import type { MetadataRoute } from "next";
import { KATALOG_VERI_TARIHI, SITE_URL } from "@/lib/seo";
import {
  getAllBolumSlugs,
  getAllIlSlugs,
  getAllUniversiteSlugs,
} from "@/lib/katalog";
import { getAllRehberler } from "@/lib/rehber";

// Bilinçli olarak sitemap DIŞI: /sonuc (noindex), /giris, /listem,
// /odeme/sonuc, /rapor/yazdir (auth/utility sayfaları).
const staticEntries: MetadataRoute.Sitemap = [
  { url: `${SITE_URL}/`, priority: 1, changeFrequency: "weekly" },
  {
    url: `${SITE_URL}/bolumler`,
    lastModified: KATALOG_VERI_TARIHI,
    priority: 0.8,
    changeFrequency: "weekly",
  },
  {
    url: `${SITE_URL}/universiteler`,
    lastModified: KATALOG_VERI_TARIHI,
    priority: 0.8,
    changeFrequency: "weekly",
  },
  {
    url: `${SITE_URL}/universite-siralamasi`,
    priority: 0.7,
    changeFrequency: "yearly",
  },
  { url: `${SITE_URL}/paket`, priority: 0.7, changeFrequency: "monthly" },
  { url: `${SITE_URL}/meraklisina`, priority: 0.6, changeFrequency: "monthly" },
  { url: `${SITE_URL}/iletisim`, priority: 0.3, changeFrequency: "yearly" },
  { url: `${SITE_URL}/gizlilik`, priority: 0.2, changeFrequency: "yearly" },
  { url: `${SITE_URL}/kosullar`, priority: 0.2, changeFrequency: "yearly" },
];

export default async function sitemap(): Promise<MetadataRoute.Sitemap> {
  const bolumler: MetadataRoute.Sitemap = getAllBolumSlugs().map((slug) => ({
    url: `${SITE_URL}/bolum/${slug}`,
    lastModified: KATALOG_VERI_TARIHI,
    priority: 0.7,
    changeFrequency: "monthly",
  }));
  const universiteler: MetadataRoute.Sitemap = getAllUniversiteSlugs().map(
    (slug) => ({
      url: `${SITE_URL}/universite/${slug}`,
      lastModified: KATALOG_VERI_TARIHI,
      priority: 0.6,
      changeFrequency: "monthly",
    }),
  );
  const iller: MetadataRoute.Sitemap = getAllIlSlugs().map((slug) => ({
    url: `${SITE_URL}/universiteler/${slug}`,
    lastModified: KATALOG_VERI_TARIHI,
    priority: 0.6,
    changeFrequency: "monthly",
  }));
  const yazilar = getAllRehberler();
  const rehberler: MetadataRoute.Sitemap = yazilar.map((y) => ({
    url: `${SITE_URL}/rehber/${y.slug}`,
    lastModified: y.guncelleme ?? y.tarih,
    priority: 0.7,
    changeFrequency: "monthly",
  }));
  // /rehber dizini en son dokunulan yazı kadar tazedir (ISO tarihler metin
  // olarak karşılaştırılabilir). Hiç yazı yoksa lastmod hiç yazılmaz.
  const rehberSonDegisiklik = yazilar
    .map((y) => y.guncelleme ?? y.tarih)
    .reduce<string | undefined>(
      (enBuyuk, t) => (enBuyuk === undefined || t > enBuyuk ? t : enBuyuk),
      undefined,
    );
  const rehberDizini: MetadataRoute.Sitemap[number] = {
    url: `${SITE_URL}/rehber`,
    lastModified: rehberSonDegisiklik,
    priority: 0.8,
    changeFrequency: "weekly",
  };
  return [
    ...staticEntries,
    rehberDizini,
    ...bolumler,
    ...universiteler,
    ...iller,
    ...rehberler,
  ];
}