Object Oriented Design for a Chess game [closed]

Question

I actually just wrote a full C# implementation of a chess board, pieces, rules, etc. Here’s roughly how I modeled it (actual implementation removed since I don’t want to take all the fun out of your coding):

public enum PieceType {
    None, Pawn, Knight, Bishop, Rook, Queen, King
}

public enum PieceColor {
    White, Black
}

public struct Piece {
    public PieceType Type { get; set; }
    public PieceColor Color { get; set; }
}

public struct Square {
    public int X { get; set; }
    public int Y { get; set; }

    public static implicit operator Square(string str) {
        // Parses strings like "a1" so you can write "a1" in code instead
        // of new Square(0, 0)
    }
}

public class Board {
    private Piece[,] board;

    public Piece this[Square square] { get; set; }

    public Board Clone() { ... }
}

public class Move {
    public Square From { get; }
    public Square To { get; }
    public Piece PieceMoved { get; }
    public Piece PieceCaptured { get; }
    public PieceType Promotion { get; }
    public string AlgebraicNotation { get; }
}

public class Game {
    public Board Board { get; }
    public IList<Move> Movelist { get; }
    public PieceType Turn { get; set; }
    public Square? DoublePawnPush { get; set; } // Used for tracking valid en passant captures
    public int Halfmoves { get; set; }

    public bool CanWhiteCastleA { get; set; }
    public bool CanWhiteCastleH { get; set; }
    public bool CanBlackCastleA { get; set; }
    public bool CanBlackCastleH { get; set; }
}

public interface IGameRules {
    // ....
}

The basic idea is that Game/Board/etc simply store the state of the game. You can manipulate them to e.g. set up a position, if that’s what you want. I have a class that implements my IGameRules interface that is responsible for:

Determining what moves are valid, including castling and en passant.
Determining if a specific move is valid.
Determining when players are in check/checkmate/stalemate.
Executing moves.

Separating the rules from the game/board classes also means you can implement variants relatively easily. All methods of the rules interface take a Game object which they can inspect to determine which moves are valid.

Note that I do not store player information on Game. I have a separate class Table that is responsible for storing game metadata such as who was playing, when the game took place, etc.

EDIT: Note that the purpose of this answer isn’t really to give you template code you can fill out — my code actually has a bit more information stored on each item, more methods, etc. The purpose is to guide you towards the goal you’re trying to achieve.

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