mchess-client/lib/chess_bloc/chess_position.dart

import 'dart:developer';
import 'package:mchess/utils/chess_utils.dart';

typedef ChessPositionType = Map<ChessCoordinate, ChessPiece>;
typedef ChessMoveHistory = List<ChessMove>;

class ChessPosition {
  static ChessPosition _instance = ChessPosition._internal();
  static ChessMoveHistory history = ChessMoveHistory.empty(growable: true);
  final ChessPositionType position;

  static ChessPosition getInstance() {
    return _instance;
  }

  ChessPosition({required this.position});

  factory ChessPosition._internal() {
    return ChessPosition(position: _getStartingPosition());
  }

  ChessPositionType get currentPosition => position;
  ChessPositionType get copyOfCurrentPosition => Map.from(position);
  ChessMove? get lastMove {
    if (history.isEmpty) return null;
    return history.last;
  }

  static ChessPositionType _getStartingPosition() {
    ChessPositionType pos = {};

    for (int i = 1; i <= 8; i++) {
      pos[ChessCoordinate(i, 7)] =
          ChessPiece(ChessPieceName.blackPawn, ChessColor.black);
      pos[ChessCoordinate(i, 2)] =
          ChessPiece(ChessPieceName.whitePawn, ChessColor.white);
    }

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

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

    return pos;
  }

  void resetToStartingPosition() {
    history = ChessMoveHistory.empty(growable: true);
    _instance = ChessPosition(position: _getStartingPosition());
  }

  void recordMove(ChessCoordinate from, ChessCoordinate to) {
    position[to] = position[from] ?? const ChessPiece.none();
    position[from] = const ChessPiece.none();

    history.add(ChessMove(from: from, to: to));

    logPosition(position);

    logHistory(history);
  }

  void logPosition(ChessPositionType p) {
    String logString = '';

    for (int row = 8; row > 0; row--) {
      for (int col = 1; col <= 8; col++) {
        var coord = ChessCoordinate(col, row);
        if (p.containsKey(coord)) {
          logString = '$logString ${p[coord]?.shortName}';
        } else {
          logString = '$logString .';
        }
      }
      logString = '$logString\n';
    }

    print(logString);
  }

  void logHistory(ChessMoveHistory hist) {
    for (var element in hist) {
      log('${element.from.toAlphabetical()} -> ${element.to.toAlphabetical()}');
    }
  }
}