import { plainToInstance } from 'class-transformer';
import { validateSync } from 'class-validator';

import { PaginationQueryDto } from './pagination-query.dto';
import { ListWagonsQueryDto } from '../../modules/wagons/dto/list-wagons-query.dto';
import { normalizePagination } from '../utils/pagination.util';

/**
 * The page-size ceiling is stated in three places that must agree: `@Max` on
 * PaginationQueryDto, the same `@Max` repeated on ListWagonsQueryDto (which
 * doesn't extend it), and `MAX_PAGE_SIZE` in pagination.util. A fourth copy
 * lives outside this package — `MAX_PAGE_SIZE` in @edr/ui-common's data-table
 * footer, which is what actually asks for the number. Drift between any of
 * them shows up as a 400 on the largest rows-per-page option, so pin them.
 */
const errorsFor = (cls: any, pageSize: unknown) =>
  validateSync(plainToInstance(cls, { pageSize }), { whitelist: false });

describe('page size ceiling', () => {
  it.each([PaginationQueryDto, ListWagonsQueryDto])('accepts 500 on %p', (cls) => {
    expect(errorsFor(cls, 500)).toHaveLength(0);
  });

  it.each([PaginationQueryDto, ListWagonsQueryDto])('rejects 501 on %p', (cls) => {
    expect(errorsFor(cls, 501)).not.toHaveLength(0);
  });

  it('does not truncate 500 in the service-side clamp', () => {
    expect(normalizePagination({ page: 1, pageSize: 500 }).take).toBe(500);
    expect(normalizePagination({ page: 1, pageSize: 501 }).take).toBe(500);
  });
});