import { BrainerceClient } from 'brainerce';
import { cache } from 'react';
import { SALES_CHANNEL_ID } from '@/core/lib/brainerce';
import { pickPublicStoreInfo, type PublicStoreInfo } from '@/core/lib/store-info';
import { getRequestOrigin } from '@/core/lib/site-url';

/**
 * SERVER-ONLY half of the SDK wiring. Kept apart from `brainerce.ts` on
 * purpose: everything here reaches `next/headers` (to resolve the request's
 * origin), and ~30 client components import `getClient` from `brainerce.ts`.
 * A single shared module would drag `next/headers` into the client bundle and
 * fail the build outright — which is exactly what happened when these two
 * functions still lived there.
 *
 * Import from here in Server Components, `generateMetadata`, route handlers,
 * `sitemap.ts` / `robots.ts`. Never from a `'use client'` file.
 */

/**
 * Server-side client — calls the backend directly (no proxy needed for public
 * data). Used by Server Components for SSR data fetching.
 *
 * ⛔ ASYNC on purpose. The backend compares the `Origin` we send against the
 * domain configured on the sales channel, and a LIVE channel rejects both a
 * mismatched Origin AND a missing one with 403. The correct value is only
 * knowable from the request when no `SITE_URL` is configured — the norm for
 * AI-builder deploys — so resolving it needs an await. This previously read
 * `process.env.NEXT_PUBLIC_SITE_URL || 'http://localhost:3000'`, which sent
 * localhost from every such deploy, so every SSR call failed the moment the
 * channel went Live.
 */
export async function getServerClient(locale?: string): Promise<BrainerceClient> {
  const apiUrl = process.env.BRAINERCE_API_URL || 'https://api.brainerce.com';
  const client = new BrainerceClient({
    salesChannelId: SALES_CHANNEL_ID,
    baseUrl: apiUrl,
    origin: await getRequestOrigin(),
  });
  if (locale) {
    client.setLocale(locale);
  }
  return client;
}

/**
 * Server-side cached fetch of store info, used to seed `<StoreProvider>` at
 * SSR so client components don't render with `null` storeInfo and bake the
 * wrong currency symbol into the HTML Googlebot indexes.
 *
 * Two cache layers:
 *   - React `cache()` dedupes calls within a single request render so the
 *     layout + `generateMetadata` share one fetch.
 *   - Next.js `fetch({ next: { revalidate, tags } })` caches the response
 *     across requests for ~60s and lets the dashboard bust the cache via
 *     `revalidateTag('store-info')` on store-config save.
 *
 * Returns `null` on hard failure so the provider's client-side `useEffect`
 * fallback can take over — behaviour identical to pre-SSR-hydration.
 *
 * Bypasses {@link getServerClient} on purpose: the SDK's internal `fetch`
 * does not forward `next:` options, so it cannot participate in the Next.js
 * Data Cache today. Switch back to the SDK once it accepts `fetchOptions`.
 */
export const fetchStoreInfo = cache(async (locale?: string): Promise<PublicStoreInfo | null> => {
  const apiUrl = process.env.BRAINERCE_API_URL || 'https://api.brainerce.com';
  const siteOrigin = await getRequestOrigin();
  const url = `${apiUrl}/api/vc/${encodeURIComponent(SALES_CHANNEL_ID)}/info`;
  try {
    const res = await fetch(url, {
      headers: {
        Origin: siteOrigin,
        ...(locale ? { 'Accept-Language': locale } : {}),
      },
      next: { revalidate: 60, tags: ['store-info'] },
    });
    if (!res.ok) return null;
    return pickPublicStoreInfo(await res.json());
  } catch {
    return null;
  }
});