import { createReadStream, createWriteStream } from 'node:fs';
import { readdir, unlink } from 'node:fs/promises';
import { extname, join } from 'node:path';
import { pipeline } from 'node:stream/promises';
import { createGzip } from 'node:zlib';

const EXTS = new Set(['.html', '.js', '.css', '.svg']);
const DIST = 'dist';

async function* walk(dir) {
  for (const entry of await readdir(dir, { withFileTypes: true })) {
    const full = join(dir, entry.name);
    if (entry.isDirectory()) {
      yield* walk(full);
    } else if (EXTS.has(extname(entry.name))) {
      yield full;
    }
  }
}

let count = 0;
for await (const file of walk(DIST)) {
  await pipeline(
    createReadStream(file),
    createGzip({ level: 9 }),
    createWriteStream(`${file}.gz`),
  );
  await unlink(file);
  count++;
  console.log(`  gzip  ${file}`);
}
console.log(`\nGzipped ${count} file${count === 1 ? '' : 's'}.`);