From 715ba070dde400a6697b0b334fe8e9d2e5706f80 Mon Sep 17 00:00:00 2001
From: Cui Zhi Feng <cuizf@fengyuntec.com>
Date: 星期四, 12 九月 2024 21:03:49 +0800
Subject: [PATCH] 下单优惠券计算

---
 src/main/java/com/mzl/flower/service/payment/OrderService.java |   33 ++++++++++++++++++++++++++++-----
 1 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/src/main/java/com/mzl/flower/service/payment/OrderService.java b/src/main/java/com/mzl/flower/service/payment/OrderService.java
index 54c79fb..18d752e 100644
--- a/src/main/java/com/mzl/flower/service/payment/OrderService.java
+++ b/src/main/java/com/mzl/flower/service/payment/OrderService.java
@@ -442,7 +442,7 @@
         order.setTransportFee(transportFee);
         order.setDeliveryName(deliveryName);
 
-        BigDecimal totalAmount = order.getFlowerAmount().add(p.getPacking()).add(transportFee);//使用优惠券之前的总价
+        BigDecimal totalAmount = order.getFlowerAmount();//使用优惠券之前的总价,使用商品价格
         CouponRecordDO coupon = useCouponRecord(order.getId(), totalAmount, dto.getCouponRecordId());
         log.info("用户优惠券: " + coupon);
         if(coupon != null){
@@ -453,7 +453,14 @@
 
             totalAmount = totalAmount.subtract(order.getMemberCouponAmount());//满足条件需要减去优惠券金额
         }
-        order.setTotalAmount(totalAmount);
+        if(totalAmount.doubleValue() < 0){//假如扣除优惠券后金额小于0,则按0计算
+            totalAmount = new BigDecimal(0);
+        }
+        totalAmount = totalAmount.add(p.getPacking()).add(transportFee);
+        if(totalAmount.doubleValue() <= 0){//假如总价小于等于0,则支付0.01元
+            totalAmount = new BigDecimal(0.01);
+        }
+        order.setTotalAmount(totalAmount.add(p.getPacking()).add(transportFee));
 
         order.setCustomer(address.getName());
         order.setCustomerTel(address.getTel());
@@ -475,7 +482,9 @@
         Map<Long, List<ParamItemDTO>> paramMap = new HashMap<>();
         final BigDecimal flowerAmount = order.getFlowerAmount();//订单商品总价
         final BigDecimal memberCouponAmount = order.getMemberCouponAmount();//使用优惠券面值
-        for (FlowerCartListDTO f : flowers) {
+        BigDecimal usedCouponAmount = new BigDecimal(0);
+        for (int i = 0; i < flowers.size(); i++) {
+            FlowerCartListDTO f = flowers.get(i);
             OrderItem t = new OrderItem();
             t.setId(UUIDGenerator.getUUID());
             t.setOrderId(order.getId());
@@ -504,9 +513,13 @@
             t.setTotal(f.getTotalMember());//使用会员总价
 
             t.setOriginalPrice(pp.getPrice());//非会员售价
-            BigDecimal couponAmount = calculateCoupon(memberCouponAmount, t.getTotal(), flowerAmount, t.getNum());
+            boolean isLastOne = i == (flowers.size() - 1);
+            BigDecimal couponAmount = calculateCoupon(memberCouponAmount, t.getTotal()
+                    , flowerAmount, t.getNum(), t.getPrice(), isLastOne, usedCouponAmount);
             t.setCouponAmount(couponAmount);//每扎平摊的优惠券面值
             t.setRealPrice(t.getPrice().subtract(couponAmount));//退款时使用的真实成交价
+
+            usedCouponAmount = usedCouponAmount.add(couponAmount.multiply(BigDecimal.valueOf(t.getNum())));
 
             t.create(userId);
             orderItemMapper.insert(t);
@@ -551,13 +564,23 @@
      * @param itemTotalAmount
      * @param totalAmount
      * @param num
+     * @param price
      * @return
      */
     private BigDecimal calculateCoupon(BigDecimal couponAmount, BigDecimal itemTotalAmount
-            , BigDecimal totalAmount, Integer num){
+            , BigDecimal totalAmount, Integer num, BigDecimal price
+            , boolean isLastOne, BigDecimal usedCouponAmount){
         if(couponAmount == null){
             return new BigDecimal(0);
         }
+
+        if(couponAmount.doubleValue() >= totalAmount.doubleValue()){
+            return price;
+        }
+        if(isLastOne){//最后的商品使用优惠券剩下的面值
+            BigDecimal subCoupon = couponAmount.subtract(usedCouponAmount);//占有的优惠券面值
+            return subCoupon.divide(BigDecimal.valueOf(num), 2, RoundingMode.HALF_UP);
+        }
         BigDecimal radio = itemTotalAmount.divide(totalAmount, 2, RoundingMode.HALF_UP);//计算该商品总价在订单中的占比
         BigDecimal subCoupon = couponAmount.multiply(radio);//占有的优惠券面值
         return subCoupon.divide(BigDecimal.valueOf(num), 2, RoundingMode.HALF_UP);

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