import { existsSync, createReadStream } from 'node:fs'
import { clipFrameThumbFile, ensureClipFirstFrame, ensureScaledThumb, fileEtag, sniffImageType } from '~/server/utils/library'

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

  let framePath = ''
  try {
    framePath = await ensureClipFirstFrame(owner, clip.id)
  } catch (error) {
    const message = error instanceof Error ? error.message : String(error)
    throw createError({ statusCode: 500, statusMessage: `Could not extract the first frame: ${message}` })
  }
  if (!framePath || !existsSync(framePath)) {
    throw createError({ statusCode: 404, statusMessage: 'Video file is missing' })
  }

  let path = framePath
  if (wantThumb) {
    const thumbPath = await ensureScaledThumb(framePath, clipFrameThumbFile(owner, clip.id, 'first'))
    if (thumbPath && existsSync(thumbPath)) path = thumbPath
  }

  const etag = fileEtag(path)
  setHeader(event, 'ETag', etag)
  setHeader(event, 'Cache-Control', wantThumb ? 'private, max-age=86400, stale-while-revalidate=604800' : 'private, max-age=3600')
  if (getHeader(event, 'if-none-match') === etag) {
    setResponseStatus(event, 304)
    return null
  }
  setHeader(event, 'Content-Type', wantThumb && path !== framePath ? 'image/jpeg' : sniffImageType(path))
  return sendStream(event, createReadStream(path))
})