// Príprava obrázkov produktových kariet pre export (ZIP / Brevo):
// vizuál karty z náhľadu v editore (fotka + cenovka + štítky) sa uloží ako JPG, nahrá do úložiska
// a jeho adresa sa zapamätá pri produkte (cardImage). Pri ďalšom exporte sa nezmenené karty nenahrávajú znova.
import { toJpeg } from 'html-to-image';
import { CardProduct, NewsletterCampaign } from '@/types/newsletter';
import { cardContextForModule, cardVisualKey, cardVisualHeight } from './productCard';

async function uploadJpeg(dataUrl: string, fileName: string): Promise<string> {
  const blob = await (await fetch(dataUrl)).blob();
  const formData = new FormData();
  formData.append('file', new File([blob], fileName, { type: 'image/jpeg' }));
  const res = await fetch('/api/upload', { method: 'POST', body: formData });
  const data = await res.json();
  if (!data.success || !data.url) {
    throw new Error(data.error || 'Nahratie obrázka karty zlyhalo');
  }
  return data.url;
}

export async function prepareCardImages(
  campaign: NewsletterCampaign,
  onProgress?: (done: number, total: number) => void
): Promise<{ campaign: NewsletterCampaign; failed: number }> {
  // Karty, ktorých obrázok chýba alebo je zastaraný
  const jobs: Array<{ mIdx: number; pIdx: number; key: string; bg: string; width: number }> = [];
  campaign.modules.forEach((m, mIdx) => {
    const isCards = m.type === 'products_grid' || (m.type === 'loyalty_club' && m.data?.enabled !== false);
    if (!isCards) return;
    const ctx = cardContextForModule(m, 'preview');
    (m.data.products || []).forEach((p: CardProduct, pIdx: number) => {
      const key = cardVisualKey(p, ctx);
      if (p.cardImage?.key !== key) {
        jobs.push({ mIdx, pIdx, key, bg: p.cardBgColor || ctx.cardBg, width: ctx.cardWidth });
      }
    });
  });

  const modules = campaign.modules.map((m) => ({ ...m, data: { ...m.data, products: m.data.products ? [...m.data.products] : m.data.products } }));
  let failed = 0;
  for (let i = 0; i < jobs.length; i++) {
    const job = jobs[i];
    onProgress?.(i, jobs.length);
    const node = document.querySelector<HTMLElement>(`[data-card-visual="${job.key}"]`);
    if (!node) {
      failed++;
      continue;
    }
    try {
      // Presná veľkosť karty v e-maile (náhľad môže byť v užšom okne)
      const height = cardVisualHeight(job.width);
      const dataUrl = await toJpeg(node, {
        pixelRatio: 2,
        quality: 0.9,
        backgroundColor: job.bg,
        width: job.width,
        height,
        style: { width: `${job.width}px`, height: `${height}px` },
        // obrázky idú cez /api/img?url=… – bez parametrov by si html-to-image pomýlil rôzne obrázky
        includeQueryParams: true
      });
      const product = modules[job.mIdx].data.products[job.pIdx];
      const url = await uploadJpeg(dataUrl, `karta-${product.id}.jpg`);
      modules[job.mIdx].data.products[job.pIdx] = { ...product, cardImage: { key: job.key, url } };
    } catch (err) {
      console.warn('Obrázok karty sa nepodarilo pripraviť:', err);
      failed++;
    }
  }
  onProgress?.(jobs.length, jobs.length);
  return { campaign: { ...campaign, modules }, failed };
}