Add route to retrieve user's current genre preferences

backend/app/api/genre/me/route.test.ts

@@ -0,0 +1,37 @@
+import { verifySession } from '@/lib/session';
+import { GET } from './route';
+import { prismaMock } from '@/__test__/singleton';
+
+jest.mock('@/lib/session', () => ({
+  verifySession: jest.fn(),
+}));
+
+const mockVerifySession = verifySession as jest.Mock;
+
+test("Preference retrieval fails if session isn't authenticated", async () => {
+  mockVerifySession.mockResolvedValue({ isAuth: false });
+
+  const res = await GET();
+  const data = await res.json();
+
+  expect(data.error).toEqual('Invalid session');
+});
+
+test('Preference retrieval succeeds for valid session and returns appropriately', async () => {
+  mockVerifySession.mockResolvedValue({ isAuth: true, uid: 2 });
+
+  prismaMock.user.findFirst.mockResolvedValue({
+    id: 2,
+    createdAt: new Date(),
+    updatedAt: new Date(),
+    preferences: ['genre 1'],
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  } as any);
+
+  const expectedGenres = ['genre 1'];
+
+  const res = await GET();
+  const data = await res.json();
+
+  expect(data.genres).toEqual(expectedGenres);
+});

backend/app/api/genre/me/route.ts

@@ -0,0 +1,30 @@
+import prisma from '@/lib/prisma';
+import { verifySession } from '@/lib/session';
+import { ErrorResponse } from '@/lib/types';
+import { Genre } from '@prisma/client';
+import { NextResponse } from 'next/server';
+
+type GetResponse = {
+  genres: Genre[];
+};
+
+export const GET = async (): Promise<
+  NextResponse<GetResponse | ErrorResponse>
+> => {
+  const session = await verifySession();
+
+  if (!session.isAuth) {
+    return NextResponse.json({ error: 'Invalid session' });
+  }
+
+  const user = await prisma.user.findFirst({
+    where: {
+      id: session.uid,
+    },
+    include: {
+      preferences: true,
+    },
+  });
+
+  return NextResponse.json({ genres: user!.preferences });
+};