middleware.ts

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

function getEnv(
  name: "NEXT_PUBLIC_SUPABASE_URL" | "NEXT_PUBLIC_SUPABASE_ANON_KEY",
): string {
  const value = process.env[name];
  if (!value) {
    throw new Error(`Missing env variable: ${name}`);
  }
  return value;
}

const supabaseUrl = getEnv("NEXT_PUBLIC_SUPABASE_URL");
const supabaseAnonKey = getEnv("NEXT_PUBLIC_SUPABASE_ANON_KEY");

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

  const supabase = createServerClient(supabaseUrl, supabaseAnonKey, {
    cookies: {
      getAll() {
        return request.cookies.getAll();
      },
      setAll(cookiesToSet) {
        for (const { name, value, options } of cookiesToSet) {
          request.cookies.set(name, value);
          response.cookies.set(name, value, options);
        }
      },
    },
  });

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

  if (!user) {
    const loginUrl = new URL("/login", request.url);
    loginUrl.searchParams.set("next", "/admin");
    return NextResponse.redirect(loginUrl);
  }

  return response;
}

export const config = {
  matcher: ["/admin/:path*"],
};