import type { Metadata } from "next";
import { siteConfig } from "@/lib/site";
import { getSiteUrl, isSiteIndexable } from "./config";

/**
 * Single shared Metadata builder used by every public page's
 * generateMetadata — guarantees every page gets its own canonical, robots,
 * Open Graph and Twitter/X card data instead of copy-pasted boilerplate
 * (and the accidental duplicate-description bugs that come with that).
 *
 * `path` is the page's path relative to the site root (e.g.
 * "/angebote/doula-begleitung", or "" for the homepage).
 */
export async function buildMetadata(args: {
  title: string;
  description: string;
  path: string;
  ogImageUrl?: string;
  keywords?: string;
  noindex?: boolean;
  type?: "website" | "article";
}): Promise<Metadata> {
  const [siteUrl, sitewideIndexable] = await Promise.all([getSiteUrl(), isSiteIndexable()]);
  const canonical = `${siteUrl}${args.path}`;
  const indexable = !args.noindex && sitewideIndexable;
  const images = args.ogImageUrl ? [{ url: args.ogImageUrl }] : undefined;

  return {
    title: args.title,
    description: args.description,
    keywords: args.keywords,
    alternates: { canonical },
    robots: indexable
      ? { index: true, follow: true }
      : { index: false, follow: false },
    openGraph: {
      title: args.title,
      description: args.description,
      url: canonical,
      siteName: siteConfig.name,
      type: args.type ?? "website",
      images,
      locale: siteConfig.locale,
    },
    twitter: {
      card: images ? "summary_large_image" : "summary",
      title: args.title,
      description: args.description,
      images: images?.map((image) => image.url),
    },
  };
}