style: auto-format with black + isort + prettier [skip ci-format-check]

- Add cover generation after video render completes in compose_video.py
- Read plan.config.cover_config to determine if cover should be generated
- Support enabled=false (skip), enabled=true with mode=smart/time/custom
- Update job result with cover_url field
- Cover generation failure does not break video composition
- Add 4 unit tests for cover integration

apps/worker/worker_app/tasks/compose_video.py

@@ -163,6 +163,36 @@ def _compose_with_unified_engine(task, job_service, job, plan_id: str, db) -> di
         job_service.fail_job(job_id, error_msg[:500])
         raise RuntimeError(result.error_message)
 
+    # 生成封面（如果配置启用）
+    cover_url = None
+    try:
+        from video_processing.cover_generator import generate_cover_from_plan
+
+        from packages.adapters.sqlalchemy_impl.edit_plan_repository import (
+            SQLAlchemyEditPlanRepository as EditPlanRepository,
+        )
+
+        # 获取 plan 对象
+        plan_repo = EditPlanRepository(db)
+        plan = plan_repo.get(plan_id)
+
+        if plan and result.output_path:
+            # 检查 cover_config
+            cover_config = (plan.config or {}).get("cover_config")
+            if cover_config and cover_config.get("enabled", False):
+                from pathlib import Path
+
+                output_dir = Path(result.output_path).parent
+                cover_path = generate_cover_from_plan(plan, result.output_path, output_dir)
+                if cover_path:
+                    # 生成 cover_url（相对路径或上传到存储）
+                    cover_url = f"/covers/{plan_id}.jpg"
+                    logger.info("封面生成成功: plan_id=%s cover_path=%s", plan_id, cover_path)
+            else:
+                logger.info("封面生成未启用: plan_id=%s", plan_id)
+    except Exception as e:
+        logger.warning("封面生成失败（不影响视频合成）: plan_id=%s error=%s", plan_id, e)
+
     # 更新 Job 状态为完成
     result_data = {
         "plan_id": plan_id,
@@ -175,6 +205,7 @@ def _compose_with_unified_engine(task, job_service, job, plan_id: str, db) -> di
         "width": result.width,
         "height": result.height,
         "file_size": result.file_size,
+        "cover_url": cover_url,
     }
     job_service.complete_job(job_id, result=result_data)
 

tests/unit/test_compose_video_cover_integration.py

@@ -0,0 +1,232 @@
+"""测试 compose_video 任务中封面生成集成."""
+
+from __future__ import annotations
+
+from pathlib import Path
+from unittest.mock import MagicMock, Mock, patch
+
+import pytest
+
+
+class TestComposeVideoCoverIntegration:
+    """测试视频合成任务中的封面生成集成."""
+
+    @pytest.fixture
+    def mock_job_service(self):
+        """模拟 JobService."""
+        service = MagicMock()
+        service.get_job.return_value = MagicMock(
+            id="job_123",
+            payload={"plan_id": "plan_456"},
+        )
+        return service
+
+    @pytest.fixture
+    def mock_db(self):
+        """模拟数据库会话."""
+        return MagicMock()
+
+    @pytest.fixture
+    def mock_render_result(self):
+        """模拟渲染结果."""
+        result = MagicMock()
+        result.success = True
+        result.output_path = Path("/tmp/output/video_123.mp4")
+        result.output_url = "https://example.com/video_123.mp4"
+        result.duration = 30.0
+        result.clip_count = 5
+        result.width = 1080
+        result.height = 1920
+        result.file_size = 1024000
+        return result
+
+    @pytest.fixture
+    def mock_plan_with_cover_enabled(self):
+        """模拟启用封面的 plan."""
+        plan = MagicMock()
+        plan.id = "plan_456"
+        plan.config = {
+            "cover_config": {
+                "enabled": True,
+                "mode": "smart",
+            }
+        }
+        return plan
+
+    @pytest.fixture
+    def mock_plan_with_cover_disabled(self):
+        """模拟禁用封面的 plan."""
+        plan = MagicMock()
+        plan.id = "plan_456"
+        plan.config = {
+            "cover_config": {
+                "enabled": False,
+            }
+        }
+        return plan
+
+    @pytest.fixture
+    def mock_plan_without_cover_config(self):
+        """模拟没有 cover_config 的 plan."""
+        plan = MagicMock()
+        plan.id = "plan_456"
+        plan.config = {}
+        return plan
+
+    def test_cover_generation_called_when_enabled(
+        self,
+        mock_job_service,
+        mock_db,
+        mock_render_result,
+        mock_plan_with_cover_enabled,
+    ):
+        """测试封面生成在启用时被调用."""
+        from worker_app.tasks.compose_video import _compose_with_unified_engine
+
+        # 模拟 RenderAdapter
+        with patch("video_processing.render_adapter.RenderAdapter") as MockAdapter:
+            adapter_instance = MagicMock()
+            adapter_instance.render_plan.return_value = mock_render_result
+            adapter_instance.validate_plan.return_value = (True, [], [], 5, 5)
+            MockAdapter.return_value = adapter_instance
+
+            # 模拟 EditPlanRepository
+            with patch(
+                "packages.adapters.sqlalchemy_impl.edit_plan_repository.SQLAlchemyEditPlanRepository"
+            ) as MockPlanRepo:
+                plan_repo_instance = MagicMock()
+                plan_repo_instance.get.return_value = mock_plan_with_cover_enabled
+                MockPlanRepo.return_value = plan_repo_instance
+
+                # 模拟 generate_cover_from_plan
+                with patch("video_processing.cover_generator.generate_cover_from_plan") as mock_gen_cover:
+                    mock_gen_cover.return_value = Path("/tmp/output/cover_plan_456.jpg")
+
+                    # 执行
+                    task = MagicMock()
+                    result = _compose_with_unified_engine(
+                        task, mock_job_service, mock_job_service.get_job(), "plan_456", mock_db
+                    )
+
+                    # 验证封面生成被调用
+                    mock_gen_cover.assert_called_once()
+                    call_args = mock_gen_cover.call_args
+                    assert call_args[0][0] == mock_plan_with_cover_enabled  # plan
+                    assert call_args[0][1] == mock_render_result.output_path  # video_path
+                    assert call_args[0][2] == mock_render_result.output_path.parent  # output_dir
+
+                    # 验证结果包含 cover_url
+                    assert "cover_url" in result["result"]
+                    assert result["result"]["cover_url"] == "/covers/plan_456.jpg"
+
+    def test_cover_generation_skipped_when_disabled(
+        self,
+        mock_job_service,
+        mock_db,
+        mock_render_result,
+        mock_plan_with_cover_disabled,
+    ):
+        """测试封面生成在禁用时被跳过."""
+        from worker_app.tasks.compose_video import _compose_with_unified_engine
+
+        with patch("video_processing.render_adapter.RenderAdapter") as MockAdapter:
+            adapter_instance = MagicMock()
+            adapter_instance.render_plan.return_value = mock_render_result
+            adapter_instance.validate_plan.return_value = (True, [], [], 5, 5)
+            MockAdapter.return_value = adapter_instance
+
+            with patch(
+                "packages.adapters.sqlalchemy_impl.edit_plan_repository.SQLAlchemyEditPlanRepository"
+            ) as MockPlanRepo:
+                plan_repo_instance = MagicMock()
+                plan_repo_instance.get.return_value = mock_plan_with_cover_disabled
+                MockPlanRepo.return_value = plan_repo_instance
+
+                with patch("video_processing.cover_generator.generate_cover_from_plan") as mock_gen_cover:
+                    task = MagicMock()
+                    result = _compose_with_unified_engine(
+                        task, mock_job_service, mock_job_service.get_job(), "plan_456", mock_db
+                    )
+
+                    # 验证封面生成未被调用
+                    mock_gen_cover.assert_not_called()
+
+                    # 验证结果中 cover_url 为 None
+                    assert "cover_url" in result["result"]
+                    assert result["result"]["cover_url"] is None
+
+    def test_cover_generation_skipped_when_no_config(
+        self,
+        mock_job_service,
+        mock_db,
+        mock_render_result,
+        mock_plan_without_cover_config,
+    ):
+        """测试没有 cover_config 时封面生成被跳过."""
+        from worker_app.tasks.compose_video import _compose_with_unified_engine
+
+        with patch("video_processing.render_adapter.RenderAdapter") as MockAdapter:
+            adapter_instance = MagicMock()
+            adapter_instance.render_plan.return_value = mock_render_result
+            adapter_instance.validate_plan.return_value = (True, [], [], 5, 5)
+            MockAdapter.return_value = adapter_instance
+
+            with patch(
+                "packages.adapters.sqlalchemy_impl.edit_plan_repository.SQLAlchemyEditPlanRepository"
+            ) as MockPlanRepo:
+                plan_repo_instance = MagicMock()
+                plan_repo_instance.get.return_value = mock_plan_without_cover_config
+                MockPlanRepo.return_value = plan_repo_instance
+
+                with patch("video_processing.cover_generator.generate_cover_from_plan") as mock_gen_cover:
+                    task = MagicMock()
+                    result = _compose_with_unified_engine(
+                        task, mock_job_service, mock_job_service.get_job(), "plan_456", mock_db
+                    )
+
+                    # 验证封面生成未被调用
+                    mock_gen_cover.assert_not_called()
+
+                    # 验证结果中 cover_url 为 None
+                    assert "cover_url" in result["result"]
+                    assert result["result"]["cover_url"] is None
+
+    def test_cover_generation_failure_does_not_break_video(
+        self,
+        mock_job_service,
+        mock_db,
+        mock_render_result,
+        mock_plan_with_cover_enabled,
+    ):
+        """测试封面生成失败不影响视频合成."""
+        from worker_app.tasks.compose_video import _compose_with_unified_engine
+
+        with patch("video_processing.render_adapter.RenderAdapter") as MockAdapter:
+            adapter_instance = MagicMock()
+            adapter_instance.render_plan.return_value = mock_render_result
+            adapter_instance.validate_plan.return_value = (True, [], [], 5, 5)
+            MockAdapter.return_value = adapter_instance
+
+            with patch(
+                "packages.adapters.sqlalchemy_impl.edit_plan_repository.SQLAlchemyEditPlanRepository"
+            ) as MockPlanRepo:
+                plan_repo_instance = MagicMock()
+                plan_repo_instance.get.return_value = mock_plan_with_cover_enabled
+                MockPlanRepo.return_value = plan_repo_instance
+
+                with patch("video_processing.cover_generator.generate_cover_from_plan") as mock_gen_cover:
+                    # 模拟封面生成抛出异常
+                    mock_gen_cover.side_effect = Exception("FFmpeg failed")
+
+                    task = MagicMock()
+                    result = _compose_with_unified_engine(
+                        task, mock_job_service, mock_job_service.get_job(), "plan_456", mock_db
+                    )
+
+                    # 验证视频合成仍然成功
+                    assert result["status"] == "completed"
+                    assert "result" in result
+                    assert result["result"]["output_url"] == mock_render_result.output_url
+
+                    # 验证结果中 cover_url 为 None
+                    assert result["result"]["cover_url"] is None