feat:add price expectation

Router/price.py

@@ -0,0 +1,35 @@
+from fastapi.responses import JSONResponse
+
+from Data.user import LoginUser, UserCreate
+from Database.database import get_db
+from fastapi import APIRouter
+from starlette.status import *
+from fastapi import Query, Request
+from Database.models import User
+from Service.item_service import ItemService
+from Service.purchase_service import PurchaseService
+from Service.useritem_service import UserItemService
+
+
+router = APIRouter(tags=["price"], prefix="/price")
+
+@router.get("/{user_id}")
+def get_expected_price(request : Request, user_id: str, date : str = Query(...)):
+    try:
+        year, month = map(int, date.split("-"))
+        user_item_list = UserItemService.get_all_userItem_filtered_by_date(user_id, year, month)
+        price = 0
+        for useritem in user_item_list:
+            purchases = PurchaseService.get_purchase_histories_by_item_id(useritem.item_id)
+            if len(purchases) == 0:
+                item = ItemService.get_item(useritem.item_name)
+                price += item.base_price * item.base_count
+            else:
+                avg_count = round(sum([purchase.count for purchase in purchases]) / len(purchases))
+                avg_price = sum([purchase.price for purchase in purchases]) / len(purchases)
+                price += avg_count * avg_price
+        return JSONResponse(status_code=HTTP_200_OK, content={"price": price})
+    except ValueError:
+        return JSONResponse(status_code=HTTP_400_BAD_REQUEST, content={"message": "Invalid date format"})
+    except Exception as e:
+        return JSONResponse(status_code=HTTP_500_INTERNAL_SERVER_ERROR, content={"message": str(e)})