feat: Add offline mode data manager

packages/smooth_app/lib/database/dao_product.dart

@@ -1,10 +1,13 @@
 import 'dart:async';
 import 'dart:convert';
-import 'package:openfoodfacts/model/Product.dart';
+import 'dart:io';
+import 'package:openfoodfacts/openfoodfacts.dart';
+import 'package:openfoodfacts/utils/ProductListQueryConfiguration.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/local_database.dart';
+import 'package:smooth_app/database/product_query.dart';
 import 'package:sqflite/sqflite.dart';
 
 class DaoProduct extends AbstractSqlDao implements BulkDeletable {
@@ -60,6 +63,26 @@ class DaoProduct extends AbstractSqlDao implements BulkDeletable {
     return result;
   }
 
+  // returns the no of rows deleted/effected from the table
+  Future<int> clearAll() async {
+    final int count = await localDatabase.database.delete(TABLE_PRODUCT);
+    return count;
+  }
+
+  //returns the approximate size of the database in MB
+  Future<double> getSize() async {
+    final String path = localDatabase.database.path;
+    final File file = File(path);
+    final double size = file.lengthSync() / 1024 / 1024;
+    return double.parse(size.floor().toStringAsFixed(2));
+  }
+
+  Future<int> getLength() async {
+    return Sqflite.firstIntValue(await localDatabase.database
+            .rawQuery('SELECT COUNT(*) FROM $TABLE_PRODUCT')) ??
+        0;
+  }
+
   Future<void> put(final Product product) async => putAll(<Product>[product]);
 
   /// Replaces products in database
@@ -130,4 +153,29 @@ class DaoProduct extends AbstractSqlDao implements BulkDeletable {
         json.decode(encodedJson) as Map<String, dynamic>;
     return Product.fromJson(decodedJson);
   }
+
+  Future<String> getFreshLocalDataBase() async {
+    try {
+      final List<String> barcodes = await getAllKeys();
+      if (barcodes.isEmpty) {
+        return 'List is Empty\nNothing to Refresh';
+      }
+      final ProductListQueryConfiguration configuration =
+          ProductListQueryConfiguration(
+        barcodes,
+        fields: ProductQuery.fields,
+        language: ProductQuery.getLanguage(),
+        country: ProductQuery.getCountry(),
+      );
+      final User user = ProductQuery.getUser();
+      // TODO(ashaman999): find a better way to do this not sure at what length it will break
+      final SearchResult products =
+          await OpenFoodAPIClient.getProductList(user, configuration);
+      final List<Product>? productList = products.products;
+      await putAll(productList!);
+      return 'OK';
+    } catch (e) {
+      return 'Error: $e';
+    }
+  }
 }

packages/smooth_app/lib/database/dao_product_list.dart

@@ -197,6 +197,10 @@ class DaoProductList extends AbstractDao {
     _put(_getKey(productList), newList);
   }
 
+  void updateTimeStamp(final ProductList productList) {
+    // TODO(ashaman999): update the timestamp for all the entries with the current timestamp
+  }
+
   void clear(final ProductList productList) {
     final _BarcodeList newList = _BarcodeList.now(<String>[]);
     _put(_getKey(productList), newList);
@@ -289,6 +293,12 @@ class DaoProductList extends AbstractDao {
     return result;
   }
 
+  // returns the number of items cleared from the box
+  Future<int> clearAll() async {
+    final int clearedItems = await _getBox().clear();
+    return clearedItems;
+  }
+
   /// Returns a write-safe copy of [_BarcodeList] barcodes.
   ///
   /// cf. https://github.com/openfoodfacts/smooth-app/issues/1786

packages/smooth_app/lib/database/dao_string_list.dart

@@ -43,4 +43,10 @@ class DaoStringList extends AbstractDao {
     }
     return false;
   }
+
+  // returns the number of items removed from the box
+  Future<int> removeAll() async {
+    final int count = await _getBox().clear();
+    return count;
+  }
 }

packages/smooth_app/lib/pages/offline_data.dart

@@ -0,0 +1,183 @@
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:flutter_svg/flutter_svg.dart';
+import 'package:provider/provider.dart';
+import 'package:smooth_app/database/dao_product.dart';
+import 'package:smooth_app/database/dao_product_list.dart';
+import 'package:smooth_app/database/local_database.dart';
+import 'package:smooth_app/generic_lib/loading_dialog.dart';
+import 'package:smooth_app/pages/preferences/user_preferences_list_tile.dart';
+import 'package:url_launcher/url_launcher.dart';
+
+class OfflineDataScreen extends StatefulWidget {
+  const OfflineDataScreen();
+  @override
+  State<OfflineDataScreen> createState() => _OfflineDataScreenState();
+}
+
+int length = 0;
+double size = 0;
+
+// TODO(ashaman999): update all the applocalizations
+class _OfflineDataScreenState extends State<OfflineDataScreen> {
+  Future<void> _refreshDetials(DaoProduct daoProduct) async {
+    length = await daoProduct.getLength();
+    size = await daoProduct.getSize();
+    setState(() {});
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final DaoProduct daoProduct = DaoProduct(context.watch<LocalDatabase>());
+    final DaoProductList daoProductList =
+        DaoProductList(context.watch<LocalDatabase>());
+    final MediaQueryData mediaQueryData = MediaQuery.of(context);
+    final bool dark = Theme.of(context).brightness == Brightness.dark;
+    const double titleHeightInExpandedMode = 50;
+    final double backgroundHeight = mediaQueryData.size.height * .20;
+    final Color? foregroundColor = dark ? null : Colors.black;
+    return Scaffold(
+      body: SafeArea(
+        child: RefreshIndicator(
+          onRefresh: () async {
+            await _refreshDetials(daoProduct);
+          },
+          child: CustomScrollView(
+            slivers: <Widget>[
+              SliverAppBar(
+                pinned: true,
+                snap: false,
+                floating: false,
+                stretch: true,
+                backgroundColor: dark ? null : Colors.white,
+                expandedHeight: backgroundHeight + titleHeightInExpandedMode,
+                foregroundColor: foregroundColor,
+                systemOverlayStyle: const SystemUiOverlayStyle(
+                  statusBarIconBrightness: Brightness.light,
+                  statusBarBrightness: Brightness.dark,
+                ),
+                flexibleSpace: FlexibleSpaceBar(
+                  title: Text(
+                    'Offline Mode',
+                    style: TextStyle(color: foregroundColor),
+                  ),
+                  background: Padding(
+                    padding: const EdgeInsets.only(
+                        bottom: titleHeightInExpandedMode),
+                    child: SvgPicture.asset(
+                      // TODO(ashaman999): add a proper header image replacing this
+                      'assets/preferences/main.svg',
+                      height: backgroundHeight,
+                    ),
+                  ),
+                ),
+              ),
+              SliverList(
+                delegate: SliverChildListDelegate(
+                  <Widget>[
+                    UserPreferencesListTile(
+                      title: const Text(
+                        'Offline Product Data',
+                      ),
+                      subtitle: FutureBuilder<int>(
+                        future: daoProduct.getLength(),
+                        builder: (BuildContext context,
+                            AsyncSnapshot<int> snapshot) {
+                          if (snapshot.hasData) {
+                            return Text(
+                              '${snapshot.data} products available for immediate scanning',
+                            );
+                          } else {
+                            return const Text('Loading...');
+                          }
+                        },
+                      ),
+                      trailing: FutureBuilder<double>(
+                        future: daoProduct.getSize(),
+                        builder: (BuildContext context,
+                            AsyncSnapshot<double> snapshot) {
+                          if (snapshot.hasData) {
+                            return Text(
+                              '${snapshot.data} MB',
+                            );
+                          } else {
+                            return const CircularProgressIndicator();
+                          }
+                        },
+                      ),
+                    ),
+                    UserPreferencesListTile(
+                      trailing: const Icon(Icons.refresh),
+                      onTap: () async {
+                        String? status = await LoadingDialog.run<String>(
+                          context: context,
+                          future: daoProduct.getFreshLocalDataBase(),
+                          title: 'Refreshing \n This may take a while',
+                          dismissible: true,
+                        );
+                        if (status == 'OK') {
+                          status = '$length items refreshed';
+                        }
+                        // TODO(ashaman999): dapproductlist.updateTimestamp();
+                        // ignore: use_build_context_synchronously
+                        ScaffoldMessenger.of(context).showSnackBar(
+                          SnackBar(
+                            content: Text(status!),
+                          ),
+                        );
+                      },
+                      title: const Text(
+                        'Update Offline Data',
+                      ),
+                      subtitle: const Text(
+                        'Update the databse with the latest data from the server',
+                      ),
+                    ),
+                    UserPreferencesListTile(
+                      trailing: const Icon(Icons.delete),
+                      onTap: () async {
+                        final int noOdDeletedProducts =
+                            await daoProduct.clearAll();
+                        await daoProductList.clearAll();
+                        await _refreshDetials(daoProduct);
+                        // ignore: use_build_context_synchronously
+                        ScaffoldMessenger.of(context).showSnackBar(
+                          SnackBar(
+                            content: Text(
+                                '$noOdDeletedProducts products deleted, freed $size Mb'),
+                          ),
+                        );
+                      },
+                      title: const Text(
+                        'Clear Offline Data',
+                      ),
+                      subtitle: const Text(
+                        'Clear All Offline Data and Free up space',
+                      ),
+                    ),
+                    UserPreferencesListTile(
+                      trailing: const Icon(Icons.info),
+                      title: const Text(
+                        'Know More ',
+                      ),
+                      subtitle: const Text(
+                        'Click to know more about the offline mode',
+                      ),
+                      onTap: () {
+                        // TODO(ashaman999): refrence the acutal link
+                        // Or maybe show something as an alert dialog
+                        launchUrl(
+                          Uri.parse('https://openfoodfacts.org/'),
+                        );
+                      },
+                    ),
+                  ],
+                ),
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+}

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

@@ -12,6 +12,7 @@ import 'package:smooth_app/database/product_query.dart';
 import 'package:smooth_app/generic_lib/dialogs/smooth_alert_dialog.dart';
 import 'package:smooth_app/helpers/data_importer/product_list_import_export.dart';
 import 'package:smooth_app/helpers/data_importer/smooth_app_data_importer.dart';
+import 'package:smooth_app/pages/offline_data.dart';
 import 'package:smooth_app/pages/onboarding/onboarding_flow_navigator.dart';
 import 'package:smooth_app/pages/preferences/abstract_user_preferences.dart';
 import 'package:smooth_app/pages/preferences/user_preferences_dialog_editor.dart';
@@ -140,6 +141,17 @@ class UserPreferencesDevMode extends AbstractUserPreferences {
           title: const Text('Change camera post frame callback duration'),
           onTap: () async => _changeCameraPostFrameCallbackDuration(),
         ),
+        ListTile(
+          title: const Text('Offline Mode'),
+          onTap: () {
+            Navigator.push<Widget>(
+              context,
+              MaterialPageRoute<Widget>(
+                builder: (BuildContext context) => const OfflineDataScreen(),
+              ),
+            );
+          },
+        ),
         SwitchListTile(
           title: Text(
             appLocalizations.dev_preferences_product_additional_features_title,