#29 - Add minimum required server version

lib/helpers/consts.dart

@@ -70,3 +70,6 @@ const ENERGY_CARBOHYDRATES = 4;
 
 /// kcal per gram of fat (approx)
 const ENERGY_FAT = 9;
+
+/// Flag to check for updates to the new version.
+const ENABLED_UPDATE = false;

lib/l10n/app_en.arb

@@ -495,5 +495,8 @@
   "dataCopied": "Data copied to new entry",
   "@dataCopied": {
     "description": "Snackbar message to show on copying data to a new log entry"
-  }
+  },
+  "appUpdateTitle" : "App Update Available",
+  "appUpdateContent" : "The newer version of the app is availibale. Please update your application.",
+  "appUpdateButoon" : "Close"
 }

lib/main.dart

@@ -38,6 +38,7 @@ import 'package:wger/screens/nutritional_diary_screen.dart';
 import 'package:wger/screens/nutritional_plan_screen.dart';
 import 'package:wger/screens/nutritional_plans_screen.dart';
 import 'package:wger/screens/splash_screen.dart';
+import 'package:wger/screens/update_app_screen.dart';
 import 'package:wger/screens/weight_screen.dart';
 import 'package:wger/screens/workout_plan_screen.dart';
 import 'package:wger/screens/workout_plans_screen.dart';
@@ -103,7 +104,13 @@ class MyApp extends StatelessWidget {
           title: 'wger',
           theme: wgerTheme,
           home: auth.isAuth
-              ? HomeTabsScreen()
+              ? FutureBuilder(
+                  future: auth.neededApplicationUpdate(),
+                  builder: (ctx, snapshot) =>
+                      snapshot.connectionState == ConnectionState.done && snapshot.data == true
+                          ? UpdateAppScreen()
+                          : HomeTabsScreen(),
+                )
               : FutureBuilder(
                   future: auth.tryAutoLogin(),
                   builder: (ctx, authResultSnapshot) =>

lib/providers/auth.dart

@@ -28,6 +28,7 @@ import 'package:flutter/widgets.dart';
 import 'package:http/http.dart' as http;
 import 'package:package_info/package_info.dart';
 import 'package:shared_preferences/shared_preferences.dart';
+import 'package:version/version.dart';
 import 'package:wger/exceptions/http_exception.dart';
 import 'package:wger/helpers/consts.dart';
 
@@ -76,6 +77,18 @@ class AuthProvider with ChangeNotifier {
     applicationVersion = packageInfo;
   }
 
+  /// Checking if there is a new version of the application.
+  Future<bool> neededApplicationUpdate() async {
+    if (!ENABLED_UPDATE) {
+      return false;
+    }
+    final response = await http.get(makeUri(serverUrl!, 'min-app-version'));
+    final applicationLatestVersion = json.decode(response.body);
+    final currentVersion = Version.parse(applicationVersion!.version);
+    final latestAppVersion = Version.parse(applicationLatestVersion);
+    return latestAppVersion > currentVersion;
+  }
+
   /// Registers a new user
   Future<void> register({
     required String username,

lib/screens/update_app_screen.dart

@@ -0,0 +1,36 @@
+/*
+ * This file is part of wger Workout Manager <https://github.com/wger-project>.
+ * Copyright (C) 2020, 2021 wger Team
+ *
+ * wger Workout Manager is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+import 'package:flutter/material.dart';
+import 'package:flutter_gen/gen_l10n/app_localizations.dart';
+
+class UpdateAppScreen extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: AlertDialog(
+        title: Text(
+          AppLocalizations.of(context).appUpdateTitle,
+          style: TextStyle(fontSize: 24),
+        ),
+        content: Text(AppLocalizations.of(context).appUpdateContent),
+        actions: null,
+      ),
+    );
+  }
+}