/**
 * COMMS MODEL — the pure, Node-testable rules of data/comms.json.
 *
 * A comm is an EVENT with a sender: { id, from, type, trigger, text,
 * audio, once, delayMs }. This module normalizes the config (dropping —
 * with a console warning — anything that can't be shown) and answers
 * the two questions the hub asks:
 *
 *   - `commsForTrigger(cfg, trigger, played)` — which comms are DUE for
 *     an event (already-played `once` comms don't re-fire; a fresh run's
 *     empty played set is what lets the new-game welcome play);
 *   - `commAssets(cfg, comm)` — the deferred-load spec: the sender's
 *     character clip (by character id, so every comm from OAC shares one
 *     cached clip) and the speech clip (by file name, so a clip shared
 *     by several comms loads once).
 *
 * Pure: it takes the `comms` config SECTION (the object from
 * data/comms.json) — never the `config` singleton — so the dev tests
 * (dev/comms.test.mjs) can feed it plain JSON.
 *
 *   import { config } from '../config/Config.js';
 *   const cfg = config.section('comms', {});
 *   const due = commsForTrigger(cfg, 'newGame', playedSet);
 */

export const COMM_TYPES = ['ack', 'visual', 'audio'];

/** The scene-loader cache key for a character's clip: comms_vid_<id>. */
export function videoKeyFor(charId) {
  return `comms_vid_${String(charId)}`;
}

/**
 * The scene-loader cache key for a speech clip, derived from the FILE.
 * The key is the folder + basename (two comms sharing a clip share one
 * key; 'assets/speech/oac/intro-01.mp3' → 'comms_au_oac-intro-01'). The
 * folder is part of the key because TWO CHARACTERS may both ship an
 * 'intro-01.mp3' — the basename alone would make Trestle speak OAC's
 * clip (the loader would see the key as already loaded).
 */
export function audioKeyFor(file) {
  const parts = String(file ?? '')
    .split('/')
    .filter(Boolean);
  const base = (parts.pop() ?? '').replace(/\.[a-z0-9]+$/i, '');
  const dir = parts.length ? parts[parts.length - 1] : null;
  const safe = `${dir ? dir + '-' : ''}${base}`.replace(/[^a-z0-9_-]+/gi, '-');
  return `comms_au_${safe || 'speech'}`;
}

/** @returns {boolean} the master switch (a config predating comms defaults on). */
export function commsEnabled(cfg) {
  return cfg?.enabled !== false;
}

/**
 * The sender's entry (characters.<from>) or null (a comm with an unknown
 * sender is dropped by listComms — the box has no face to put on it).
 */
export function charEntry(cfg, from) {
  const chars = cfg?.characters;
  if (!chars || typeof chars !== 'object' || from == null) return null;
  const entry = chars[from];
  return entry && typeof entry === 'object' ? entry : null;
}

/**
 * Normalize one comm entry: returns a clean object, or null when the
 * entry can't be shown (with a console warning — the rest of the list
 * still plays).
 *
 * Rules:
 *   - type in ack|visual|audio (else the comm is unplayable);
 *   - trigger: a non-empty string (a comm that can't fire is dead weight);
 *   - from: must resolve to a character (the box needs its face);
 *   - text: required for ack|visual (a box with no words is noise) —
 *     optional for 'audio' (voice only);
 *   - audio: required for 'audio' (voice is the whole comm) — optional
 *     for ack|visual (a text-only comm is a valid comm);
 *   - once defaults true (comms don't repeat unless the author says so);
 *   - delayMs defaults 0 (clamped to >= 0).
 */
export function normalizeComm(raw) {
  if (!raw || typeof raw !== 'object') return null;
  const id = String(raw.id ?? '').trim();
  if (!id) return null;
  const type = String(raw.type ?? '').trim();
  if (!COMM_TYPES.includes(type)) {
    console.warn(`[comms] "${id}" has unknown type "${type}" (expected ${COMM_TYPES.join(' | ')}) — dropped`);
    return null;
  }
  const trigger = String(raw.trigger ?? '').trim();
  if (!trigger) {
    console.warn(`[comms] "${id}" has no trigger — dropped`);
    return null;
  }
  const from = String(raw.from ?? '').trim();
  const text = String(raw.text ?? '').trim();
  const audio = String(raw.audio ?? '').trim();
  if (!text && type !== 'audio') {
    console.warn(`[comms] "${id}" (${type}) has no text — dropped`);
    return null;
  }
  if (!audio && type === 'audio') {
    console.warn(`[comms] "${id}" (audio) has no speech clip — dropped`);
    return null;
  }
  return {
    id,
    from,
    type,
    trigger,
    text,
    audio: audio || null,
    once: raw.once !== false,
    delayMs: Math.max(0, Number(raw.delayMs) || 0),
  };
}

/**
 * The playable roster: the normalized comms in config order, minus the
 * ones whose sender has no character entry (warned per id).
 * @returns {Array<object>}
 */
export function listComms(cfg) {
  const list = Array.isArray(cfg?.comms) ? cfg.comms : [];
  const out = [];
  const seen = new Set();
  for (const raw of list) {
    const comm = normalizeComm(raw);
    if (!comm) continue;
    if (!charEntry(cfg, comm.from)) {
      console.warn(`[comms] "${comm.id}" speaks for unknown sender "${comm.from}" — dropped`);
      continue;
    }
    if (seen.has(comm.id)) {
      console.warn(`[comms] duplicate id "${comm.id}" — the first entry wins`);
      continue;
    }
    seen.add(comm.id);
    out.push(comm);
  }
  return out;
}

/**
 * The comm's deferred-load spec. The character clip is keyed BY CHARACTER
 * (every OAC comm shares one 185 KB clip); the speech clip BY FILE (a clip
 * reused across comms loads once).
 *
 * @returns {{video: {key:string,url:string}|null, audio: {key:string,url:string}|null}}
 */
export function commAssets(cfg, comm) {
  const entry = charEntry(cfg, comm.from);
  const videoUrl = String(entry?.video ?? '').trim();
  const audioUrl = String(comm.audio ?? '').trim();
  return {
    video: videoUrl ? { key: videoKeyFor(comm.from), url: videoUrl } : null,
    audio: audioUrl ? { key: audioKeyFor(audioUrl), url: audioUrl } : null,
  };
}

/**
 * The comms due for a trigger: the roster entries bound to it, in config
 * order, minus the ones already played (`once` comms the run has heard;
 * `once: false` comms re-arm on every trigger — the author's repeat).
 *
 * @param {object} cfg the comms config section
 * @param {string} trigger e.g. 'newGame'
 * @param {Set<string>} [played] the run's already-played ids (a save's ledger)
 * @returns {Array<object>} the normalized comms
 */
export function commsForTrigger(cfg, trigger, played = new Set()) {
  const name = String(trigger ?? '').trim();
  if (!name) return [];
  return listComms(cfg).filter((c) => c.trigger === name && !(c.once && played.has(c.id)));
}

/** The set of trigger names the roster uses (the dev tests + docs). */
export function triggersUsed(cfg) {
  return new Set(listComms(cfg).map((c) => c.trigger));
}