/**
 * schema.org JSON-LD builders for content pages.
 *
 * Emitting structured data gives Google rich-result eligibility and gives
 * LLMs clean, linked facts (who authored it, which work it belongs to, when).
 * Every page renders one of these via the <JsonLd> component
 * (components/seo/json-ld.tsx).
 *
 * The author entity carries `sameAs` links to Wikipedia/Wikidata so search
 * engines and LLMs can resolve it to the canonical Śrīla Prabhupāda entity.
 */

const SITE_URL =
  process.env.NEXT_PUBLIC_SITE_URL || "https://prabhupadasays.org";

const AUTHOR = {
  "@type": "Person",
  name: "His Divine Grace A.C. Bhaktivedanta Swami Prabhupāda",
  alternateName: "A.C. Bhaktivedanta Swami Prabhupāda",
  sameAs: [
    "https://en.wikipedia.org/wiki/A._C._Bhaktivedanta_Swami_Prabhupada",
    "https://www.wikidata.org/wiki/Q318439",
  ],
} as const;

const PUBLISHER = {
  "@type": "Organization",
  name: "Prabhupāda Says",
  url: SITE_URL,
} as const;

function abs(path: string): string {
  return path.startsWith("http") ? path : `${SITE_URL}${path}`;
}

/** Trim a (possibly HTML) string to a clean plain-text description. */
function clean(text: string | undefined, max = 300): string | undefined {
  if (!text) return undefined;
  const plain = text
    .replace(/<[^>]+>/g, "")
    .replace(/\s+/g, " ")
    .trim();
  if (!plain) return undefined;
  return plain.length > max ? plain.slice(0, max - 1).trimEnd() + "…" : plain;
}

/**
 * An Article — used for every leaf content page (verses, letters, transcripts,
 * prose chapters, essays, magazine/journal pages). `isPartOf` names the parent
 * work (book/magazine); `datePublished` must be ISO 8601 (omit otherwise).
 */
export function articleJsonLd(params: {
  path: string;
  headline: string;
  description?: string;
  datePublished?: string;
  isPartOf?: string;
}) {
  const url = abs(params.path);
  const obj: Record<string, unknown> = {
    "@context": "https://schema.org",
    "@type": "Article",
    headline: params.headline,
    author: AUTHOR,
    publisher: PUBLISHER,
    inLanguage: "en",
    isAccessibleForFree: true,
    url,
    mainEntityOfPage: url,
  };
  const desc = clean(params.description);
  if (desc) obj.description = desc;
  if (params.datePublished) obj.datePublished = params.datePublished;
  if (params.isPartOf) {
    obj.isPartOf = { "@type": "Book", name: params.isPartOf, author: AUTHOR };
  }
  return obj;
}

/** A public profile page → ProfilePage wrapping the Person. */
export function profileJsonLd(params: {
  path: string;
  name: string;
  handle: string;
  image?: string | null;
}) {
  const url = abs(params.path);
  const person: Record<string, unknown> = {
    "@type": "Person",
    name: params.name,
    alternateName: `@${params.handle}`,
    url,
  };
  if (params.image) person.image = params.image;
  return {
    "@context": "https://schema.org",
    "@type": "ProfilePage",
    url,
    mainEntity: person,
  };
}

/** A Book — used for book landing pages. */
export function bookJsonLd(params: {
  path: string;
  name: string;
  description?: string;
}) {
  const obj: Record<string, unknown> = {
    "@context": "https://schema.org",
    "@type": "Book",
    name: params.name,
    author: AUTHOR,
    publisher: PUBLISHER,
    inLanguage: "en",
    url: abs(params.path),
  };
  const desc = clean(params.description);
  if (desc) obj.description = desc;
  return obj;
}