// GET /og/events/[slug].png — generated Open Graph image for an event.
// Cached on disk by slug + event.updatedAt so any admin edit busts the cache.

export default defineEventHandler(async (event) => {
  const slug = getRouterParam(event, 'slug')
  if (!slug) {
    throw createError({ statusCode: 400, statusMessage: 'Missing slug' })
  }

  // .png suffix is part of the route filename, but slugs in DB don't include it.
  const cleanSlug = slug.replace(/\.png$/, '')

  const eventDoc = await loadPublicEvent(event, cleanSlug, { lean: true })
  const key = eventCacheKey(eventDoc)

  let png = await getCachedOG(key)
  if (!png) {
    png = await renderEventOG(eventDoc)
    await setCachedOG(key, png)
  }

  setHeader(event, 'Content-Type', 'image/png')
  setHeader(
    event,
    'Cache-Control',
    'public, max-age=3600, s-maxage=86400, stale-while-revalidate=86400'
  )
  return png
})