// @ts-check

import { join } from 'node:path';
import { workerData } from 'node:worker_threads';
import { readdir, unlink, readFile } from 'node:fs/promises';

const directory = workerData.directory;
const pruneIntervalInMs = workerData.pruneInterval;

/**
 * Read the file content and delete it if it's expired
 *
 * @param {string} filePath
 */
async function deleteFileIfExpired(filePath: string) {
  const content = await readFile(filePath, 'utf-8');
  const [, expiresAt] = JSON.parse(content);

  const expiry = new Date(expiresAt).getTime();
  if (+expiry === -1) return;

  if (expiry < Date.now()) {
    await unlink(filePath);
  }
}

/**
 * Get recursive list of files in the cache directory and delete expired files
 */
async function prune() {
  const dirEntries = await readdir(directory, { recursive: true, withFileTypes: true });

  for (const dirEntry of dirEntries) {
    if (dirEntry.isDirectory()) continue;

    const filePath = join(dirEntry.path, dirEntry.name);
    await deleteFileIfExpired(filePath).catch((error) => {
      console.error('[mastercache] file cleaner worker error', error);
    });
  }
}

setInterval(async () => {
  try {
    await prune();
  } catch (error) {
    console.error('[mastercache] file cleaner worker error', error);
  }
}, pruneIntervalInMs);