const fs = require("fs");
const fm = require("front-matter");

const siteUrl = process.env.SITE_URL || "https://www.aaronjy.me";
/** @type {import('next-sitemap').IConfig} */
module.exports = {
  siteUrl,
  changefreq: "weekly",
  generateRobotsTxt: true,
  autoLastmod: false,
  generateIndexSitemap: false,
  exclude: ["/server-sitemap-index.xml"], // <= exclude here
  robotsTxtOptions: {
    policies: [
      {
        userAgent: "*",
        allow: "/",
      },
    ],
    additionalSitemaps: [
      `${siteUrl}/server-sitemap-index.xml`, // <==== Add here
    ],
  },
  transform: async (config, path) => {
    const metadata = {
      loc: path,
    };

    if (isHomepage(path)) {
      metadata.priority = 1;
    } else if (isBasePage(path)) {
      metadata.priority = 0.8;
    } else if (isArticle(path)) {
      metadata.priority = 0.6;
    }

    return metadata;
  },
};

function isHomepage(path) {
  return path === "/";
}

function isBasePage(path) {
  return path.split("/").length === 2;
}

function isArticle(path) {
  return path.startsWith("/writing/") || path.startsWith("/library/");
}