draft

backend/internal/service/service_fee.go

@@ -0,0 +1,189 @@
+package service
+
+import (
+	"context"
+	"fmt"
+	"log/slog"
+	"math"
+
+	"pay-bridge/internal/channel"
+	"pay-bridge/internal/model"
+	"pay-bridge/internal/repository"
+)
+
+// ServiceFeeService 服务费服务
+type ServiceFeeService struct {
+	feeRepo    *repository.ServiceFeeRepository
+	tradeRepo  *repository.TradeOrderRepository
+	channelSvc *ChannelService
+}
+
+func NewServiceFeeService(
+	feeRepo *repository.ServiceFeeRepository,
+	tradeRepo *repository.TradeOrderRepository,
+	channelSvc *ChannelService,
+) *ServiceFeeService {
+	return &ServiceFeeService{
+		feeRepo:    feeRepo,
+		tradeRepo:  tradeRepo,
+		channelSvc: channelSvc,
+	}
+}
+
+// ChargeServiceFee 交易完成后扣收服务费
+func (s *ServiceFeeService) ChargeServiceFee(ctx context.Context, tradeNo string) error {
+	order, err := s.tradeRepo.GetByTradeNo(ctx, tradeNo)
+	if err != nil || order == nil {
+		return fmt.Errorf("order not found: %s", tradeNo)
+	}
+
+	// 幂等检查
+	existing, err := s.feeRepo.GetLog(ctx, tradeNo, "CHARGE")
+	if err != nil {
+		return err
+	}
+	if existing != nil {
+		return nil // 已扣收
+	}
+
+	// 获取服务费配置
+	group := model.PayMethodToGroup(order.PayMethod)
+	cfg, err := s.feeRepo.GetConfig(ctx, order.AppID, group)
+	if err != nil {
+		return err
+	}
+	if cfg == nil || cfg.FeeRate == 0 {
+		return nil // 未配置或费率为0
+	}
+
+	// 计算服务费（四舍五入到分）
+	feeAmount := calculateFee(order.Amount, cfg.FeeRate)
+	if feeAmount <= 0 {
+		return nil // 不足1分不扣收
+	}
+
+	// 更新订单服务费金额快照
+	s.tradeRepo.UpdateStatus(ctx, tradeNo, model.TradeStatusPaid, model.TradeStatusPaid,
+		map[string]any{"service_fee_amount": feeAmount})
+
+	// 创建服务费流水
+	log := &model.ServiceFeeLog{
+		TradeNo:            tradeNo,
+		ConfigID:           cfg.ID,
+		FeeAmount:          feeAmount,
+		FeeRate:            cfg.FeeRate,
+		ReceiverMerchantID: cfg.FeeReceiverMerchantID,
+		Action:             "CHARGE",
+		Status:             "PENDING",
+	}
+	if err := s.feeRepo.CreateLog(ctx, log); err != nil {
+		return err
+	}
+
+	// 调用渠道分账
+	ch, err := s.channelSvc.GetChannel(ctx, order.AppID, order.ChannelCode)
+	if err != nil {
+		s.feeRepo.UpdateLogStatus(ctx, log.ID, "FAILED", "")
+		return err
+	}
+
+	resp, err := ch.ProfitSharing(ctx, &channel.ProfitSharingReq{
+		TradeNo:            tradeNo,
+		ChannelTradeNo:     order.ChannelTradeNo,
+		SharingNo:          fmt.Sprintf("FEE%s", tradeNo),
+		ReceiverMerchantID: cfg.FeeReceiverMerchantID,
+		Amount:             feeAmount,
+	})
+	if err != nil {
+		s.feeRepo.UpdateLogStatus(ctx, log.ID, "FAILED", "")
+		slog.WarnContext(ctx, "charge service fee failed", "trade_no", tradeNo, "err", err)
+		return err
+	}
+
+	s.feeRepo.UpdateLogStatus(ctx, log.ID, "SUCCESS", resp.ChannelSharingNo)
+	slog.InfoContext(ctx, "service fee charged", "trade_no", tradeNo, "fee_amount", feeAmount)
+	return nil
+}
+
+// RollbackServiceFee 退款时回退服务费
+func (s *ServiceFeeService) RollbackServiceFee(ctx context.Context, tradeNo string) error {
+	// 幂等检查
+	existing, err := s.feeRepo.GetLog(ctx, tradeNo, "ROLLBACK")
+	if err != nil {
+		return err
+	}
+	if existing != nil {
+		return nil // 已回退
+	}
+
+	chargeLog, err := s.feeRepo.GetLog(ctx, tradeNo, "CHARGE")
+	if err != nil {
+		return err
+	}
+	if chargeLog == nil || chargeLog.Status != "SUCCESS" {
+		return nil // 没有成功扣收，无需回退
+	}
+
+	order, err := s.tradeRepo.GetByTradeNo(ctx, tradeNo)
+	if err != nil || order == nil {
+		return fmt.Errorf("order not found: %s", tradeNo)
+	}
+
+	rollbackLog := &model.ServiceFeeLog{
+		TradeNo:            tradeNo,
+		ConfigID:           chargeLog.ConfigID,
+		FeeAmount:          chargeLog.FeeAmount,
+		FeeRate:            chargeLog.FeeRate,
+		ReceiverMerchantID: chargeLog.ReceiverMerchantID,
+		Action:             "ROLLBACK",
+		Status:             "PENDING",
+	}
+	if err := s.feeRepo.CreateLog(ctx, rollbackLog); err != nil {
+		return err
+	}
+
+	ch, err := s.channelSvc.GetChannel(ctx, order.AppID, order.ChannelCode)
+	if err != nil {
+		return err
+	}
+
+	sharingNo := fmt.Sprintf("FEE%s", tradeNo)
+	if err := ch.RollbackProfitSharing(ctx, &channel.RollbackSharingReq{
+		SharingNo:        sharingNo,
+		ChannelSharingNo: chargeLog.ChannelSharingNo,
+		TradeNo:          tradeNo,
+	}); err != nil {
+		s.feeRepo.UpdateLogStatus(ctx, rollbackLog.ID, "FAILED", "")
+		return err
+	}
+
+	s.feeRepo.UpdateLogStatus(ctx, rollbackLog.ID, "SUCCESS", "")
+	return nil
+}
+
+// CalculateAndValidate 下单时校验分润+服务费不超过订单金额
+func (s *ServiceFeeService) CalculateAndValidate(ctx context.Context, appID string, payMethod model.PayMethod, orderAmount, sharingAmount int64) (int64, error) {
+	group := model.PayMethodToGroup(payMethod)
+	cfg, err := s.feeRepo.GetConfig(ctx, appID, group)
+	if err != nil {
+		return 0, err
+	}
+
+	var feeAmount int64
+	if cfg != nil && cfg.FeeRate > 0 {
+		feeAmount = calculateFee(orderAmount, cfg.FeeRate)
+	}
+
+	if sharingAmount+feeAmount > orderAmount {
+		return 0, fmt.Errorf(errSharingFeeExceed)
+	}
+	return feeAmount, nil
+}
+
+const errSharingFeeExceed = "30007" // errcode.ErrSharingFeeExceed
+
+// calculateFee 计算服务费（四舍五入到分）
+func calculateFee(amount int64, rate float64) int64 {
+	fee := float64(amount) * rate
+	return int64(math.Round(fee))
+}