middleware.ts

import { type NextRequest, NextResponse } from 'next/server';
import { rootDomain } from '@/lib/utils';
import { getSubdomainByCustomDomain } from '@/lib/subdomains';
import { isSubdomain } from '@/lib/domain-utils';

function extractSubdomain(request: NextRequest): string | null {
  const url = request.url;
  const host = request.headers.get('host') || '';
  const hostname = host.split(':')[0];

  // Local development environment
  if (url.includes('localhost') || url.includes('127.0.0.1')) {
    // Try to extract subdomain from the full URL
    const fullUrlMatch = url.match(/http:\/\/([^.]+)\.localhost/);
    if (fullUrlMatch && fullUrlMatch[1]) {
      return fullUrlMatch[1];
    }

    // Fallback to host header approach
    if (hostname.includes('.localhost')) {
      return hostname.split('.')[0];
    }

    return null;
  }

  // Production environment
  const rootDomainFormatted = rootDomain.split(':')[0];

  // Handle Cloudflare Workers preview URLs (tenant---branch-name.pages.dev)
  if (hostname.includes('---') && hostname.endsWith('.pages.dev')) {
    const parts = hostname.split('---');
    return parts.length > 0 ? parts[0] : null;
  }

  // Regular subdomain detection
  const isSubdomain =
    hostname !== rootDomainFormatted &&
    hostname !== `www.${rootDomainFormatted}` &&
    hostname.endsWith(`.${rootDomainFormatted}`);

  return isSubdomain ? hostname.replace(`.${rootDomainFormatted}`, '') : null;
}

export async function middleware(request: NextRequest) {
  const { pathname } = request.nextUrl;
  const host = request.headers.get('host') || '';
  const hostname = host.split(':')[0];
  
  const subdomain = extractSubdomain(request);

  // Avoid rewriting already rewritten paths to prevent loops
  if (pathname.startsWith('/s/')) {
    return NextResponse.next();
  }

  if (subdomain) {
    // Block access to admin page from subdomains
    if (pathname.startsWith('/admin')) {
      return NextResponse.redirect(new URL('/', request.url));
    }

    // Rewrite all paths on a subdomain to the subdomain page
    return NextResponse.rewrite(new URL(`/s/${subdomain}${pathname}`, request.url));
  } else {
    // Check if this is a custom domain
    const rootDomainFormatted = rootDomain.split(':')[0];
    
    // Skip if it's the root domain or www subdomain
    if (hostname === rootDomainFormatted || hostname === `www.${rootDomainFormatted}`) {
      return NextResponse.next();
    }
    
    // Skip localhost and preview URLs
    if (hostname.includes('localhost') || hostname.includes('127.0.0.1') || hostname.includes('pages.dev') || hostname.includes('workers.dev')) {
      return NextResponse.next();
    }
    
    // Check if this hostname is a custom domain
    const customDomainData = await getSubdomainByCustomDomain(hostname);
    
    if (customDomainData) {
      // Block access to admin page from custom domains
      if (pathname.startsWith('/admin')) {
        return NextResponse.redirect(new URL('/', request.url));
      }

      // Rewrite all paths on a custom domain to the associated subdomain page
      return NextResponse.rewrite(new URL(`/s/${customDomainData.subdomain}${pathname}`, request.url));
    }
  }

  // On the root domain, allow normal access
  return NextResponse.next();
}

export const config = {
  matcher: [
    /*
     * Match all paths except for:
     * 1. /api routes
     * 2. /_next (Next.js internals)
     * 3. all root files inside /public (e.g. /favicon.ico)
     */
    '/((?!api|_next|[\\w-]+\\.\\w+).*)'
  ]
};