const int notePositionScale = 10;
const int notePositionStep = 1000 * notePositionScale;
const int notePositionRebalanceThreshold = 1;

int toStoredNotePosition(double position) {
  return (position * notePositionScale).round();
}

double fromStoredNotePosition(int storedPosition) {
  return storedPosition / notePositionScale;
}

int nextTopNotePosition(Iterable<int> storedPositions) {
  int? highestPosition;

  for (final int position in storedPositions) {
    if (highestPosition == null || position > highestPosition) {
      highestPosition = position;
    }
  }

  if (highestPosition == null) {
    return 0;
  }

  return highestPosition + notePositionStep;
}

int? midpointNotePosition({
  required int higherPosition,
  required int lowerPosition,
}) {
  final int gap = higherPosition - lowerPosition;
  if (gap <= notePositionRebalanceThreshold) {
    return null;
  }

  return lowerPosition + (gap ~/ 2);
}

List<int> rebalanceNotePositions(int itemCount) {
  return List<int>.generate(
    itemCount,
    (int index) => (itemCount - 1 - index) * notePositionStep,
  );
}