fix(mall): 修复优惠券满减逻辑

KKSU

2025-01-10 a86cfc379cd61a01182942ca34fec0adcd330df0

fix(mall): 修复优惠券满减逻辑

- 重构 getCouponAmountMap 方法，优化满减计算逻辑
- 添加对不同类型优惠券的处理支持
- 修复多个 SKU 商品满减分配不准确的问题
- 优化代码结构，提高可读性和可维护性

 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);