/**
 * The three ways a locale ships broken without anything failing.
 *
 * `check-i18n.mjs` already answers "is this catalog complete?" on every build. These
 * are the questions it cannot ask, because each one looks like a working page:
 *
 *   wiring       a locale in LOCALES whose catalog `index.ts` never imports. It does
 *                not throw: `catalogFor()` falls back to English by design, so the
 *                locale renders the English site under its own `lang`, its own URL
 *                prefix and a full reciprocal hreflang set. Twenty-one locales sat in
 *                that state once. Nothing caught it but reading the built HTML.
 *
 *   brand        `site.name` translated as a phrase. The bulk machine translation did
 *                this to four catalogs: Greek shipped "Καταιγίδες. Διάστημα" ("Storms.
 *                Space") and Japanese "ログイン スペース" ("Login Space") as the name of
 *                the site, in the header, the title and every JSON-LD node.
 *
 *   placeholder  a `{n}` or `{year}` dropped or renamed in translation. `t()` leaves an
 *                unknown placeholder alone and silently ignores a missing one, so the
 *                string renders as prose with a hole in it, or with a literal "{n}".
 *
 * Plain node, no build step: config.ts is read as text, catalogs as JSON.
 */
import test from 'node:test';
import assert from 'node:assert/strict';
import { readFileSync } from 'node:fs';
import path from 'node:path';
import { fileURLToPath } from 'node:url';

const i18nDir = path.resolve(path.dirname(fileURLToPath(import.meta.url)), '../src/i18n');
const read = (file) => readFileSync(path.join(i18nDir, file), 'utf8');
const catalog = (code) => JSON.parse(read(`${code}.json`));

const configSource = read('config.ts');
const indexSource = read('index.ts');

const codes = [...configSource.matchAll(/\{\s*code:\s*'([a-z-]+)'/g)].map((m) => m[1]);
const defaultLocale = /DEFAULT_LOCALE\s*=\s*'([a-z-]+)'/.exec(configSource)?.[1];

const base = catalog(defaultLocale);

/** `{n}`, `{year}`, `{mints}` — the names `t()` substitutes, as a comparable set. */
const placeholders = (value) =>
  new Set(typeof value === 'string' ? (value.match(/\{[a-zA-Z0-9_]+\}/g) ?? []) : []);

test('every locale in LOCALES has its own catalog behind it', () => {
  assert.ok(codes.length > 0, 'no locales parsed out of config.ts');

  for (const code of codes) {
    assert.doesNotThrow(() => catalog(code), `src/i18n/${code}.json is missing or invalid`);

    // The import and the CATALOGS entry, which are the step that gets forgotten. A
    // hyphenated code cannot be a bare identifier, so `ar-eg` arrives as `areg`.
    const ident = code.replace(/-/g, '');
    assert.match(
      indexSource,
      new RegExp(`import ${ident} from '\\./${code}\\.json'`),
      `index.ts does not import ${code}.json, so /${code}/ would render in ${defaultLocale}`,
    );
    assert.match(
      indexSource,
      new RegExp(`(^|\\s)'?${code}'?:\\s*${ident} as Catalog`, 'm'),
      `index.ts imports ${code}.json but never puts it in CATALOGS`,
    );
  }
});

test('config.ts and locales.mjs list the same locales', async () => {
  const { DEFAULT_LOCALE, LOCALE_CODES } = await import(path.join(i18nDir, 'locales.mjs'));
  assert.equal(DEFAULT_LOCALE, defaultLocale);
  assert.deepEqual(LOCALE_CODES, codes, 'the two locale lists have drifted');
});

test('the brand is never translated', () => {
  for (const code of codes) {
    assert.equal(
      catalog(code)['site.name'],
      base['site.name'],
      `${code}.json translated site.name; the brand is a name, not a phrase`,
    );
  }
});

test('every translated string keeps the placeholders English has', () => {
  for (const code of codes) {
    if (code === defaultLocale) continue;
    const own = catalog(code);

    for (const [key, english] of Object.entries(base)) {
      const translated = own[key];
      if (translated === undefined) continue;
      assert.deepEqual(
        [...placeholders(translated)].sort(),
        [...placeholders(english)].sort(),
        `${code}.json ${key}: placeholders differ from ${defaultLocale}`,
      );
    }
  }
});