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_MAX_INDEX ||
startY < 0 || startY > Board.c_MAX_INDEX ||
finishX < 0 || finishX > Board.c_MAX_INDEX ||
finishY < 0 || finishY > Board.c_MAX_INDEX)
{
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_MAX_INDEX - 1;
int actualY = finishY + (moveShift << 1);
if (actualY >= 0 && actualY < Board.c_MAX_COORDINATE)
{
startSquare = Board.GetSquare(startX, actualY);
if (actualY == possibleY && startSquare.IsOccupiedBy(CurrentPlayer.Color))
{
return(new Move(startSquare, finishSquare));
}
}
}
return(null);
}
public static bool ValidSquare(Square x)
{
return(x.X >= 0 && x.X < Board.c_MaxCoord &&
x.Y >= 0 && x.Y < Board.c_MaxCoord);
}
public static bool CheckSimpleCapture(Square to, Color playerColor) => (to.Color == playerColor.Inverse());
public static bool CheckForwardMove(Square to) => to.Color == Color.None;
public Move(Square from, Square to) : this(from, to, false, false)
{
}