draft

backend/internal/service/refund.go

@@ -0,0 +1,213 @@
+package service
+
+import (
+	"context"
+	"errors"
+	"log/slog"
+
+	"time"
+
+	"pay-bridge/internal/channel"
+	"pay-bridge/internal/errcode"
+	"pay-bridge/internal/model"
+	"pay-bridge/internal/repository"
+	"pay-bridge/pkg/sequence"
+)
+
+// CreateRefundReq 退款请求
+type CreateRefundReq struct {
+	AppID        string
+	TradeNo      string
+	RefundAmount int64
+	Reason       string
+	NotifyURL    string
+}
+
+// RefundService 退款服务
+type RefundService struct {
+	refundRepo *repository.RefundOrderRepository
+	tradeRepo  *repository.TradeOrderRepository
+	channelSvc *ChannelService
+	seqSvc     *sequence.Service
+	notifySvc  *NotifyService
+}
+
+func NewRefundService(
+	refundRepo *repository.RefundOrderRepository,
+	tradeRepo *repository.TradeOrderRepository,
+	channelSvc *ChannelService,
+	seqSvc *sequence.Service,
+	notifySvc *NotifyService,
+) *RefundService {
+	return &RefundService{
+		refundRepo: refundRepo,
+		tradeRepo:  tradeRepo,
+		channelSvc: channelSvc,
+		seqSvc:     seqSvc,
+		notifySvc:  notifySvc,
+	}
+}
+
+// CreateRefund 发起退款
+func (s *RefundService) CreateRefund(ctx context.Context, req *CreateRefundReq) (*model.RefundOrder, error) {
+	// 查询原交易
+	order, err := s.tradeRepo.GetByTradeNo(ctx, req.TradeNo)
+	if err != nil {
+		return nil, err
+	}
+	if order == nil || order.AppID != req.AppID {
+		return nil, errors.New(errcode.ErrOrderNotFound)
+	}
+	if order.Status != model.TradeStatusPaid && order.Status != model.TradeStatusRefunded {
+		return nil, errors.New(errcode.ErrOrderNotPaid)
+	}
+
+	// 校验可退金额
+	refunded, err := s.refundRepo.SumRefundedAmount(ctx, req.TradeNo)
+	if err != nil {
+		return nil, err
+	}
+	if refunded+req.RefundAmount > order.Amount {
+		return nil, errors.New(errcode.ErrRefundAmountExceed)
+	}
+
+	// 生成退款单号
+	refundNo, err := s.seqSvc.NextRefundNo(ctx, req.AppID)
+	if err != nil {
+		return nil, err
+	}
+
+	// 创建退款记录
+	refund := &model.RefundOrder{
+		RefundNo:     refundNo,
+		TradeNo:      req.TradeNo,
+		AppID:        req.AppID,
+		ChannelCode:  order.ChannelCode,
+		RefundAmount: req.RefundAmount,
+		Reason:       req.Reason,
+		Status:       model.RefundStatusPending,
+		NotifyURL:    req.NotifyURL,
+	}
+	if err := s.refundRepo.Create(ctx, refund); err != nil {
+		return nil, err
+	}
+
+	// 调用渠道退款
+	ch, err := s.channelSvc.GetChannel(ctx, req.AppID, order.ChannelCode)
+	if err != nil {
+		return nil, err
+	}
+
+	channelResp, err := ch.Refund(ctx, &channel.RefundReq{
+		TradeNo:        req.TradeNo,
+		ChannelTradeNo: order.ChannelTradeNo,
+		RefundNo:       refundNo,
+		RefundAmount:   req.RefundAmount,
+		TotalAmount:    order.Amount,
+		Reason:         req.Reason,
+		NotifyURL:      req.NotifyURL,
+	})
+	if err != nil {
+		s.refundRepo.UpdateStatus(ctx, refundNo, model.RefundStatusPending, model.RefundStatusFailed, nil)
+		return nil, errors.New(errcode.ErrChannelRefundFail)
+	}
+
+	// 更新渠道退款单号
+	updates := map[string]any{
+		"channel_refund_no": channelResp.ChannelRefundNo,
+		"status":            model.RefundStatusProcessing,
+	}
+	s.refundRepo.UpdateStatus(ctx, refundNo, model.RefundStatusPending, model.RefundStatusProcessing, updates)
+
+	refund.ChannelRefundNo = channelResp.ChannelRefundNo
+	refund.Status = model.RefundStatusProcessing
+	return refund, nil
+}
+
+// QueryRefund 查询退款状态
+func (s *RefundService) QueryRefund(ctx context.Context, appID, refundNo string) (*model.RefundOrder, error) {
+	refund, err := s.refundRepo.GetByRefundNo(ctx, refundNo)
+	if err != nil {
+		return nil, err
+	}
+	if refund == nil || refund.AppID != appID {
+		return nil, errors.New(errcode.ErrRefundNotFound)
+	}
+
+	// 如果处于处理中，主动查询渠道
+	if refund.Status == model.RefundStatusProcessing {
+		s.syncRefundStatus(ctx, refund)
+		// 重新查询最新状态
+		refund, _ = s.refundRepo.GetByRefundNo(ctx, refundNo)
+	}
+
+	return refund, nil
+}
+
+// HandleRefundNotify 处理退款回调
+func (s *RefundService) HandleRefundNotify(ctx context.Context, refundNo string, channelRefundNo string, status model.RefundStatus) error {
+	refund, err := s.refundRepo.GetByRefundNo(ctx, refundNo)
+	if err != nil || refund == nil {
+		return errors.New(errcode.ErrRefundNotFound)
+	}
+
+	if refund.Status == model.RefundStatusSuccess {
+		return nil // 幂等
+	}
+
+	updates := map[string]any{
+		"channel_refund_no": channelRefundNo,
+	}
+	if status == model.RefundStatusSuccess {
+		now := time.Now()
+		updates["refund_time"] = now
+	}
+
+	ok, err := s.refundRepo.UpdateStatus(ctx, refundNo, model.RefundStatusProcessing, status, updates)
+	if err != nil {
+		return err
+	}
+	if !ok {
+		return nil // 幂等
+	}
+
+	// 退款成功后通知下游
+	if status == model.RefundStatusSuccess && refund.NotifyURL != "" && s.notifySvc != nil {
+		go func() {
+			bgCtx := context.Background()
+			if err := s.notifySvc.SendNotify(bgCtx, refund.TradeNo, model.NotifyTypeRefund, refund.NotifyURL); err != nil {
+				slog.Error("send refund notify failed", "refund_no", refundNo, "err", err)
+			}
+		}()
+	}
+
+	return nil
+}
+
+func (s *RefundService) syncRefundStatus(ctx context.Context, refund *model.RefundOrder) {
+	order, err := s.tradeRepo.GetByTradeNo(ctx, refund.TradeNo)
+	if err != nil || order == nil {
+		return
+	}
+	ch, err := s.channelSvc.GetChannel(ctx, refund.AppID, refund.ChannelCode)
+	if err != nil {
+		return
+	}
+	resp, err := ch.QueryRefund(ctx, &channel.QueryRefundReq{
+		RefundNo:        refund.RefundNo,
+		ChannelRefundNo: refund.ChannelRefundNo,
+	})
+	if err != nil {
+		return
+	}
+	if resp.Status != refund.Status {
+		updates := map[string]any{
+			"channel_refund_no": resp.ChannelRefundNo,
+		}
+		if resp.RefundTime != nil {
+			updates["refund_time"] = resp.RefundTime
+		}
+		s.refundRepo.UpdateStatus(ctx, refund.RefundNo, refund.Status, resp.Status, updates)
+	}
+}
+