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

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

class TerminalService {
  WebSocketChannel? _channel;
  String? _token;
  String? _sessionName;

  final _outputController = StreamController<String>.broadcast();
  final _stateController = StreamController<TerminalConnectionState>.broadcast();

  Stream<String> get output => _outputController.stream;
  Stream<TerminalConnectionState> get connectionState => _stateController.stream;

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

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

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

    _sessionName = sessionName;
    _updateState(TerminalConnectionState.connecting);

    try {
      final uri = Uri.parse('${ApiConfig.wsUrl}${ApiConfig.wsTerminal(sessionName)}');
      _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(TerminalConnectionState.connected);
            } else if (message['type'] == 'output') {
              _outputController.add(message['data'] ?? '');
            }
          } catch (e) {
            // Raw data
            _outputController.add(data.toString());
          }
        },
        onError: (error) {
          _updateState(TerminalConnectionState.error);
        },
        onDone: () {
          _updateState(TerminalConnectionState.disconnected);
        },
      );
    } catch (e) {
      _updateState(TerminalConnectionState.error);
    }
  }

  void sendInput(String input) {
    if (_channel == null || _currentState != TerminalConnectionState.connected) {
      return;
    }

    _channel!.sink.add(jsonEncode({
      'type': 'input',
      'data': input,
    }));
  }

  void resize(int rows, int cols) {
    if (_channel == null || _currentState != TerminalConnectionState.connected) {
      return;
    }

    _channel!.sink.add(jsonEncode({
      'type': 'resize',
      'rows': rows,
      'cols': cols,
    }));
  }

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

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

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