From a86cfc379cd61a01182942ca34fec0adcd330df0 Mon Sep 17 00:00:00 2001
From: KKSU <15274802129@163.com>
Date: Fri, 10 Jan 2025 10:25:33 +0800
Subject: [PATCH] fix(mall): 修复优惠券满减逻辑

---
 src/main/java/cc/mrbird/febs/mall/service/impl/ApiMallOrderInfoServiceImpl.java |   57 +++++++++++++++++++++++++++++++++++++++------------------
 1 files changed, 39 insertions(+), 18 deletions(-)

diff --git a/src/main/java/cc/mrbird/febs/mall/service/impl/ApiMallOrderInfoServiceImpl.java b/src/main/java/cc/mrbird/febs/mall/service/impl/ApiMallOrderInfoServiceImpl.java
index cf964c3..1ddb84c 100644
--- a/src/main/java/cc/mrbird/febs/mall/service/impl/ApiMallOrderInfoServiceImpl.java
+++ b/src/main/java/cc/mrbird/febs/mall/service/impl/ApiMallOrderInfoServiceImpl.java
@@ -285,8 +285,8 @@
      * @return Map<Long,BigDecimal> skuId,实际支付金额
      */
     @Override
-    public Map<Long,BigDecimal> getCouponAmountMap(Long memberCouponId,List<AddOrderItemDto> items){
-        HashMap<Long,BigDecimal> couponAmountMap = new HashMap<>();
+    public Map<Long, BigDecimal> getCouponAmountMap(Long memberCouponId, List<AddOrderItemDto> items) {
+        HashMap<Long, BigDecimal> couponAmountMap = new HashMap<>();
         // 获取优惠券信息
         Optional<MallMemberCoupon> optionalMallMemberCoupon = Optional.ofNullable(mallMemberCouponMapper.selectById(memberCouponId));
         MallMemberCoupon mallMemberCoupon = optionalMallMemberCoupon.orElse(null);
@@ -295,7 +295,7 @@
             return couponAmountMap;
         }
 
-        Set<Long> intersection = items.stream().map(AddOrderItemDto::getSkuId).collect(Collectors.toSet());//订单中的全部skuIds
+        Set<Long> intersection = items.stream().map(AddOrderItemDto::getSkuId).collect(Collectors.toSet()); // 订单中的全部skuIds
 
         if (intersection.isEmpty()) {
             return couponAmountMap;
@@ -333,33 +333,54 @@
 
         BigDecimal costAmount = mallGoodsCoupon.getCostAmount();
         BigDecimal realAmount = mallGoodsCoupon.getRealAmount();
+        Integer type = mallGoodsCoupon.getType();
+        if (MallGoodsCoupon.TYPE_ONE == type) {
+            realAmount = mallGoodsCoupon.getRealAmount();
+        } else if (MallGoodsCoupon.TYPE_TWO == type) {
+            BigDecimal divideTime = totalAmount.divide(costAmount, 0, RoundingMode.DOWN); // 累计减免次数
+            realAmount = divideTime.multiply(realAmount); // 实际减免金额
+        }
 
         if (totalAmount.compareTo(costAmount) < 0) {
             return couponAmountMap;
         }
-        for (Map.Entry<Long,BigDecimal> entry : skuMap.entrySet()) {
+
+        BigDecimal totalDiscount = BigDecimal.ZERO;
+        for (Map.Entry<Long, BigDecimal> entry : skuMap.entrySet()) {
             Long keySkuId = entry.getKey();
             BigDecimal valueSkuAmount = entry.getValue();
-            BigDecimal divide = valueSkuAmount.divide(totalAmount, 4, RoundingMode.DOWN);//每个商品占符合满减的总额的比例
-            Integer type = mallGoodsCoupon.getType();
-            if(MallGoodsCoupon.TYPE_ONE == type){
-                BigDecimal bigDecimalOne = realAmount.multiply(divide).setScale(2, RoundingMode.DOWN);//每个SKU的减免金额(比例*减免金额)
-                BigDecimal skuRealAmountOne = valueSkuAmount.subtract(bigDecimalOne.max(BigDecimal.ZERO));//实际支付金额
-                couponAmountMap.put(keySkuId, skuRealAmountOne);
-                continue;
+            BigDecimal divide = valueSkuAmount.divide(totalAmount, 4, RoundingMode.DOWN); // 每个商品占符合满减的总额的比例
+            BigDecimal skuRealAmount = BigDecimal.ZERO;
+            if (MallGoodsCoupon.TYPE_ONE == type) {
+                BigDecimal bigDecimalOne = realAmount.multiply(divide).setScale(2, RoundingMode.DOWN); // 每个SKU的减免金额(比例*减免金额)
+                skuRealAmount = valueSkuAmount.subtract(bigDecimalOne.max(BigDecimal.ZERO)).setScale(2, RoundingMode.DOWN);
+                totalDiscount = totalDiscount.add(bigDecimalOne);
+            } else if (MallGoodsCoupon.TYPE_TWO == type) {
+                BigDecimal divideTime = totalAmount.divide(costAmount, 0, RoundingMode.DOWN); // 累计减免次数
+                BigDecimal multiply = divideTime.multiply(realAmount); // 实际减免金额
+                BigDecimal bigDecimalTwo = multiply.multiply(divide).setScale(2, RoundingMode.DOWN); // 每个SKU的减免金额(比例*实际减免金额)
+                skuRealAmount = valueSkuAmount.subtract(bigDecimalTwo.max(BigDecimal.ZERO)).setScale(2, RoundingMode.DOWN);
+                totalDiscount = totalDiscount.add(bigDecimalTwo);
             }
-            if(MallGoodsCoupon.TYPE_TWO == type){
-                BigDecimal divideTime = totalAmount.divide(costAmount, 0, RoundingMode.DOWN);//累计减免次数
-                BigDecimal multiply = divideTime.multiply(realAmount);//实际减免金额
-                BigDecimal bigDecimalTwo = multiply.multiply(divide).setScale(2, RoundingMode.DOWN);//每个SKU的减免金额(比例*实际减免金额)
-                BigDecimal skuRealAmountTwo = valueSkuAmount.subtract(bigDecimalTwo.max(BigDecimal.ZERO));//实际支付金额
-                couponAmountMap.put(keySkuId, skuRealAmountTwo);
-                continue;
+            couponAmountMap.put(keySkuId, skuRealAmount);
+        }
+
+        // 调整最后一个商品的减免金额以确保总减免金额达到预期
+        if (totalDiscount.compareTo(realAmount) < 0) {
+            BigDecimal difference = realAmount.subtract(totalDiscount);
+            for (Map.Entry<Long, BigDecimal> entry : couponAmountMap.entrySet()) {
+                Long keySkuId = entry.getKey();
+                BigDecimal skuRealAmount = entry.getValue();
+                BigDecimal newSkuRealAmount = skuRealAmount.subtract(difference).setScale(2, RoundingMode.DOWN);
+                couponAmountMap.put(keySkuId, newSkuRealAmount);
+                break; // 调整最后一个商品的减免金额
             }
         }
+
         return couponAmountMap;
     }
 
+
     public static void main(String[] args) {
         List<Integer> a = new ArrayList<>();
         a.add(1);

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