tutorbookapp/tutorbook

import Router, { useRouter } from 'next/router';
import { useEffect, useMemo } from 'react';

import { useUser } from 'lib/context/user';

export interface PageData {
  login?: boolean;
  admin?: boolean;
}

export default function usePage(name: string, { login, admin }: PageData = {}): void {
  const { loggedIn, orgs, orgsLoaded } = useUser();
  const { query, asPath } = useRouter();

  // Redirect to the login page if authentication is required but missing.
  const loginURL = useMemo(
    () => `/login?href=${encodeURIComponent(asPath)}`,
    [asPath]
  );
  useEffect(() => {
    if (login) {
      void Router.prefetch(loginURL);
    }
  }, [login, loginURL]);

  // Wait for the login URL redirect location to be populated.
  useEffect(() => {
    if (login && loggedIn === false && !loginURL.includes('undefined')) {
      void Router.replace(loginURL);
    }
  }, [login, loggedIn, loginURL]);

  // Log the analytics page event specifying a name for easier grouping (e.g. it
  // is practically impossible to identify a page by dynamic URL alone).
  useEffect(() => {
    // The `orgId` prop is required to connect events with Mixpanel groups.
    // @see {@link https://bit.ly/36YrRsT}
    window.analytics?.page('', name, { orgId: query.org || 'default' });
  }, [name, query.org]);

  // Redirect to a 404 page if admin access is required but missing.
  // TODO: Should we instead redirect to a 403 page?
  useEffect(() => {
    if (admin) {
      void Router.prefetch('/404');
    }
  }, [admin]);
  useEffect(() => {
    if (admin && loggedIn === true && orgsLoaded && !orgs.some((o) => o.id === query.org)) {
      void Router.replace('/404');
    }
  }, [admin, loggedIn, orgs, query.org, orgsLoaded]);
}