fluffychat/lib/widgets/app_lock.dart

import 'package:flutter/material.dart';

import 'package:flutter_secure_storage/flutter_secure_storage.dart';
import 'package:matrix/matrix.dart';
import 'package:provider/provider.dart';

import 'package:fluffychat/widgets/lock_screen.dart';

class AppLockWidget extends StatefulWidget {
  const AppLockWidget({
    required this.child,
    required this.pincode,
    required this.clients,
    super.key,
  });

  final List<Client> clients;
  final String? pincode;
  final Widget child;

  @override
  State<AppLockWidget> createState() => AppLock();
}

class AppLock extends State<AppLockWidget> with WidgetsBindingObserver {
  String? _pincode;
  bool _isLocked = false;
  bool _paused = false;
  bool get isActive =>
      _pincode != null &&
      int.tryParse(_pincode!) != null &&
      _pincode!.length == 4 &&
      !_paused;

  @override
  void initState() {
    _pincode = widget.pincode;
    _isLocked = isActive;
    super.initState();
    WidgetsBinding.instance.addObserver(this);
    WidgetsBinding.instance.addPostFrameCallback(_checkLoggedIn);
  }

  void _checkLoggedIn(dynamic _) async {
    if (widget.clients.any((client) => client.isLogged())) return;

    await changePincode(null);
    setState(() {
      _isLocked = false;
    });
  }

  @override
  void didChangeAppLifecycleState(AppLifecycleState state) {
    if (isActive &&
        state == AppLifecycleState.hidden &&
        !_isLocked &&
        isActive) {
      showLockScreen();
    }
  }

  bool get isLocked => _isLocked;

  Future<void> changePincode(String? pincode) async {
    await const FlutterSecureStorage().write(
      key: 'chat.fluffy.app_lock',
      value: pincode,
    );
    _pincode = pincode;
    return;
  }

  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()],
    ),
  );
}