Grade rule library

export function cleanEntry(raw) {
  if (!raw || typeof raw !== 'object') return null;
  const name = clean(raw.name, 80);
  const sizes = Array.isArray(raw.sizes) ? [...new Set(raw.sizes.slice(0, MAXS).map((s) => clean(s, 12)).filter(Boolean))] : [];
  if (!name || !sizes.length || !Array.isArray(raw.rule) || raw.rule.length !== sizes.length * 2 || !raw.rule.every((v) => fin(+v))) return null;
  const base = sizes.includes(raw.base) ? raw.base : sizes[0];
  const rule = raw.rule.map(Number);
  const b = sizes.indexOf(base);
  rule[2 * b] = 0; rule[2 * b + 1] = 0;
  return { name, u: raw.u === 'in' ? 'in' : 'mm', sizes, base, rule };
}

/** The entry as a rule for a piece's size range (names matched, measured from the piece's base) in the piece's units. */
export function ruleFor(entry, sizes, u) {
  const k = entry.u === u ? 1 : entry.u === 'in' ? 25.4 : 1 / 25.4;
  const at = (s) => { const i = entry.sizes.indexOf(s); return i >= 0 ? [entry.rule[2 * i], entry.rule[2 * i + 1]] : null; };
  const b = at(sizes.base) || [0, 0];
  return sizes.list.flatMap((s) => { const m = at(s) || b; return [+((m[0] - b[0]) * k).toFixed(6), +((m[1] - b[1]) * k).toFixed(6)]; });
}

/** A RUL file's rules as entries ("<table> 7", or "<name> 7"). */
export function fromRul(text, name = '') {
  const r = parseRul(text);
  if (!r) return [];
  const base = r.sizes.includes(r.sample) ? r.sample : r.sizes[0];
  const bi = r.sizes.indexOf(base);
  const label = clean(name || r.name || 'RUL', 60);
  const out = [];
  for (const [n, pairs] of r.rules) {
    if (pairs.length < r.sizes.length) continue;
    const rule = r.sizes.flatMap((_, i) => [pairs[i][0] - pairs[bi][0], pairs[i][1] - pairs[bi][1]]);
    const e = cleanEntry({ name: label + ' ' + n, u: r.units.startsWith('ENG') ? 'in' : 'mm', sizes: r.sizes, base, rule });
    if (e) out.push(e);
  }
  return out;
}

const pairs = e.sizes.map((_, k) => [e.rule[2 * k], e.rule[2 * k + 1]]);
for (let k = 0; k < pairs.length; k += 4) L.push(pairs.slice(k, k + 4).map(([x, y]) => x.toFixed(2).padStart(9) + y.toFixed(2).padStart(9)).join(''));