#!/usr/bin/env node
/**
 * fetch-tmdb-art.mjs
 * ---------------------------------------------------------------------------
 * Support tool for the Movies and TV pages. For each favorite item (those with
 * `favorite: true`) in src/data/media/movies.json and src/data/media/tv.json
 * that is missing an `image`, it looks the title up on the TMDB API and
 * downloads the poster to public/images/<kind>/<slug>.jpg, then writes the
 * local public path back into the JSON.
 *
 * Idempotent: items that already have an `image` are skipped. Be gentle on TMDB
 * — there's a small delay between requests.
 *
 * PREREQUISITES
 *   1. Get a free TMDB API key: https://www.themoviedb.org/settings/api
 *   2. Put it in a `.env` file at the project root:
 *        TMDB_API_KEY=your_key_here
 *      (`.env` is gitignored; `.env.example` is the template.)
 *
 * USAGE
 *   node scripts/fetch-tmdb-art.mjs                  # fetch both movies + tv
 *   node scripts/fetch-tmdb-art.mjs --kind movies    # movies only
 *   node scripts/fetch-tmdb-art.mjs --kind tv        # tv only
 *   node scripts/fetch-tmdb-art.mjs --force          # re-fetch even if image set
 *   node scripts/fetch-tmdb-art.mjs --sleep 250      # ms between TMDB calls
 *   node scripts/fetch-tmdb-art.mjs --help
 *
 * Run with `--env-file=.env` to auto-load the key (Node 20.6+):
 *   node --env-file=.env scripts/fetch-tmdb-art.mjs
 */
import { mkdir, readFile, writeFile } from 'node:fs/promises';
import { dirname, join, resolve } from 'node:path';
import { fileURLToPath } from 'node:url';

const __dirname = dirname(fileURLToPath(import.meta.url));
const PROJECT_ROOT = resolve(__dirname, '..');
const DATA_DIR = join(PROJECT_ROOT, 'src', 'data', 'media');
const IMAGES_ROOT = join(PROJECT_ROOT, 'public', 'images');

const TMDB_BASE = 'https://api.themoviedb.org/3';
const TMDB_IMG = 'https://image.tmdb.org/t/p/w500';

// --- args -------------------------------------------------------------------
const args = process.argv.slice(2);
if (args.includes('-h') || args.includes('--help')) {
  console.log(`Usage: node scripts/fetch-tmdb-art.mjs [options]

Reads movies.json + tv.json favorites and fills in the "image" field for any
favorite missing one, using the TMDB API (free key required).

Options:
  --kind <k>     only fetch one kind: "movies" or "tv" (default: both)
  --force        re-fetch even for items that already have an image
  --sleep <ms>   delay between TMDB API calls (default 250)
  -h, --help     show this help

Tip: run with \`node --env-file=.env scripts/fetch-tmdb-art.mjs ...\` to auto-load
the TMDB_API_KEY from your .env file.`);
  process.exit(0);
}

const force = args.includes('--force');
const sleepMsIdx = args.indexOf('--sleep');
const sleepMs = sleepMsIdx !== -1 ? Number(args[sleepMsIdx + 1]) || 250 : 250;
const kindIdx = args.indexOf('--kind');
const kindFilter = kindIdx !== -1 ? args[kindIdx + 1] : null;
if (kindFilter && !['movies', 'tv'].includes(kindFilter)) {
  console.error(`✖ Unknown --kind "${kindFilter}". Use "movies" or "tv".`);
  process.exit(1);
}

const API_KEY = process.env.TMDB_API_KEY;
if (!API_KEY) {
  console.error(
    '✖ TMDB_API_KEY is not set. Add it to .env (see .env.example) and run with\n' +
      '  node --env-file=.env scripts/fetch-tmdb-art.mjs',
  );
  process.exit(1);
}

// --- helpers ----------------------------------------------------------------
const sleep = (ms) => new Promise((r) => setTimeout(r, ms));

const slugify = (s) =>
  s
    .toLowerCase()
    .replace(/['’.:()]/g, '')
    .replace(/[^a-z0-9]+/g, '-')
    .replace(/^-+|-+$/g, '');

/** Search TMDB for a title, returning the best result's poster path. */
async function fetchPoster(title, kind, year) {
  const mediaType = kind === 'movies' ? 'movie' : 'tv';
  const params = new URLSearchParams({
    api_key: API_KEY,
    query: title,
    include_adult: 'false',
  });
  if (year) {
    // TMDB uses different year param names per type.
    params.set(mediaType === 'movie' ? 'year' : 'first_air_date_year', String(year));
  }
  const url = `${TMDB_BASE}/search/${mediaType}?${params}`;
  const res = await fetch(url);
  if (res.status === 429) {
    console.warn('  ! rate-limited by TMDB (429). Wait and re-run; skipping rest.');
    return { rateLimited: true };
  }
  if (!res.ok) throw new Error(`search ${res.status} ${res.statusText}`);
  const data = await res.json();
  const result = data.results?.find((r) => r.poster_path) ?? data.results?.[0];
  if (!result?.poster_path) return null;
  return { posterPath: result.poster_path, name: result.title ?? result.name };
}

// --- per-kind processing ----------------------------------------------------
async function processKind(kind) {
  const DATA_FILE = join(DATA_DIR, `${kind}.json`);
  const OUT_DIR = join(IMAGES_ROOT, kind);
  const PUBLIC_PREFIX = `/images/${kind}`;

  let items;
  try {
    items = JSON.parse(await readFile(DATA_FILE, 'utf8'));
  } catch (err) {
    if (err?.code === 'ENOENT') {
      console.warn(`  ! ${DATA_FILE} not found; skipping ${kind}.`);
      return;
    }
    throw err;
  }

  const favorites = items.filter((i) => i.favorite);
  console.log(
    `\n→ ${kind}: ${favorites.length} favorite(s) in ${kind}.json` +
      (force ? ' (force re-fetch)' : ''),
  );

  await mkdir(OUT_DIR, { recursive: true });
  let changed = false;

  for (let i = 0; i < favorites.length; i++) {
    const item = favorites[i];
    if (item.image && !force) {
      console.log(`  ✓ ${item.title} — already has image, skipping.`);
      continue;
    }
    if (i > 0) await sleep(sleepMs);

    console.log(`→ [${i + 1}/${favorites.length}] ${item.title}`);
    let result;
    try {
      result = await fetchPoster(item.title, kind, item.year);
    } catch (err) {
      console.warn(`  ! network error: ${err?.message ?? err}; skipping.`);
      continue;
    }
    if (result?.rateLimited) break;
    if (!result?.posterPath) {
      console.warn(`  ! no poster found for "${item.title}"; skipping.`);
      continue;
    }

    const imageUrl = `${TMDB_IMG}${result.posterPath}`;
    const fileName = `${slugify(item.title)}.jpg`;
    let buf;
    try {
      const imgRes = await fetch(imageUrl);
      if (!imgRes.ok) throw new Error(`${imgRes.status} ${imgRes.statusText}`);
      buf = Buffer.from(await imgRes.arrayBuffer());
    } catch (err) {
      console.warn(`  ! image download failed (${err?.message ?? err}); skipping.`);
      continue;
    }
    await writeFile(join(OUT_DIR, fileName), buf);
    item.image = `${PUBLIC_PREFIX}/${fileName}`;
    // Write the path back onto the original array entry (same object reference).
    const orig = items.find((o) => o.title === item.title && o.favorite);
    if (orig) orig.image = item.image;
    changed = true;
    console.log(`  ✔ ${item.title} → ${item.image}`);
  }

  if (changed) {
    await writeFile(DATA_FILE, JSON.stringify(items, null, 2) + '\n', 'utf8');
    console.log(`✔ Updated ${DATA_FILE}`);
  } else {
    console.log(`— Nothing to update for ${kind} (all favorites already had images).`);
  }
}

// --- main -------------------------------------------------------------------
const kinds = kindFilter ? [kindFilter] : ['movies', 'tv'];
for (const k of kinds) {
  await processKind(k);
}