import * as cron from "node-cron";
import { createClient } from "@supabase/supabase-js";

const TMDB_API_BASE_URL = "https://api.themoviedb.org/3";
const REEL_POSTER_COUNT = 20;
// Over-fetch discover so cert-rejections / dedupe don't starve the final set.
const DISCOVER_FETCH_PAGES = 2;

// Mirror of PINNED_REEL_POSTERS in src/app/api/tmdb/reel-posters/route.ts.
// Keep in sync if either side changes.
const PINNED_REEL_POSTERS: ReelPoster[] = [
  {
    tmdb_id: 615,
    title: "The Passion of the Christ",
    poster_path: "/rBM5o2HpmCfDejuIPybI09tkY3V.jpg",
  },
];

// Pinned entries are an explicit editorial policy override: they bypass
// the PG-13-or-better cert filter at every layer they touch. The route
// layer already serves these unconditionally; this set is used in the
// cron to skip per-movie cert checks for the same titles.
const PINNED_TMDB_IDS = new Set<number>(PINNED_REEL_POSTERS.map((p) => p.tmdb_id));

// Inlined from src/lib/tmdb/certification.ts — the cron container builds
// standalone (cron/Dockerfile copies only index.ts), so we cannot import
// from src/. Keep in sync with that file.
const ALLOWED_CERTIFICATIONS: Record<string, string[]> = {
  US: ["G", "PG", "PG-13"],
  GB: ["U", "PG", "12", "12A"],
  DE: ["0", "6", "12"],
  FR: ["U", "10", "12"],
  AU: ["G", "PG", "M"],
  CA: ["G", "PG", "14A"],
  NL: ["AL", "6", "9", "12"],
  ES: ["A", "7", "12"],
  IT: ["T", "6+", "12+"],
  JP: ["G", "PG12"],
  KR: ["ALL", "12"],
  BR: ["L", "10", "12"],
  MX: ["AA", "A", "B"],
  IE: ["G", "PG", "12A"],
  SE: ["Btl", "7", "11"],
};

const DISCOVER_CERT_PARAMS: Record<string, string> = {
  certification_country: "US",
  "certification.lte": "PG-13",
  include_adult: "false",
};

interface TMDBReleaseDate {
  certification: string;
  iso_639_1: string;
  note: string;
  release_date: string;
  type: number;
}

interface TMDBReleaseDatesCountry {
  iso_3166_1: string;
  release_dates: TMDBReleaseDate[];
}

interface TMDBReleaseDatesResponse {
  results: TMDBReleaseDatesCountry[];
}

function isMovieAllowedByCert(releaseDates: TMDBReleaseDatesResponse | undefined | null): boolean {
  if (!releaseDates?.results?.length) return false;

  let sawRecognizedCert = false;
  let sawPositiveMatch = false;

  for (const country of releaseDates.results) {
    const allow = ALLOWED_CERTIFICATIONS[country.iso_3166_1];
    if (!allow) continue;

    for (const rd of country.release_dates ?? []) {
      const cert = (rd.certification ?? "").trim();
      if (!cert) continue;
      sawRecognizedCert = true;
      if (allow.includes(cert)) {
        sawPositiveMatch = true;
      } else {
        return false;
      }
    }
  }

  return sawRecognizedCert && sawPositiveMatch;
}

interface ReelPoster {
  tmdb_id: number;
  poster_path: string;
  title: string;
}

interface TMDBMovie {
  id: number;
  title: string;
  poster_path: string | null;
  adult: boolean;
}

interface TMDBDiscoverResponse {
  results: TMDBMovie[];
}

interface TMDBMovieDetails {
  id: number;
  title: string;
  poster_path: string | null;
  adult: boolean;
  release_dates?: TMDBReleaseDatesResponse;
}

const SUPABASE_URL = process.env.SUPABASE_URL;
const SUPABASE_SERVICE_ROLE_KEY = process.env.SUPABASE_SERVICE_ROLE_KEY;
const TMDB_API_KEY = process.env.TMDB_API_KEY;

function requireEnv(): { supabaseUrl: string; serviceKey: string; tmdbKey: string } {
  if (!SUPABASE_URL) throw new Error("SUPABASE_URL not set");
  if (!SUPABASE_SERVICE_ROLE_KEY) throw new Error("SUPABASE_SERVICE_ROLE_KEY not set");
  if (!TMDB_API_KEY) throw new Error("TMDB_API_KEY not set");
  return {
    supabaseUrl: SUPABASE_URL,
    serviceKey: SUPABASE_SERVICE_ROLE_KEY,
    tmdbKey: TMDB_API_KEY,
  };
}

async function tmdbGet<T>(
  tmdbKey: string,
  path: string,
  params: Record<string, string>,
): Promise<T> {
  const qs = new URLSearchParams(params);
  const res = await fetch(`${TMDB_API_BASE_URL}${path}?${qs.toString()}`, {
    headers: {
      Authorization: `Bearer ${tmdbKey}`,
      Accept: "application/json",
    },
  });
  if (!res.ok) {
    throw new Error(`TMDB ${path} request failed: ${res.status}`);
  }
  return (await res.json()) as T;
}

async function fetchTMDBDiscover(tmdbKey: string, page: number): Promise<TMDBMovie[]> {
  const data = await tmdbGet<TMDBDiscoverResponse>(tmdbKey, "/discover/movie", {
    language: "en-US",
    page: String(page),
    sort_by: "popularity.desc",
    ...DISCOVER_CERT_PARAMS,
  });
  // Server-side adult filter (defense in depth alongside include_adult=false).
  return data.results.filter((m) => !m.adult && m.poster_path);
}

/**
 * Per-movie cert check via /movie/{id}?append_to_response=release_dates.
 * Returns true iff TMDB confirms the title is PG-13-or-better.
 * Individual fetch failures are treated as "not allowed" (log + skip),
 * so a transient TMDB blip never lets a movie slip past the policy.
 */
async function isAllowedByCertCheck(tmdbKey: string, tmdbId: number): Promise<boolean> {
  // Pinned entries are an explicit editorial override — bypass the cert filter.
  if (PINNED_TMDB_IDS.has(tmdbId)) {
    console.log(`[cron] policy override: pinned tmdb_id=${tmdbId}`);
    return true;
  }
  try {
    const details = await tmdbGet<TMDBMovieDetails>(tmdbKey, `/movie/${tmdbId}`, {
      append_to_response: "release_dates",
    });
    if (details.adult) return false;
    return isMovieAllowedByCert(details.release_dates);
  } catch (err) {
    console.warn(
      `[${new Date().toISOString()}] Cert check failed for tmdb_id=${tmdbId}, skipping:`,
      err instanceof Error ? err.message : err,
    );
    return false;
  }
}

async function filterByCertConcurrent<T extends { tmdb_id: number }>(
  tmdbKey: string,
  items: T[],
): Promise<T[]> {
  const CONCURRENCY = 6;
  const results = new Array<boolean>(items.length);
  let cursor = 0;

  async function worker(): Promise<void> {
    while (true) {
      const i = cursor++;
      if (i >= items.length) return;
      results[i] = await isAllowedByCertCheck(tmdbKey, items[i].tmdb_id);
    }
  }

  await Promise.all(Array.from({ length: Math.min(CONCURRENCY, items.length) }, () => worker()));
  return items.filter((_, i) => results[i]);
}

async function refreshReelPosters(): Promise<void> {
  const { supabaseUrl, serviceKey, tmdbKey } = requireEnv();

  // 1. Pinned entries are an explicit editorial policy override and bypass
  //    the cert filter (see PINNED_TMDB_IDS in isAllowedByCertCheck). They
  //    are always inserted; each override is logged at filter time.
  const allowedPins = await filterByCertConcurrent(tmdbKey, PINNED_REEL_POSTERS);

  // 2. Fetch popular via discover with cert pre-filter, then belt-and-suspenders
  //    per-movie cert check (mirrors fetchAndFilterByCert in src/lib/tmdb/client.ts).
  const discoverMovies: TMDBMovie[] = [];
  for (let page = 1; page <= DISCOVER_FETCH_PAGES; page++) {
    discoverMovies.push(...(await fetchTMDBDiscover(tmdbKey, page)));
  }
  const discoverPosters: ReelPoster[] = discoverMovies.map((m) => ({
    tmdb_id: m.id,
    poster_path: m.poster_path!,
    title: m.title,
  }));
  const allowedDiscover = await filterByCertConcurrent(tmdbKey, discoverPosters);

  const seen = new Set<number>();
  const posters: ReelPoster[] = [];
  for (const p of [...allowedPins, ...allowedDiscover]) {
    if (seen.has(p.tmdb_id)) continue;
    seen.add(p.tmdb_id);
    posters.push(p);
    if (posters.length >= REEL_POSTER_COUNT) break;
  }

  if (posters.length === 0) {
    throw new Error("No posters resolved; aborting refresh to avoid wiping table");
  }

  const supabase = createClient(supabaseUrl, serviceKey, {
    auth: { persistSession: false, autoRefreshToken: false },
  });

  // Replace full set: delete-all then insert. Bi-weekly cadence makes this safe.
  const { error: delErr } = await supabase.from("landing_reel_posters").delete().gte("id", 0);
  if (delErr) throw new Error(`Delete failed: ${delErr.message}`);

  const { error: insErr } = await supabase.from("landing_reel_posters").insert(
    posters.map((p) => ({
      tmdb_id: p.tmdb_id,
      poster_path: p.poster_path,
      title: p.title,
    })),
  );
  if (insErr) throw new Error(`Insert failed: ${insErr.message}`);

  console.log(`[${new Date().toISOString()}] Reel refresh: wrote ${posters.length} posters`);
}

console.log("MovieDice cron service started");

// Refresh landing reel posters — bi-weekly on the 1st and 15th at 3:00 AM UTC.
// (PROJECT_SCOPE.md task 5.2 specifies bi-weekly cadence.)
cron.schedule("0 3 1,15 * *", async () => {
  console.log(`[${new Date().toISOString()}] Reel refresh: starting`);
  try {
    await refreshReelPosters();
    console.log(`[${new Date().toISOString()}] Reel refresh: complete`);
  } catch (err) {
    console.error(`[${new Date().toISOString()}] Reel refresh: failed`, err);
  }
});

// Refresh trailer URLs — daily at 4:00 AM UTC
cron.schedule("0 4 * * *", async () => {
  console.log(`[${new Date().toISOString()}] Trailer refresh: starting`);
  // TODO: re-validate trailer URLs for movies missing trailers.
  // When implemented: this stub does not touch TMDB. If it ever fetches new
  // movie metadata from TMDB, gate every result with isMovieAllowedByCert
  // (use append_to_response=release_dates as in refreshReelPosters).
  console.log(`[${new Date().toISOString()}] Trailer refresh: complete`);
});

// Refresh TMDB metadata — monthly on the 1st at 5:00 AM UTC
cron.schedule("0 5 1 * *", async () => {
  console.log(`[${new Date().toISOString()}] Metadata refresh: starting`);
  // TODO: refresh metadata for movies where metadata_refreshed_at > 30 days.
  // When implemented: re-check isMovieAllowedByCert on each refreshed title;
  // if a movie has fallen out of the allowlist, surface it to admin review
  // rather than silently keeping stale metadata.
  console.log(`[${new Date().toISOString()}] Metadata refresh: complete`);
});

// Run reel refresh once at startup if the table appears empty, so a fresh
// deploy doesn't have to wait up to two weeks for the first cron tick.
(async () => {
  try {
    const { supabaseUrl, serviceKey } = requireEnv();
    const supabase = createClient(supabaseUrl, serviceKey, {
      auth: { persistSession: false, autoRefreshToken: false },
    });
    const { count, error } = await supabase
      .from("landing_reel_posters")
      .select("id", { count: "exact", head: true });
    if (error) {
      console.error("Startup reel-table check failed:", error.message);
      return;
    }
    if ((count ?? 0) === 0) {
      console.log(
        `[${new Date().toISOString()}] Reel refresh: table empty at startup, running initial refresh`,
      );
      await refreshReelPosters();
    }
  } catch (err) {
    console.error("Startup reel-refresh check failed:", err);
  }
})();

// Keep the process alive
process.on("SIGTERM", () => {
  console.log("Received SIGTERM, shutting down cron service");
  process.exit(0);
});