fix(frontend): refine streamed presentation and resolve stream edge cases

frontend/tests/useChatStream.test.ts

@@ -13,14 +13,16 @@ vi.mock('../src/lib/recommendationStream', async (importOriginal) => {
 const streamMock = vi.mocked(streamRecommendations)
 const unmountCallbacks: Array<() => void> = []
 
-function mountChat() {
+function mountChat(
+  createPlaylist: Parameters<typeof useChatStream>[0] = vi.fn(async () => ({ url: null })),
+) {
   let chat: ReturnType<typeof useChatStream> | undefined
   const root = document.createElement('div')
   document.body.append(root)
   const app = createApp(
     defineComponent({
       setup() {
-        chat = useChatStream(vi.fn(async () => ({ url: null })))
+        chat = useChatStream(createPlaylist)
         return () => h('div')
       },
     }),
@@ -106,6 +108,22 @@ describe('useChatStream', () => {
     expect(turn?.transportFailure).toBeNull()
   })
 
+  it('stores a metadata-free terminal error as a normal stream error', async () => {
+    streamMock.mockImplementation(async (_request, _signal, onEvent) => {
+      onEvent({ type: 'error', code: 'first_stage_failed', message: 'Planning failed.' })
+    })
+    const chat = mountChat()
+
+    await chat.send('error')
+
+    expect(assistantTurns(chat)[0]).toMatchObject({
+      status: 'error',
+      requestId: null,
+      error: { code: 'first_stage_failed', message: 'Planning failed.' },
+      transportFailure: null,
+    })
+  })
+
   it('stores an incomplete stream as a transport failure', async () => {
     streamMock.mockRejectedValue(
       new StreamTransportError('unexpected_eof', 'The stream ended early.'),
@@ -239,4 +257,26 @@ describe('useChatStream', () => {
 
     expect(receivedQuery).toHaveLength(1000)
   })
+
+  it('uses the bare query as the capped playlist name', async () => {
+    const createPlaylist = vi.fn(async () => ({ url: null }))
+    streamMock.mockImplementation(async (_request, _signal, onEvent) => {
+      onEvent(metadata('playlist'))
+      onEvent(track(1))
+      onEvent({ type: 'done', track_count: 1, total_ms: 5 })
+    })
+    const chat = mountChat(createPlaylist)
+    const query = `Late-night instrumental focus ${'x'.repeat(100)}`
+
+    await chat.send(query)
+    const turn = assistantTurns(chat)[0]
+    if (!turn) throw new Error('Assistant turn was not created.')
+    await chat.savePlaylist(turn.id)
+
+    expect(createPlaylist).toHaveBeenCalledWith({
+      schema_version: 1,
+      name: query.slice(0, 100),
+      track_uris: ['spotify:track:1'],
+    })
+  })
 })