middleware.ts

import { createServerClient, type CookieOptions } from '@supabase/ssr';
import { NextResponse, type NextRequest } from 'next/server';

export async function middleware(request: NextRequest) {
  let response = NextResponse.next({
    request: {
      headers: request.headers,
    },
  });

  const supabase = createServerClient(
    process.env.NEXT_PUBLIC_SUPABASE_URL!,
    process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!,
    {
      cookies: {
        get(name: string) {
          return request.cookies.get(name)?.value;
        },
        set(name: string, value: string, options: CookieOptions) {
          request.cookies.set({
            name,
            value,
            ...options,
          });
          response = NextResponse.next({
            request: {
              headers: request.headers,
            },
          });
          response.cookies.set({
            name,
            value,
            ...options,
          });
        },
        remove(name: string, options: CookieOptions) {
          request.cookies.set({
            name,
            value: '',
            ...options,
          });
          response = NextResponse.next({
            request: {
              headers: request.headers,
            },
          });
          response.cookies.set({
            name,
            value: '',
            ...options,
          });
        },
      },
    }
  );

  const {
    data: { user },
  } = await supabase.auth.getUser();

  // Protected routes that require authentication
  const protectedPaths = ['/upload', '/review', '/exclusions', '/processing', '/results', '/student', '/admin'];
  const adminOnlyPaths = ['/upload', '/review', '/exclusions', '/processing', '/admin'];
  
  const isProtectedPath = protectedPaths.some(path => request.nextUrl.pathname.startsWith(path));
  const isAdminOnlyPath = adminOnlyPaths.some(path => request.nextUrl.pathname.startsWith(path));

  // Redirect to login if not authenticated and trying to access protected route
  if (isProtectedPath && !user) {
    return NextResponse.redirect(new URL('/login', request.url));
  }

  // Check user role for admin-only paths
  if (isAdminOnlyPath && user) {
    const { data: profile } = await supabase
      .from('profiles')
      .select('role')
      .eq('id', user.id)
      .single();

    if (profile?.role !== 'admin') {
      return NextResponse.redirect(new URL('/dashboard', request.url));
    }
  }

  // Redirect authenticated users away from auth pages
  if (user && (request.nextUrl.pathname === '/login' || request.nextUrl.pathname === '/signup')) {
    return NextResponse.redirect(new URL('/dashboard', request.url));
  }

  return response;
}

export const config = {
  matcher: [
    /*
     * Match all request paths except for the ones starting with:
     * - _next/static (static files)
     * - _next/image (image optimization files)
     * - favicon.ico (favicon file)
     * Feel free to modify this pattern to include more paths.
     */
    '/((?!_next/static|_next/image|favicon.ico|.*\\.(?:svg|png|jpg|jpeg|gif|webp)$).*)',
  ],
};