Revert "disable admin login"

This reverts commit eb15f4b29c.

pages/_app.tsx

@@ -4,24 +4,48 @@ import { useEffect } from 'react'
 
 import type { AppProps } from 'next/app'
 
+import { useSession, signIn, SessionProvider } from 'next-auth/react'
 import Layout from '../components/layout';
 
 import '../styles/index.css'
 import '../styles/gfm.css'
 
+function Auth({ children }) {
+  const { data: session, status } = useSession()
+  const isUser = !!session?.user
+
+  useEffect(() => {
+    if (status === 'loading') return // Do nothing while loading
+    if (!isUser) signIn() // If not authenticated, force log in
+  }, [isUser, status])
+
+  if (isUser) {
+    return children
+  }
+
+  // Session is being fetched, or no user.
+  // If no user, useEffect() will redirect.
+  return <div>Loading...</div>
+}
+
 export default function MyApp({
   Component,
-  pageProps,
+  pageProps: { session, ...pageProps },
 }) {
-  // Use the layout defined at the page level, if available
-  const getLayout = Component.getLayout ?? ((page) => page)
- 
   return (
     <div className="flex flex-col min-h-screen">
-      <Layout>
-        { getLayout(<Component {...pageProps}/>) }
-        <Analytics />
-      </Layout>
+      <SessionProvider session={session}>
+        <Layout>
+          {Component.authenticationRequired ? (
+            <Auth>
+              <Component {...pageProps} />
+            </Auth>
+          ) : (
+            <Component {...pageProps} />
+          )}
+          <Analytics />
+        </Layout>
+      </SessionProvider>
       <AxiomWebVitals />
     </div>
   )