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

// Public routes that don't require a logged-in user.
const PUBLIC_PATHS = ["/login", "/auth"];

// Refreshes the Supabase session cookie on every request and redirects
// unauthenticated users to /login. Wired in from the root middleware.ts.
export async function updateSession(request: NextRequest) {
  let response = 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),
          );
          response = NextResponse.next({ request });
          cookiesToSet.forEach(({ name, value, options }) =>
            response.cookies.set(name, value, options),
          );
        },
      },
    },
  );

  // IMPORTANT: getUser() revalidates the token; do not trust getSession() here.
  const {
    data: { user },
  } = await supabase.auth.getUser();

  const path = request.nextUrl.pathname;
  const isPublic = PUBLIC_PATHS.some(
    (p) => path === p || path.startsWith(`${p}/`),
  );

  if (!user && !isPublic) {
    const url = request.nextUrl.clone();
    url.pathname = "/login";
    url.searchParams.set("redirect", path);
    return NextResponse.redirect(url);
  }

  // If a logged-in user hits /login, send them home.
  if (user && path === "/login") {
    const url = request.nextUrl.clone();
    url.pathname = "/";
    url.search = "";
    return NextResponse.redirect(url);
  }

  return response;
}