import 'dart:async';
import 'dart:convert';
import 'package:web_socket_channel/web_socket_channel.dart';
import '../config/api_config.dart';

enum ChatConnectionState {
  disconnected,
  connecting,
  connected,
  error,
}

class ChatService {
  WebSocketChannel? _channel;
  String? _token;

  final _messageController = StreamController<Map<String, dynamic>>.broadcast();
  final _stateController = StreamController<ChatConnectionState>.broadcast();

  Stream<Map<String, dynamic>> get messages => _messageController.stream;
  Stream<ChatConnectionState> get connectionState => _stateController.stream;

  ChatConnectionState _currentState = ChatConnectionState.disconnected;
  ChatConnectionState get currentState => _currentState;

  void setToken(String? token) {
    _token = token;
  }

  Future<void> connect() async {
    if (_token == null) {
      _updateState(ChatConnectionState.error);
      return;
    }

    _updateState(ChatConnectionState.connecting);

    try {
      final uri = Uri.parse('${ApiConfig.wsUrl}${ApiConfig.wsChat}');
      _channel = WebSocketChannel.connect(uri);

      await _channel!.ready;

      // Send auth token
      _channel!.sink.add(jsonEncode({'token': _token}));

      _channel!.stream.listen(
        (data) {
          try {
            final message = jsonDecode(data);
            if (message['type'] == 'connected') {
              _updateState(ChatConnectionState.connected);
            }
            _messageController.add(message);
          } catch (e) {
            // Handle parse error
          }
        },
        onError: (error) {
          _updateState(ChatConnectionState.error);
        },
        onDone: () {
          _updateState(ChatConnectionState.disconnected);
        },
      );
    } catch (e) {
      _updateState(ChatConnectionState.error);
    }
  }

  void sendMessage(String content, {List<String>? files}) {
    if (_channel == null || _currentState != ChatConnectionState.connected) {
      return;
    }

    _channel!.sink.add(jsonEncode({
      'type': 'message',
      'content': content,
      'files': files ?? [],
    }));
  }

  void ping() {
    if (_channel != null && _currentState == ChatConnectionState.connected) {
      _channel!.sink.add(jsonEncode({'type': 'ping'}));
    }
  }

  void _updateState(ChatConnectionState state) {
    _currentState = state;
    _stateController.add(state);
  }

  void disconnect() {
    _channel?.sink.close();
    _channel = null;
    _updateState(ChatConnectionState.disconnected);
  }

  void dispose() {
    disconnect();
    _messageController.close();
    _stateController.close();
  }
}