// Recherche / channel / trending YouTube SANS clé API via yt-dlp (Step 17 P1).
// Binaire résolu via YT_DLP_PATH > PATH. Jamais de secret en log.
import { execFile as execFileCb } from 'node:child_process';
import { promisify } from 'node:util';
import { getYtDlpTimeoutMs, buildYtDlpExtraArgs, resolveYtDlpBin } from './youtube-common.mjs';

const execFileAsync = promisify(execFileCb);

/**
 * Normalise une entrée yt-dlp flat-playlist vers Suggestion (même contrat que youtube.mjs).
 * @param {any} e entrée yt-dlp
 */
export function mapFlatEntry(e) {
  if (!e || typeof e !== 'object') return null;
  const id = e.id || e.display_id || null;
  if (!id) return null;
  const thumbs = Array.isArray(e.thumbnails) ? e.thumbnails : [];
  const thumb = thumbs.length
    ? (thumbs.find((t) => t?.url && (t.height || 0) >= 360)?.url || thumbs[thumbs.length - 1]?.url)
    : (e.thumbnail || undefined);
  const duration = e.duration != null ? Number(e.duration) : undefined;
  const views = e.view_count != null ? Number(e.view_count) : (e.views != null ? Number(e.views) : undefined);
  const channelId = e.channel_id || e.uploader_id || undefined;
  const uploaderName = e.channel || e.uploader || undefined;
  return {
    title: e.title || '',
    id: String(id),
    url: String(id).startsWith('http') ? String(id) : `https://www.youtube.com/watch?v=${id}`,
    thumbnail: thumb,
    uploaderName,
    type: 'video',
    ...(Number.isFinite(duration) && duration > 0 ? { duration } : {}),
    ...(Number.isFinite(views) ? { views } : {}),
    ...(e.timestamp ? { publishedAt: new Date(Number(e.timestamp) * 1000).toISOString() } : {}),
    ...(channelId ? { channelId: String(channelId), channelExternalId: String(channelId), channelUrl: `https://www.youtube.com/channel/${channelId}` } : {}),
    ...(uploaderName ? { channelHandle: String(uploaderName) } : {}),
  };
}

/** Parse le JSON de `yt-dlp --dump-single-json --flat-playlist` (objet ou NDJSON fog). */
export function parseFlatPlaylistJson(raw) {
  try {
    const text = String(raw || '').trim();
    if (!text) return [];
    // Cas standard : un seul objet JSON avec .entries
    try {
      const obj = JSON.parse(text);
      const entries = Array.isArray(obj?.entries) ? obj.entries : (Array.isArray(obj) ? obj : []);
      return entries.map(mapFlatEntry).filter(Boolean);
    } catch {
      // Fallback NDJSON (une ligne = un JSON)
      const out = [];
      for (const line of text.split('\n')) {
        const t = line.trim();
        if (!t) continue;
        try {
          const o = JSON.parse(t);
          const m = mapFlatEntry(o);
          if (m) out.push(m);
        } catch {}
      }
      return out;
    }
  } catch { return []; }
}

export function classifyScrapeError(e) {
  if (e?.code === 'yt_scrape_no_binary') return e;
  const msg = String(e?.message || e || '');
  if (/ENOENT/i.test(msg) || e?.code === 'ENOENT' || e?.errno === 'ENOENT') {
    return Object.assign(
      new Error('yt-dlp introuvable (ni PATH ni bundled). Installez yt-dlp ou définissez YT_DLP_PATH.'),
      { ytStatus: 503, code: 'yt_scrape_no_binary' },
    );
  }
  if (/bot|sign in to confirm|challenge|cookies|login/i.test(msg)) {
    return Object.assign(new Error('YouTube bot-check (cookies/PO-Token requis)'), { ytStatus: 502, code: 'yt_scrape_bot_check' });
  }
  if (/timed out|timeout|ETIMEDOUT|killed|SIGKILL/i.test(msg)) {
    return Object.assign(new Error('YouTube scrape timeout'), { ytStatus: 504, code: 'yt_scrape_timeout' });
  }
  if (/unable to|unsupported|not available|private|deleted/i.test(msg)) {
    return Object.assign(new Error(`YouTube scrape upstream: ${msg.slice(0, 160)}`), { ytStatus: 502, code: 'yt_scrape_upstream' });
  }
  return Object.assign(new Error(`YouTube scrape failed: ${msg.slice(0, 200)}`), { ytStatus: 502, code: 'yt_scrape_failed' });
}

async function runYtDlpFlat(queryOrUrl, { limit = 10, playlistStart = 1 } = {}) {
  const bin = await resolveYtDlpBin();
  const timeout = getYtDlpTimeoutMs();
  const end = playlistStart + Math.max(1, Math.min(50, Number(limit || 10))) - 1;
  const args = [
    '--dump-single-json',
    '--flat-playlist',
    '--no-warnings',
    '--no-check-certificates',
    '--skip-download',
    '--no-playlist',
    '--playlist-start', String(playlistStart),
    '--playlist-end', String(end),
    ...buildYtDlpExtraArgs(),
    queryOrUrl,
  ];
  try {
    const { stdout } = await execFileAsync(bin, args, { timeout, maxBuffer: 16 * 1024 * 1024 });
    return parseFlatPlaylistJson(stdout);
  } catch (e) {
    // yt-dlp peut écrire du JSON partiel sur stdout même en exit non-zero
    const partial = e?.stdout ? parseFlatPlaylistJson(String(e.stdout)) : [];
    if (partial.length) return partial;
    throw classifyScrapeError(e);
  }
}

/** Recherche sans clé. sort: relevance|date|views */
export async function searchViaScrape(q, opts = {}) {
  const query = String(q || '').trim();
  if (query.length < 2) return [];
  const limit = Math.min(50, Math.max(1, Number(opts?.limit || 10)));
  const page = Math.max(1, Number(opts?.page || 1));
  const sort = String(opts?.sort || 'relevance').toLowerCase();
  const perPage = limit;
  const start = (page - 1) * perPage + 1;
  let prefix = 'ytsearch';
  if (sort === 'date') prefix = 'ytsearchdate';
  // views : pas de préfixe natif stable -> ytsearch + tri local
  const target = `${prefix}${perPage}:${query}`;
  let items = await runYtDlpFlat(target, { limit: perPage, playlistStart: start });
  if (sort === 'views') items = [...items].sort((a, b) => (b.views || 0) - (a.views || 0));
  return items.slice(0, perPage);
}

const CHANNEL_TABS = { videos: 'videos', shorts: 'shorts', streams: 'streams', live: 'streams', playlists: 'playlists' };

/** Contenu chaîne sans clé. type: videos|shorts|playlists|live */
export async function fetchChannelViaScrape(externalId, { type = 'videos', page = 1, limit = 24 } = {}) {
  const raw = String(externalId || '').trim().replace(/^@/, '');
  if (!raw) return { items: [], nextPage: null };
  const tab = CHANNEL_TABS[String(type)] || 'videos';
  const perPage = Math.min(50, Math.max(1, Number(limit || 24)));
  const pageNum = Math.max(1, Number(page || 1));
  const start = (pageNum - 1) * perPage + 1;
  // UC... -> /channel/UC.../tab, sinon -> /@/handle/tab
  const base = /^UC[\w-]{20,}$/.test(raw)
    ? `https://www.youtube.com/channel/${raw}/${tab}`
    : `https://www.youtube.com/@${raw}/${tab}`;
  const items = await runYtDlpFlat(base, { limit: perPage, playlistStart: start });
  // playlists renvoient des ids PL... : on les garde tels quels avec un shape playlist
  if (tab === 'playlists') {
    const mapped = items.map((s) => ({ id: s.id, title: s.title, thumbnail: s.thumbnail, videoCount: null, updatedAt: s.publishedAt || null }));
    return { items: mapped, nextPage: items.length >= perPage ? pageNum + 1 : null };
  }
  let filtered = items;
  if (type === 'shorts') filtered = items.filter((s) => !s.duration || s.duration <= 70);
  return { items: filtered, nextPage: items.length >= perPage ? pageNum + 1 : null };
}

/** Trending sans clé. Les onglets /feed/trending ont été retirés côté YouTube
 *  (redirect home -> erreur tab) ; on tente les tabs puis repli ytsearch trié par vues. */
export async function getTrendingViaScrape(limit = 24) {
  const n = Math.min(50, Math.max(1, Number(limit || 24)));
  const tabs = [
    'https://www.youtube.com/feed/trending',
    'https://www.youtube.com/trending',
  ];
  for (const url of tabs) {
    try {
      const items = await runYtDlpFlat(url, { limit: n, playlistStart: 1 });
      if (items.length) return items;
    } catch {}
  }
  // Repli : recherche générique triée par vues (0 quota, toujours disponible)
  return runYtDlpFlat(`ytsearch${n}:top trending videos world`, { limit: n, playlistStart: 1 });
}

/** Résout un channel_id via scrape (imprime channel_id sans appel API). */
export async function resolveChannelIdViaScrape(externalId) {
  const raw = String(externalId || '').trim();
  if (/^UC[\w-]{20,}$/.test(raw)) return raw;
  const handle = raw.replace(/^@/, '');
  const bin = await resolveYtDlpBin().catch(() => null);
  if (!bin) {
    throw Object.assign(
      new Error('yt-dlp introuvable (ni PATH ni bundled). Installez yt-dlp ou définissez YT_DLP_PATH.'),
      { ytStatus: 503, code: 'yt_scrape_no_binary' },
    );
  }
  const timeout = Math.min(15000, getYtDlpTimeoutMs());
  try {
    const { stdout } = await execFileAsync(bin,
      ['--print', '%(channel_id)s', '--no-warnings', '--skip-download', '--playlist-end', '1', ...buildYtDlpExtraArgs(), `https://www.youtube.com/@${handle}/videos`],
      { timeout });
    const id = String(stdout || '').trim().split('\n')[0].trim();
    if (/^UC[\w-]{20,}$/.test(id)) return id;
  } catch {}
  return raw;
}