type NavItem = {
  /** Visible label (e.g. 'Usługi'). */
  name: string
  /** Absolute URL (e.g. 'https://example.com/pl/uslugi'). */
  url: string
}

/**
 * Builds SiteNavigationElement JSON-LD (schema.org) from the main navigation —
 * declares the site's primary nav as structured data. A weaker sitelinks signal
 * than WebSite/breadcrumbs, but cheap: it tells Google which pages are the main
 * navigation targets.
 *
 * Feed it the SAME nav items the header renders (from the panel/nav global), so
 * the structured data matches the visible menu — not a separate hardcoded list.
 *
 *   import { buildSiteNavigationJsonLd } from '@intecion/ipal-kit'
 *   const jsonLd = buildSiteNavigationJsonLd(
 *     navItems.map(i => ({ name: i.label, url: `${base}${i.href}` }))
 *   )
 *   <script type="application/ld+json" ... />
 *
 * Emit once (site-wide, root layout). Data from the nav source, never hardcoded.
 * Returns null for empty nav.
 */
export function buildSiteNavigationJsonLd(items: NavItem[]) {
  if (!items || items.length === 0) {return null}

  return {
    '@context': 'https://schema.org',
    '@type': 'ItemList',
    itemListElement: items.map((item, index) => ({
      name: item.name,
      '@type': 'SiteNavigationElement',
      position: index + 1,
      url: item.url,
    })),
  }
}