refactor: consolidate generation workflow helpers

backend/app/services/story_service.py

@@ -19,6 +19,8 @@ from app.schemas.story_schemas import (
     StorybookRequest,
     StorybookResponse,
 )
+from app.services.adapters.storybook.primary import Storybook
+from app.services.adapters.text.models import StoryOutput
 from app.services.audio_storage import (
     audio_cache_exists,
     read_audio_cache,
@@ -91,6 +93,233 @@ def _resolve_storybook_image_status(
     return StoryAssetStatus.FAILED
 
 
+async def _prepare_generation_context(
+    *,
+    profile_id: str | None,
+    universe_id: str | None,
+    user_id: str,
+    db: AsyncSession,
+) -> tuple[str | None, str | None, str]:
+    """Validate ownership and build the shared generation context."""
+
+    resolved_profile_id, resolved_universe_id = await validate_profile_and_universe(
+        profile_id, universe_id, user_id, db
+    )
+    memory_context = await build_enhanced_memory_context(
+        resolved_profile_id,
+        resolved_universe_id,
+        db,
+    )
+    return resolved_profile_id, resolved_universe_id, memory_context
+
+
+def _trigger_story_postprocessing(story: Story) -> None:
+    """Trigger non-blocking post-processing for a persisted story."""
+
+    if story.universe_id:
+        extract_story_achievements.delay(story.id, story.universe_id)
+
+
+async def _persist_text_story_result(
+    *,
+    result: StoryOutput,
+    user_id: str,
+    profile_id: str | None,
+    universe_id: str | None,
+    db: AsyncSession,
+) -> Story:
+    """Persist generated text content as the unified story record."""
+
+    story = Story(
+        user_id=user_id,
+        child_profile_id=profile_id,
+        universe_id=universe_id,
+        title=result.title,
+        story_text=result.story_text,
+        cover_prompt=result.cover_prompt_suggestion,
+        mode=result.mode,
+    )
+    sync_story_status(
+        story,
+        image_status=StoryAssetStatus.NOT_REQUESTED,
+        audio_status=StoryAssetStatus.NOT_REQUESTED,
+        last_error=None,
+    )
+    db.add(story)
+    await db.commit()
+    await db.refresh(story)
+    _trigger_story_postprocessing(story)
+    return story
+
+
+def _storybook_pages_to_data(storybook: Storybook) -> list[dict]:
+    """Convert generated storybook pages to the persisted JSON shape."""
+
+    return [
+        {
+            "page_number": page.page_number,
+            "text": page.text,
+            "image_prompt": page.image_prompt,
+            "image_url": page.image_url,
+        }
+        for page in storybook.pages
+    ]
+
+
+def _storybook_pages_to_response(pages_data: list[dict]) -> list[StorybookPageResponse]:
+    """Convert persisted storybook page JSON to API response models."""
+
+    return [
+        StorybookPageResponse(
+            page_number=page["page_number"],
+            text=page["text"],
+            image_prompt=page["image_prompt"],
+            image_url=page.get("image_url"),
+        )
+        for page in pages_data
+    ]
+
+
+async def _generate_storybook_image_assets(
+    storybook: Storybook,
+    db: AsyncSession,
+) -> tuple[str | None, bool, list[int]]:
+    """Generate storybook cover and page images before persistence."""
+
+    final_cover_url = storybook.cover_url
+    cover_failed = False
+    failed_pages: list[int] = []
+
+    logger.info("storybook_parallel_generation_start", page_count=len(storybook.pages))
+
+    async def _gen_cover() -> str | None:
+        nonlocal cover_failed
+
+        if storybook.cover_prompt and not storybook.cover_url:
+            try:
+                return await generate_image(storybook.cover_prompt, db=db)
+            except Exception as exc:
+                cover_failed = True
+                logger.warning("cover_gen_failed", error=str(exc))
+        return storybook.cover_url
+
+    async def _gen_page(page) -> None:
+        if not page.image_prompt or page.image_url:
+            return
+
+        try:
+            page.image_url = await generate_image(page.image_prompt, db=db)
+        except Exception as exc:
+            failed_pages.append(page.page_number)
+            logger.warning("page_gen_failed", page=page.page_number, error=str(exc))
+
+    results = await asyncio.gather(
+        _gen_cover(),
+        *(_gen_page(page) for page in storybook.pages),
+        return_exceptions=True,
+    )
+
+    cover_result = results[0]
+    if isinstance(cover_result, str):
+        final_cover_url = cover_result
+
+    logger.info("storybook_parallel_generation_complete")
+    return final_cover_url, cover_failed, failed_pages
+
+
+async def _persist_storybook_result(
+    *,
+    storybook: Storybook,
+    user_id: str,
+    profile_id: str | None,
+    universe_id: str | None,
+    final_cover_url: str | None,
+    generate_images: bool,
+    cover_failed: bool,
+    failed_pages: list[int],
+    db: AsyncSession,
+) -> tuple[Story, list[dict]]:
+    """Persist generated storybook content as the unified story record."""
+
+    pages_data = _storybook_pages_to_data(storybook)
+    story = Story(
+        user_id=user_id,
+        child_profile_id=profile_id,
+        universe_id=universe_id,
+        title=storybook.title,
+        mode="storybook",
+        pages=pages_data,
+        story_text=None,
+        cover_prompt=storybook.cover_prompt,
+        image_url=final_cover_url,
+    )
+    sync_story_status(
+        story,
+        image_status=_resolve_storybook_image_status(
+            generate_images=generate_images,
+            cover_prompt=storybook.cover_prompt,
+            cover_url=final_cover_url,
+            pages_data=pages_data,
+        ),
+        audio_status=StoryAssetStatus.NOT_REQUESTED,
+        last_error=_build_storybook_error_message(
+            cover_failed=cover_failed,
+            failed_pages=failed_pages,
+        ),
+    )
+    db.add(story)
+    await db.commit()
+    await db.refresh(story)
+    _trigger_story_postprocessing(story)
+    return story, pages_data
+
+
+async def _complete_cover_image_asset(
+    story: Story,
+    db: AsyncSession,
+    *,
+    raise_on_failure: bool = False,
+    last_error_prefix: str | None = None,
+    log_event: str = "cover_asset_generation_failed",
+) -> tuple[str | None, str | None]:
+    """Generate or retry a text story cover through one asset workflow."""
+
+    if not story.cover_prompt:
+        raise HTTPException(status_code=400, detail="Story has no cover prompt")
+
+    sync_story_status(story, image_status=StoryAssetStatus.GENERATING)
+    await db.commit()
+
+    try:
+        image_url = await generate_image(story.cover_prompt, db=db)
+        story.image_url = image_url
+        sync_story_status(story, image_status=StoryAssetStatus.READY)
+        await db.commit()
+        return image_url, None
+    except Exception as exc:
+        provider_error = str(exc)
+        last_error = (
+            f"{last_error_prefix}: {provider_error}"
+            if last_error_prefix
+            else provider_error
+        )
+        sync_story_status(
+            story,
+            image_status=StoryAssetStatus.FAILED,
+            last_error=last_error,
+        )
+        await db.commit()
+        logger.warning(log_event, story_id=story.id, error=provider_error)
+
+        if raise_on_failure:
+            raise HTTPException(
+                status_code=500,
+                detail=f"Image generation failed: {provider_error}",
+            ) from exc
+
+        return None, provider_error
+
+
 async def validate_profile_and_universe(
     profile_id: str | None,
     universe_id: str | None,
@@ -138,15 +367,13 @@ async def generate_and_save_story(
     db: AsyncSession,
 ) -> Story:
     """Generate generic story content and save to DB."""
-    # 1. Validate
-    profile_id, universe_id = await validate_profile_and_universe(
-        request.child_profile_id, request.universe_id, user_id, db
+    profile_id, universe_id, memory_context = await _prepare_generation_context(
+        profile_id=request.child_profile_id,
+        universe_id=request.universe_id,
+        user_id=user_id,
+        db=db,
     )
 
-    # 2. Build Context
-    memory_context = await build_enhanced_memory_context(profile_id, universe_id, db)
-
-    # 3. Generate
     try:
         result = await generate_story_content(
             input_type=request.type,
@@ -161,31 +388,13 @@ async def generate_and_save_story(
             detail="Story generation failed, please try again.",
         ) from exc
 
-    # 4. Save
-    story = Story(
+    return await _persist_text_story_result(
+        result=result,
         user_id=user_id,
-        child_profile_id=profile_id,
+        profile_id=profile_id,
         universe_id=universe_id,
-        title=result.title,
-        story_text=result.story_text,
-        cover_prompt=result.cover_prompt_suggestion,
-        mode=result.mode,
+        db=db,
     )
-    sync_story_status(
-        story,
-        image_status=StoryAssetStatus.NOT_REQUESTED,
-        audio_status=StoryAssetStatus.NOT_REQUESTED,
-        last_error=None,
-    )
-    db.add(story)
-    await db.commit()
-    await db.refresh(story)
-
-    # 5. Trigger Async Tasks
-    if universe_id:
-        extract_story_achievements.delay(story.id, universe_id)
-
-    return story
 
 
 async def generate_full_story_service(
@@ -194,35 +403,18 @@ async def generate_full_story_service(
     db: AsyncSession,
 ) -> FullStoryResponse:
     """Generate story with parallel image generation."""
-    # 1. Generate text part
-    # We can reuse logic or call generate_story_content directly if we want finer control
-    # reusing generate_and_save_story to ensure consistency (it handles validation + saving)
     story = await generate_and_save_story(request, user_id, db)
-
-    # 2. Generate Image (Parallel/Async step in this flow)
     image_url: str | None = None
     errors: dict[str, str | None] = {}
 
     if story.cover_prompt:
-        sync_story_status(story, image_status=StoryAssetStatus.GENERATING)
-        await db.commit()
-        try:
-            image_url = await generate_image(story.cover_prompt, db=db)
-            story.image_url = image_url
-            sync_story_status(
+        image_url, image_error = await _complete_cover_image_asset(
             story,
-                image_status=StoryAssetStatus.READY,
+            db,
+            log_event="image_generation_failed",
         )
-            await db.commit()
-        except Exception as exc:
-            errors["image"] = str(exc)
-            sync_story_status(
-                story,
-                image_status=StoryAssetStatus.FAILED,
-                last_error=str(exc),
-            )
-            await db.commit()
-            logger.warning("image_generation_failed", story_id=story.id, error=str(exc))
+        if image_error:
+            errors["image"] = image_error
 
     return FullStoryResponse(
         id=story.id,
@@ -248,9 +440,11 @@ async def generate_storybook_service(
     db: AsyncSession,
 ) -> StorybookResponse:
     """Generate storybook with parallel image generation for pages."""
-    # 1. Validate
-    profile_id, universe_id = await validate_profile_and_universe(
-        request.child_profile_id, request.universe_id, user_id, db
+    profile_id, universe_id, memory_context = await _prepare_generation_context(
+        profile_id=request.child_profile_id,
+        universe_id=request.universe_id,
+        user_id=user_id,
+        db=db,
     )
 
     logger.info(
@@ -262,10 +456,6 @@ async def generate_storybook_service(
         universe_id=universe_id,
     )
 
-    # 2. Context
-    memory_context = await build_enhanced_memory_context(profile_id, universe_id, db)
-
-    # 3. Generate Text Structure
     try:
         storybook = await generate_storybook(
             keywords=request.keywords,
@@ -278,101 +468,30 @@ async def generate_storybook_service(
         logger.error("storybook_generation_failed", error=str(e))
         raise HTTPException(status_code=500, detail=f"故事书生成失败: {e}")
 
-    # 4. Parallel Image Generation
     final_cover_url = storybook.cover_url
     cover_failed = False
     failed_pages: list[int] = []
 
     if request.generate_images:
-        logger.info("storybook_parallel_generation_start", page_count=len(storybook.pages))
+        (
+            final_cover_url,
+            cover_failed,
+            failed_pages,
+        ) = await _generate_storybook_image_assets(storybook, db)
 
-        tasks = []
-
-        async def _gen_cover():
-            nonlocal cover_failed
-
-            if storybook.cover_prompt and not storybook.cover_url:
-                try:
-                    return await generate_image(storybook.cover_prompt, db=db)
-                except Exception as exc:
-                    cover_failed = True
-                    logger.warning("cover_gen_failed", error=str(exc))
-            return storybook.cover_url
-
-        tasks.append(_gen_cover())
-
-        async def _gen_page(page):
-            if page.image_prompt and not page.image_url:
-                try:
-                    page.image_url = await generate_image(page.image_prompt, db=db)
-                except Exception as exc:
-                    failed_pages.append(page.page_number)
-                    logger.warning("page_gen_failed", page=page.page_number, error=str(exc))
-
-        for page in storybook.pages:
-            tasks.append(_gen_page(page))
-
-        results = await asyncio.gather(*tasks, return_exceptions=True)
-
-        cover_res = results[0]
-        if isinstance(cover_res, str):
-            final_cover_url = cover_res
-
-        logger.info("storybook_parallel_generation_complete")
-
-    # 5. Save to DB
-    pages_data = [
-        {
-            "page_number": p.page_number,
-            "text": p.text,
-            "image_prompt": p.image_prompt,
-            "image_url": p.image_url,
-        }
-        for p in storybook.pages
-    ]
-
-    story = Story(
+    story, pages_data = await _persist_storybook_result(
+        storybook=storybook,
         user_id=user_id,
-        child_profile_id=profile_id,
+        profile_id=profile_id,
         universe_id=universe_id,
-        title=storybook.title,
-        mode="storybook",
-        pages=pages_data,
-        story_text=None,
-        cover_prompt=storybook.cover_prompt,
-        image_url=final_cover_url,
-    )
-    sync_story_status(
-        story,
-        image_status=_resolve_storybook_image_status(
+        final_cover_url=final_cover_url,
         generate_images=request.generate_images,
-            cover_prompt=storybook.cover_prompt,
-            cover_url=final_cover_url,
-            pages_data=pages_data,
-        ),
-        audio_status=StoryAssetStatus.NOT_REQUESTED,
-        last_error=_build_storybook_error_message(
         cover_failed=cover_failed,
         failed_pages=failed_pages,
-        ),
+        db=db,
     )
-    db.add(story)
-    await db.commit()
-    await db.refresh(story)
 
-    if universe_id:
-        extract_story_achievements.delay(story.id, universe_id)
-
-    # 6. Build Response
-    response_pages = [
-        StorybookPageResponse(
-            page_number=p["page_number"],
-            text=p["text"],
-            image_prompt=p["image_prompt"],
-            image_url=p.get("image_url"),
-        )
-        for p in pages_data
-    ]
+    response_pages = _storybook_pages_to_response(pages_data)
 
     return StorybookResponse(
         id=story.id,
@@ -523,59 +642,31 @@ async def delete_story(
 
 
 async def create_story_from_result(
-    result,  # StoryOutput
+    result: StoryOutput,
     user_id: str,
     profile_id: str | None,
     universe_id: str | None,
     db: AsyncSession,
 ) -> Story:
     """Save a generated story to DB (helper for stream endpoint)."""
-    story = Story(
+    return await _persist_text_story_result(
+        result=result,
         user_id=user_id,
-        child_profile_id=profile_id,
+        profile_id=profile_id,
         universe_id=universe_id,
-        title=result.title,
-        story_text=result.story_text,
-        cover_prompt=result.cover_prompt_suggestion,
-        mode=result.mode,
+        db=db,
     )
-    sync_story_status(
-        story,
-        image_status=StoryAssetStatus.NOT_REQUESTED,
-        audio_status=StoryAssetStatus.NOT_REQUESTED,
-        last_error=None,
-    )
-    db.add(story)
-    await db.commit()
-    await db.refresh(story)
-
-    if universe_id:
-        extract_story_achievements.delay(story.id, universe_id)
-
-    return story
 
 
 async def _retry_cover_image_asset(story: Story, db: AsyncSession) -> None:
     """Retry cover generation for a text story."""
 
-    if not story.cover_prompt:
-        raise HTTPException(status_code=400, detail="Story has no cover prompt")
-
-    sync_story_status(story, image_status=StoryAssetStatus.GENERATING)
-    await db.commit()
-
-    try:
-        story.image_url = await generate_image(story.cover_prompt, db=db)
-        sync_story_status(story, image_status=StoryAssetStatus.READY)
-    except Exception as exc:
-        sync_story_status(
+    await _complete_cover_image_asset(
         story,
-            image_status=StoryAssetStatus.FAILED,
-            last_error=f"封面生成失败: {exc}",
+        db,
+        last_error_prefix="封面生成失败",
+        log_event="cover_asset_retry_failed",
     )
-        logger.error("cover_asset_retry_failed", story_id=story.id, error=str(exc))
-
-    await db.commit()
 
 
 async def _retry_storybook_image_assets(story: Story, db: AsyncSession) -> None:
@@ -682,30 +773,16 @@ async def generate_story_cover(
     """Generate cover image for an existing story."""
     story = await get_story_detail(story_id, user_id, db)
 
-    if not story.cover_prompt:
-        raise HTTPException(status_code=400, detail="Story has no cover prompt")
-
-    sync_story_status(story, image_status=StoryAssetStatus.GENERATING)
-    await db.commit()
-
-    try:
-        image_url = await generate_image(story.cover_prompt, db=db)
-        story.image_url = image_url
-        sync_story_status(
+    image_url, _ = await _complete_cover_image_asset(
         story,
-            image_status=StoryAssetStatus.READY,
+        db,
+        raise_on_failure=True,
+        log_event="cover_generation_failed",
     )
-        await db.commit()
+    if image_url is not None:
         return image_url
-    except Exception as e:
-        sync_story_status(
-            story,
-            image_status=StoryAssetStatus.FAILED,
-            last_error=str(e),
-        )
-        await db.commit()
-        logger.error("cover_generation_failed", story_id=story_id, error=str(e))
-        raise HTTPException(status_code=500, detail=f"Image generation failed: {e}")
+
+    raise HTTPException(status_code=500, detail="Image generation failed")
 
 
 async def generate_story_audio(

backend/tests/test_stories.py

@@ -428,6 +428,33 @@ class TestUnifiedGenerations:
         assert data["generation_status"] == "narrative_ready"
         assert data["image_status"] == "not_requested"
 
+    def test_create_story_generation_image_failure(
+        self,
+        auth_client: TestClient,
+        mock_text_provider,
+    ):
+        with patch("app.services.story_service.generate_image", new_callable=AsyncMock) as mock_img:
+            mock_img.side_effect = Exception("Image API error")
+
+            response = auth_client.post(
+                "/api/generations",
+                json={
+                    "output_mode": "story",
+                    "type": "keywords",
+                    "data": "小兔子, 森林",
+                    "generate_images": True,
+                },
+            )
+
+        assert response.status_code == 200
+        data = response.json()
+        assert data["image_url"] is None
+        assert data["generation_status"] == "degraded_completed"
+        assert data["image_status"] == "failed"
+        assert data["audio_status"] == "not_requested"
+        assert "Image API error" in data["errors"]["image"]
+        assert "Image API error" in data["last_error"]
+
     def test_create_storybook_generation_success(self, auth_client: TestClient):
         with patch(
             "app.services.story_service.generate_storybook",

docs/planning/week-1-execution-backlog.md

@@ -53,7 +53,7 @@
 - 已新增数据库迁移：
   - `0009_add_story_generation_statuses.py`
   - `0010_add_story_audio_cache_path.py`
-- 已完成一轮后端回归验证：`backend/` 下 `pytest -q` 结果为 `63 passed`
+- 已完成一轮后端回归验证：`backend/` 下 `pytest -q` 结果为 `64 passed`
 - 已完成全量后端 lint 清理：`ruff check app tests` 可通过
 - 已修复 admin-frontend 构建阻塞，主前端与管理端前端均可生产构建
 - 已落地首版统一资产重试入口：`POST /api/stories/{story_id}/assets/retry`
@@ -62,12 +62,17 @@
   - `GET /api/generations/{story_id}`
   - `POST /api/generations/{story_id}/retry-assets`
 - 用户前端与 admin 前端创建弹窗已切换到统一生成入口
+- service 内部已抽取统一工作流公共步骤：
+  - 档案/宇宙校验与 memory context 构建
+  - 文本故事主记录保存
+  - 绘本主记录保存
+  - 普通故事封面生成/重试
 
 ### What Is In Progress
 
-- 统一状态模型与统一外部 API 已落地，但内部 service workflow 仍未真正收束成单一路径
+- 统一状态模型与统一外部 API 已落地，内部 service workflow 已开始收束公共步骤
 - 旧生成 API 仍保留为兼容层，后续需要继续降低重复实现
-- 资产补全已经具备统一重试入口首版，但仍需要继续抽象统一补全过程和 generation job 边界
+- 资产补全已经具备统一重试入口首版，但绘本插图与音频还需要继续抽象统一补全过程和 generation job 边界
 
 ### What Is Still Pending
 

docs/product/unified-generation-workflow-prd.md

@@ -39,12 +39,16 @@ DreamWeaver 当前同时支持普通故事生成、完整故事生成和绘本
   - `GET /api/generations/{story_id}`
   - `POST /api/generations/{story_id}/retry-assets`
 - 用户前端与 admin 前端创建弹窗已切换到 `POST /api/generations`
+- service 内部已开始收束统一工作流步骤：
+  - 上下文准备：档案/宇宙校验 + memory context 构建
+  - 主记录保存：文本故事与绘本统一持久化入口
+  - 资产补全：普通故事封面生成/重试统一封装
 - 故事详情页封面补全已切换到统一资产重试入口
 - 管理端前端构建阻塞已修复，主前端与 admin 前端均可完成生产构建
 
 ### Still Missing
 
-- 普通故事、完整生成、绘本生成已有统一外部入口，但内部仍通过兼容 service 路径编排
+- 普通故事、完整生成、绘本生成已有统一外部入口，内部 workflow 已开始抽取公共步骤，但旧 service 函数仍作为兼容层保留
 - 统一资产重试入口仍是首版：已覆盖普通故事封面、绘本缺失插图、故事音频，但尚未抽象成完整 generation job 模型
 - `partial_ready`、`retryable_assets` 等更细粒度状态仍停留在目标态
 
@@ -60,11 +64,11 @@ DreamWeaver 当前同时支持普通故事生成、完整故事生成和绘本
 
 DreamWeaver 当前存在以下工作流层面问题：
 
-1. **生成入口正在统一中**
-   当前前端已切到 `/api/generations`，旧的 `/api/stories/generate`、`/api/stories/generate/full`、`/api/storybook/generate` 仍作为兼容入口保留。下一步重点是继续收束 service 内部路径。
+1. **生成入口已建立，内部路径正在收束**
+   当前前端已切到 `/api/generations`，旧的 `/api/stories/generate`、`/api/stories/generate/full`、`/api/storybook/generate` 仍作为兼容入口保留。service 内部已抽取上下文准备、主记录保存和封面资产补全 helper，下一步重点是继续统一音频与绘本插图补全过程。
 
-2. **保存与资产补全过程不统一**  
-   有的流程先存文本再补图，有的流程只返回绘本对象并依赖前端 store，有的流程不考虑音频状态。
+2. **保存与资产补全过程正在统一**
+   文本故事和绘本已拥有更清晰的主记录保存 helper；普通故事封面生成与重试已共用资产补全 helper。剩余差异集中在绘本插图补全和音频补全过程还未统一成 generation job。
 
 3. **状态表达不统一**  
    系统缺少标准的“生成中、部分完成、已完成、失败、可重试”等状态定义，导致前端难以做出成熟体验。