cinny/src/app/state/translation.test.ts

import { test } from 'node:test';
import assert from 'node:assert/strict';
import { createStore } from 'jotai';

// The module evaluates atomWithStorage(..., { getOnInit: true }) which reads
// localStorage at load time. node has none — install a no-op mock, then import
// dynamically (a static import would hoist above the mock).
const localStorageBacking = new Map<string, string>();
(globalThis as { localStorage?: unknown }).localStorage = {
  getItem: (k: string) => localStorageBacking.get(k) ?? null,
  setItem: (k: string, v: string) => {
    localStorageBacking.set(k, v);
  },
  removeItem: (k: string) => {
    localStorageBacking.delete(k);
  },
};

const {
  addTranslation,
  findTranslation,
  makeCacheKey,
  translationCacheAtom,
  translationEntryAtomFamily,
  msgTranslationActiveAtomFamily,
  wasAutoTranslateTried,
  markAutoTranslateTried,
  clearTranslationCache,
} = await import('./translation');

const entry = (key: string, translated = `t-${key}`, fromLang = 'de') => ({
  key,
  translated,
  fromLang,
});

test('makeCacheKey: eventId + normalized target + content fingerprint', () => {
  // Same event + target + text is stable and prefixed by event:normalizedTarget.
  const k1 = makeCacheKey('$abc', 'en-US', 'hola');
  const k2 = makeCacheKey('$abc', 'EN', 'hola');
  assert.equal(k1, k2);
  assert.ok(k1.startsWith('$abc:en:'));
  // Different body (an edit) => different key, so a stale translation misses.
  assert.notEqual(makeCacheKey('$abc', 'en', 'hola'), makeCacheKey('$abc', 'en', 'adios'));
  // Missing text arg still yields a stable key.
  assert.ok(makeCacheKey('$abc', 'en').startsWith('$abc:en:'));
});

test('addTranslation: prepends, newest first', () => {
  const out = addTranslation([entry('a'), entry('b')], entry('c'));
  assert.deepEqual(
    out.map((e) => e.key),
    ['c', 'a', 'b'],
  );
});

test('addTranslation: de-dupes by key, moving to front (and updates value)', () => {
  const out = addTranslation([entry('a', 'old'), entry('b')], entry('a', 'new'));
  assert.deepEqual(
    out.map((e) => e.key),
    ['a', 'b'],
  );
  assert.equal(out[0].translated, 'new');
});

test('addTranslation: caps at max (newest kept)', () => {
  const out = addTranslation([entry('a'), entry('b'), entry('c')], entry('d'), 3);
  assert.deepEqual(
    out.map((e) => e.key),
    ['d', 'a', 'b'],
  );
});

test('addTranslation: ignores empty key or translated', () => {
  const start = [entry('a')];
  assert.equal(addTranslation(start, entry('', 'x')), start);
  assert.equal(addTranslation(start, entry('b', '')), start);
});

test('findTranslation: returns match or undefined', () => {
  const list = [entry('a'), entry('b')];
  assert.equal(findTranslation(list, 'b')?.key, 'b');
  assert.equal(findTranslation(list, 'z'), undefined);
});

// [Gitea #39] Keyed cache subscription: a message only re-renders for its own
// entry, not the whole array.
test('translationEntryAtomFamily: looks up only its own key, unaffected by others', () => {
  const store = createStore();
  store.set(translationCacheAtom, () => [entry('a'), entry('b')]);

  assert.equal(store.get(translationEntryAtomFamily('a'))?.translated, 't-a');
  assert.equal(store.get(translationEntryAtomFamily('z')), undefined);
});

test('translationEntryAtomFamily: does not notify a subscriber when an unrelated key changes', () => {
  const store = createStore();
  store.set(translationCacheAtom, () => [entry('a')]);

  let notifications = 0;
  const unsub = store.sub(translationEntryAtomFamily('a'), () => {
    notifications += 1;
  });
  // atomWithStorage's `onMount` resyncs the base atom from storage as soon as
  // it gets its first subscriber, which — via the JSON round trip — produces
  // a structurally-equal-but-different-reference array, firing exactly one
  // notification unrelated to what this test checks. Drain it before
  // asserting so we're isolating the behaviour under test.
  notifications = 0;
  try {
    // Add an unrelated entry — 'a's object reference in the array is
    // preserved by addTranslation, so selectAtom's Object.is bails.
    store.set(translationCacheAtom, (prev) => addTranslation(prev, entry('other')));
    assert.equal(notifications, 0);

    // Changing 'a' itself does notify.
    store.set(translationCacheAtom, (prev) => addTranslation(prev, entry('a', 'new-a')));
    assert.equal(notifications, 1);
  } finally {
    unsub();
  }
});

test('msgTranslationActiveAtomFamily: FIFO-capped at 500 members', () => {
  const store = createStore();
  // Prime "e0" with non-default state.
  store.set(msgTranslationActiveAtomFamily('e0'), true);
  assert.equal(store.get(msgTranslationActiveAtomFamily('e0')), true);

  // Create 500 more distinct members so the cap evicts "e0" (oldest-created);
  // real usage is one member per mounted message regardless of translation.
  for (let i = 1; i <= 500; i += 1) {
    msgTranslationActiveAtomFamily(`e${i}`);
  }

  // Evicted members are unmounted (`.remove()`d): re-accessing "e0" creates a
  // fresh atom, so it comes back at its default (inactive) value — evidence
  // the family doesn't grow without bound as the timeline is scrolled.
  assert.equal(store.get(msgTranslationActiveAtomFamily('e0')), false);
});

test('translationEntryAtomFamily: stays usable well past the FIFO cap', () => {
  const store = createStore();
  store.set(translationCacheAtom, () => [entry('k0')]);
  for (let i = 1; i <= 500; i += 1) {
    translationEntryAtomFamily(`k${i}`);
  }
  // Unlike the active family, this family is *derived* from the persisted
  // cache array, so a re-created (evicted-then-reaccessed) atom still finds
  // the entry — eviction here is a memory-hygiene concern, not a data-loss
  // one. Confirms the cap doesn't corrupt lookups either way.
  assert.equal(store.get(translationEntryAtomFamily('k0'))?.key, 'k0');
  assert.equal(store.get(translationEntryAtomFamily('k250')), undefined);
});

test('clearTranslationCache: wipes storage, live family members, and the auto-translate guard', () => {
  const store = createStore();
  localStorageBacking.set('cinny_translation_cache_v1', '[{"key":"x"}]');

  store.set(msgTranslationActiveAtomFamily('ev1'), true);
  markAutoTranslateTried('ev1', 'hola');
  assert.equal(wasAutoTranslateTried('ev1', 'hola'), true);

  clearTranslationCache();

  assert.equal(localStorageBacking.has('cinny_translation_cache_v1'), false);
  // Family member was `.remove()`d, so re-accessing it yields a fresh atom
  // back at its default value.
  assert.equal(store.get(msgTranslationActiveAtomFamily('ev1')), false);
  assert.equal(wasAutoTranslateTried('ev1', 'hola'), false);
});