fix: gallery.yaml album order on homepage + stale settings cache (#391)

* fix: honour gallery.yaml order for homepage albums

getStandaloneAlbums() filtered the Immich API album list but kept the
API's own (creation/update) order, so reordering the albums list in
gallery.yaml or the admin panel had no effect on the homepage. Sort by
the config list's index instead.

Fixes #352

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* fix: serve fresh settings after admin save without restart

getConfig() short-circuited on a per-worker in-memory cache in
production. Admin saves invalidate that cache only in the worker that
handles the API request; when Next.js renders pages in a different
worker/process, its copy stayed stale until a container restart.

Drop the in-memory config cache entirely and rebuild the config per
call. Freshness comes from the existing mtime-checked YAML cache in
loadYaml() — one statSync per file, negligible next to Immich API
calls, and the same behaviour dev mode has always had.

Fixes #351

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: ralksta <ralksta@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

lib/__tests__/config-cache.test.ts

@@ -0,0 +1,62 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+
+// Mock env.ts so importing config.ts doesn't trigger Zod validation
+vi.mock('@/lib/env', () => ({
+  env: {
+    IMMICH_API_URL: 'http://localhost:2283',
+    IMMICH_API_KEY: 'test-key',
+    SITE_TITLE: 'Test Gallery',
+    SITE_SUBTITLE: '',
+    CACHE_TTL: 300,
+    RATE_LIMIT_RPM: 120,
+  },
+}));
+
+vi.mock('@/lib/secret', () => ({
+  resolveAuthSecret: () => 'test-auth-secret-32-chars-long-min',
+}));
+
+// Replace the filesystem-backed YAML layer. The real loadYaml() already
+// revalidates by mtime, so "the file changed on disk" is modelled by the
+// mock returning different content.
+vi.mock('@/lib/config/parser', () => ({
+  loadYaml: vi.fn(),
+  clearYamlCache: vi.fn(),
+  validateUuid: (id: string) => id,
+}));
+
+import { getConfig, invalidateConfigCache } from '@/lib/config';
+import { loadYaml } from '@/lib/config/parser';
+
+const ALBUM_ID = '11111111-1111-1111-1111-111111111111';
+
+function mockYamlFiles(settings: Record<string, unknown>) {
+  vi.mocked(loadYaml).mockImplementation((filename: string) => {
+    if (filename === 'gallery.yaml') return { albums: [ALBUM_ID] };
+    if (filename === 'settings.yaml') return settings;
+    return null;
+  });
+}
+
+describe('getConfig() in production', () => {
+  beforeEach(() => {
+    vi.stubEnv('NODE_ENV', 'production');
+    invalidateConfigCache();
+  });
+
+  afterEach(() => {
+    vi.unstubAllEnvs();
+  });
+
+  it('picks up settings.yaml changes without invalidateConfigCache()', () => {
+    // An admin save may run in a different worker/process than page
+    // rendering, so this worker never sees invalidateConfigCache().
+    // getConfig() must delegate freshness to the mtime-checked YAML layer
+    // instead of short-circuiting on a stale in-memory copy.
+    mockYamlFiles({ title: 'Old Title' });
+    expect(getConfig().siteTitle).toBe('Old Title');
+
+    mockYamlFiles({ title: 'New Title' });
+    expect(getConfig().siteTitle).toBe('New Title');
+  });
+});

lib/__tests__/immich.test.ts

@@ -12,7 +12,7 @@ vi.mock('../config', async () => {
       immich: { apiUrl: 'http://immich.test/api', apiKey: 'test-key' },
       authSecret: 'test-auth-secret-32-chars-long-min',
       albums: ['album-1', 'album-2'],
-      standaloneAlbums: ['album-1'],
+      standaloneAlbums: ['album-2', 'album-1'],
       subpages: [],
       albumOverrides: { 'album-1': 'Override Name' },
       albumDescriptions: {},
@@ -78,6 +78,24 @@ describe('ImmichClient', () => {
     });
   });
 
+  describe('getStandaloneAlbums()', () => {
+    it('orders albums by gallery.yaml order, not Immich API order', async () => {
+      // The Immich API returns albums in its own (creation/update) order;
+      // the config lists album-2 first, so that must win on the homepage.
+      mockFetch.mockResolvedValueOnce({
+        ok: true,
+        headers: { get: () => 'application/json' },
+        json: async () => [
+          { id: 'album-1', albumName: 'First in API', assetCount: 1 },
+          { id: 'album-2', albumName: 'Second in API', assetCount: 1 },
+        ],
+      });
+
+      const albums = await immich.getStandaloneAlbums();
+      expect(albums.map((a) => a.id)).toEqual(['album-2', 'album-1']);
+    });
+  });
+
   describe('getAlbum()', () => {
     it('returns null for unallowed album IDs', async () => {
       const album = await immich.getAlbum('album-3');