public static List <Move> ValidMovesForPawn
(Color player, Square pawn, Board board, Game game)
{
List <Move> moves = new List <Move>(4);
Move lastMove = game.LastMove;
bool lastMoveWasLong
= lastMove != null &&
lastMove.IsLong &&
lastMove.To.IsOccupiedBy(player.Inverse());
int moveShift = player == Color.White ? 1 : -1;
int yForLongMove = player == Color.White ? 1 : Board.c_MaxIndex - 1;
int newY = pawn.Y + moveShift;
Square movePosition = board.GetSquare(pawn.X, newY);
if (!movePosition.IsOccupied)
{
moves.Add(new Move(pawn, movePosition));
if (pawn.Y == yForLongMove)
{
int longMoveY = newY + moveShift;
Square longMovePosition = board.GetSquare(pawn.X, longMoveY);
if (!longMovePosition.IsOccupied)
{
moves.Add(new Move(pawn, longMovePosition));
}
}
}
bool epCapturePossible = lastMoveWasLong && lastMove.To.Y == pawn.Y;
for (int attackShift = -1; attackShift <= 1; attackShift += 2)
{
int newX = pawn.X + attackShift;
if (newX < 0 || newX > Board.c_MaxIndex)
{
continue;
}
Square newSquare = board.GetSquare(newX, newY);
if (newSquare.IsOccupiedBy(player.Inverse()))
{
moves.Add(new Move(pawn, newSquare, true, false));
}
else if (epCapturePossible && lastMove.To.X == newX)
{
moves.Add(new Move(pawn, newSquare, true, true));
}
}
return(moves);
}
public IList <Move> GetAvailableMovesForPawn(Square pawn)
{
List <Move> moves = new List <Move>(c_MaxMovesForPawn);
Move lastMove = m_Game.LastMove;
bool lastMoveWasLong
= lastMove != null &&
lastMove.IsLong &&
lastMove.To.IsOccupiedBy(Opponent.Color);
int newY = pawn.Y + r_MoveShift;
Square movePosition = Board.GetSquare(pawn.X, newY);
if (!movePosition.IsOccupied)
{
moves.Add(new Move(pawn, movePosition));
if (pawn.Y == r_YForLongMove)
{
int longMoveY = newY + r_MoveShift;
Square longMovePosition = Board.GetSquare(pawn.X, longMoveY);
if (!longMovePosition.IsOccupied)
{
moves.Add(new Move(pawn, longMovePosition));
}
}
}
bool epCapturePossible = lastMoveWasLong && lastMove.To.Y == pawn.Y;
for (int attackShift = -1; attackShift <= 1; attackShift += 2)
{
int newX = pawn.X + attackShift;
if (newX < 0 || newX > Board.c_MaxIndex)
{
continue;
}
Square newSquare = Board.GetSquare(newX, newY);
if (newSquare.IsOccupiedBy(Opponent.Color))
{
moves.Add(new Move(pawn, newSquare, true, false));
}
else if (epCapturePossible && lastMove.To.X == newX)
{
moves.Add(new Move(pawn, newSquare, true, true));
}
}
return(moves);
}
public Move ParseMove(string san)
{
if (!(san.Length == 4 || san.Length == 2))
{
return(null);
}
char[] sanChars = san.ToCharArray();
int moveShift = CurrentPlayer.Color == Color.White ? -1 : 1;
int xIndex = sanChars[1] == 'x' ? 2 : 0;
int finishX = sanChars[xIndex] - 'a';
int finishY = sanChars[xIndex + 1] - '1';
int startY = finishY + moveShift;
int startX = finishX;
if (startX < 0 || startX > Board.c_MaxIndex ||
startY < 0 || startY > Board.c_MaxIndex ||
finishX < 0 || finishX > Board.c_MaxIndex ||
finishY < 0 || finishY > Board.c_MaxIndex)
{
return(null);
}
Square finishSquare = Board.GetSquare(finishX, finishY);
Square startSquare = Board.GetSquare(startX, startY);
if (sanChars.Length == 4 && sanChars[1] == 'x')
{
startX = sanChars[0] - 'a';
startSquare = Board.GetSquare(startX, startY);
if (SquareOccupiedByCurrentPlayer(startX, startY))
{
if (SquareOccupiedByOtherPlayer(finishX, finishY))
{
return(new Move(startSquare, finishSquare, true, false));
}
else if (LastMove != null && LastMove.IsLong &&
SquareOccupiedByOtherPlayer(finishX, startY))
{
return(new Move(startSquare, finishSquare, true, true));
}
}
return(null);
}
if (SquareOccupiedByCurrentPlayer(startX, startY))
{
return(new Move(startSquare, finishSquare));
}
else
{
int possibleY = CurrentPlayer.Color == Color.White ? 1 : Board.c_MaxIndex - 1;
int actualY = finishY + (moveShift << 1);
if (actualY >= 0 && actualY < Board.c_MaxCoord)
{
startSquare = Board.GetSquare(startX, actualY);
if (actualY == possibleY && startSquare.IsOccupiedBy(CurrentPlayer.Color))
{
return(new Move(startSquare, finishSquare));
}
}
}
return(null);
}
