private void UndoMovePiece(Position origin, Position destination, Piece capturedPiece)
{
Piece movingPiece = board.PickUpPiece(destination);
movingPiece.DecreaseMovementAmount();
if (capturedPiece != null)
{
capturedPiece.DecreaseMovementAmount();
board.PlacePiece(capturedPiece, destination);
capturedPiece.DecreaseMovementAmount();
capturedPieces.Remove(capturedPiece);
}
board.PlacePiece(movingPiece, origin);
movingPiece.DecreaseMovementAmount();
// # Special move: castling
if (movingPiece is King)
{
// Castling king side
if (destination.column == origin.column + 2)
{
Position rookOrigin = new Position(origin.line, origin.column + 3);
Position rookDestination = new Position(origin.line, origin.column + 1);
Piece rook = board.PickUpPiece(rookDestination);
rook.DecreaseMovementAmount();
board.PlacePiece(rook, rookOrigin);
rook.DecreaseMovementAmount();
}
// Castling queen side
if (destination.column == origin.column - 2)
{
Position rookOrigin = new Position(origin.line, origin.column - 4);
Position rookDestination = new Position(origin.line, origin.column - 1);
Piece rook = board.PickUpPiece(rookDestination);
rook.DecreaseMovementAmount();
board.PlacePiece(rook, rookOrigin);
rook.DecreaseMovementAmount();
}
}
// # Special move: en passant
if (movingPiece is Pawn)
{
if (origin.column != destination.column && capturedPiece == enPassantVulnerable)
{
Piece pawn = board.PickUpPiece(destination);
Position pawnPos;
if (movingPiece.color == Color.White)
{
pawnPos = new Position(3, destination.column);
}
else
{
pawnPos = new Position(4, destination.column);
}
board.PlacePiece(pawn, pawnPos);
pawn.DecreaseMovementAmount();
}
}
}