Add series fields to audiobooks and update related logic

Introduces 'series' and 'seriesPart' fields to the Audiobook model and database schema. Updates API routes, file organization, and path template utilities to support series metadata. Enhances chapter merging logic, improves notification backend testing, and expands test coverage for admin and API routes.

tests/api/audiobooks-browse.routes.test.ts

@@ -94,6 +94,16 @@ describe('Audiobooks browse routes', () => {
     expect(payload.audiobooks[0].coverArtUrl).toBe('/api/cache/thumbnails/asin.jpg');
   });
 
+  it('returns 400 for invalid new releases pagination', async () => {
+    const { GET } = await import('@/app/api/audiobooks/new-releases/route');
+
+    const response = await GET({ nextUrl: new URL('http://app/api/audiobooks/new-releases?page=0') } as any);
+    const payload = await response.json();
+
+    expect(response.status).toBe(400);
+    expect(payload.error).toBe('ValidationError');
+  });
+
   it('returns new release audiobooks', async () => {
     prismaMock.audibleCache.findMany.mockResolvedValueOnce([]);
     prismaMock.audibleCache.count.mockResolvedValueOnce(0);
@@ -106,6 +116,54 @@ describe('Audiobooks browse routes', () => {
     expect(payload.count).toBe(0);
   });
 
+  it('enriches new releases and uses cached cover URLs', async () => {
+    prismaMock.audibleCache.findMany.mockResolvedValueOnce([
+      {
+        asin: 'ASIN',
+        title: 'Title',
+        author: 'Author',
+        narrator: null,
+        description: null,
+        coverArtUrl: 'http://image',
+        cachedCoverPath: '/tmp/cache/asin.jpg',
+        durationMinutes: 90,
+        releaseDate: new Date('2024-01-01'),
+        rating: '4.2',
+        genres: ['Fiction'],
+        lastSyncedAt: new Date('2024-01-02'),
+      },
+    ]);
+    prismaMock.audibleCache.count.mockResolvedValueOnce(1);
+    currentUserMock.mockReturnValue({ sub: 'user-1' });
+    enrichMock.mockResolvedValueOnce([{ asin: 'ASIN', available: true }]);
+
+    const { GET } = await import('@/app/api/audiobooks/new-releases/route');
+    const response = await GET({ nextUrl: new URL('http://app/api/audiobooks/new-releases?page=1&limit=1') } as any);
+    const payload = await response.json();
+
+    expect(payload.success).toBe(true);
+    expect(enrichMock).toHaveBeenCalledWith(
+      [
+        expect.objectContaining({
+          asin: 'ASIN',
+          coverArtUrl: '/api/cache/thumbnails/asin.jpg',
+        }),
+      ],
+      'user-1'
+    );
+  });
+
+  it('returns 500 when new releases query fails', async () => {
+    prismaMock.audibleCache.findMany.mockRejectedValueOnce(new Error('db down'));
+
+    const { GET } = await import('@/app/api/audiobooks/new-releases/route');
+    const response = await GET({ nextUrl: new URL('http://app/api/audiobooks/new-releases?page=1&limit=1') } as any);
+    const payload = await response.json();
+
+    expect(response.status).toBe(500);
+    expect(payload.error).toBe('FetchError');
+  });
+
   it('returns audiobook details when ASIN is valid', async () => {
     audibleServiceMock.getAudiobookDetails.mockResolvedValue({ asin: 'ASIN123456', title: 'Title' });
     const { GET } = await import('@/app/api/audiobooks/[asin]/route');
@@ -117,6 +175,38 @@ describe('Audiobooks browse routes', () => {
     expect(payload.audiobook.asin).toBe('ASIN123456');
   });
 
+  it('returns 400 when ASIN is invalid', async () => {
+    const { GET } = await import('@/app/api/audiobooks/[asin]/route');
+
+    const response = await GET({} as any, { params: Promise.resolve({ asin: 'BAD' }) });
+    const payload = await response.json();
+
+    expect(response.status).toBe(400);
+    expect(payload.error).toBe('ValidationError');
+  });
+
+  it('returns 404 when audiobook is not found', async () => {
+    audibleServiceMock.getAudiobookDetails.mockResolvedValue(null);
+    const { GET } = await import('@/app/api/audiobooks/[asin]/route');
+
+    const response = await GET({} as any, { params: Promise.resolve({ asin: 'ASIN123456' }) });
+    const payload = await response.json();
+
+    expect(response.status).toBe(404);
+    expect(payload.error).toBe('NotFound');
+  });
+
+  it('returns 500 when audiobook lookup fails', async () => {
+    audibleServiceMock.getAudiobookDetails.mockRejectedValue(new Error('fail'));
+    const { GET } = await import('@/app/api/audiobooks/[asin]/route');
+
+    const response = await GET({} as any, { params: Promise.resolve({ asin: 'ASIN123456' }) });
+    const payload = await response.json();
+
+    expect(response.status).toBe(500);
+    expect(payload.error).toBe('FetchError');
+  });
+
   it('returns cached covers for login', async () => {
     prismaMock.audibleCache.findMany.mockResolvedValueOnce([
       { asin: 'ASIN', title: 'Title', author: 'Author', cachedCoverPath: '/tmp/asin.jpg', coverArtUrl: null },