增加商家订单积分抵扣的逻辑。

app/api/endpoints/merchant_order.py

@@ -33,11 +33,21 @@ async def create_order(
     if not product:
         return error_response(code=404, message="商品不存在")
     
+    # 计算积分抵扣
+    available_points = current_user.points or 0
+    deduct_amount = min(
+        float(product.max_deduct_points),
+        available_points
+    ) if available_points > 0 else 0
+    
+    # 计算实际支付金额
+    original_amount = float(product.sale_price)
+    pay_amount = max(0, original_amount - deduct_amount)
+    
     # 生成订单号和核销码
     while True:
         order_id = generate_order_id()
         verify_code = generate_verify_code()
-        # 检查是否已存在
         exists = db.query(MerchantOrderDB).filter(
             (MerchantOrderDB.order_id == order_id) |
             (MerchantOrderDB.order_verify_code == verify_code)
@@ -50,10 +60,17 @@ async def create_order(
         order_id=order_id,
         user_id=current_user.userid,
         merchant_product_id=order.merchant_product_id,
-        order_amount=order.order_amount,
-        status=MerchantOrderStatus.CREATED,  # 创建时状态为已下单
+        order_amount=original_amount,
+        deduct_amount=deduct_amount,
+        pay_amount=pay_amount,
+        status=MerchantOrderStatus.CREATED,
         order_verify_code=verify_code
     )
+    
+    # 扣除用户积分
+    if deduct_amount > 0:
+        current_user.points -= deduct_amount
+    
     db.add(db_order)
     
     try:
@@ -290,3 +307,43 @@ async def get_order_detail(
     }
     
     return success_response(data=order_data)
+
+@router.post("/calculate-price", response_model=ResponseModel)
+async def calculate_order_price(
+    order: MerchantOrderCreate,
+    db: Session = Depends(get_db),
+    current_user: UserDB = Depends(get_current_user)
+):
+    """计算订单价格
+    
+    1. 获取商品信息和用户积分
+    2. 计算最高可抵扣金额
+    3. 返回最终支付金额
+    """
+    # 查询商品信息
+    product = db.query(MerchantProductDB).filter(
+        MerchantProductDB.id == order.merchant_product_id
+    ).first()
+    
+    if not product:
+        return error_response(code=404, message="商品不存在")
+    
+    # 获取用户积分
+    available_points = current_user.points or 0
+    
+    # 计算最高可抵扣金额（1积分 = 1分钱）
+    max_deduct_amount = min(
+        float(product.max_deduct_points),  # 商品最高可抵扣金额
+        available_points  # 用户可用积分
+    ) if available_points > 0 else 0
+    
+    # 计算最终支付金额
+    final_amount = max(0, float(product.sale_price) - max_deduct_amount)
+    
+    return success_response(data={
+        "original_price": float(product.sale_price),
+        "available_points": available_points,
+        "max_deduct_points": float(product.max_deduct_points),
+        "max_deduct_amount": max_deduct_amount,
+        "final_amount": final_amount
+    }) 

app/models/merchant_order.py

@@ -24,6 +24,8 @@ class MerchantOrderDB(Base):
     user_id = Column(Integer, ForeignKey("users.userid"), nullable=False)
     merchant_product_id = Column(Integer, ForeignKey("merchant_products.id"), nullable=False)
     order_amount = Column(DECIMAL(10,2), nullable=False)
+    deduct_amount = Column(DECIMAL(10,2), nullable=False, default=0)
+    pay_amount = Column(DECIMAL(10,2), nullable=False, default=0)
     status = Column(Enum(MerchantOrderStatus), nullable=False, default=MerchantOrderStatus.CREATED)
     order_verify_code = Column(String(21), unique=True, nullable=False)
     verify_time = Column(DateTime(timezone=True), nullable=True)
@@ -41,6 +43,8 @@ class MerchantOrderInfo(BaseModel):
     user_id: int
     merchant_product_id: int
     order_amount: float
+    deduct_amount: float
+    pay_amount: float
     status: MerchantOrderStatus
     order_verify_code: str
     verify_time: Optional[datetime]