import 'package:flutter/material.dart';
import 'package:flutter_secure_storage/flutter_secure_storage.dart';
import 'backend.dart';
import 'login_screen.dart';
import 'chat_screen.dart';
import 'chat_list_screen.dart';

class UserChecker extends StatefulWidget {
  @override
  _UserCheckerState createState() => _UserCheckerState();
}

class _UserCheckerState extends State<UserChecker> {
  String? username;
  bool isLoading = true;
  final _storage = const FlutterSecureStorage();

  @override
  void initState() {
    super.initState();
    _checkSavedCredentials();
  }

  Future<void> _checkSavedCredentials() async {
    final savedUsername = await _storage.read(key: 'username');
    final savedPassword = await _storage.read(key: 'password');

    if (savedUsername != null && savedPassword != null) {
      _handleLogin(savedUsername, savedPassword);
    } else {
      setState(() {
        isLoading = false;
      });
    }
  }

  static void fetchChats(Function(List<int>) onSuccess) {
    Backend.sendAction("get-chats", {}).then((response) {
      print("chats response: $response");
      List<dynamic> chatObjects = response['chats'];
      List<int> chatIds = chatObjects.map((chat) => chat['id'] as int).toList();
      onSuccess(chatIds);
    });
  }

  void _handleLogin(String user, String password) async {
    setState(() {
      username = user;
      isLoading = true;
    });
  
    await Backend.auth(user, password);
    await _storage.write(key: 'username', value: user);
    await _storage.write(key: 'password', value: password);

    fetchChats((chatIds) {
      if (chatIds.isEmpty) {
        Navigator.pushReplacement(
          context,
          MaterialPageRoute(builder: (_) => ChatListScreen()),
        );
      } else {
        Navigator.pushReplacement(
          context,
          MaterialPageRoute(builder: (_) => ChatScreen(chatId: chatIds.first)),
        );
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    print("Build UserChecker: $username $isLoading");
    if (isLoading) {
      return Center(child: CircularProgressIndicator());
    }

    return LoginScreen(onLogin: _handleLogin);
  }
}