import axios from 'axios'
import { SitemapStream, streamToPromise } from 'sitemap'
import { Readable } from 'stream'
import { AppUrl } from '../../lib/api'
import { SITE_URL, sitemapLinks } from '../../lib/seo'

export default async function sitemap(req, res) {
  let news = []
  let newsAvailable = false
  try {
    const { data } = await axios.get(AppUrl('news'), { timeout: 5000 })
    const posts = Array.isArray(data) ? data : data && data.data
    if (!Array.isArray(posts)) throw new Error('Unexpected news response')
    news = posts
    newsAvailable = true
  } catch (error) {
    // Keep core pages discoverable during a news API outage; retry soon.
    console.warn('Sitemap: news API unavailable:', error.message)
  }

  const stream = new SitemapStream({ hostname: SITE_URL })
  const xml = await streamToPromise(Readable.from(sitemapLinks(news).map(url => ({ url }))).pipe(stream))
  res.setHeader('Content-Type', 'application/xml; charset=utf-8')
  res.setHeader('Cache-Control', newsAvailable ? 'public, s-maxage=3600, stale-while-revalidate=86400' : 'public, s-maxage=60')
  res.status(200).send(xml.toString())
}