internal void SetGameState()
{
Player opponent = WhoseTurn;
Player lastPlayer = ChessUtilities.RevertPlayer(opponent);
bool isInCheck = ChessUtilities.IsPlayerInCheck(opponent, this);
var hasValidMoves = ChessUtilities.GetValidMoves(this).Count > 0;
if (isInCheck && !hasValidMoves)
{
GameState = lastPlayer == Player.White ? GameState.WhiteWinner : GameState.BlackWinner;
return;
}
if (!hasValidMoves)
{
GameState = GameState.Stalemate;
return;
}
if (isInCheck)
{
GameState = opponent == Player.White ? GameState.WhiteInCheck : GameState.BlackInCheck;
return;
}
GameState = IsInsufficientMaterial() ? GameState.Draw : GameState.NotCompleted;
}
internal bool PlayerWillBeInCheck(Move move)
{
if (move == null)
{
throw new ArgumentNullException(nameof(move));
}
ChessGame clone = DeepClone(); // Make the move on this board to keep original board as is.
Piece piece = clone[move.Source];
clone.Board[(int)move.Source.Rank, (int)move.Source.File] = null;
clone.Board[(int)move.Destination.Rank, (int)move.Destination.File] = piece;
return(ChessUtilities.IsPlayerInCheck(move.Player, clone));
}
internal bool PlayerWillBeInCheck(Move move)
{
if (move == null)
{
throw new ArgumentNullException(nameof(move));
}
ChessGame clone = DeepClone(); // Make the move on this board to keep original board as is.
Piece? piece = clone[move.Source.File, move.Source.Rank]; // TODO: throwing causes un-intended behavior. ?? throw new ArgumentException("Invalid move", nameof(move));
clone.Board[(int)move.Source.Rank][(int)move.Source.File] = null;
clone.Board[(int)move.Destination.Rank][(int)move.Destination.File] = piece;
return(ChessUtilities.IsPlayerInCheck(move.Player, clone));
}
/// <summary>Makes a move in the game.</summary>
/// <param name="move">The <see cref="Move"/> you want to make.</param>
/// <param name="isMoveValidated">Only pass true when you've already checked that the move is valid.</param>
/// <returns>Returns true if the move is made; false otherwise.</returns>
/// <exception cref="ArgumentNullException">
/// The <c>move</c> is null.
/// </exception>
/// <exception cref="InvalidOperationException">
/// The <see cref="Move.Source"/> square of the <c>move</c> doesn't contain a piece.
/// </exception>
/// <exception cref="ArgumentNullException">
/// The <c>move.PromoteTo</c> is null and the move is a pawn promotion move.
/// </exception>
public bool MakeMove(Move move, bool isMoveValidated)
{
if (move == null)
{
throw new ArgumentNullException(nameof(move));
}
Piece piece = this[move.Source];
if (piece == null)
{
throw new InvalidOperationException("Source square has no piece.");
}
if (!isMoveValidated && !IsValidMove(move))
{
return(false);
}
SetCastleStatus(move, piece);
if (piece is King && move.GetAbsDeltaX() == 2)
{
// Queen-side castle
if (move.Destination.File == File.C)
{
var rook = this[File.A, move.Source.Rank];
Board[(int)move.Source.Rank, (int)File.A] = null;
Board[(int)move.Source.Rank, (int)File.D] = rook;
}
// King-side castle
if (move.Destination.File == File.G)
{
var rook = this[File.H, move.Source.Rank];
Board[(int)move.Source.Rank, (int)File.H] = null;
Board[(int)move.Source.Rank, (int)File.F] = rook;
}
}
if (piece is Pawn)
{
if ((move.Player == Player.White && move.Destination.Rank == Rank.Eighth) ||
(move.Player == Player.Black && move.Destination.Rank == Rank.First))
{
switch (move.PromoteTo)
{
case PawnPromotion.Knight:
piece = new Knight(piece.Owner);
break;
case PawnPromotion.Bishop:
piece = new Bishop(piece.Owner);
break;
case PawnPromotion.Rook:
piece = new Rook(piece.Owner);
break;
case PawnPromotion.Queen:
piece = new Queen(piece.Owner);
break;
default:
throw new ArgumentNullException(nameof(move.PromoteTo));
}
}
// Enpassant
if (Pawn.GetPawnMoveType(move) == PawnMoveType.Capture &&
this[move.Destination] == null)
{
Board[(int)Moves.Last().Destination.Rank, (int)Moves.Last().Destination.File] = null;
}
}
Board[(int)move.Source.Rank, (int)move.Source.File] = null;
Board[(int)move.Destination.Rank, (int)move.Destination.File] = piece;
Moves.Add(move);
WhoseTurn = ChessUtilities.RevertPlayer(move.Player);
SetGameState();
return(true);
}
