/*
* The Pawn has 4 different moves it can make. A Pawn can only move forward, never backward.
* It may move 1 space forward as long as that space is not occupied by any other piece. It can
* move 2 spaces forward as long as it has never moved before. It can move diagonally forward 1
* space as long as that space is an enemy. It asks the MoveValidator if it can En Passant.
* Under these conditions it is a Valid Move and if the square it's moving from has a piece and it is not
* moving to itself. Also need to check if the space it's moving to is not occupied by it's own colored pieces.
*/
public bool IsValidMove(GameBoard gb, Square fromSquare, Square toSquare)
{
int fromRow = fromSquare.RowID;
int fromCol = fromSquare.ColID;
int toRow = toSquare.RowID;
int toCol = toSquare.ColID;
bool isOccupied = MoveValidator.IsOccupied(toSquare);
bool isEnemy = MoveValidator.IsEnemy(fromSquare, toSquare);
if (fromSquare.Piece == null || fromSquare.Piece == toSquare.Piece)
{
return(false);
}
bool enPassant = MoveValidator.IsEnPassant(gb, fromSquare, toSquare);
int sign = fromSquare.Piece.Color == ChessColor.White ? 1 : -1;
if (MoveCount == 0)
{
if ((toRow == fromRow + (2 * sign) && fromCol == toCol && !isOccupied) &&
(!MoveValidator.IsOccupied(gb.squares[fromRow + (1 * sign), fromCol])))
{
return(true);
}
}
if (toRow == fromRow + (1 * sign) && fromCol == toCol && !isOccupied)
{
return(true);
}
else if (toRow == fromRow + (1 * sign) && toCol == fromCol + 1 && (isEnemy || enPassant))
{
return(true);
}
else if (toRow == fromRow + (1 * sign) && toCol == fromCol - 1 && (isEnemy || enPassant))
{
return(true);
}
else
{
return(false);
}
}