public BoardState ApplyMove(BoardState currentState, Move move, MoveValidationResult moveValidation)
{
var newBoardState = new BoardState();
Piece[,] piecePositions = (Piece[, ])currentState.PiecePositions.Clone();
MovePiece(move, piecePositions);
MovePiece(moveValidation.CastleRookMove, piecePositions);
RemoveEnPassantCapture(moveValidation, piecePositions);
PromotePawn(move, moveValidation, piecePositions);
newBoardState.PiecePositions = piecePositions;
newBoardState.EnPassantTarget = moveValidation.NewEnPassantTarget;
newBoardState.ActiveColor = currentState.ActiveColor == Color.White ? Color.Black : Color.White;
newBoardState.CastlingState = GetNewCastlingState(move, currentState);
if (currentState.ActiveColor == Color.Black)
{
newBoardState.FullmoveNumber += 1;
}
if (moveValidation.ShouldResetHalfmoveClock)
{
newBoardState.HalfmoveClock = 0;
}
else
{
newBoardState.HalfmoveClock += 1;
}
return(newBoardState);
}
private void RemoveEnPassantCapture(MoveValidationResult moveValidation, Piece[,] piecePositions)
{
var enPassantCapture = moveValidation.EnPassantCapture;
if (enPassantCapture == null)
{
return;
}
piecePositions[enPassantCapture.X, enPassantCapture.Y] = null;
}
private void PromotePawn(Move move, MoveValidationResult moveValidation, Piece[,] piecePositions)
{
if (moveValidation.Promotion != null)
{
var piece = piecePositions[move.EndPosition.X, move.EndPosition.Y];
piecePositions[move.EndPosition.X, move.EndPosition.Y] = new Piece
{
Color = piece.Color,
Type = moveValidation.Promotion.Value
};
}
}
