// « Info ouverture doc de réf. » (lot U3; Yvv, 2026-11-03: « un petit chapitre qui explicite les
// réglages initiaux de l'auteur, notamment Quorum et Inertie »): what the chapter says is read in
// the data of the document, never written in. Pure: the component only says it.

import type { DocView, Inertia, Unit } from './types';

/**
 * The level a module opened at: the one before the first change voted. A change of the seed's own
 * settings (an amendment, « réglage de départ du texte ») is the author's, part of the opening.
 */
export function openedAt(u: Unit): Inertia {
  const voted = u.inertiaChanges.find((c) => c.cause === 'vote');
  return voted?.from ?? u.inertia;
}

/** A Proposition d'amorce (ADR 0011): put forward by the seed, open or in force since. */
export function isAmorce(u: Unit): boolean {
  return [u.inForce, ...u.proposals].some((p) => p?.seedFeatured === true);
}

/** An article the seed wrote (the author's): not one a member proposed since. */
function fromSeed(u: Unit): boolean {
  return [u.inForce, ...u.proposals].some((p) => p?.origin === 'seed');
}

const levels = (units: (Unit | null | undefined)[]): Inertia[] =>
  [...new Set(units.filter((u): u is Unit => !!u).map(openedAt))].sort((a, b) => a - b);

export interface OpeningLevels {
  amorce: Inertia[];
  title: Inertia[];
  orders: Inertia[];
  others: Inertia[];
}

/** The levels at the opening, by kind of module, each said once, lowest first. */
export function openingLevels(view: Pick<DocView, 'units' | 'modules'>): OpeningLevels {
  const seeded = view.units.filter(fromSeed);
  return {
    amorce: levels(seeded.filter(isAmorce)),
    title: levels([view.modules.title]),
    orders: levels(view.modules.orders),
    others: levels(seeded.filter((u) => !isAmorce(u))),
  };
}

/** The quorum of each level, 1 to 5 (ADR 0013): said once when they are all the same. */
export function quorumsOf(quorums: number[] | undefined): { same: number | null; list: number[] } | null {
  if (!quorums?.length) return null;
  const first = quorums[0] ?? 0;
  return { same: quorums.every((q) => q === first) ? first : null, list: quorums };
}