add top-bid router

Author: snu-BuMinSeong

carrot/app/auction/exceptions.py

@@ -40,4 +40,12 @@ def __init__(self) -> None:
             status_code=status.HTTP_400_BAD_REQUEST,
             error_code="AUC_005",
             error_msg="The bid price is too low.",
+        )
+
+class NoBidsFoundError(CarrotException):
+    def __init__(self) -> None:
+        super().__init__(
+            status_code=status.HTTP_404_NOT_FOUND,
+            error_code="AUC_006",
+            error_msg="No bids found for this auction.",
         )

carrot/app/auction/repositories.py

@@ -112,5 +112,15 @@ async def gets_user_bids(self, user_id: str) -> List[Bid]:
         )
         result = await self.session.execute(stmt)
         return result.scalars().all()
+    
+    async def get_top_bid_for_auction(self, auction_id: str) -> Optional[Bid]:
+        stmt = (
+            select(Bid)
+            .where(Bid.auction_id == auction_id)
+            .order_by(Bid.bid_price.desc())
+            .limit(1)
+        )
+        result = await self.session.execute(stmt)
+        return result.scalar_one_or_none()
 
 

carrot/app/auction/router.py

@@ -26,4 +26,14 @@ async def place_bid(
         bid_price=bid_data.bid_price
     )
 
-    return BidResponse.model_validate(bid)
+    return BidResponse.model_validate(bid)
+
+@auction_router.get("/{auction_id}/top-bid", response_model=BidResponse)
+async def get_top_bid(
+    auction_id: str,
+    service: Annotated[AuctionService, Depends()],
+) -> BidResponse:
+    
+    top_bid = await service.get_top_bid(auction_id)
+
+    return BidResponse.model_validate(top_bid)

carrot/app/auction/services.py

@@ -12,7 +12,8 @@
 
 from carrot.app.auction.exceptions import (
     AuctionAlreadyExistsError, 
-    AuctionNotFoundError, 
+    AuctionNotFoundError,
+    NoBidsFoundError, 
     NotAllowedActionError,
     AuctionAlreadyFinishedError
 )
@@ -50,4 +51,17 @@ async def place_bid(self, auction_id: str, bidder_id: str, bid_price: int) -> Bi
         await self.db_session.commit()
         await self.db_session.refresh(new_bid)
         await self.db_session.refresh(auction)
-        return new_bid
+        return new_bid
+    
+    async def get_top_bid(self, auction_id: str) -> Bid:
+        auction = await self.repository.get_auction_by_id(auction_id)
+
+        if auction is None:
+            raise AuctionNotFoundError()
+
+        top_bid = await self.repository.get_top_bid_by_auction_id(auction_id)
+
+        if top_bid is None:
+            raise NoBidsFoundError()  # 입찰이 없는 경우
+
+        return top_bid