feat(order): 优化优惠券处理逻辑

- 重构优惠券处理流程，提高代码可读性和可维护性
- 增加优惠券有效性验证，包括用户归属、使用状态和有效期
-优化优惠金额计算逻辑，支持满减券、折扣券和免费券
- 新增标记优惠券为已使用功能
- 在订单创建流程中应用优惠券并更新相关金额

src/main/java/com/gxwebsoft/shop/controller/ShopUserAddressController.java

@@ -44,6 +44,7 @@
         @GetMapping()
         public ApiResult<List<ShopUserAddress>> list(ShopUserAddressParam param) {
             // 使用关联查询
+            param.setUserId(getLoginUser().getUserId());
             return success(shopUserAddressService.listRel(param));
         }
 

src/main/java/com/gxwebsoft/shop/service/OrderBusinessService.java

@@ -81,7 +81,12 @@ public class OrderBusinessService {
         // 6. 保存订单商品
         saveOrderGoods(request, shopOrder);
 
-        // 7. 创建微信支付订单
+        // 7. 标记优惠券为已使用
+        if (shopOrder.getCouponId() != null && shopOrder.getCouponId() > 0) {
+            markCouponAsUsed(shopOrder.getCouponId(), shopOrder.getOrderId());
+        }
+
+        // 8. 创建微信支付订单
         try {
             return shopOrderService.createWxOrder(shopOrder);
         } catch (Exception e) {
@@ -277,32 +282,87 @@ public class OrderBusinessService {
             shopOrder.setPayType(1); // 默认微信支付
         }
 
-        // 优惠券
+        // 优惠券处理
         if (shopOrder.getCouponId() != null && shopOrder.getCouponId() > 0) {
-            ShopUserCoupon coupon = shopUserCouponService.getById(shopOrder.getCouponId());
-            if (coupon != null) {
-                BigDecimal reducePrice = BigDecimal.ZERO;
-                boolean doReduce = true;
-                if (coupon.getType().equals(10)) {
-                    reducePrice = coupon.getReducePrice();
-                    if (shopOrder.getTotalPrice().compareTo(coupon.getMinPrice()) < 0) doReduce = false;
-                } else if (coupon.getType().equals(20)) {
-                    reducePrice = shopOrder.getTotalPrice()
-                            .multiply(BigDecimal.valueOf(coupon.getDiscount()).divide(new BigDecimal(100), RoundingMode.HALF_UP));
-                } else if (coupon.getType().equals(30)) {
-                    reducePrice = shopOrder.getTotalPrice();
-                }
-                if (doReduce) {
-                    shopOrder.setReducePrice(shopOrder.getReducePrice().add(reducePrice));
-                    shopOrder.setPayPrice(shopOrder.getPayPrice().subtract(reducePrice));
-                }
-                // todo 商品/分类限制
-            }
+            processCoupon(shopOrder, loginUser);
         }
 
         return shopOrder;
     }
 
+    /**
+     * 处理优惠券
+     */
+    private void processCoupon(ShopOrder shopOrder, User loginUser) {
+        ShopUserCoupon coupon = shopUserCouponService.getById(shopOrder.getCouponId());
+        if (coupon == null) {
+            throw new BusinessException("优惠券不存在");
+        }
+
+        // 验证优惠券是否属于当前用户
+        if (!coupon.getUserId().equals(loginUser.getUserId())) {
+            throw new BusinessException("优惠券不属于当前用户");
+        }
+
+        // 验证优惠券是否已使用
+        if (coupon.getIsUse() != null && coupon.getIsUse().equals(1)) {
+            throw new BusinessException("优惠券已使用");
+        }
+
+        // 验证优惠券是否过期
+        if (coupon.getIsExpire() != null && coupon.getIsExpire().equals(1)) {
+            throw new BusinessException("优惠券已过期");
+        }
+
+        // 计算优惠金额
+        BigDecimal reducePrice = BigDecimal.ZERO;
+        boolean canUse = true;
+
+        if (coupon.getType().equals(10)) {
+            // 满减券
+            reducePrice = coupon.getReducePrice() != null ? coupon.getReducePrice() : BigDecimal.ZERO;
+            BigDecimal minPrice = coupon.getMinPrice() != null ? coupon.getMinPrice() : BigDecimal.ZERO;
+            if (shopOrder.getTotalPrice().compareTo(minPrice) < 0) {
+                canUse = false;
+                throw new BusinessException("订单金额不满足优惠券使用条件，最低消费：" + minPrice + "元");
+            }
+        } else if (coupon.getType().equals(20)) {
+            // 折扣券 - 计算减免金额（不是折扣后金额）
+            Integer discount = coupon.getDiscount() != null ? coupon.getDiscount() : 100;
+            if (discount < 0 || discount > 100) {
+                throw new BusinessException("优惠券折扣率异常");
+            }
+            // 减免金额 = 原价 * (100 - 折扣率) / 100
+            reducePrice = shopOrder.getTotalPrice()
+                    .multiply(new BigDecimal(100 - discount))
+                    .divide(new BigDecimal(100), 2, RoundingMode.HALF_UP);
+        } else if (coupon.getType().equals(30)) {
+            // 免费券
+            reducePrice = shopOrder.getTotalPrice();
+        } else {
+            throw new BusinessException("不支持的优惠券类型");
+        }
+
+        if (canUse && reducePrice.compareTo(BigDecimal.ZERO) > 0) {
+            // 确保减免金额不超过订单总额
+            if (reducePrice.compareTo(shopOrder.getTotalPrice()) > 0) {
+                reducePrice = shopOrder.getTotalPrice();
+            }
+
+            // 应用优惠
+            shopOrder.setReducePrice(shopOrder.getReducePrice().add(reducePrice));
+            shopOrder.setPayPrice(shopOrder.getPayPrice().subtract(reducePrice));
+
+            // 确保实付金额不为负数
+            if (shopOrder.getPayPrice().compareTo(BigDecimal.ZERO) < 0) {
+                shopOrder.setPayPrice(BigDecimal.ZERO);
+            }
+
+            log.info("应用优惠券成功 - 优惠券ID：{}，类型：{}，减免金额：{}，实付金额：{}",
+                    coupon.getId(), coupon.getType(), reducePrice, shopOrder.getPayPrice());
+        }
+    }
+
     /**
      * 处理收货地址信息
      * 优先级：前端传入地址 > 指定地址ID > 用户默认地址
@@ -588,6 +648,24 @@ public class OrderBusinessService {
         log.info("库存扣减完成");
     }
 
+    /**
+     * 标记优惠券为已使用
+     */
+    private void markCouponAsUsed(Integer couponId, Integer orderId) {
+        try {
+            ShopUserCoupon coupon = shopUserCouponService.getById(couponId);
+            if (coupon != null) {
+                // 使用实体类提供的方法标记为已使用
+                coupon.markAsUsed(orderId, null); // orderNo 在这里可以为null，因为已经有orderId了
+                shopUserCouponService.updateById(coupon);
+                log.info("优惠券标记为已使用 - 优惠券ID：{}，订单ID：{}", couponId, orderId);
+            }
+        } catch (Exception e) {
+            log.error("标记优惠券为已使用失败 - 优惠券ID：{}，订单ID：{}", couponId, orderId, e);
+            // 不抛出异常，避免影响订单创建流程
+        }
+    }
+
     /**
      * 检查是否为测试账号11
      */