// POST /api/__journal__/cache/purge: removes every Nitro route-cache entry
// (pages, _payload.json and feeds), so a Journal save in the admin shows on
// the next page view. The backend calls it on loopback after the save
// commits, with `Authorization: Bearer <runtimeConfig.journal.cachePurgeToken>`
// and the body {"kind":"post"|"category","slug":"<slug>"}; the answer is
// {"purged":<n>}.
//
// 404 without a token of at least 32 characters, and for any request that
// came through a reverse proxy (X-Forwarded-For, X-Real-IP or Forwarded);
// 401 for a missing or wrong bearer token. The layer's routeRules keep this
// route out of the route cache.

import { authorizePurge, parsePurgeEvent, purgeRouteCache } from '../../../../app/utils/siteCache.ts'

const PROXY_HEADERS = ['x-forwarded-for', 'x-real-ip', 'forwarded']

export default defineEventHandler(async (event) => {
  setResponseHeader(event, 'cache-control', 'no-store')
  const config = useRuntimeConfig(event)
  const verdict = authorizePurge({
    token: (config.journal as { cachePurgeToken?: unknown }).cachePurgeToken,
    authorization: getRequestHeader(event, 'authorization'),
    proxied: PROXY_HEADERS.some((name) => getRequestHeader(event, name) !== undefined),
  })
  if (verdict === 'disabled' || verdict === 'proxied') {
    throw createError({ statusCode: 404, statusMessage: 'Not Found' })
  }
  if (verdict === 'unauthorized') {
    throw createError({ statusCode: 401, statusMessage: 'Unauthorized' })
  }

  const { kind, slug } = parsePurgeEvent(await readBody(event).catch(() => null))
  const purged = await purgeRouteCache(useStorage('cache'))
  console.info(`[journal] cache purge: removed ${purged} route cache entries (${kind} ${slug})`)
  return { purged }
})