import 'server-only';
import { NextResponse } from 'next/server';
import { getCurrentUser, type SessionUser } from './auth';
import { canDelete, canImport, canWrite, isCrmRole } from '@/lib/rbac';

export type Guarded = { user: SessionUser; error?: undefined } | { user?: undefined; error: NextResponse };

const forbidden = () => NextResponse.json({ error: 'Forbidden' }, { status: 403 });

/** API guard: a signed-in CRM user (admin | editor | viewer). */
export async function apiStaff(): Promise<Guarded> {
  const user = await getCurrentUser();
  if (!user) return { error: NextResponse.json({ error: 'Unauthorized' }, { status: 401 }) };
  if (!isCrmRole(user.role)) return { error: forbidden() };
  return { user };
}

/** API guard for mutations a writer/editor may perform. */
export async function apiWrite(): Promise<Guarded> {
  const g = await apiStaff();
  if (g.error) return g;
  if (!canWrite(g.user.role)) return { error: forbidden() };
  return g;
}

/** API guard for destructive actions (admin only). */
export async function apiDelete(): Promise<Guarded> {
  const g = await apiStaff();
  if (g.error) return g;
  if (!canDelete(g.user.role)) return { error: forbidden() };
  return g;
}

/** API guard for CSV import (admin or editor). */
export async function apiImport(): Promise<Guarded> {
  const g = await apiStaff();
  if (g.error) return g;
  if (!canImport(g.user.role)) return { error: forbidden() };
  return g;
}