#!/usr/bin/env node
// 持久下载缓存可以保留旧版本；交付给 CI 镜像的快照只带当前 lock 已下载的包。
import fs from 'node:fs/promises';
import { createRequire } from 'node:module';
import path from 'node:path';
import { pipeline } from 'node:stream/promises';

const [npmRoot, lockPath, source, destination] = process.argv.slice(2);
if (!npmRoot || !lockPath || !source || !destination) {
  throw new Error(
    'usage: export-ci-npm-download-cache.mjs <npm-root> <lock> <source> <destination>',
  );
}
const require = createRequire(path.resolve(npmRoot, 'package.json'));
const cacache = require('cacache');
const lock = JSON.parse(await fs.readFile(lockPath, 'utf8'));
const integrities = new Set(
  Object.values(lock.packages).flatMap((entry) =>
    typeof entry.integrity === 'string' ? [entry.integrity] : [],
  ),
);
let count = 0;
for await (const entry of cacache.ls.stream(source)) {
  if (!integrities.has(entry.integrity)) continue;
  await pipeline(
    cacache.get.stream(source, entry.key, { integrity: entry.integrity }),
    cacache.put.stream(destination, entry.key, {
      integrity: entry.integrity,
      metadata: entry.metadata,
    }),
  );
  count += 1;
}
console.log(
  `[ci-image] exported ${count} npm cache entries for the current lock`,
);