add chinese subtitles

sentence_api/tests/test_api.py

@@ -202,6 +202,72 @@ def test_sentence_explanation_uses_server_side_ai_client(tmp_path, monkeypatch):
     ]
 
 
+
+def _ready_video(repository):
+    repository.upsert_upload(
+        video_hash=VIDEO_HASH,
+        title="Greetings",
+        filename="lesson.mp4",
+        stored_filename=f"{VIDEO_HASH}.mp4",
+        content_type="video/mp4",
+        size_bytes=5,
+        language="en",
+    )
+    repository.save_processing_result(
+        SentenceBoundaryDocument(
+            video_hash=VIDEO_HASH,
+            duration_ms=9000,
+            algorithm_version="test",
+            sentences=[
+                SentenceBoundary(index=0, start_ms=0, end_ms=4000, text="Hello.", language="en", reference_speech_duration_ms=3000),
+                SentenceBoundary(index=1, start_ms=4000, end_ms=9000, text="Nice to meet you.", language="en", reference_speech_duration_ms=4000),
+            ],
+        ),
+        None,
+    )
+
+
+def test_subtitle_translation_requires_login(tmp_path):
+    client = make_client(tmp_path)
+    client.headers.clear()
+    response = client.post(f"/api/v1/videos/{VIDEO_HASH}/subtitle-translation")
+    assert response.status_code == 401
+
+
+def test_subtitle_translation_uses_full_document_and_is_cached(tmp_path, monkeypatch):
+    client = make_client(tmp_path)
+    _ready_video(client.app.state.video_repository)
+    requested = []
+
+    def translate_sentences(sentences, **kwargs):
+        requested.append((sentences, kwargs))
+        return {index: f"中文{index}" for index, _text in sentences}
+
+    class StubAITutor:
+        pass
+
+    stub = StubAITutor()
+    stub.translate_sentences = translate_sentences
+    monkeypatch.setattr(client.app.state, "ai_tutor", stub)
+
+    response = client.post(f"/api/v1/videos/{VIDEO_HASH}/subtitle-translation")
+    assert response.status_code == 200, response.text
+    payload = response.json()
+    assert payload["video_hash"] == VIDEO_HASH
+    assert payload["translations"] == [
+        {"index": 0, "zh_text": "中文0"},
+        {"index": 1, "zh_text": "中文1"},
+    ]
+    document = client.app.state.video_repository.get_document(VIDEO_HASH)
+    assert [sentence.zh_text for sentence in document.sentences] == ["中文0", "中文1"]
+
+    second = client.post(f"/api/v1/videos/{VIDEO_HASH}/subtitle-translation")
+    assert second.status_code == 200
+    assert second.json() == payload
+    assert len(requested) == 1
+    assert requested[0][0] == [(0, "Hello."), (1, "Nice to meet you.")]
+
+
 def test_oss_video_url_is_used_for_catalog_and_content(tmp_path):
     index_path = tmp_path / "boundaries.json"
     index_path.write_text("{}", encoding="utf-8")