private string ValidateCastleling(string error)
{
Span <Player> players = stackalloc Player[] { Player.White, Player.Black };
Span <CastlelingRights> crs = stackalloc CastlelingRights[] { CastlelingRights.None, CastlelingRights.None };
foreach (var c in players)
{
crs[0] = CastlelingRights.KingSide.MakeCastlelingRights(c);
crs[1] = CastlelingRights.QueenSide.MakeCastlelingRights(c);
var ourRook = PieceTypes.Rook.MakePiece(c);
foreach (var cr in crs)
{
if (!_pos.CanCastle(cr))
{
continue;
}
var rookSq = _pos.CastlingRookSquare(cr);
if (_board.PieceAt(rookSq) != ourRook)
{
error = AddError(error, $"rook does not appear on its position for {c}");
}
if (_pos.GetCastlelingRightsMask(rookSq) != cr)
{
error = AddError(error, $"castleling rights mask at {rookSq} does not match for player {c}");
}
if ((_pos.GetCastlelingRightsMask(_pos.GetKingSquare(c).AsInt()) & cr) != cr)
{
error = AddError(error, $"castleling rights mask at {_pos.GetKingSquare(c)} does not match for player {c}");
}
}
}
return(error);
}