import 'package:flutter/material.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 = false;

  @override
  void initState() {
    super.initState();
    username = null;
  }

  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) {
    Backend.auth(user, password);
  
    setState(() {
      username = user;
      isLoading = true; // Show loading spinner
    });

    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()); // Loading state UI
    }

    return LoginScreen(onLogin: _handleLogin);
  }
}