middleware.ts

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

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

    const supabase = createServerClient(
        process.env.NEXT_PUBLIC_SUPABASE_URL!,
        process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!,
        {
            cookies: {
                getAll() {
                    return request.cookies.getAll();
                },
                setAll(cookiesToSet) {
                    cookiesToSet.forEach(({ name, value }) =>
                        request.cookies.set(name, value)
                    );
                    supabaseResponse = NextResponse.next({
                        request,
                    });
                    cookiesToSet.forEach(({ name, value, options }) =>
                        supabaseResponse.cookies.set(name, value, options)
                    );
                },
            },
        }
    );

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

    const pathname = request.nextUrl.pathname;

    // Protected routes - require authentication
    const protectedPaths = ['/app'];
    const isProtectedPath = protectedPaths.some((path) =>
        pathname.startsWith(path)
    );

    // Auth routes - redirect to app if already logged in
    const authPaths = ['/login', '/signup'];
    const isAuthPath = authPaths.some((path) => pathname.startsWith(path));

    // Redirect unauthenticated users from protected routes to login
    if (isProtectedPath && !user) {
        const url = request.nextUrl.clone();
        url.pathname = '/login';
        url.searchParams.set('redirectTo', pathname);
        return NextResponse.redirect(url);
    }

    // Redirect authenticated users from auth routes to app
    if (isAuthPath && user) {
        const url = request.nextUrl.clone();
        const redirectTo = url.searchParams.get('redirectTo') || '/app';
        url.pathname = redirectTo;
        url.searchParams.delete('redirectTo');
        return NextResponse.redirect(url);
    }

    return supabaseResponse;
}

export const config = {
    matcher: [
        /*
         * Match all request paths except for:
         * - _next/static (static files)
         * - _next/image (image optimization files)
         * - favicon.ico (favicon file)
         * - public files (images, etc.)
         */
        '/((?!_next/static|_next/image|favicon.ico|.*\\.(?:svg|png|jpg|jpeg|gif|webp)$).*)',
    ],
};