接入订单结账确认流程

backend/internal/modules/order/service.go

@@ -14,6 +14,10 @@ var (
 	ErrOrderCannotReceive    = errors.New("order cannot receive")
 	ErrOrderCannotReturn     = errors.New("order cannot return")
 	ErrOrderCannotComplete   = errors.New("order cannot complete")
+	ErrCheckoutCannotSubmit  = errors.New("checkout cannot submit")
+	ErrCheckoutCannotConfirm = errors.New("checkout cannot confirm")
+	ErrCheckoutCannotCounter = errors.New("checkout cannot counter")
+	ErrInvalidCheckoutAmount = errors.New("invalid checkout amount")
 	ErrPermissionDenied      = errors.New("permission denied")
 )
 
@@ -88,6 +92,16 @@ func (s *Service) SubmitReturn(userID uint64, orderID uint64, req SubmitReturnRe
 	return s.repo.SubmitReturn(userID, orderID, req)
 }
 
+func (s *Service) SubmitCheckout(userID uint64, orderID uint64, req SubmitCheckoutRequest) (*HandoffRecordDTO, error) {
+	if s.repo == nil {
+		return nil, ErrDependencyUnavailable
+	}
+	if orderID == 0 || req.Content == "" {
+		return nil, ErrCheckoutCannotSubmit
+	}
+	return s.repo.SubmitCheckout(userID, orderID, req)
+}
+
 func (s *Service) ConfirmReturn(userID uint64, orderID uint64) error {
 	if s.repo == nil {
 		return ErrDependencyUnavailable
@@ -95,6 +109,30 @@ func (s *Service) ConfirmReturn(userID uint64, orderID uint64) error {
 	return s.repo.ConfirmReturn(userID, orderID)
 }
 
+func (s *Service) ConfirmCheckout(userID uint64, orderID uint64) error {
+	if s.repo == nil {
+		return ErrDependencyUnavailable
+	}
+	return s.repo.ConfirmCheckout(userID, orderID)
+}
+
+func (s *Service) CounterCheckout(userID uint64, orderID uint64, req CounterCheckoutRequest) (*CheckoutDTO, error) {
+	if s.repo == nil {
+		return nil, ErrDependencyUnavailable
+	}
+	if orderID == 0 || req.Reason == "" {
+		return nil, ErrCheckoutCannotCounter
+	}
+	return s.repo.CounterCheckout(userID, orderID, req)
+}
+
+func (s *Service) AcceptCheckout(userID uint64, orderID uint64) error {
+	if s.repo == nil {
+		return ErrDependencyUnavailable
+	}
+	return s.repo.AcceptCheckout(userID, orderID)
+}
+
 func (s *Service) ListForUser(userID uint64) ([]OrderDTO, error) {
 	if s.repo == nil {
 		return nil, ErrDependencyUnavailable