增加限购功能。

app/api/endpoints/merchant_order.py

@@ -1,5 +1,6 @@
 from fastapi import APIRouter, Depends, HTTPException
 from sqlalchemy.orm import Session
+from sqlalchemy import func
 from typing import List
 from app.models.merchant_order import (
     MerchantOrderDB,
@@ -35,6 +36,25 @@ async def create_merchant_order(
     if not product:
         return error_response(code=404, message="商品不存在")
     
+    # 检查限购
+    if product.purchase_limit:
+        # 查询用户已购买数量
+        purchased_count = db.query(func.count(MerchantOrderDB.id)).filter(
+            MerchantOrderDB.user_id == current_user.userid,
+            MerchantOrderDB.merchant_product_id == product.id,
+            MerchantOrderDB.status.in_([
+                MerchantOrderStatus.CREATED,
+                MerchantOrderStatus.VERIFIED,
+                MerchantOrderStatus.UNVERIFIED
+            ])
+        ).scalar()
+        
+        if purchased_count >= product.purchase_limit:
+            return error_response(
+                code=400, 
+                message=f"该商品限购{product.purchase_limit}次，您已达到限购次数"
+            )
+    
     original_amount = float(product.sale_price)
     pay_amount = original_amount
     

app/models/merchant_product.py

@@ -1,4 +1,4 @@
-from sqlalchemy import Column, String, Integer, Float, DateTime, ForeignKey, Enum
+from sqlalchemy import Column, String, Integer, Float, DateTime, ForeignKey, Enum, Boolean
 from sqlalchemy.dialects.mysql import DECIMAL
 from sqlalchemy.sql import func
 from pydantic import BaseModel, Field
@@ -23,6 +23,7 @@ class MerchantProductDB(Base):
     sale_price = Column(Float, nullable=False)     # 售价
     settlement_amount = Column(DECIMAL(10,2), nullable=False)  # 商家结算金额
     tags = Column(String(200))                     # 标签，逗号分隔
+    purchase_limit = Column(Integer, nullable=False, default=0)  # 限购次数，0表示不限购
     create_time = Column(DateTime(timezone=True), server_default=func.now())
     update_time = Column(DateTime(timezone=True), onupdate=func.now())
     status = Column(Enum(ProductStatus), nullable=False, default=ProductStatus.UNLISTING)
@@ -37,6 +38,7 @@ class MerchantProductCreate(BaseModel):
     sale_price: float = Field(..., gt=0)
     settlement_amount: float = Field(..., gt=0)
     tags: str = Field("", max_length=200)
+    purchase_limit: int = Field(0, ge=0)  # 限购次数，默认0表示不限购
     status: ProductStatus = ProductStatus.UNLISTING
 
 class MerchantProductUpdate(BaseModel):
@@ -46,6 +48,7 @@ class MerchantProductUpdate(BaseModel):
     sale_price: Optional[float] = Field(None, gt=0)
     settlement_amount: Optional[float] = Field(None, gt=0)
     tags: Optional[str] = Field(None, max_length=200)
+    purchase_limit: Optional[int] = Field(None, ge=0)  # 限购次数，可选字段
     status: Optional[ProductStatus] = None
 
 class MerchantProductInfo(BaseModel):
@@ -58,6 +61,7 @@ class MerchantProductInfo(BaseModel):
     sale_price: float
     settlement_amount: float
     tags: str
+    purchase_limit: int  # 限购次数
     create_time: datetime
     update_time: Optional[datetime]
     status: ProductStatus