import fs from 'fs';
import matter from 'gray-matter';

const postsDirectory = path.join(process.cwd(), 'posts');

const URL = "https://yourwebsitedomain.com";

function generateSiteMap(posts) {
  return `<?xml version="1.0" encoding="UTF-8"?>
   <urlset xmlns="https://www.sitemaps.org/schemas/sitemap/0.9">
     <!-- Add the static URLs manually -->
     <url>
       <loc>${URL}</loc>
     </url>
     ${posts
       .map(({ id }) => {
         return `
           <url>
               <loc>${`${URL}/posts/${id}`}</loc>
               <lastmod>${new Date().toISOString()}</lastmod>
           </url>
         `;
       })
       .join("")}
   </urlset>
 `;
}

export function getSortedPostsData() {
  // Get file names under /posts
  const fileNames = fs.readdirSync(postsDirectory);
  const allPostsData = fileNames.map((fileName) => {
    // Remove ".md" from file name to get id
    const id = fileName.replace(/\.md$/, '');

    // Read markdown file as string
    const fullPath = path.join(postsDirectory, fileName);
    const fileContents = fs.readFileSync(fullPath, 'utf8');

    // Use gray-matter to parse the post metadata section
    const matterResult = matter(fileContents);

    // Combine the data with the id
    return {
      id,
      ...matterResult.data,
    };
  });
  // Filter out draft posts
  const livePosts = allPostsData.filter((postData) => {
    return postData.draft == false
  })
  // Sort posts by date
  return livePosts.sort((a, b) => {
    if (a.date < b.date) {
      return 1;
    } else {
      return -1;
    }
  });
}

export async function getServerSideProps({ res }) {
  const posts = getSortedPostsData();

  // Generate the XML sitemap with the blog data
  const sitemap = generateSiteMap(posts);

  res.setHeader("Content-Type", "text/xml");
  // Send the XML to the browser
  res.write(sitemap);
  res.end();

  return {
    props: {},
  };
}

export default function SiteMap() {}