Add update notifier

lib/apis/github_api.dart

@@ -0,0 +1,50 @@
+import 'dart:convert';
+
+import 'package:http/http.dart' as http;
+
+class SemVer {
+  final int major;
+  final int minor;
+  final int patch;
+
+  SemVer({required this.major, required this.minor, required this.patch});
+
+  factory SemVer.fromString(String str) {
+    final split = str.split(".");
+    if (split.length != 3) {
+      throw "Invalid version format";
+    }
+    return SemVer(major: int.parse(split[0]), minor: int.parse(split[1]), patch: int.parse(split[2]));
+  }
+
+
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      other is SemVer &&
+          runtimeType == other.runtimeType &&
+          major == other.major &&
+          minor == other.minor &&
+          patch == other.patch;
+
+  @override
+  int get hashCode => major.hashCode ^ minor.hashCode ^ patch.hashCode;
+
+  bool operator >(SemVer other) {
+    if (major > other.major || (major == other.major && minor > other.minor) || (major == other.major && minor == other.minor && patch > other.patch)) {
+      return true;
+    }
+    return false;
+  }
+}
+
+class GithubApi {
+  static const baseUrl = "https://api.github.com";
+
+  static Future<String> getLatestTagName() async {
+    final response = await http.get(Uri.parse("$baseUrl/repos/Nutcake/contacts-plus-plus/releases/latest"));
+    if (response.statusCode != 200) return "";
+    final body = jsonDecode(response.body);
+    return body["tag_name"] ?? "";
+  }
+}

lib/main.dart

@@ -1,14 +1,18 @@
 import 'dart:developer';
 import 'dart:io' show Platform;
 
+import 'package:contacts_plus_plus/apis/github_api.dart';
 import 'package:contacts_plus_plus/client_holder.dart';
 import 'package:contacts_plus_plus/clients/messaging_client.dart';
 import 'package:contacts_plus_plus/clients/settings_client.dart';
 import 'package:contacts_plus_plus/widgets/friends/friends_list.dart';
 import 'package:contacts_plus_plus/widgets/login_screen.dart';
+import 'package:contacts_plus_plus/widgets/update_notifier.dart';
+import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter_phoenix/flutter_phoenix.dart';
 import 'package:logging/logging.dart';
+import 'package:package_info_plus/package_info_plus.dart';
 import 'package:provider/provider.dart';
 import 'package:workmanager/workmanager.dart';
 import 'models/authentication_data.dart';
@@ -51,16 +55,45 @@ class ContactsPlusPlus extends StatefulWidget {
 class _ContactsPlusPlusState extends State<ContactsPlusPlus> {
   final Typography _typography = Typography.material2021(platform: TargetPlatform.android);
   AuthenticationData _authData = AuthenticationData.unauthenticated();
+  bool _checkedForUpdate = false;
+
+  void showUpdateDialogOnFirstBuild(BuildContext context) {
+    final navigator = Navigator.of(context);
+    if (_checkedForUpdate || kDebugMode) return;
+    _checkedForUpdate = true;
+    GithubApi.getLatestTagName().then((value) async {
+      final currentVer = (await PackageInfo.fromPlatform()).version;
+
+      try {
+        final currentSem = SemVer.fromString(currentVer);
+        final remoteSem = SemVer.fromString(value);
+        if (remoteSem > currentSem && navigator.overlay?.context != null) {
+          showDialog(
+            context: navigator.overlay!.context,
+            builder: (context) {
+              return const UpdateNotifier();
+            },
+          );
+        }
+      } catch (e) {
+        if (currentVer != value && navigator.overlay?.context != null) {
+          showDialog(
+            context: navigator.overlay!.context,
+            builder: (context) {
+              return const UpdateNotifier();
+            },
+          );
+        }
+      }
+    });
+  }
 
   @override
   Widget build(BuildContext context) {
     return ClientHolder(
       settingsClient: widget.settingsClient,
       authenticationData: _authData,
-      child: Builder(
-          builder: (context) {
-            final clientHolder = ClientHolder.of(context);
-            return MaterialApp(
+      child: MaterialApp(
           debugShowCheckedModeBanner: false,
           title: 'Contacts++',
           theme: ThemeData(
@@ -68,7 +101,11 @@ class _ContactsPlusPlusState extends State<ContactsPlusPlus> {
               textTheme: _typography.white,
               colorScheme: ColorScheme.fromSeed(seedColor: Colors.purple, brightness: Brightness.dark)
           ),
-                home: _authData.isAuthenticated ?
+          home: Builder(
+            builder: (context) {
+              showUpdateDialogOnFirstBuild(context);
+              final clientHolder = ClientHolder.of(context);
+              return _authData.isAuthenticated ?
               ChangeNotifierProvider( // This doesn't need to be a proxy provider since the arguments should never change during it's lifetime.
                 create: (context) =>
                     MessagingClient(
@@ -85,9 +122,9 @@ class _ContactsPlusPlusState extends State<ContactsPlusPlus> {
                     });
                   }
                 },
-                )
               );
             }
+          )
       ),
     );
   }

lib/widgets/update_notifier.dart

@@ -0,0 +1,46 @@
+import 'package:flutter/material.dart';
+import 'package:url_launcher/url_launcher.dart';
+
+class UpdateNotifier extends StatelessWidget {
+  const UpdateNotifier({super.key});
+
+  @override
+  Widget build(BuildContext context) {
+    return AlertDialog(
+      title: Text("Update Available", style: Theme
+          .of(context)
+          .textTheme
+          .titleLarge),
+      content: Column(
+        mainAxisSize: MainAxisSize.min,
+        children: [
+          const Text("There is a new version available for download!"),
+          const SizedBox(height: 24,),
+          Row(
+            mainAxisAlignment: MainAxisAlignment.center,
+            mainAxisSize: MainAxisSize.min,
+            children: [
+              TextButton.icon(
+                onPressed: () {
+                  launchUrl(Uri.parse("https://github.com/Nutcake/contacts-plus-plus/releases/latest"),
+                    mode: LaunchMode.externalApplication,
+                  );
+                },
+                style: TextButton.styleFrom(
+                  padding: const EdgeInsets.symmetric(vertical: 12, horizontal: 24),
+                  foregroundColor: Theme.of(context).colorScheme.onSecondary,
+                  backgroundColor: Theme.of(context).colorScheme.secondary
+                ),
+                icon: const Icon(Icons.download),
+                label: const Text("Get it on Github"),
+              ),
+            ],
+          ),
+        ],
+      ),
+      actions: [
+        TextButton(onPressed: () => Navigator.of(context).pop(), child: const Text("I'll do it later."))
+      ],
+    );
+  }
+}