private IEnumerable<RotatedPiece> GetNextOrientationPermutation(RotatedPieceHolder[] orderPermutation)
{
var lastPiece = orderPermutation.Last();
if (lastPiece.RotationNumber > 4) {
lastPiece.Reset();
if (!RotateEarlierPieces(orderPermutation))
return null;
}
var rotatedPieces = (from rph in orderPermutation select new RotatedPiece(rph.Piece, rph.Orientation)).ToList();
lastPiece.Rotate();
return rotatedPieces;
}
private bool RotateEarlierPieces(RotatedPieceHolder[] orderPermutation)
{
int numPieces = orderPermutation.Length;
if (numPieces <= 1)
return false;
var indexZeroHasBeenReset = false;
for (int i = numPieces - 2; i >= 0; i--) {
if (orderPermutation[i].RotationNumber < 4) {
orderPermutation[i].Rotate();
break;
}
orderPermutation[i].Reset();
indexZeroHasBeenReset = i == 0;
}
return !indexZeroHasBeenReset;
}
