import { once } from 'node:events'
import { createServer } from 'node:http2'
import { setTimeout as sleep } from 'node:timers/promises'
import { H2CClient } from 'undici'

let active = 0
let maxActive = 0

const server = createServer({
  settings: { maxConcurrentStreams: 1 }
})

server.on('stream', async (stream) => {
  active++
  maxActive = Math.max(maxActive, active)

  stream.respond({ ':status': 200 })

  await sleep(100)
  active--
  stream.end('ok')
})

server.listen(0)
await once(server, 'listening')

const client = new H2CClient(`http://localhost:${server.address().port}`, {
  maxConcurrentStreams: 10,
  pipelining: 10
})

const results = await Promise.allSettled(Array.from({ length: 5 }, async (_, i) => {
  const res = await client.request({ path: `/${i}`, method: 'GET' })
  return { statusCode: res.statusCode, body: await res.body.text() }
}))

console.log(results.map((result) => {
  if (result.status === 'fulfilled') {
    return `fulfilled ${result.value.statusCode} ${result.value.body}`
  }

  return `rejected ${result.reason.message}`
}))

console.log({ maxActive })

await client.close()
server.close()