add summary

app/main.py

@@ -88,6 +88,35 @@ def _wants_add_next(submit_action: str | None) -> bool:
     return submit_action == "save_and_add_next"
 
 
+def _format_average(total: int, divisor: int) -> str:
+    if divisor == 0:
+        return "0.0"
+    return f"{total / divisor:.1f}"
+
+
+def _build_boxes_overview_summary(db: Session) -> dict[str, int | str]:
+    box_count = db.query(func.count(Box.id)).scalar() or 0
+    item_count = db.query(func.count(Item.id)).scalar() or 0
+    subitem_count = db.query(func.count(SubItem.id)).scalar() or 0
+    container_item_count = (
+        db.query(func.count(Item.id))
+        .filter(Item.is_container.is_(True))
+        .scalar()
+        or 0
+    )
+
+    return {
+        "box_count": box_count,
+        "item_count": item_count,
+        "item_and_subitem_count": item_count + subitem_count,
+        "avg_items_per_box": _format_average(item_count, box_count),
+        "avg_subitems_per_container_item": _format_average(
+            subitem_count,
+            container_item_count,
+        ),
+    }
+
+
 def _build_search_results(db: Session, query: str) -> list[dict]:
     keyword = f"%{query.lower()}%"
     results: list[dict] = []
@@ -231,10 +260,11 @@ def create_app() -> FastAPI:
     @app.get("/boxes")
     def list_boxes(request: Request, db: Session = Depends(get_db)):
         boxes = db.query(Box).order_by(Box.id.desc()).all()
+        summary = _build_boxes_overview_summary(db)
         return templates.TemplateResponse(
             request=request,
             name="boxes/index.html",
-            context={"page_title": "箱子", "boxes": boxes},
+            context={"page_title": "箱子", "boxes": boxes, "summary": summary},
         )
 
     @app.get("/boxes/new")