/// <summary>
/// Makes a chess move in the data structure
/// </summary>
/// <param name="move">The move to make</param>
/// <returns>true if everything was fine, false if unable to progress - fx castleling position under attack</returns>
public bool MakeMove(Move move)
{
if (!Position.MakeMove(move))
{
return(false);
}
// advances the position
var previous = _stateList[PositionIndex++];
State = Position.State = _stateList[PositionIndex];
State.SideToMove = ~previous.SideToMove;
State.Material = previous.Material;
State.HalfMoveCount = PositionIndex;
State.LastMove = move;
// compute in-check
Position.InCheck = Position.IsAttacked(Position.GetPieceSquare(EPieceType.King, State.SideToMove), ~State.SideToMove);
State.CastlelingRights = _stateList[PositionIndex - 1].CastlelingRights & _castleRightsMask[move.GetFromSquare().AsInt()] & _castleRightsMask[move.GetToSquare().AsInt()];
State.NullMovesInRow = 0;
// compute reversible half move count
State.ReversibleHalfMoveCount = move.IsCaptureMove() || move.GetMovingPieceType() == EPieceType.Pawn
? 0
: previous.ReversibleHalfMoveCount + 1;
// compute en-passant if present
State.EnPassantSquare = move.IsDoublePush()
? move.GetFromSquare() + move.GetMovingSide().PawnPushDistance()
: ESquare.none;
State.Key = previous.Key;
State.PawnStructureKey = previous.PawnStructureKey;
UpdateKey(move);
State.Material.MakeMove(move);
//State.GenerateMoves();
return(true);
}
/// <summary>
/// Updates the hash key depending on a move
/// </summary>
/// <param name="move">The move the hash key is depending on</param>
private void UpdateKey(Move move)
{
// TODO : Merge with MakeMove to avoid duplicate ifs
var pawnKey = State.PawnStructureKey;
var key = State.Key ^ pawnKey;
pawnKey ^= Zobrist.GetZobristSide();
if (_stateList[PositionIndex - 1].EnPassantSquare != ESquare.none)
{
key ^= _stateList[PositionIndex - 1].EnPassantSquare.File().GetZobristEnPessant();
}
if (State.EnPassantSquare != ESquare.none)
{
key ^= State.EnPassantSquare.File().GetZobristEnPessant();
}
if (move.IsNullMove())
{
State.Key = key ^ pawnKey;
State.PawnStructureKey = pawnKey;
return;
}
var pawnPiece = move.GetMovingPieceType() == EPieceType.Pawn;
var squareTo = move.GetToSquare();
if (move.IsPromotionMove())
{
key ^= move.GetPromotedPiece().GetZobristPst(squareTo);
}
else
{
if (pawnPiece)
{
pawnKey ^= move.GetMovingPiece().GetZobristPst(squareTo);
}
else
{
key ^= move.GetMovingPiece().GetZobristPst(squareTo);
}
}
if (pawnPiece)
{
pawnKey ^= move.GetMovingPiece().GetZobristPst(move.GetFromSquare());
if (move.IsEnPassantMove())
{
pawnKey ^= move.GetCapturedPiece().GetZobristPst(squareTo + State.SideToMove.PawnPushDistance());
}
else if (move.IsCaptureMove())
{
pawnKey ^= move.GetCapturedPiece().GetZobristPst(squareTo);
}
}
else
{
key ^= move.GetMovingPiece().GetZobristPst(move.GetFromSquare());
if (move.IsCaptureMove())
{
key ^= move.GetCapturedPiece().GetZobristPst(squareTo);
}
else if (move.IsCastlelingMove())
{
var piece = EPieceType.Rook.MakePiece(Position.State.SideToMove);
key ^= piece.GetZobristPst(Position.GetRookCastleFrom(squareTo));
key ^= piece.GetZobristPst(squareTo.GetRookCastleTo());
}
}
// castling rights
if (State.CastlelingRights != _stateList[PositionIndex - 1].CastlelingRights)
{
key ^= _stateList[PositionIndex - 1].CastlelingRights.GetZobristCastleling();
key ^= State.CastlelingRights.GetZobristCastleling();
}
State.Key = key ^ pawnKey;
State.PawnStructureKey = pawnKey;
}
/// <summary>
/// Updates the hash key depending on a move
/// </summary>
/// <param name="move">The move the hash key is depending on</param>
private void UpdateKey(Move move)
{
// TODO : Merge with MakeMove to avoid duplicate ifs
var pawnKey = State.PawnStructureKey;
var key = State.Key ^ pawnKey;
pawnKey ^= Zobrist.GetZobristSide();
if (_stateList[PositionIndex - 1].EnPassantSquare != ESquare.none)
{
key ^= Zobrist.GetZobristEnPessant(_stateList[PositionIndex - 1].EnPassantSquare.File().AsInt());
}
if (State.EnPassantSquare != ESquare.none)
{
key ^= Zobrist.GetZobristEnPessant(State.EnPassantSquare.File().AsInt());
}
if (move.IsNullMove())
{
key ^= pawnKey;
State.Key = key;
State.PawnStructureKey = pawnKey;
return;
}
var pawnPiece = move.GetMovingPieceType() == EPieceType.Pawn;
if (pawnPiece)
{
pawnKey ^= Zobrist.GetZobristPst(move.GetMovingPiece(), move.GetFromSquare());
}
else
{
key ^= Zobrist.GetZobristPst(move.GetMovingPiece(), move.GetFromSquare());
}
var squareTo = move.GetToSquare();
if (move.IsPromotionMove())
{
key ^= Zobrist.GetZobristPst(move.GetPromotedPiece(), squareTo);
}
else
{
if (pawnPiece)
{
pawnKey ^= Zobrist.GetZobristPst(move.GetMovingPiece(), squareTo);
}
else
{
key ^= Zobrist.GetZobristPst(move.GetMovingPiece(), squareTo);
}
}
if (pawnPiece && move.IsEnPassantMove())
{
pawnKey ^= Zobrist.GetZobristPst(move.GetCapturedPiece().Type() + (State.SideToMove << 3), squareTo + (State.SideToMove.Side == 0 ? 8 : -8));
}
else if (move.IsCaptureMove())
{
if (pawnPiece)
{
pawnKey ^= Zobrist.GetZobristPst(move.GetCapturedPiece(), squareTo);
}
else
{
key ^= Zobrist.GetZobristPst(move.GetCapturedPiece(), squareTo);
}
}
else if (move.IsCastlelingMove())
{
var piece = (EPieces)(EPieceType.Rook + move.GetSideMask());
key ^= Zobrist.GetZobristPst(piece, Position.GetRookCastleFrom(squareTo));
key ^= Zobrist.GetZobristPst(piece, squareTo.GetRookCastleTo());
}
// castleling
// castling rights
if (State.CastlelingRights != _stateList[PositionIndex - 1].CastlelingRights)
{
key ^= Zobrist.GetZobristCastleling(_stateList[PositionIndex - 1].CastlelingRights);
key ^= Zobrist.GetZobristCastleling(State.CastlelingRights);
}
key ^= pawnKey;
State.Key = key;
State.PawnStructureKey = pawnKey;
}