contentful.ts

/**
 * Contentful-shaped adapter STUB (stretch goal).
 *
 * This is intentionally non-functional: it demonstrates the *shape* of the seam
 * a real CMS slots into. It shows two things a production adapter must do:
 *
 *   1. Map the CMS's response shape onto this repo's `Post`/`Product` types.
 *   2. Validate the mapped record against the contract before returning it, so
 *      a CMS schema change surfaces as a loud error at the boundary instead of
 *      a silent SEO regression downstream.
 *
 * To use it for real: install the Contentful client, replace `fetchEntry` with
 * a live query, and point `lib/cms/index.ts` at these functions.
 */
import type { Post } from '../types';
import { assertValidRecord } from '../../contract/validate';

/** A trimmed view of a Contentful entry envelope (`{ sys, fields }`). */
interface ContentfulEntry<TFields> {
  sys: {
    id: string;
    createdAt: string;
    updatedAt: string;
  };
  fields: TFields;
}

interface ContentfulPostFields {
  slug: string;
  title: string;
  excerpt: string;
  body: string;
  publishedState: 'published' | 'draft' | 'archived';
  contentUpdatedAt: string;
  metaTitle?: string;
  metaDescription?: string;
  canonicalOverride?: string;
  noindex?: boolean;
  ogImage?: string;
}

/** Map a Contentful entry onto this repo's `Post` contract. */
export function mapContentfulPost(entry: ContentfulEntry<ContentfulPostFields>): Post {
  const { sys, fields } = entry;
  const post: Post = {
    type: 'post',
    id: sys.id,
    slug: fields.slug,
    status: fields.publishedState,
    title: fields.title,
    excerpt: fields.excerpt,
    body: fields.body,
    createdAt: sys.createdAt,
    updatedAt: sys.updatedAt,
    contentUpdatedAt: fields.contentUpdatedAt,
    seo: {
      metaTitle: fields.metaTitle ?? null,
      metaDescription: fields.metaDescription ?? null,
      canonicalOverride: fields.canonicalOverride ?? null,
      noindex: fields.noindex ?? false,
      ogImage: fields.ogImage ?? null,
    },
  };

  // Catch schema drift at the boundary — never let an invalid record through.
  assertValidRecord(post);
  return post;
}

/* eslint-disable @typescript-eslint/no-unused-vars */
export async function getPost(_slug: string): Promise<Post | null> {
  throw new Error(
    'Contentful adapter is a stub. Wire up the Contentful client, then point ' +
      'lib/cms/index.ts at mapContentfulPost(). See lib/cms/adapters/contentful.ts.',
  );
}