middleware.ts

import { NextFetchEvent, NextRequest, NextResponse } from 'next/server';
import { withMiddlewareAuthRequired } from '@auth0/nextjs-auth0/edge';

export function middleware(request: NextRequest, event: NextFetchEvent) {
  const url = request.nextUrl;
  const hostname = request.headers.get('host') || '';
  const subdomains = hostname.split('.');
  const path = url.pathname;

  /* Check if it's a subdomain app request.
    Allow: my-app.localhost:3000 or my-app.appine.app
    Disallow: xyz.my-app.localhost:3000 or my-app.appine.tech or xyz.my-app.appine.app
  */
  if ((hostname.includes('localhost') && subdomains.length === 2) || (subdomains.length === 3 && subdomains[2] === 'app')) {

    // Rewrite the URL to include the subdomain as a path
    const subdomain = subdomains[0];
    url.pathname = `/app/${subdomain}${path}`;
    
    // Redirect to the new URL
    return NextResponse.rewrite(url);
  } 

  // Allow access to the root route without authentication
  if (path === '/') {
    return NextResponse.next();
  }  
  
  // For non-subdomain requests (except root), apply authentication
  return withMiddlewareAuthRequired()(request, event);
};

export const config = {
  matcher: [
    '/',
    '/dashboard/:path*',
    '/projects/:id/:path*',
    '/settings/:path*'
  ],
};