entryAt method

FeedEntry entryAt(int step)

The entry for new-theme step step under the current filter: a hero on hero steps (every 8–12 steps, seeded), otherwise a generated theme whose seed and family come from Rng.stream(feedSeed, 'feed/step/k').

While steering, steps from the one steer started at are generated under the intent from steeredFamilies (that first step centred), with no heroes.

Implementation

FeedEntry entryAt(int step) {
  final intent = _intent;
  if (intent != null && step >= _intentStep) {
    final families = steeredFamilies;
    final r = Rng.stream(feedSeed, RngTag.sub(RngTag.feed, 'step', step));
    final seed = r.nextU32();
    final family = families[r.nextInt(families.length)];
    final recipe = intent.forEntry;
    return recipe.isEmpty
        ? FeedEntry.generated(seed: seed, family: family)
        : FeedEntry.generated(
            seed: seed,
            family: family,
            intent: recipe,
            centred: step == _intentStep,
          );
  }
  final families = _filter.families;
  final heroIndex = _heroIndexAt(step);
  if (heroIndex != null) {
    final order = _heroOrderIds();
    final allowed = [
      for (final id in order)
        if (families.contains(heroById(id)!.family)) id,
    ];
    if (allowed.isNotEmpty) {
      return FeedEntry.hero(allowed[heroIndex % allowed.length]);
    }
  }
  final r = Rng.stream(feedSeed, RngTag.sub(RngTag.feed, 'step', step));
  final seed = r.nextU32();
  final family = families[r.nextInt(families.length)];
  return FeedEntry.generated(seed: seed, family: family);
}