把“章节正文 + 图片”从 chapters 单表/JSON 结构，重构为“章节 chapter + 段落 section + 图片 memoir_images 独立表”的新数据模型，同时联动修改接口、PDF 导出、异步任务、迁移脚本、测试，以及修复 Android 端聊天列表显示问题。 (#9)

* refactor: 表结构重构，新增段落section和图片image新表

* fix: fix android app import error

* refactor: 重构文件名

* fix: 优化提示词

* fix: 消息气泡显示位置异常问题

---------

Co-authored-by: yangshilin <2157598560@qq.com>

api/routers/books.py

@@ -112,14 +112,20 @@ async def export_pdf(
     if book.user_id != current_user.id:
         raise HTTPException(status_code=403, detail="无权导出此回忆录")
     
-    # 获取所有 active 章节
+    # 获取所有 active 章节并预加载 sections（供 PDF 按段渲染）
     from database.models import Chapter
-    stmt = select(Chapter).where(
-        Chapter.user_id == current_user.id,
-        Chapter.is_active == True
-    ).order_by(Chapter.order_index)
+    from sqlalchemy.orm import joinedload
+    stmt = (
+        select(Chapter)
+        .where(
+            Chapter.user_id == current_user.id,
+            Chapter.is_active == True,
+        )
+        .options(joinedload(Chapter.sections))
+        .order_by(Chapter.order_index)
+    )
     result = await db.execute(stmt)
-    chapters = result.scalars().all()
+    chapters = result.unique().scalars().all()
     
     # 生成 PDF
     pdf_bytes = await pdf_service.generate_pdf(book, chapters)

api/routers/chapters.py

@@ -8,9 +8,10 @@ from typing import List, Optional
 from fastapi import APIRouter, Depends, HTTPException, Query
 from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
+from sqlalchemy.orm import joinedload
 
 from database import get_async_db
-from database.models import Chapter as ChapterModel
+from database.models import Chapter as ChapterModel, ChapterSection
 from database.models import User as UserModel
 from middleware.auth import get_current_user
 from agents.prompts.memory_prompts import CHAPTER_CATEGORIES, CHAPTER_ORDER, STAGE_TO_ORDER
@@ -19,6 +20,7 @@ from services.memoir_images.schema import (
     IMAGE_STATUS_COMPLETED,
     normalize_image_assets,
 )
+from services.memoir_images.serializers import memoir_image_to_dict
 from services.memoir_images.settings import MemoirImageSettings
 from services.memoir_images.storage import (
     CosDownloadUrlError,
@@ -72,16 +74,68 @@ def _normalize_image_assets(images: list[dict] | None) -> list[dict]:
     return normalized_assets
 
 
+def _section_image_to_dict(section) -> dict | None:
+    """从 section.image_id 关联的 memoir_images（image_record）取配图。"""
+    if getattr(section, "image_record", None):
+        return memoir_image_to_dict(section.image_record)
+    return None
+
+
+def _chapter_cover_to_dict(ch) -> dict | None:
+    """优先从 memoir_images 表（section_id 为空的一条）取封面，否则回退到 chapter.cover_image JSON。"""
+    images = getattr(ch, "images", None) or []
+    for m in images:
+        if getattr(m, "section_id", None) is None:
+            return memoir_image_to_dict(m)
+    if getattr(ch, "cover_image", None) and isinstance(ch.cover_image, dict):
+        return ch.cover_image
+    return None
+
+
+def _sections_to_content_and_images(ch):
+    """
+    从 chapter.sections 按 order_index 顺序拼出 content 与 images，保证每段文字与配图一一对应。
+    客户端依赖 content 中的占位符（与 images 中每项的 placeholder 一致）来切分正文并插入图片。
+    """
+    sections = getattr(ch, "sections", None) or []
+    ordered = sorted(sections, key=lambda s: getattr(s, "order_index", 0))
+    parts = []
+    images = []
+    for s in ordered:
+        text = (s.content or "").strip()
+        if text:
+            parts.append(text)
+        img = _section_image_to_dict(s)
+        if img:
+            images.append(img)
+            placeholder = (img.get("placeholder") or "").strip()
+            if placeholder:
+                parts.append(placeholder)
+    content = "\n\n".join(parts) if parts else ""
+    return content, images
+
+
 def _chapter_to_dict(ch: ChapterModel) -> dict:
-    normalized_images = _normalize_image_assets(ch.images)
+    content, images_list = _sections_to_content_and_images(ch)
+    normalized_images = _normalize_image_assets(images_list)
+    cover = _chapter_cover_to_dict(ch)
+    cover_normalized = _normalize_image_assets([cover] if cover else [])[0] if cover else None
+    sections_data = []
+    if getattr(ch, "sections", None):
+        for s in sorted(ch.sections, key=lambda x: getattr(x, "order_index", 0)):
+            sec_img = _section_image_to_dict(s)
+            sec_img = _normalize_image_assets([sec_img] if sec_img else [])[0] if sec_img else None
+            sections_data.append({"content": (s.content or "").strip(), "image": sec_img})
     return {
         "id": ch.id,
         "title": ch.title,
-        "content": ch.content,
+        "content": content,
         "order_index": ch.order_index,
         "status": ch.status,
         "category": ch.category,
         "images": normalized_images,
+        "cover_image": cover_normalized,
+        "sections": sections_data,
         "updated_at": ch.updated_at.isoformat() if ch.updated_at else None,
         "is_new": ch.is_new,
         "source_segments": ch.source_segments or [],
@@ -98,15 +152,23 @@ async def get_chapters(
     获取用户所有章节（需要认证，仅返回 active 章节）。
     始终返回全部 8 个预定义类别，没有内容的类别用占位符返回。
     """
-    stmt = select(ChapterModel).where(
-        ChapterModel.user_id == current_user.id,
-        ChapterModel.is_active == True
+    stmt = (
+        select(ChapterModel)
+        .where(
+            ChapterModel.user_id == current_user.id,
+            ChapterModel.is_active == True,
+        )
+        .options(
+            joinedload(ChapterModel.sections),
+            joinedload(ChapterModel.images),
+            joinedload(ChapterModel.sections).joinedload(ChapterSection.image_record),
+        )
+        .order_by(ChapterModel.order_index)
     )
     if is_new is True:
         stmt = stmt.where(ChapterModel.is_new == True)
-    stmt = stmt.order_by(ChapterModel.order_index)
     result = await db.execute(stmt)
-    chapters = result.scalars().all()
+    chapters = result.unique().scalars().all()
 
     chapter_by_category: dict[str, ChapterModel] = {}
     for ch in chapters:
@@ -129,6 +191,8 @@ async def get_chapters(
                 "status": "empty",
                 "category": category,
                 "images": [],
+                "cover_image": None,
+                "sections": [],
                 "updated_at": None,
                 "is_new": False,
                 "source_segments": [],
@@ -147,26 +211,22 @@ async def get_chapter(
     db: AsyncSession = Depends(get_async_db)
 ):
     """获取章节详情（需要认证，只能访问自己的章节）"""
-    chapter = await db.get(ChapterModel, chapter_id)
+    stmt = (
+        select(ChapterModel)
+        .where(ChapterModel.id == chapter_id)
+        .options(
+            joinedload(ChapterModel.sections),
+            joinedload(ChapterModel.images),
+            joinedload(ChapterModel.sections).joinedload(ChapterSection.image_record),
+        )
+    )
+    result = await db.execute(stmt)
+    chapter = result.unique().scalar_one_or_none()
     if not chapter:
         raise HTTPException(status_code=404, detail="Chapter not found")
-    
-    # 验证用户权限
     if chapter.user_id != current_user.id:
         raise HTTPException(status_code=403, detail="无权访问此章节")
-    
-    return {
-        "id": chapter.id,
-        "title": chapter.title,
-        "content": chapter.content,
-        "order_index": chapter.order_index,
-        "status": chapter.status,
-        "category": chapter.category,
-        "images": _normalize_image_assets(chapter.images),
-        "updated_at": chapter.updated_at.isoformat() if chapter.updated_at else None,
-        "is_new": chapter.is_new,
-        "source_segments": chapter.source_segments or [],
-    }
+    return _chapter_to_dict(chapter)
 
 
 @router.delete("/{chapter_id}")