datahub/site/pages/[...slug].tsx

import fs from 'fs';

import parse from '../lib/markdown.mjs';

import MDXPage from '../components/MDXPage';
import clientPromise from '@/lib/mddb';
import Layout from 'components/Layout';
import { useEffect, useState } from 'react';
import { useRouter } from 'next/router.js';
import { NavGroup, NavItem, collectHeadings } from '@portaljs/core';
import { GetStaticProps, GetStaticPropsResult } from 'next';
import { CustomAppProps } from './_app.jsx';
import computeFields from '@/lib/computeFields';
import { getAuthorsDetails } from '@/lib/getAuthorsDetails';

export default function Page({ source, meta, sidebarTree }) {
  source = JSON.parse(source);

  const router = useRouter();

  const [tableOfContents, setTableOfContents] = useState([]);

  useEffect(() => {
    const headingNodes = document.querySelectorAll(
      'h2,h3'
    ) as NodeListOf<HTMLHeadingElement>;
    const toc = collectHeadings(headingNodes);
    setTableOfContents(toc ?? []);
  }, [router.asPath]); // update table of contents on route change with next/link

  return (
    <Layout
      tableOfContents={tableOfContents}
      title={meta.title}
      description={meta.description}
      sidebarTree={sidebarTree}
      urlPath={meta.urlPath}
    >
      <MDXPage source={source} frontMatter={meta} />
    </Layout>
  );
}

interface SlugPageProps extends CustomAppProps {
  source: any;
}

export const getStaticProps: GetStaticProps = async ({
  params,
}): Promise<GetStaticPropsResult<SlugPageProps>> => {
  const urlPath = params?.slug ? (params.slug as string[]).join('/') : '/';

  const mddb = await clientPromise;
  const dbFile = await mddb.getFileByUrl(urlPath);
  const filePath = dbFile!.file_path;
  const frontMatter = dbFile!.metadata ?? {};

  // Temporary, so that blogs work properly
  if (dbFile.metadata.filetype === 'blog') {
    frontMatter.layout = 'blog';
    frontMatter.authorsDetails = await getAuthorsDetails(
      dbFile.metadata.authors
    );
  }

  // Temporary, docs pages should present the LHS sidebar
  if (dbFile.url_path.startsWith('docs')) {
    frontMatter.showSidebar = true;
    frontMatter.sidebarTreeFile = 'content/assets/sidebar.json';
  }

  const source = fs.readFileSync(filePath, { encoding: 'utf-8' });
  const { mdxSource } = await parse(source, 'mdx', {});

  // TODO temporary replacement for contentlayer's computedFields
  const frontMatterWithComputedFields = await computeFields({
    frontMatter,
    urlPath,
    filePath,
    source,
  });

  let sidebarTree: Array<NavGroup | NavItem> = [];

  if (frontMatterWithComputedFields?.showSidebar) {
    let sidebarTreeFile = frontMatterWithComputedFields?.sidebarTreeFile;

    //  Added this file funcionality so that we can control
    //  which items appear in the sidebar and the order via
    //  a json file
    if (sidebarTreeFile) {
      const tree = fs.readFileSync(sidebarTreeFile, { encoding: 'utf-8' });
      sidebarTree = JSON.parse(tree);
    } else {
      const allPages = await mddb.getFiles({ extensions: ['md', 'mdx'] });
      const pages = allPages.filter((p) => !p.metadata?.isDraft);
      pages.forEach((page) => {
        addPageToSitemap(page, sidebarTree);
      });
    }
  }

  return {
    props: {
      source: JSON.stringify(mdxSource),
      meta: frontMatterWithComputedFields,
      sidebarTree,
    },
  };
};

export async function getStaticPaths() {
  const mddb = await clientPromise;
  let allDocuments = await mddb.getFiles({ extensions: ['md', 'mdx'] });

  const paths = allDocuments
    .filter((page) => page.metadata?.isDraft !== true)
    .map((page) => {
      const parts = page.url_path!.split('/');
      return { params: { slug: parts } };
    });

  return {
    paths,
    fallback: false,
  };
}

function capitalize(str: string) {
  return str.charAt(0).toUpperCase() + str.slice(1);
}

/* function addPageToGroup(page: MddbFile, sitemap: Array<NavGroup>) { */
function addPageToSitemap(page: any, sitemap: Array<NavGroup | NavItem>) {
  const urlParts = page.url_path!.split('/').filter((part) => part);
  // don't add home page to the sitemap
  if (urlParts.length === 0) return;
  // top level, root pages
  if (urlParts.length === 1) {
    sitemap.push({
      name: page.metadata?.title || urlParts[0],
      href: page.url_path,
    });
  } else {
    // /blog/blogtest
    const nestingLevel = urlParts.length - 1; // 1
    let currArray: Array<NavItem | NavGroup> = sitemap;

    for (let level = 0; level <= nestingLevel; level++) {
      if (level === nestingLevel) {
        currArray.push({
          name: urlParts[level],
          href: page.url_path,
        });
        continue;
      }

      const matchingGroup = currArray
        .filter(isNavGroup)
        .find(
          (group) =>
            group.path !== undefined && page.url_path.startsWith(group.path)
        );
      if (!matchingGroup) {
        const newGroup: NavGroup = {
          name: capitalize(urlParts[level]),
          path: urlParts.slice(0, level + 1).join('/'),
          level,
          children: [],
        };
        currArray.push(newGroup);
        currArray = newGroup.children;
      } else {
        currArray = matchingGroup.children;
      }
    }
  }
}

function isNavGroup(item: NavItem | NavGroup): item is NavGroup {
  return (item as NavGroup).children !== undefined;
}