back/internal/api/mobile/order_preview/coupon_update.go

package order_preview

import (
	"github.com/gin-gonic/gin"
	"github.com/shopspring/decimal"
	"recook/internal/back"
	"recook/internal/dbc"
	"recook/internal/model/order_preview"
	"recook/internal/model/user"
	"recook/tools"
)

type updateOrderCouponUseStatusParam struct {
	UserID  uint `json:"userId" validate:"required"`
	OrderID uint `json:"orderId" validate:"required"`
}

func UpdatePreOrderNoUseCoupon(c *gin.Context) {
	var p updateOrderCouponUseStatusParam
	if err := tools.ParseParams(&p, c); err != nil {
		back.Fail(c, err.Error())
		return
	}

	var preOrderInfo order_preview.Information
	if err := dbc.DB.First(&preOrderInfo, "id = ?", p.OrderID).Error; err != nil {
		back.Err(c, err.Error())
		return
	}

	var coupons []order_preview.CouponDetail
	if err := dbc.DB.Find(&coupons, "order_id = ?", p.OrderID).Error; err != nil {
		back.Err(c, err.Error())
		return
	}

	if len(coupons) == 0 {
		back.Fail(c, "没有优惠券可以使用")
		return
	}

	var preGoodsList []order_preview.GoodsDetail
	if err := dbc.DB.Find(&preGoodsList, "order_id = ?", p.OrderID).Error; err != nil {
		back.Err(c, err.Error())
		return
	}

	tx := dbc.DB.Begin()
	{
		// 将优惠券记录删除 将订单中的优惠券金额减去 将实际支付价格修改成没有优惠券的价格 瑞币抵扣重新计算
		brandCouponTotalAmount := decimal.NewFromFloat(0.0)
		universeCouponTotalAmount := decimal.NewFromFloat(0.0)
		coinTotalAmount := decimal.NewFromFloat(0.0)

		var wallet user.Wallet
		if err := dbc.DB.First(&wallet, "user_id = ?", p.UserID).Error; err != nil {
			back.Err(c, err.Error())
			return
		}

		for _, v := range coupons {
			if v.Scope == 0 { // 通用的
				universeCouponTotalAmount = universeCouponTotalAmount.Add(v.DeductedAmount)
			} else if v.Scope == 1 {
				brandCouponTotalAmount = brandCouponTotalAmount.Add(v.DeductedAmount)
			}

			if err := tx.Delete(&v).Error; err != nil {
				tx.Rollback()
				back.Err(c, err.Error())
				return
			}
		}

		if wallet.Coin.GreaterThanOrEqual(decimal.NewFromInt(1)) { // 瑞币金额不小于1块钱时可以抵扣
			//walletCoinAmount := decimal.NewFromInt(int64(wallet.Coin)).Div(decimal.NewFromInt(100))                    // 将瑞币折算为实际金额
			walletCoinAmount := wallet.Coin                                                                            // 1 瑞币 == 1 rmb
			if preOrderInfo.ActualTotalAmount.Add(preOrderInfo.CoinTotalAmount).GreaterThanOrEqual(walletCoinAmount) { // 只能抵扣部分价格, 全部花光瑞比
				coinTotalAmount = walletCoinAmount
			} else {
				// 不能全部花光瑞比，瑞比足够支付时 将瑞币直接使用掉 订单金额为0
				coinTotalAmount = preOrderInfo.ActualTotalAmount.Add(preOrderInfo.CoinTotalAmount)
			}
		}

		if err := tx.Model(&preOrderInfo).Updates(map[string]interface{}{
			"brand_coupon_total_amount":    0.0,
			"universe_coupon_total_amount": 0.0,
			"coin_total_amount":            coinTotalAmount,
			"actual_total_amount":          preOrderInfo.ActualTotalAmount.Add(preOrderInfo.CoinTotalAmount).Sub(coinTotalAmount).Add(preOrderInfo.BrandCouponTotalAmount).Add(preOrderInfo.UniverseCouponTotalAmount),
		}).Error; err != nil {
			tx.Rollback()
			back.Err(c, err.Error())
			return
		}

		length := len(preGoodsList)
		previousCoinTotalAmount := decimal.NewFromFloat(0.0)
		for i, v := range preGoodsList {
			coinAmount := decimal.NewFromFloat(0.0)
			if i == length-1 { // 保证没有循环小数
				coinAmount = coinTotalAmount.Sub(previousCoinTotalAmount)
			} else {
				rate := (v.GoodsAmount.Add(v.ExpressFee)).Div(preOrderInfo.GoodsTotalAmount.Add(preOrderInfo.ExpressTotalFee))
				coinAmount = coinTotalAmount.Mul(rate).Round(2)
				previousCoinTotalAmount = previousCoinTotalAmount.Add(coinAmount)
			}

			if err := tx.Model(&v).Updates(map[string]interface{}{
				"brand_coupon_amount":    0.0,
				"universe_coupon_amount": 0.0,
				"coin_amount":            coinAmount,
				"actual_amount":          v.ActualAmount.Add(v.BrandCouponAmount).Add(v.UniverseCouponAmount).Sub(coinAmount),
			}).Error; err != nil {
				tx.Rollback()
				back.Err(c, err.Error())
				return
			}
		}
	}
	tx.Commit()
	back.Suc(c, "", queryPreviewOrderGroup(preOrderInfo.ID))
}