public override bool IsSpecialMove(Square origin, Square destination)
{
if (origin.Color == GetEnPassantSquare(origin, destination).Color) return false;
var occupierOfEnPassantPosition = GetEnPassantSquare(origin, destination).Occupier;
return (origin.DiagonallyForwardTo(destination)
&& origin.DistanceOfRanksIsOneTo(destination)
&& destination.Color == PieceColor.Empty
&& occupierOfEnPassantPosition.MoveCount == 1);
}
private bool Attacking(Square origin, Square destination)
{
return (origin.Color != destination.Color
&& destination.Color != PieceColor.Empty
&& origin.DistanceOfRanksIsOneTo(destination)
&& origin.DiagonallyForwardTo(destination));
}