import { redirect } from 'next/navigation';
import { NextResponse } from 'next/server';
import type { User } from '@supabase/supabase-js';
import { createSupabaseServerClient } from '@/lib/supabase/server';

export function isAdmin(user: User | null | undefined): boolean {
  return user?.app_metadata?.role === 'admin';
}

/**
 * For server components / pages. Redirects to /login if unauthenticated,
 * or /dashboard if authenticated but not an admin (does not leak /admin).
 */
export async function requireAdmin(): Promise<User> {
  const supabase = createSupabaseServerClient();
  const {
    data: { user },
  } = await supabase.auth.getUser();
  if (!user) redirect('/login');
  if (!isAdmin(user)) redirect('/dashboard');
  return user;
}

/**
 * For route handlers. Returns the authenticated admin user, or a NextResponse
 * (401 when no session, 403 when not admin) that the caller must return.
 */
export async function requireAdminApi(): Promise<
  { ok: true; user: User } | { ok: false; response: NextResponse }
> {
  const supabase = createSupabaseServerClient();
  const {
    data: { user },
  } = await supabase.auth.getUser();
  if (!user) {
    return {
      ok: false,
      response: NextResponse.json({ error: 'unauthorized' }, { status: 401 }),
    };
  }
  if (!isAdmin(user)) {
    return {
      ok: false,
      response: NextResponse.json({ error: 'forbidden' }, { status: 403 }),
    };
  }
  return { ok: true, user };
}