In your translation, I think you should do something like this on ProcessMove function:

if (MoveIsOutOfRange(tempPosition, selectionLength))
{
// Added IF - ELSE, it should consider RotationOn
if (RotationOn)
{
tempPosition = MovePositionToOppositeSide(selectionLength, lastValidPosition);
}
else
{
tempPosition = lastValidPosition;
}
}