Initial commit

lib/widgets/app_lock.dart

@@ -0,0 +1,146 @@
+// SPDX-FileCopyrightText: 2019-Present Christian Kußowski
+// SPDX-FileCopyrightText: 2019-Present Contributors to FluffyChat
+//
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+import 'package:tatchat/widgets/lock_screen.dart';
+import 'package:flutter_secure_storage/flutter_secure_storage.dart';
+import 'package:local_auth/local_auth.dart';
+import 'package:material_ui/material_ui.dart';
+import 'package:provider/provider.dart';
+
+class AppLockWidget extends StatefulWidget {
+  const AppLockWidget({
+    required this.child,
+    required this.pincode,
+    required this.useBiometrics,
+    required this.isLoggedIn,
+    super.key,
+  });
+
+  final bool isLoggedIn, useBiometrics;
+  final String? pincode;
+  final Widget child;
+
+  @override
+  State<AppLockWidget> createState() => AppLock();
+}
+
+class AppLock extends State<AppLockWidget> with WidgetsBindingObserver {
+  String? _pincode;
+  bool _isLocked = false;
+  bool _useBiometrics = false;
+  bool _triedAutoBiometrics = false;
+  bool _paused = false;
+  bool get isActive =>
+      _pincode != null &&
+      int.tryParse(_pincode!) != null &&
+      _pincode!.length >= 4 &&
+      !_paused;
+  bool get useBiometrics => _useBiometrics;
+
+  @override
+  void initState() {
+    _useBiometrics = widget.useBiometrics;
+    _pincode = widget.pincode;
+    _isLocked = isActive;
+    super.initState();
+    WidgetsBinding.instance.addObserver(this);
+    WidgetsBinding.instance.addPostFrameCallback(_checkLoggedIn);
+    if (isActive && useBiometrics) unlockWithBiometrics();
+  }
+
+  Future<void> _checkLoggedIn(_) async {
+    if (widget.isLoggedIn) return;
+
+    await changePincode(null);
+    setState(() {
+      _isLocked = false;
+    });
+  }
+
+  @override
+  void didChangeAppLifecycleState(AppLifecycleState state) {
+    if (isActive && state == AppLifecycleState.hidden && !_isLocked) {
+      showLockScreen();
+    }
+    if (_isLocked &&
+        state == AppLifecycleState.resumed &&
+        useBiometrics &&
+        !_triedAutoBiometrics) {
+      unlockWithBiometrics();
+    }
+  }
+
+  bool get isLocked => _isLocked;
+
+  Future<void> changeUseBiometrics(bool useBiometrics) async {
+    await const FlutterSecureStorage().write(
+      key: 'chat.fluffy.use_biometrics',
+      value: useBiometrics.toString(),
+    );
+    _useBiometrics = useBiometrics;
+    return;
+  }
+
+  Future<void> changePincode(String? pincode) async {
+    await const FlutterSecureStorage().write(
+      key: 'chat.fluffy.app_lock',
+      value: pincode,
+    );
+    _pincode = pincode;
+    return;
+  }
+
+  Future<bool> unlockWithBiometrics() async {
+    _triedAutoBiometrics = true;
+    final localAuth = LocalAuthentication();
+    final unlocked = await localAuth.authenticate(
+      localizedReason: 'Please authenticate to unlock the app.',
+      persistAcrossBackgrounding: true,
+      biometricOnly: true,
+    );
+    if (unlocked) {
+      setState(() {
+        _isLocked = false;
+        _triedAutoBiometrics = false;
+      });
+    }
+    return unlocked;
+  }
+
+  bool unlock(String pincode) {
+    final isCorrect = pincode == _pincode;
+    if (isCorrect) {
+      setState(() {
+        _isLocked = false;
+      });
+    }
+    return isCorrect;
+  }
+
+  void showLockScreen() => setState(() {
+    _isLocked = true;
+  });
+
+  Future<T> pauseWhile<T>(Future<T> future) async {
+    _paused = true;
+    try {
+      return await future;
+    } finally {
+      _paused = false;
+    }
+  }
+
+  static AppLock of(BuildContext context) =>
+      Provider.of<AppLock>(context, listen: false);
+
+  @override
+  Widget build(BuildContext context) => Provider<AppLock>(
+    create: (_) => this,
+    child: Stack(
+      fit: StackFit.expand,
+      children: [widget.child, if (isLocked) const LockScreen()],
+    ),
+  );
+}