/**
 * GET /api/accounting/amazon-ads/document?invoiceNo=…[&download=1]
 * Streams the original Amazon PDF: local cache first, otherwise downloaded from
 * the Ads API (and cached), otherwise — with &cInvoiceId= — the ORIGINAL PDF attached to
 * the iDempiere document (Strapi, PO_Invoice). The last fallback is what makes the page
 * independent of the local store: a booked invoice always has its PDF on the document.
 */
import { isAdsApiConnected, downloadAdsInvoicePdf } from '../../../utils/amazonAds/adsApi'
import { getInvoice, readInvoicePdf, upsertInvoice } from '../../../utils/amazonAds/invoiceStore'
import { orgIdOf } from '../../../utils/amazonAds/routeShared'
import getTokenHelper from '../../../utils/getTokenHelper'
import { findInvoiceOriginalPdf } from '../../../utils/invoiceOriginalPdf'

export default defineEventHandler(async (event) => {
  const q = getQuery(event)
  const no = String(q.invoiceNo || '').trim()
  if (!no) { setResponseStatus(event, 400); return { status: 400, message: 'invoiceNo fehlt' } }
  const token = await getTokenHelper(event)
  let row: any = null
  let pdf: Buffer | null = null
  try { row = await getInvoice(event, token, no); pdf = await readInvoicePdf(event, token, row) }
  catch (e: any) { console.warn('[AmazonAds] store lookup failed:', e?.data?.detail || e?.message || e) }
  let name = row?.pdfName || `INVOICE-${no}.pdf`
  if (!pdf && row?.invoice && isAdsApiConnected(event)) {
    try {
      const doc = await downloadAdsInvoicePdf(event, no, 'INVOICE')
      if (doc) { pdf = doc.buffer; name = doc.fileName; try { await upsertInvoice(event, token, orgIdOf(event), row.invoice, { pdf, pdfName: name }) } catch {} }
    } catch (e: any) { setResponseStatus(event, 502); return { status: 502, message: e?.message || String(e) } }
  }
  const cInvoiceId = Number(q.cInvoiceId || 0)
  if (!pdf && cInvoiceId) {
    try {
      const orig = await findInvoiceOriginalPdf(event, cInvoiceId)
      if (orig?.buffer?.length) { pdf = orig.buffer; name = orig.fileName || name }
    } catch (e: any) { console.warn('[AmazonAds] attachment lookup failed:', e?.message || e) }
  }
  if (!pdf) { setResponseStatus(event, 404); return { status: 404, message: 'Kein PDF für diese Rechnung vorhanden' } }
  setHeader(event, 'Content-Type', 'application/pdf')
  setHeader(event, 'Content-Disposition', `${q.download ? 'attachment' : 'inline'}; filename="${name.replace(/[^A-Za-z0-9._-]/g, '_')}"`)
  setHeader(event, 'Cache-Control', 'private, max-age=300')
  return pdf
})