import { writeFileSync } from "node:fs";
import { prisma } from "@streamclipper/db";
import { env } from "./env";

const LEGACY_COOKIES_PATH = "/tmp/yt-cookies.txt";
const LEGACY_COOKIES_SETTING_KEY = "ytdlp_cookies";

// Oxylabs' static ISP pool: one dedicated (non-rotating) IP per port,
// confirmed against the dashboard's Proxy list (isp.oxylabs.io:8001..8010 ->
// 10 distinct IPs). PROXY_URL's own port is the base; funneling every
// channel through that single port meant 7-8 simultaneous channels' worth
// of YouTube-facing traffic all looked like it came from one IP.
const PROXY_PORT_POOL_SIZE = 10;

function simpleHash(input: string): number {
  let hash = 0;
  for (let i = 0; i < input.length; i++) {
    hash = (hash * 31 + input.charCodeAt(i)) >>> 0;
  }
  return hash;
}

/** Deterministically pins a channel to one of the pool's ports — same channel always gets the same IP (so it isn't mid-session IP-mismatched against a live URL signed for a different one), different channels spread across the pool. */
function proxyUrlForChannel(baseProxyUrl: string, channelKey: string): string {
  const match = baseProxyUrl.match(/^(.*:)(\d+)$/);
  if (!match) return baseProxyUrl;
  const [, prefix, basePortStr] = match;
  const basePort = Number(basePortStr);
  const offset = simpleHash(channelKey) % PROXY_PORT_POOL_SIZE;
  return `${prefix}${basePort + offset}`;
}

/**
 * Picks which cookie profile a channel uses (same deterministic-hash
 * pinning as proxyUrlForChannel — same channel always gets the same
 * account, different channels spread across the pool) and writes it to a
 * profile-specific temp file. Falls back to the old single global
 * ytdlp_cookies AppSetting if no profiles have been added yet, so nothing
 * breaks before the panel's Settings page is used to add accounts.
 *
 * A single shared cookie file was a real bottleneck once several channels
 * were active at once: it isn't just proxy IP reputation that YouTube can
 * flag, it's the *account* — one Google session making requests that look
 * like it's scanning many unrelated channels trips its own abuse signal,
 * independent of which IP each request came from. Splitting across
 * separate throwaway accounts dilutes that per-account signal the same way
 * the proxy pool dilutes per-IP signal.
 *
 * Profile-specific file paths (not one shared /tmp/yt-cookies.txt) matter
 * once multiple channels can be using *different* profiles concurrently —
 * a shared path would let one channel's capture process read a file another
 * channel's poll check just overwrote with a different account's cookies.
 */
async function cookiesFilePathForChannel(channelKey: string): Promise<string | null> {
  const profiles = await prisma.cookieProfile.findMany({ orderBy: { createdAt: "asc" } });

  if (profiles.length === 0) {
    const legacy = await prisma.appSetting.findUnique({ where: { key: LEGACY_COOKIES_SETTING_KEY } });
    if (!legacy?.value) return null;
    writeFileSync(LEGACY_COOKIES_PATH, legacy.value, { mode: 0o600 });
    return LEGACY_COOKIES_PATH;
  }

  const profile = profiles[simpleHash(channelKey) % profiles.length];
  const path = `/tmp/yt-cookies-${profile.id}.txt`;
  writeFileSync(path, profile.value, { mode: 0o600 });
  return path;
}

/**
 * YouTube's anti-bot layer against yt-dlp has three parts, all needed
 * together: a "Sign in to confirm you're not a bot" wall (avoided with an
 * authenticated session's cookies), a "The page needs to be reloaded"
 * proof-of-origin token check (avoided by querying the bgutil-ytdlp-pot-
 * provider sidecar — see docker-compose.yml sc_pot_provider), and — once the
 * Coolify server's own IP had a day of heavy testing behind it — outright
 * blocking tied to that IP's reputation specifically (avoided by routing
 * through a clean residential/ISP proxy, PROXY_URL).
 *
 * Cookies rotate/expire over hours, so they're stored in the DB (updated
 * from the panel's Settings page — see apps/frontend/app/settings) rather
 * than baked in at container start from an env var. Every call re-reads the
 * current value and rewrites the temp file, so a panel update takes effect
 * on the very next yt-dlp invocation without a redeploy.
 */
export async function ytdlpAntiBotArgs(
  channelKey: string,
  { includeAndroidClient = true }: { includeAndroidClient?: boolean } = {},
): Promise<string[]> {
  const args: string[] = [];

  const cookiesPath = await cookiesFilePathForChannel(channelKey);
  if (cookiesPath) {
    args.push("--cookies", cookiesPath);
  }

  if (env.ytdlpPotProviderUrl) {
    args.push("--extractor-args", `youtubepot-bgutilhttp:base_url=${env.ytdlpPotProviderUrl}`);
  }

  // Büyük/popüler kanallarda (ör. NASA, çok izleyicili yayınlar) sade "web"
  // client'ı cookie+PO-token kombinasyonuna rağmen "Sign in to confirm
  // you're not a bot" ile tıkanabiliyor — küçük kanallarda aynı kombinasyon
  // sorunsuz çalışıyor. mweb/android'i cookie-uyumlu fallback olarak
  // ekleyip yt-dlp'nin ilk başarılı client'ı kullanmasını sağlıyoruz.
  //
  // Ama "android" client'ı yt-dlp'nin kendi GitHub issue'larında birden
  // fazla kez videoplayback/segment isteklerinde 403 Forbidden'a sebep
  // olarak raporlanmış — sade metadata/tespit isteğinde (--simulate, format
  // çözümlemesi yok) risk taşımıyor ama gerçek segment indirimi sırasında
  // (asıl capture) bu 403'lerin kaynağı olabilir. O yüzden capture çağrısı
  // android'i devre dışı bırakıyor, sadece tespit çağrısı kullanıyor.
  const clients = includeAndroidClient ? "web,mweb,android" : "web,mweb";
  args.push("--extractor-args", `youtube:player_client=${clients}`);

  if (env.proxyUrl) {
    args.push("--proxy", proxyUrlForChannel(env.proxyUrl, channelKey));
  }

  return args;
}