// Features behind the review ordering, shared by the fitter (fit-order.mjs) and
// the page builder (build-um.mjs) so the two cannot drift apart -- a score built
// from differently-computed features would silently rank on nonsense.
export const FEATS = ["dur", "f0", "spread", "rms", "margin", "isoB", "isoA", "isoMin", "overlap", "isUm"];

export function featuresOf(c, words) {
  let before = -Infinity, after = Infinity, overlap = 0;
  for (const w of words) {
    if (w.end > c.start + 0.02 && w.start < c.end - 0.02) overlap += 1;
    if (w.end <= c.start) before = Math.max(before, w.end);
    if (w.start >= c.end && after === Infinity) after = w.start;
  }
  const isoB = Number.isFinite(before) ? Math.min(3, c.start - before) : 3;
  const isoA = Number.isFinite(after) ? Math.min(3, after - c.end) : 3;
  return {
    dur: c.dur ?? 0,
    f0: c.f0 ?? 0,
    spread: Math.min(400, c.spreadCents ?? 0),
    rms: Math.max(-60, c.rms ?? -60),
    margin: Math.min(0.5, Math.min(c.marginBefore ?? 0, c.marginAfter ?? 0)),
    isoB, isoA, isoMin: Math.min(isoB, isoA),
    overlap: overlap > 0 ? 1 : 0,
    isUm: /^u+m+$/.test(c.token ?? "") ? 1 : 0,
  };
}

// Score a candidate with a model written by fit-order.mjs. Higher = more likely
// to earn a "good" by ear.
export function scoreWith(model, c, words) {
  const f = featuresOf(c, words);
  let z = model.b;
  model.feats.forEach((name, j) => { z += model.w[j] * ((f[name] - model.mean[name]) / model.sd[name]); });
  return z;
}