mchess-client/lib/chess_bloc/chess_bloc.dart

import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:mchess/chess_bloc/chess_events.dart';
import 'package:mchess/chessapp/chess_utils.dart';
import 'dart:developer';

class ChessBloc extends Bloc<ChessEvent, ChessBoardState> {
  static final ChessBloc _instance = ChessBloc._internal();
  late ChessColor? myColor;

  ChessBloc._internal() : super(ChessBoardState.init()) {
    on<InitBoard>(initBoard);
    on<ColorDetermined>(flipBoard);
    on<PieceMoved>(moveHandler);
  }

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

  factory ChessBloc() {
    return _instance;
  }

  void initBoard(InitBoard event, Emitter<ChessBoardState> emit) {
    emit(ChessBoardState.init());
  }

  void flipBoard(ColorDetermined event, Emitter<ChessBoardState> emit) {
    emit(ChessBoardState(event.myColor, state.newTurnColor, state.position));
  }

  void moveHandler(PieceMoved event, Emitter<ChessBoardState> emit) {
    Map<ChessCoordinate, ChessPiece> newPosition = state.position;

    newPosition[event.endSquare] = state.position[event.startSquare]!;
    newPosition[event.startSquare] = const ChessPiece.none();

    var newTurnColor = state.newTurnColor == ChessColor.white
        ? ChessColor.black
        : ChessColor.white;

    log('emitting new state with position $newPosition');
    emit(
      ChessBoardState(
        state.bottomColor,
        newTurnColor,
        newPosition,
      ),
    );
  }
}

class ChessBoardState {
  late ChessColor bottomColor;
  final ChessColor newTurnColor;
  final Map<ChessCoordinate, ChessPiece> position;

  ChessBoardState._(this.bottomColor, this.newTurnColor, this.position);

  factory ChessBoardState(
    ChessColor bottomColor,
    ChessColor turnColor,
    Map<ChessCoordinate, ChessPiece> position,
  ) {
    return ChessBoardState._(bottomColor, turnColor, position);
  }

  factory ChessBoardState.init() {
    ChessColor bottomColor = ChessColor.white;
    ChessColor turnColor = ChessColor.white;
    Map<ChessCoordinate, ChessPiece> position = {};

    for (int i = 0; i <= 8; i++) {
      position[ChessCoordinate(i, 7)] =
          ChessPiece(ChessPieceName.blackPawn, ChessColor.black);
      position[ChessCoordinate(i, 2)] =
          ChessPiece(ChessPieceName.whitePawn, ChessColor.white);
    }

    position[ChessCoordinate(1, 8)] =
        ChessPiece(ChessPieceName.blackRook, ChessColor.black);
    position[ChessCoordinate(2, 8)] =
        ChessPiece(ChessPieceName.blackKnight, ChessColor.black);
    position[ChessCoordinate(3, 8)] =
        ChessPiece(ChessPieceName.blackBishop, ChessColor.black);
    position[ChessCoordinate(4, 8)] =
        ChessPiece(ChessPieceName.blackQueen, ChessColor.black);
    position[ChessCoordinate(5, 8)] =
        ChessPiece(ChessPieceName.blackKing, ChessColor.black);
    position[ChessCoordinate(6, 8)] =
        ChessPiece(ChessPieceName.blackBishop, ChessColor.black);
    position[ChessCoordinate(7, 8)] =
        ChessPiece(ChessPieceName.blackKnight, ChessColor.black);
    position[ChessCoordinate(8, 8)] =
        ChessPiece(ChessPieceName.blackRook, ChessColor.black);

    position[ChessCoordinate(1, 1)] =
        ChessPiece(ChessPieceName.whiteRook, ChessColor.black);
    position[ChessCoordinate(2, 1)] =
        ChessPiece(ChessPieceName.whiteKnight, ChessColor.black);
    position[ChessCoordinate(3, 1)] =
        ChessPiece(ChessPieceName.whiteBishop, ChessColor.black);
    position[ChessCoordinate(4, 1)] =
        ChessPiece(ChessPieceName.whiteQueen, ChessColor.black);
    position[ChessCoordinate(5, 1)] =
        ChessPiece(ChessPieceName.whiteKing, ChessColor.black);
    position[ChessCoordinate(6, 1)] =
        ChessPiece(ChessPieceName.whiteBishop, ChessColor.black);
    position[ChessCoordinate(7, 1)] =
        ChessPiece(ChessPieceName.whiteKnight, ChessColor.black);
    position[ChessCoordinate(8, 1)] =
        ChessPiece(ChessPieceName.whiteRook, ChessColor.black);

    return ChessBoardState._(bottomColor, turnColor, position);
  }
}