import { test } from '@japa/runner'
import { delimitedReader } from '#lib/nntp/delimited_reader'

const CRLF = Buffer.from('\r\n')
const END = Buffer.from('\r\n.\r\n')

async function* chunks(...parts: string[]) {
  for (const part of parts) yield Buffer.from(part, 'latin1')
}

test.group('nntp / delimitedReader', () => {
  test('reads an empty multi-line reply (XOVER of a range without articles)', async ({ assert }) => {
    const reader = delimitedReader(chunks('224 Overview follows\r\n.\r\n', '211 1 2 3 g\r\n'), CRLF)
    assert.equal((await reader.next()).value!.toString(), '224 Overview follows')
    assert.equal((await reader.next(END)).value!.toString(), '')
    assert.equal((await reader.next(CRLF)).value!.toString(), '211 1 2 3 g')
  })

  test('reads multi-line data, also with the terminator split over chunks', async ({ assert }) => {
    for (const split of [1, 2, 3, 4, 5, 6, 7]) {
      const reply = '224 ok\r\nline 1\r\n..dotted\r\nline 3\r\n.\r\n200 next\r\n'
      const at = reply.indexOf('.\r\n200') - 2 + split - 1
      const reader = delimitedReader(chunks(reply.slice(0, at), reply.slice(at)), CRLF)
      assert.equal((await reader.next()).value!.toString(), '224 ok')
      assert.equal((await reader.next(END)).value!.toString(), 'line 1\r\n..dotted\r\nline 3', `split ${split}`)
      assert.equal((await reader.next(CRLF)).value!.toString(), '200 next')
    }
  })

  test('reads replies byte by byte', async ({ assert }) => {
    const text = '200 welcome\r\n224 ok\r\na\r\n.\r\n224 ok\r\n.\r\n211 x\r\n'
    const reader = delimitedReader(chunks(...text.split('')), CRLF)
    assert.equal((await reader.next()).value!.toString(), '200 welcome')
    assert.equal((await reader.next(CRLF)).value!.toString(), '224 ok')
    assert.equal((await reader.next(END)).value!.toString(), 'a')
    assert.equal((await reader.next(CRLF)).value!.toString(), '224 ok')
    assert.equal((await reader.next(END)).value!.toString(), '')
    assert.equal((await reader.next(CRLF)).value!.toString(), '211 x')
  })

  test('keeps binary data intact', async ({ assert }) => {
    const body = Buffer.from([0, 13, 255, 10, 46, 13, 46, 10, 13])
    const source = (async function* () {
      yield Buffer.from('222 body\r\n')
      yield body
      yield Buffer.from('\r\n.\r\n')
    })()
    const reader = delimitedReader(source, CRLF)
    await reader.next()
    assert.deepEqual((await reader.next(END)).value, body)
  })
})