public IEnumerable <Move> GetMoves(Checkerboard checkerboard, Pawn pawn)
{
Position posPlus1;
Position posPlus2;
if (pawn.PawnColor == PawnColor.White)
{
posPlus1 = pawn.Position + new Position(0, 1);
posPlus2 = posPlus1 + new Position(0, 1);
}
else
{
posPlus1 = pawn.Position - new Position(0, 1);
posPlus2 = posPlus1 - new Position(0, 1);
}
bool canMove1SquareForward = checkerboard.IsEmptyButExists(posPlus1);
bool canMove2SquareForward = pawn.Position.Digit == (pawn.PawnColor == PawnColor.White ? 1 : 6) && checkerboard.IsEmptyButExists(posPlus2);
if (canMove1SquareForward)
{
yield return(checkerboard.GetMove(pawn, posPlus1));
if (canMove2SquareForward)
{
yield return(checkerboard.GetMove(pawn, posPlus2));
}
}
foreach (var take in GetTakes(checkerboard, pawn))
{
yield return(checkerboard.GetMove(pawn, take.NewPawnPos, take.TakenPawn));
}
}
Move?FindMove(Checkerboard checkerboard, Pawn pawn, Position position)
{
if (checkerboard.IsEmptyButExists(position))
{
return(checkerboard.GetMove(pawn, position));
}
return(null);
}
public IEnumerable <Move> GetTakes(Checkerboard checkerboard, Pawn pawn)
{
Position leftPos;
Position rightPos;
Position frontLeftPos;
Position frontRightPos;
int curPawnLetter = pawn.Position.Letter;
int curPawnDigit = pawn.Position.Digit;
if (pawn.PawnColor == PawnColor.White)
{
frontLeftPos = new Position((curPawnLetter - 1), curPawnDigit + 1);
frontRightPos = new Position((curPawnLetter + 1), curPawnDigit + 1);
leftPos = new Position((curPawnLetter - 1), curPawnDigit);
rightPos = new Position((curPawnLetter + 1), curPawnDigit);
}
else
{
frontLeftPos = new Position((curPawnLetter + 1), curPawnDigit - 1);
frontRightPos = new Position((curPawnLetter - 1), curPawnDigit - 1);
leftPos = new Position((curPawnLetter - 1), curPawnDigit);
rightPos = new Position((curPawnLetter + 1), curPawnDigit);
}
if (checkerboard.IsOccupied(leftPos, out Pawn oppositeLeftPawn) && CanTakeEnPassant(checkerboard, pawn, oppositeLeftPawn, frontLeftPos, out Pawn frontLeftPawn))
{
yield return(checkerboard.GetMove(pawn, frontLeftPos, frontLeftPawn));
}
if (checkerboard.IsOccupied(rightPos, out Pawn oppositeRightPawn) && CanTakeEnPassant(checkerboard, pawn, oppositeRightPawn, frontRightPos, out Pawn frontRightPawn))
{
yield return(checkerboard.GetMove(pawn, frontRightPos, frontRightPawn));
}
if (checkerboard.IsOccupied(frontLeftPos, out Pawn frontLeftPawn1) && pawn.AreOppositeColor(frontLeftPawn1))
{
yield return(checkerboard.GetMove(pawn, frontLeftPos, frontLeftPawn1));
}
if (checkerboard.IsOccupied(frontRightPos, out Pawn frontRightPawn1) && pawn.AreOppositeColor(frontRightPawn1))
{
yield return(checkerboard.GetMove(pawn, frontRightPos, frontRightPawn1));
}
}
public static IEnumerable <Move> FindMovesAlongDirection(this Checkerboard checkerboard, Pawn pawn, Position delta)
{
var currPosition = pawn.Position + delta;
while (Checkerboard.Exists(currPosition))
{
if (checkerboard.IsOccupied(currPosition, out Pawn currPosPawn))
{
if (currPosPawn.AreOppositeColor(pawn))
{
yield return(checkerboard.GetMove(pawn, currPosition, currPosPawn));
}
break;
}
else if (checkerboard.IsEmptyButExists(currPosition))
{
yield return(checkerboard.GetMove(pawn, currPosition));
}
currPosition += delta;
}
}
