mchess-client/lib/connection/ws_connection.dart

import 'dart:convert';
import 'dart:developer';
import 'package:flutter/material.dart';
import 'package:go_router/go_router.dart';
import 'package:mchess/api/move.dart';
import 'package:mchess/api/websocket_message.dart';
import 'package:mchess/chess_bloc/chess_bloc.dart';
import 'package:mchess/chess_bloc/chess_events.dart';
import 'package:mchess/api/register.dart';
import 'package:mchess/chess_bloc/chess_position.dart';
import 'package:mchess/connection_cubit/connection_cubit.dart';
import 'package:mchess/utils/chess_router.dart';
import 'package:mchess/utils/chess_utils.dart';
import 'package:mchess/utils/config.dart' as config;
import 'package:web_socket_channel/web_socket_channel.dart';

class ServerConnection {
  WebSocketChannel? channel;
  Stream broadcast = const Stream.empty();

  static final ServerConnection _instance = ServerConnection._internal();

  ServerConnection._internal() {
    log("ServerConnection._internal constructor is called");
  }

  factory ServerConnection() {
    return _instance;
  }

  factory ServerConnection.getInstance() {
    return ServerConnection();
  }

  void send(String message) {
    if (channel == null) {
      log("Sending on channel without initializing");
      return;
    }
    channel!.sink.add(message);
  }

  void connect(String? passphrase) {
    disconnectExistingConnection();
    channel = WebSocketChannel.connect(Uri.parse(config.getWebsocketURL()));

    send(jsonEncode(passphrase));

    log(channel!.closeCode.toString());
    broadcast = channel!.stream.asBroadcastStream();
    broadcast.listen(handleIncomingData);
  }

  void disconnectExistingConnection() {
    if (channel == null) return;
    channel!.sink.close();

    broadcast = const Stream.empty();
  }

  void handleIncomingData(dynamic data) {
    log('${DateTime.now()}: Data received:');
    log(data);
    var apiMessage = ApiWebsocketMessage.fromJson(jsonDecode(data));

    switch (apiMessage.type) {
      case MessageType.boardState:
        handleBoardStateMessage(apiMessage);
        break;

      case MessageType.colorDetermined:
        handleIncomingColorDeterminedMessage(apiMessage);
        break;

      case MessageType.move:
        log('ERROR: move message received');
        break;

      case MessageType.invalidMove:
        handleInvalidMoveMessage(apiMessage);
      case MessageType.gameEnded:
        handleGameEndedMessage(apiMessage);
    }
  }

  void handleBoardStateMessage(ApiWebsocketMessage apiMessage) {
    ChessMove? move;
    if (apiMessage.move != null) {
      move = ChessMove.fromApiMove(apiMessage.move!);
    }

    if (apiMessage.position != null) {
      ChessBloc.getInstance().add(
        ReceivedBoardState(
            startSquare: move?.from,
            endSquare: move?.to,
            position: ChessPositionManager.getInstance()
                .fromPGNString(apiMessage.position!),
            squareInCheck: ChessCoordinate.fromApiCoordinate(
                apiMessage.squareInCheck ??
                    const ApiCoordinate(col: 0, row: 0)),
            turnColor: ChessColor.fromApiColor(apiMessage.turnColor!)),
      );
    } else {
      log('Error: no position received');
    }
  }

  void handleIncomingColorDeterminedMessage(ApiWebsocketMessage apiMessage) {
    ConnectionCubit.getInstance().opponentConnected();
    ChessBloc.getInstance().add(InitBoard());
    ChessBloc.getInstance().add(ColorDetermined(
        myColor: ChessColor.fromApiColor(apiMessage.playerColor!)));
  }

  void handleInvalidMoveMessage(ApiWebsocketMessage apiMessage) {
    log("invalid move message received, with move: ${apiMessage.move.toString()}");
    ChessBloc.getInstance().add(
      InvalidMovePlayed(
        move: ChessMove.fromApiMove(apiMessage.move!),
        squareInCheck: ChessCoordinate.fromApiCoordinate(
            apiMessage.squareInCheck ?? const ApiCoordinate(col: 0, row: 0)),
      ),
    );
  }

  void handleGameEndedMessage(ApiWebsocketMessage apiMessage) {
    showDialog(
      context: navigatorKey.currentContext!,
      builder: (context) {
        String msg = '';
        if (apiMessage.reason == 'whiteIsCheckmated') {
          msg = 'Black won! White is checkmated';
        } else if (apiMessage.reason == 'blackIsCheckmated') {
          msg = 'White won! Black is checkmated';
        }
        return AlertDialog(
            title: const Text('Game ended'),
            content: Text(msg),
            actions: <Widget>[
              TextButton(
                child: const Text('Home'),
                onPressed: () {
                  navigatorKey.currentContext!.goNamed('lobbySelector');
                },
              ),
            ]);
      },
    );
  }
}