feat: auto-updater

lib/viewmodels/settings_view_model.dart

@@ -1,4 +1,6 @@
 import 'package:flutter/foundation.dart';
+import 'package:kooltab2/utils/app_update_util.dart';
+import 'package:ota_update/ota_update.dart';
 
 import '../models/settings.dart';
 import '../services/settings_service.dart';
@@ -13,6 +15,14 @@ class SettingsViewModel extends ChangeNotifier {
   bool _hasLoaded = false;
   String? _errorMessage;
 
+  final AppUpdateUtil _updater = AppUpdateUtil(
+    serverUrl: "https://updater.brammie15.dev",
+  );
+
+  bool _checkingForUpdates = false;
+
+  bool get checkingForUpdates => _checkingForUpdates;
+
   AppSettings get settings => _settings;
   bool get isLoading => _isLoading;
   bool get hasLoaded => _hasLoaded;
@@ -41,6 +51,64 @@ class SettingsViewModel extends ChangeNotifier {
     }
   }
 
+  Future<UpdateInfo?> checkForUpdates() async {
+    if (_checkingForUpdates) return null;
+
+    _checkingForUpdates = true;
+    notifyListeners();
+
+    try {
+      return await _updater.checkForUpdate();
+    } finally {
+      _checkingForUpdates = false;
+      notifyListeners();
+    }
+  }
+
+  Future<void> installUpdate(
+      UpdateInfo update, {
+        void Function(double progress)? onProgress,
+      }) async {
+
+    final url = update.download.startsWith("http")
+        ? update.download
+        : "https://updater.brammie15.dev${update.download}";
+
+    debugPrint("Download Url: ${url}");
+
+    final stream = OtaUpdate().execute(
+      url,
+      destinationFilename: "update.apk",
+      sha256checksum: update.sha256,
+    );
+
+    await for (final event in stream) {
+
+      debugPrint(
+        "OTA: ${event.status} ${event.value}",
+      );
+
+      if (event.status == OtaStatus.DOWNLOADING) {
+        final progress =
+            double.tryParse(event.value ?? "0") ?? 0;
+
+        onProgress?.call(progress / 100);
+      }
+
+      if (event.status == OtaStatus.DOWNLOAD_ERROR) {
+        throw Exception(
+          "Download failed: ${event.value}",
+        );
+      }
+
+      if (event.status == OtaStatus.INSTALLATION_ERROR) {
+        throw Exception(
+          "Installation failed: ${event.value}",
+        );
+      }
+    }
+  }
+
   /// Just flips the preference flag. Caller is responsible for having
   /// already set/verified the actual PIN via PinLockViewModel first.
   Future<void> updatePinRequired(bool value) =>