mchess-client/lib/chess_bloc/chess_bloc.dart

import 'dart:convert';

import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:mchess/api/websocket_message.dart';
import 'package:mchess/chess_bloc/chess_events.dart';
import 'package:mchess/chess_bloc/chess_position.dart';
import 'package:mchess/connection/ws_connection.dart';
import 'package:mchess/utils/chess_utils.dart';
import 'dart:developer';

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

  static ChessColor? getSidesColor() {
    return myColor;
  }

  ChessBloc._internal() : super(ChessBoardState.init()) {
    on<InitBoard>(initBoard);
    on<ColorDetermined>(flipBoard);
    on<ReceivedMove>(moveHandler);
    on<ReceivedPromotion>(promotionHandler);
    on<OwnPieceMoved>(ownMoveHandler);
    on<OwnPromotionPlayed>(ownPromotionHandler);
    on<InvalidMovePlayed>(invalidMoveHandler);
  }

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

  factory ChessBloc() {
    return _instance;
  }

  void initBoard(InitBoard event, Emitter<ChessBoardState> emit) {
    ChessPosition.getInstance().resetToStartingPosition();
    emit(ChessBoardState(ChessColor.white, ChessColor.white,
        ChessPosition.getInstance().currentPosition));
  }

  void flipBoard(ColorDetermined event, Emitter<ChessBoardState> emit) {
    log("My Color is $myColor");
    myColor = event.myColor;
    emit(ChessBoardState(event.myColor, state.newTurnColor, state.position));
  }

  void moveHandler(ReceivedMove event, Emitter<ChessBoardState> emit) {
    log('opponentMoveHandler()');

    var move = ChessMove(from: event.startSquare, to: event.endSquare);
    bool wasEnPassant = move.wasEnPassant();
    bool wasCastling = move.wasCastling();

    var oldPosition = ChessPosition.getInstance().copyOfCurrentPosition;
    ChessPosition.getInstance().recordMove(event.startSquare, event.endSquare);
    var newPosition = ChessPosition.getInstance().currentPosition;

    if (wasEnPassant) {
      if (turnColor == ChessColor.white) {
        newPosition[ChessCoordinate(
                event.endSquare.column, event.endSquare.row - 1)] =
            const ChessPiece.none();
      } else {
        newPosition[ChessCoordinate(
                event.endSquare.column, event.endSquare.row + 1)] =
            const ChessPiece.none();
      }
    } else if (wasCastling) {
      ChessPiece rookToMove;
      ChessPiece kingToMove;
      if (move.to.column == 7) {
        rookToMove = oldPosition[ChessCoordinate(8, move.to.row)]!;
        newPosition[ChessCoordinate(6, move.to.row)] = rookToMove;
        newPosition[ChessCoordinate(8, move.to.row)] = const ChessPiece.none();

        kingToMove = oldPosition[ChessCoordinate(5, move.to.row)]!;
        newPosition[ChessCoordinate(7, move.to.row)] = kingToMove;
        newPosition[ChessCoordinate(5, move.to.row)] = const ChessPiece.none();
      }
      if (move.to.column == 3) {
        rookToMove = oldPosition[ChessCoordinate(1, move.to.row)]!;
        newPosition[ChessCoordinate(4, move.to.row)] = rookToMove;
        newPosition[ChessCoordinate(1, move.to.row)] = const ChessPiece.none();

        kingToMove = oldPosition[ChessCoordinate(5, move.to.row)]!;
        newPosition[ChessCoordinate(3, move.to.row)] = kingToMove;
        newPosition[ChessCoordinate(5, move.to.row)] = const ChessPiece.none();
      }
    }

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

    emit(
      ChessBoardState(
        state.bottomColor,
        turnColor,
        newPosition,
      ),
    );
  }

  void promotionHandler(
    ReceivedPromotion event,
    Emitter<ChessBoardState> emit,
  ) {
    var pieceAtStartSquare = ChessPosition.getInstance().getPieceAt(
        ChessCoordinate(event.startSquare.column, event.startSquare.row));
    if (pieceAtStartSquare == null) {
      log('received a promotion but piece on start square was empty');
      return;
    }

    ChessPieceClass pieceClass = ChessPieceClass.none;
    for (var piece in chessPiecesShortName.entries) {
      if (piece.value.toLowerCase() == event.piece) {
        pieceClass = piece.key.pieceClass;
        break;
      }
    }
    var newPosition = ChessPosition.getInstance().currentPosition;
    newPosition[
            ChessCoordinate(event.startSquare.column, event.startSquare.row)] =
        const ChessPiece.none();
    newPosition[ChessCoordinate(event.endSquare.column, event.endSquare.row)] =
        ChessPiece(pieceClass, pieceAtStartSquare.color);

    emit(ChessBoardState(
      state.bottomColor,
      turnColor,
      newPosition,
    ));
  }

  void ownMoveHandler(OwnPieceMoved event, Emitter<ChessBoardState> emit) {
    log('ownMoveHandler()');
    var apiMove =
        ChessMove(from: event.startSquare, to: event.endSquare).toApiMove();
    var apiMessage = ApiWebsocketMessage(
        type: MessageType.move, move: apiMove, color: null, reason: null);

    ServerConnection.getInstance().send(jsonEncode(apiMessage));

    //Temporary chess position until server responds with acknowledgement
    var move = ChessMove.fromApiMove(apiMove);
    var tempPosition = ChessPosition.getInstance().copyOfCurrentPosition;
    tempPosition[move.to] = tempPosition[move.from] ?? const ChessPiece.none();
    tempPosition[move.from] = const ChessPiece.none();

    emit(
      ChessBoardState(
        state.bottomColor,
        turnColor,
        tempPosition,
      ),
    );
  }

  void ownPromotionHandler(
      OwnPromotionPlayed event, Emitter<ChessBoardState> emit) {
    var apiMove = event.move.toApiMove();
    var shorNameForPiece = chessPiecesShortName[
            ChessPieceAssetKey(pieceClass: event.pieceClass, color: myColor!)]!
        .toLowerCase();
    apiMove.promotionToPiece = shorNameForPiece;
    var message = ApiWebsocketMessage(
      type: MessageType.move,
      move: apiMove,
      color: null,
      reason: null,
    );
    log(jsonEncode(message));
    ServerConnection.getInstance().send(jsonEncode(message));
  }

  void invalidMoveHandler(
      InvalidMovePlayed event, Emitter<ChessBoardState> emit) {
    emit(
      ChessBoardState(
        state.bottomColor,
        turnColor,
        ChessPosition.getInstance().currentPosition,
      ),
    );
  }
}

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;

    ChessPosition.getInstance().resetToStartingPosition();

    return ChessBoardState(
        bottomColor, turnColor, ChessPosition.getInstance().currentPosition);
  }

  void logPosition(Map<ChessCoordinate, ChessPiece> pos) {
    // for (int i = 0; i < 7; i++)
  }
}