// In-memory registry of tournaments. Every mutation goes through `mutate()`, which
// persists the new state and notifies subscribers (the WebSocket layer) with the public view.
import { Tournament } from '../engine/tournament.js';
import { CourtEngine } from '../engine/courts.js';
import { publicState } from './public-state.js';

const slugify = s => String(s).toLowerCase().replace(/[^a-z0-9]+/g, '-').replace(/^-|-$/g, '').slice(0, 40) || 'tournament';

export class Registry {
  constructor(store) {
    this.store = store;
    this.items = new Map(); // slug -> { t, engine }
    this.subscribers = new Map(); // slug -> Set<fn(state)>
    for (const row of store.loadAll()) {
      const t = Tournament.fromJSON(row.tournament);
      t.slug = row.slug;
      const engine = row.engine ? CourtEngine.fromJSON(t, row.engine) : new CourtEngine(t, { courtCount: t.courtCount });
      this._attach(row.slug, t, engine);
      // Re-run bye settling on load: a tournament saved by an older version may have bracket slots
      // that could never be filled (the 18-team double-elim case). Cheap and idempotent.
      if (t.matches.some(m => m.stage !== 'pool') && t.phase !== 'final') {
        const before = JSON.stringify(t.matches.map(m => [m.status, m.teamA, m.teamB]));
        t.settleByes(); t._checkComplete();
        if (t.phase === 'live') engine.tick();
        if (before !== JSON.stringify(t.matches.map(m => [m.status, m.teamA, m.teamB]))) { console.log(`[load] ${row.slug}: settled bracket byes`); this.persist(row.slug); }
      }
    }
  }

  list() { return [...this.items.entries()].map(([slug, { t }]) => ({ slug, name: t.name, date: t.date, phase: t.phase, teams: t.activeTeams().length, createdAt: t.createdAt })); }
  get(slug) { return this.items.get(slug) ?? null; }

  create({ name, date, courtCount = 2, rules = {}, stages = ['pool', 'bracket'], notes = '', timezone = null, slug: wanted = null }) {
    const base = slugify(wanted ?? name);
    let slug = base, n = 2;
    while (this.items.has(slug)) slug = `${base}-${n++}`;
    const t = new Tournament({ name, courtCount: Number(courtCount), rules, stages });
    t.slug = slug; t.date = date || null; t.notes = notes; t.timezone = timezone || null; t.createdAt = Date.now();
    const engine = new CourtEngine(t, { courtCount: t.courtCount });
    this._attach(slug, t, engine);
    this.persist(slug);
    return this.items.get(slug);
  }

  remove(slug) { this.items.delete(slug); this.subscribers.delete(slug); this.store.remove(slug); }

  _attach(slug, t, engine) {
    this.items.set(slug, { t, engine });
    t.on(evt => { try { this.store.logEvent(slug, evt); } catch { /* audit log is best-effort */ } });
  }

  /** Run fn against a tournament, then persist and broadcast. Throws propagate to the caller. */
  mutate(slug, fn) {
    const item = this.get(slug);
    if (!item) throw new Error('No such tournament');
    const result = fn(item.t, item.engine);
    // keep the queue/on-deck fresh after any change during live play
    if (item.t.phase === 'live') item.engine.tick();
    this.persist(slug);
    this.notify(slug);
    return result;
  }

  persist(slug) {
    const { t, engine } = this.get(slug);
    this.store.save(slug, t.toJSON(), engine.toJSON());
  }

  subscribe(slug, fn) {
    if (!this.subscribers.has(slug)) this.subscribers.set(slug, new Set());
    this.subscribers.get(slug).add(fn);
    return () => this.subscribers.get(slug)?.delete(fn);
  }

  notify(slug) {
    const subs = this.subscribers.get(slug);
    if (!subs?.size) return;
    const state = publicState(this.get(slug));
    for (const fn of subs) { try { fn(state); } catch { /* a dead socket must not break the others */ } }
  }
}