import { createServer } from 'node:http'
import type { AddressInfo } from 'node:net'

/** Serves a `Request → Response` handler over a real socket (test helper). */
export async function serve(handle: (request: Request) => Promise<Response>): Promise<{ url: string; close: () => Promise<void> }> {
  const server = createServer(async (req, res) => {
    const chunks: Buffer[] = []
    for await (const chunk of req) chunks.push(chunk as Buffer)
    const response = await handle(
      new Request(`http://localhost${req.url}`, {
        method: req.method,
        headers: Object.entries(req.headers).flatMap(([name, value]) => (typeof value === 'string' ? [[name, value] as [string, string]] : [])),
        body: req.method === 'POST' ? Buffer.concat(chunks) : undefined,
      }),
    )
    res.writeHead(response.status, Object.fromEntries(response.headers))
    if (!response.body) return void res.end()
    const reader = response.body.getReader()
    res.on('close', () => void reader.cancel().catch(() => {}))
    for (let next = await reader.read(); !next.done; next = await reader.read()) res.write(next.value)
    res.end()
  })
  await new Promise<void>((resolve) => server.listen(0, '127.0.0.1', resolve))
  return {
    url: `http://127.0.0.1:${(server.address() as AddressInfo).port}`,
    close: () => new Promise((resolve) => (server.closeAllConnections(), server.close(() => resolve()))),
  }
}