feat: 4941 - refresh products when switching app language

packages/smooth_app/lib/background/background_task_language_refresh.dart

@@ -0,0 +1,136 @@
+import 'package:flutter/painting.dart';
+import 'package:flutter_gen/gen_l10n/app_localizations.dart';
+import 'package:openfoodfacts/openfoodfacts.dart';
+import 'package:smooth_app/background/background_task.dart';
+import 'package:smooth_app/background/operation_type.dart';
+import 'package:smooth_app/database/dao_product.dart';
+import 'package:smooth_app/database/local_database.dart';
+import 'package:smooth_app/query/product_query.dart';
+
+/// Background task about downloading products to translate.
+class BackgroundTaskLanguageRefresh extends BackgroundTask {
+  BackgroundTaskLanguageRefresh._({
+    required super.processName,
+    required super.uniqueId,
+    required super.stamp,
+    required this.excludeBarcodes,
+  });
+
+  BackgroundTaskLanguageRefresh.fromJson(Map<String, dynamic> json)
+      : excludeBarcodes = _getStringList(json, _jsonTagExcludeBarcodes),
+        super.fromJson(json);
+
+  static List<String> _getStringList(
+      final Map<String, dynamic> json, final String tag) {
+    final List<dynamic> dynamicList =
+        json[_jsonTagExcludeBarcodes] as List<dynamic>;
+    final List<String> result = <String>[];
+    for (final dynamic item in dynamicList) {
+      result.add(item.toString());
+    }
+    return result;
+  }
+
+  final List<String> excludeBarcodes;
+
+  static const String _jsonTagExcludeBarcodes = 'excludeBarcodes';
+
+  @override
+  Map<String, dynamic> toJson() {
+    final Map<String, dynamic> result = super.toJson();
+    result[_jsonTagExcludeBarcodes] = excludeBarcodes;
+    return result;
+  }
+
+  static const OperationType _operationType = OperationType.languageRefresh;
+
+  static Future<void> addTask(
+    final LocalDatabase localDatabase, {
+    final List<String> excludeBarcodes = const <String>[],
+  }) async {
+    final String uniqueId = await _operationType.getNewKey(
+      localDatabase,
+    );
+    final BackgroundTask task = _getNewTask(
+      uniqueId,
+      excludeBarcodes,
+    );
+    await task.addToManager(localDatabase);
+  }
+
+  @override
+  (String, AlignmentGeometry)? getFloatingMessage(
+          final AppLocalizations appLocalizations) =>
+      null;
+
+  static BackgroundTask _getNewTask(
+    final String uniqueId,
+    final List<String> excludeBarcodes,
+  ) =>
+      BackgroundTaskLanguageRefresh._(
+        processName: _operationType.processName,
+        uniqueId: uniqueId,
+        stamp: ';languageRefresh',
+        excludeBarcodes: excludeBarcodes,
+      );
+
+  @override
+  Future<void> preExecute(final LocalDatabase localDatabase) async {}
+
+  @override
+  bool get hasImmediateNextTask => true;
+
+  /// Number of products to download each time.
+  static const int _pageSize = 20;
+
+  @override
+  Future<void> execute(final LocalDatabase localDatabase) async {
+    final DaoProduct daoProduct = DaoProduct(localDatabase);
+    final OpenFoodFactsLanguage language = ProductQuery.getLanguage();
+    final List<String> barcodes = await daoProduct.getTopProductsToTranslate(
+      language,
+      limit: _pageSize,
+      excludeBarcodes: excludeBarcodes,
+    );
+    if (barcodes.isEmpty) {
+      return;
+    }
+    final SearchResult searchResult = await OpenFoodAPIClient.searchProducts(
+      getUser(),
+      ProductSearchQueryConfiguration(
+        fields: ProductQuery.fields,
+        parametersList: <Parameter>[
+          const PageSize(size: _pageSize),
+          const PageNumber(page: 1),
+          BarcodeParameter.list(barcodes),
+        ],
+        language: language,
+        country: ProductQuery.getCountry(),
+        version: ProductQuery.productQueryVersion,
+      ),
+      uriHelper: uriProductHelper,
+    );
+    if (searchResult.products == null || searchResult.count == null) {
+      throw Exception('Cannot refresh language');
+    }
+
+    // save into database and refresh all visible products.
+    await daoProduct.putAll(searchResult.products!, language);
+    localDatabase.upToDate.setLatestDownloadedProducts(searchResult.products!);
+
+    // Next page
+    final List<String> newExcludeBarcodes = <String>[];
+    // we keep the old "excluded" barcodes,...
+    newExcludeBarcodes.addAll(excludeBarcodes);
+    // ...add the new barcodes...
+    newExcludeBarcodes.addAll(barcodes);
+    // ...and remove barcodes we actually found on the server.
+    for (final Product product in searchResult.products!) {
+      newExcludeBarcodes.remove(product.barcode);
+    }
+    await addTask(
+      localDatabase,
+      excludeBarcodes: newExcludeBarcodes,
+    );
+  }
+}

packages/smooth_app/lib/background/background_task_manager.dart

@@ -41,7 +41,7 @@ class BackgroundTaskManager {
     );
     await DaoStringList(localDatabase).add(DaoStringList.keyTasks, taskId);
     await task.preExecute(localDatabase);
-    run(); // no await
+    run();
   }
 
   /// Finishes a task cleanly.
@@ -80,11 +80,13 @@ class BackgroundTaskManager {
       final String processName = BackgroundTask.getProcessName(map);
       for (final OperationType operationType in OperationType.values) {
         if (processName == operationType.processName) {
+          _debugPrint('found: $processName, $map');
           return operationType.fromJson(map);
         }
       }
     } catch (e) {
       // unexpected
+      _debugPrint('_get exception: $e');
     }
     return null;
   }
@@ -140,14 +142,20 @@ class BackgroundTaskManager {
 
   bool _running = false;
 
+  /// Runs all the pending tasks, and then smoothly ends, without awaiting.
+  void run() {
+    // no await
+    _runAsync();
+  }
+
   /// Runs all the pending tasks, and then smoothly ends.
   ///
   /// If a task fails, we continue with the other tasks: and we'll retry the
   /// failed tasks later.
   /// If a task fails and another task with the same stamp comes after,
   /// we can remove the failed task from the list: it would have been
   /// overwritten anyway.
-  Future<void> run() async {
+  Future<void> _runAsync() async {
     final int? now = _canStartNow();
     if (now == null) {
       return;

packages/smooth_app/lib/background/operation_type.dart

@@ -6,6 +6,7 @@ import 'package:smooth_app/background/background_task_download_products.dart';
 import 'package:smooth_app/background/background_task_full_refresh.dart';
 import 'package:smooth_app/background/background_task_hunger_games.dart';
 import 'package:smooth_app/background/background_task_image.dart';
+import 'package:smooth_app/background/background_task_language_refresh.dart';
 import 'package:smooth_app/background/background_task_offline.dart';
 import 'package:smooth_app/background/background_task_progressing.dart';
 import 'package:smooth_app/background/background_task_refresh_later.dart';
@@ -33,6 +34,7 @@ enum OperationType {
   offlineBarcodes('B', 'OFFLINE_BARCODES'),
   offlineProducts('P', 'OFFLINE_PRODUCTS'),
   fullRefresh('F', 'FULL_REFRESH'),
+  languageRefresh('L', 'LANGUAGE_REFRESH'),
   details('D', 'PRODUCT_EDIT');
 
   const OperationType(this.header, this.processName);
@@ -85,6 +87,8 @@ enum OperationType {
         return BackgroundTaskDownloadProducts.fromJson(map);
       case fullRefresh:
         return BackgroundTaskFullRefresh.fromJson(map);
+      case languageRefresh:
+        return BackgroundTaskLanguageRefresh.fromJson(map);
     }
   }
 
@@ -113,6 +117,8 @@ enum OperationType {
         return 'Downloading products';
       case OperationType.fullRefresh:
         return 'Refreshing the full local database';
+      case OperationType.languageRefresh:
+        return 'Refreshing the local database to a new language';
     }
   }
 

packages/smooth_app/lib/data_models/up_to_date_mixin.dart

@@ -49,7 +49,7 @@ mixin UpToDateMixin<T extends StatefulWidget> on State<T> {
   /// To be used in the `build` method, after a call to
   /// `context.watch<LocalDatabase>()`.
   void refreshUpToDate() {
-    BackgroundTaskManager.getInstance(_localDatabase).run(); // no await
+    BackgroundTaskManager.getInstance(_localDatabase).run();
     _refreshUpToDate();
   }
 

packages/smooth_app/lib/data_models/up_to_date_product_provider.dart

@@ -75,9 +75,8 @@ class UpToDateProductProvider {
 
   /// Typical use-case: a product list page is refreshed through a pull-gesture.
   void setLatestDownloadedProducts(
-    final Iterable<Product> products, {
-    final bool notify = true,
-  }) {
+    final Iterable<Product> products,
+  ) {
     if (_interest.isEmpty) {
       return;
     }
@@ -88,7 +87,7 @@ class UpToDateProductProvider {
         setLatestDownloadedProduct(product, notify: false);
       }
     }
-    if (notify && atLeastOne) {
+    if (atLeastOne) {
       localDatabase.notifyListeners();
     }
   }

packages/smooth_app/lib/database/dao_product.dart

@@ -8,6 +8,7 @@ import 'package:openfoodfacts/openfoodfacts.dart';
 import 'package:smooth_app/database/abstract_sql_dao.dart';
 import 'package:smooth_app/database/bulk_deletable.dart';
 import 'package:smooth_app/database/bulk_manager.dart';
+import 'package:smooth_app/database/dao_product_last_access.dart';
 import 'package:smooth_app/database/local_database.dart';
 import 'package:sqflite/sqflite.dart';
 
@@ -255,4 +256,50 @@ class DaoProduct extends AbstractSqlDao implements BulkDeletable {
     // We return the number of rows deleted ie the number of products deleted
     return localDatabase.database.delete(_TABLE_PRODUCT);
   }
+
+  /// Returns the most recently locally accessed products with wrong language.
+  ///
+  /// Typical use-case: when the user changes the app language, downloading
+  /// incrementally all products with a different (or null) download language.
+  /// We need [excludeBarcodes] because in some rare cases products may not be
+  /// found anymore on the server - it happened to me with obviously fake test
+  /// products being probably wiped out.
+  Future<List<String>> getTopProductsToTranslate(
+    final OpenFoodFactsLanguage language, {
+    required final int limit,
+    required final List<String> excludeBarcodes,
+  }) async {
+    final List<Map<String, dynamic>> queryResults =
+        await localDatabase.database.rawQuery(
+      'select p.$_TABLE_PRODUCT_COLUMN_BARCODE '
+      'from'
+      ' $_TABLE_PRODUCT p'
+      ' left outer join ${DaoProductLastAccess.TABLE} a'
+      '  on p.$_TABLE_PRODUCT_COLUMN_BARCODE = a.${DaoProductLastAccess.COLUMN_BARCODE} '
+      'where'
+      ' p.$_TABLE_PRODUCT_COLUMN_LANGUAGE is null'
+      ' or p.$_TABLE_PRODUCT_COLUMN_LANGUAGE != ? '
+      'order by a.${DaoProductLastAccess.COLUMN_LAST_ACCESS} desc nulls last '
+      'limit ?',
+      <Object>[
+        language.offTag,
+        limit + excludeBarcodes.length,
+      ],
+    );
+
+    final List<String> result = <String>[];
+
+    for (final Map<String, dynamic> row in queryResults) {
+      final String barcode = row[_TABLE_PRODUCT_COLUMN_BARCODE] as String;
+      if (excludeBarcodes.contains(barcode)) {
+        continue;
+      }
+      result.add(barcode);
+      if (result.length == limit) {
+        break;
+      }
+    }
+
+    return result;
+  }
 }

packages/smooth_app/lib/database/local_database.dart

@@ -40,7 +40,7 @@ class LocalDatabase extends ChangeNotifier {
 
   @override
   void notifyListeners() {
-    BackgroundTaskManager.getInstance(this).run(); // no await
+    BackgroundTaskManager.getInstance(this).run();
     super.notifyListeners();
   }
 

packages/smooth_app/lib/pages/offline_tasks_page.dart

@@ -31,7 +31,7 @@ class _OfflineTaskState extends State<OfflineTaskPage> {
         ),
         actions: <Widget>[
           IconButton(
-            onPressed: () => // no await
+            onPressed: () =>
                 BackgroundTaskManager.getInstance(localDatabase).run(),
             icon: const Icon(Icons.refresh),
           ),

packages/smooth_app/lib/pages/preferences/user_preferences_language_selector.dart

@@ -2,8 +2,10 @@ import 'package:flutter/material.dart';
 import 'package:flutter_gen/gen_l10n/app_localizations.dart';
 import 'package:openfoodfacts/openfoodfacts.dart';
 import 'package:provider/provider.dart';
+import 'package:smooth_app/background/background_task_language_refresh.dart';
 import 'package:smooth_app/data_models/preferences/user_preferences.dart';
 import 'package:smooth_app/data_models/product_preferences.dart';
+import 'package:smooth_app/database/local_database.dart';
 import 'package:smooth_app/generic_lib/design_constants.dart';
 import 'package:smooth_app/generic_lib/widgets/language_selector.dart';
 import 'package:smooth_app/pages/preferences/user_preferences_item.dart';
@@ -24,19 +26,6 @@ class UserPreferencesLanguageSelector extends StatelessWidget {
     );
   }
 
-  Future<void> _changeAppLanguage(
-    BuildContext context,
-    UserPreferences userPreferences, {
-    required OpenFoodFactsLanguage language,
-  }) async {
-    ProductQuery.setLanguage(
-      context,
-      userPreferences,
-      languageCode: language.code,
-    );
-    await context.read<ProductPreferences>().refresh();
-  }
-
   @override
   Widget build(BuildContext context) {
     final AppLocalizations appLocalizations = AppLocalizations.of(context);
@@ -56,12 +45,19 @@ class UserPreferencesLanguageSelector extends StatelessWidget {
             if (language == null) {
               return;
             }
-
-            _changeAppLanguage(
+            ProductQuery.setLanguage(
               context,
               userPreferences,
-              language: language,
+              languageCode: language.code,
+            );
+            final ProductPreferences productPreferences =
+                context.read<ProductPreferences>();
+            await BackgroundTaskLanguageRefresh.addTask(
+              context.read<LocalDatabase>(),
             );
+            // TODO(monsieurtanuki): make it a background task also?
+            // no await
+            productPreferences.refresh();
           },
           selectedLanguages: <OpenFoodFactsLanguage>[
             ProductQuery.getLanguage(),

packages/smooth_app/lib/pages/product/common/product_refresher.dart

@@ -172,7 +172,6 @@ class ProductRefresher {
       if (result.product != null) {
         await DaoProduct(localDatabase).put(result.product!, language);
         localDatabase.upToDate.setLatestDownloadedProduct(result.product!);
-        localDatabase.notifyListeners();
         return FetchedProduct.found(result.product!);
       }
       return const FetchedProduct.internetNotFound();
@@ -216,7 +215,6 @@ class ProductRefresher {
       await DaoProduct(localDatabase).putAll(searchResult.products!, language);
       localDatabase.upToDate
           .setLatestDownloadedProducts(searchResult.products!);
-      localDatabase.notifyListeners();
       return searchResult.products!.length;
     } catch (e) {
       Logs.e('Refresh from server error', ex: e);