import type { components } from '@pipu/api-client';

export type UserArchive = components['schemas']['UserArchive'];
export const MAX_ARCHIVE_BYTES = 16 * 1024 * 1024;

/** Only previews metadata; the server validates every account before writing. */
export function parseUserArchive(text: string): UserArchive {
  const data: unknown = JSON.parse(text.replace(/^\uFEFF/, ''));
  if (!data || typeof data !== 'object' || !('version' in data) || data.version !== 1 ||
      !('users' in data) || !Array.isArray(data.users) || data.users.length > 10000) throw new Error('archive');
  for (const entry of data.users) {
    if (!entry || typeof entry !== 'object' || typeof entry.username !== 'string' ||
        !['admin', 'moderator', 'user'].includes(entry.role) || typeof entry.password_hash !== 'string') {
      throw new Error('archive');
    }
  }
  return data as UserArchive;
}

export function downloadUserArchive(archive: UserArchive) {
  const url = URL.createObjectURL(new Blob([JSON.stringify(archive, null, 2)], { type: 'application/json' }));
  const link = document.createElement('a');
  link.href = url;
  link.download = 'pipu-users.json';
  document.body.append(link);
  link.click();
  link.remove();
  setTimeout(() => URL.revokeObjectURL(url), 1000);
}