/**
 * GET /api/mail/lead-emails/attachment?leadId=<AD_User_ID>&uid=<archive id>&index=<n>
 * Partner mode (admin roles): `partnerId=<C_BPartner_ID>&address=<one of its addresses>` instead of `leadId`.
 * Download one attachment of an archived e-mail (mailpiler provider only — the
 * IMAP provider lists attachments without offering them). The message must
 * involve the lead's address. Staff only.
 */
import { gateFromEvent } from '../../../utils/chatAccess'
import { fetchArchiveAttachment } from '../../../utils/mail/mailArchive'
import { resolveMailTarget } from '../../../utils/mail/leadEmailAddress'

export default defineEventHandler(async (event) => {
  const { token } = await gateFromEvent(event)
  const q = getQuery(event)
  const leadId = Number(q.leadId) || 0
  const partnerId = Number(q.partnerId) || 0
  const uid = Number(q.uid) || 0
  const index = Number(q.index)
  if ((!leadId && !partnerId) || !uid || !Number.isInteger(index) || index < 0) throw createError({ statusCode: 400, statusMessage: 'Missing parameters' })
  const { email } = await resolveMailTarget(event, q, token)
  if (!email) throw createError({ statusCode: 404, statusMessage: 'Not found' })
  let upstream: Response
  try { upstream = await fetchArchiveAttachment(uid, index, email) } catch { throw createError({ statusCode: 502, statusMessage: 'Mail archive unavailable' }) }
  if (!upstream.ok || !upstream.body) throw createError({ statusCode: upstream.status === 404 ? 404 : 502, statusMessage: 'Attachment not available' })
  for (const h of ['content-type', 'content-length', 'content-disposition']) {
    const v = upstream.headers.get(h)
    if (v) setResponseHeader(event, h, v)
  }
  setResponseHeader(event, 'cache-control', 'private, no-store')
  setResponseHeader(event, 'x-content-type-options', 'nosniff')
  return sendStream(event, upstream.body as any)
})