import { describe, it } from 'node:test';
import assert from 'node:assert/strict';
import { once } from 'node:events';
import { createServer, connect } from 'node:net';
import { Worker } from 'node:worker_threads';

describe('fd-passing spike', () => {
  it('fd extracted on main and reconstructed as net.Socket on a worker thread', { timeout: 5000 }, async () => {
    // Spawn worker with an inline string source
    const workerCode = `
      const { parentPort } = require('node:worker_threads');
      const { Socket } = require('node:net');
      parentPort.on('message', ({ fd }) => {
        const sock = new Socket({ fd, readable: true, writable: true });
        sock.setNoDelay(true);
        sock.write('hello\\n');
        sock.end();
      });
    `;
    const worker = new Worker(workerCode, { eval: true });

    // Main TCP server
    const server = createServer();
    server.on('connection', (socket: any) => {
      const handle = socket._handle;
      const fd: number = handle.fd;
      // Deregister libuv's read interest; no-op close to preserve the fd.
      handle.readStop();
      handle.close = (cb: any) => {
        if (cb) cb();
      };
      socket._handle = null;
      socket.destroy();
      worker.postMessage({ fd });
    });
    server.listen(0);
    await once(server, 'listening');
    const port = (server.address() as any).port;

    // Client connects, reads the reply
    const client = connect(port);
    const chunks: Buffer[] = [];
    client.on('data', (c) => chunks.push(Buffer.isBuffer(c) ? c : Buffer.from(c)));
    await once(client, 'end');

    assert.equal(Buffer.concat(chunks).toString('utf8'), 'hello\n');

    server.close();
    await worker.terminate();
  });
});