lib/main/sharezone_bloc_providers.dart

@@ -31,6 +31,7 @@ import 'package:hausaufgabenheft_logik/hausaufgabenheft_logik_setup.dart';
 import 'package:holidays/holidays.dart' hide State;
 import 'package:http/http.dart' as http;
 import 'package:key_value_store/in_memory_key_value_store.dart';
+import 'package:key_value_store/key_value_store.dart';
 import 'package:provider/provider.dart';
 import 'package:provider/single_child_widget.dart';
 import 'package:sharezone/account/account_page_bloc_factory.dart';
@@ -334,6 +335,10 @@ class _SharezoneBlocProvidersState extends State<SharezoneBlocProviders> {
       firestore: widget.blocDependencies.firestore,
       functions: widget.blocDependencies.functions,
     );
+
+    final keyValueStore =
+        FlutterKeyValueStore(widget.blocDependencies.sharedPreferences);
+
     // In the past we used BlocProvider for everything (even non-bloc classes).
     // This forced us to use BlocProvider wrapper classes for non-bloc entities,
     // Provider allows us to skip using these wrapper classes.
@@ -485,9 +490,11 @@ class _SharezoneBlocProvidersState extends State<SharezoneBlocProviders> {
         create: (context) => AdsController(
           subscriptionService: subscriptionService,
           remoteConfiguration: widget.blocDependencies.remoteConfiguration,
+          keyValueStore: keyValueStore,
         ),
         lazy: false,
       ),
+      Provider<KeyValueStore>.value(value: keyValueStore)
     ];
 
     mainBlocProviders = <BlocProvider>[