import { randomUUID } from "node:crypto";

import { getRedisClient, redisEventPrefix } from "@/lib/redis/client";

const LOCK_TTL_MS = 120_000;
const RENEW_INTERVAL_MS = 30_000;

const renewScript = `
if redis.call("get", KEYS[1]) == ARGV[1] then
  return redis.call("pexpire", KEYS[1], ARGV[2])
end
return 0
`;

const releaseScript = `
if redis.call("get", KEYS[1]) == ARGV[1] then
  return redis.call("del", KEYS[1])
end
return 0
`;

export class CatalogSyncBusyError extends Error {
  constructor() {
    super("กำลัง Sync Catalog อยู่");
    this.name = "CatalogSyncBusyError";
  }
}

export async function withCatalogSyncLock<T>(
  task: () => Promise<T>,
): Promise<T> {
  const redis = await getRedisClient();
  const key = `${redisEventPrefix()}:catalog-sync-lock`;
  const token = randomUUID();
  const acquired = await redis.set(key, token, "PX", LOCK_TTL_MS, "NX");
  if (acquired !== "OK") throw new CatalogSyncBusyError();

  let renewing = false;
  const timer = setInterval(() => {
    if (renewing) return;
    renewing = true;
    void redis
      .eval(renewScript, 1, key, token, String(LOCK_TTL_MS))
      .catch(() => undefined)
      .finally(() => {
        renewing = false;
      });
  }, RENEW_INTERVAL_MS);
  timer.unref();

  try {
    return await task();
  } finally {
    clearInterval(timer);
    await redis.eval(releaseScript, 1, key, token).catch(() => undefined);
  }
}