import { describe, expect, test } from 'bun:test';
import { readdirSync, readFileSync } from 'node:fs';
import { join } from 'node:path';
import { findMissingKeys, findExtraKeys } from 'i18n';
import en from './en-GB.json';

/**
 * Parity, over whatever locales are actually ON DISK — not a list written here.
 *
 * This used to name its locales literally, and that made it a check you had to remember to update. Adding
 * `sv-SE` added a file no parity test looked at, so it shipped out of step and every test stayed green.
 * A guard that needs maintaining to keep guarding is the thing it was written to prevent.
 *
 * Both directions, too. `findMissingKeys` alone reports half of a rename: the new key is missing from the
 * translation and caught, while the stale one it still carries is invisible. That is exactly how sv-SE
 * ended up naming two keys en-GB did not have.
 */
const LOCALES: Record<string, Record<string, unknown>> = Object.fromEntries(
  readdirSync(__dirname)
    .filter((f) => f.endsWith('.json') && f !== 'en-GB.json')
    .map((f) => [f.replace(/\.json$/, ''), JSON.parse(readFileSync(join(__dirname, f), 'utf8'))]),
);

describe('officer-web (app.*) locale catalogs', () => {
  test('there is at least one locale besides en-GB', () => {
    // Otherwise every assertion below passes over an empty set and says nothing.
    expect(Object.keys(LOCALES).length).toBeGreaterThan(0);
  });

  test('every locale has every key en-GB has', () => {
    expect(findMissingKeys(en, LOCALES)).toEqual([]);
  });

  test('no locale has a key en-GB does not', () => {
    expect(findExtraKeys(en, LOCALES)).toEqual([]);
  });
});