import { existsSync, createReadStream } from 'node:fs'
import { fileEtag, stillPath, stillThumbPath, sniffImageType } from '~/server/utils/library'

export default defineEventHandler(async (event) => {
  const { owner } = assertLibraryOwner(event)
  const id = String(getRouterParam(event, 'id') || '')
  const still = getStill(owner, id)
  assertFolderAccess(event, still.folderId)
  const wantThumb = String(getQuery(event).thumb || '') === '1'
  const original = stillPath(owner, still.id)

  let path = original
  if (wantThumb) {
    path = await stillThumbPath(owner, id)
    // Never fall back to the archive PNG/JPEG for ?thumb=1
    if (!path || path === original || !existsSync(path)) {
      throw createError({ statusCode: 404, statusMessage: 'Thumbnail not found' })
    }
  } else if (!existsSync(path)) {
    throw createError({ statusCode: 404, statusMessage: 'Image file is missing' })
  }

  const etag = fileEtag(path)
  setHeader(event, 'ETag', etag)
  setHeader(
    event,
    'Cache-Control',
    wantThumb ? 'public, max-age=86400' : 'private, max-age=3600'
  )
  if (getHeader(event, 'if-none-match') === etag) {
    setResponseStatus(event, 304)
    return null
  }
  setHeader(event, 'Content-Type', wantThumb ? 'image/jpeg' : sniffImageType(path))
  return sendStream(event, createReadStream(path))
})