/**
 * /c/[id] — public collection.
 *
 * Server shell: exports `generateMetadata` so a shared collection link
 * unfurls with a rich OG card (pointing at /api/og/collection/<id>), then
 * mounts the client body. The server fetch is unauthenticated, so only
 * public collections produce a card — private ones fall back to the default
 * (and never leak).
 */

import type { Metadata } from "next";
import { bff } from "@/lib/bff";
import { ogDefault, ogForCollection } from "@/lib/og";
import { CollectionContent } from "./collection-content";

type Props = { params: Promise<{ id: string }> };

type CollectionEnvelope = {
  collection: {
    id: string;
    title: string;
    description: string | null;
    is_public: boolean;
    item_count: number;
  };
};

export async function generateMetadata({ params }: Props): Promise<Metadata> {
  const { id } = await params;
  try {
    const data = await bff<CollectionEnvelope>(
      `/collections/${encodeURIComponent(id)}`,
      { revalidate: 60 },
    );
    const c = data?.collection;
    if (!c || !c.is_public) return ogDefault();
    return ogForCollection({
      id: c.id,
      title: c.title,
      description: c.description,
      itemCount: c.item_count,
    });
  } catch {
    // Private (403) / unreachable → fall back to the site card.
    return ogDefault();
  }
}

export default function PublicCollectionPage({ params }: Props) {
  return <CollectionContent params={params} />;
}