fix: remove unused preload/snapshot functions and fix gofmt

backend/internal/handler/admin/admin_service_stub_test.go

@@ -10,23 +10,23 @@ import (
 )
 
 type stubAdminService struct {
-	users            []service.User
-	apiKeys          []service.APIKey
-	groups           []service.Group
-	accounts         []service.Account
-	proxies          []service.Proxy
-	proxyCounts      []service.ProxyWithAccountCount
-	redeems          []service.RedeemCode
-	createdAccounts  []*service.CreateAccountInput
-	createdProxies   []*service.CreateProxyInput
-	updatedProxyIDs  []int64
-	updatedProxies   []*service.UpdateProxyInput
-	testedProxyIDs   []int64
+	users                []service.User
+	apiKeys              []service.APIKey
+	groups               []service.Group
+	accounts             []service.Account
+	proxies              []service.Proxy
+	proxyCounts          []service.ProxyWithAccountCount
+	redeems              []service.RedeemCode
+	createdAccounts      []*service.CreateAccountInput
+	createdProxies       []*service.CreateProxyInput
+	updatedProxyIDs      []int64
+	updatedProxies       []*service.UpdateProxyInput
+	testedProxyIDs       []int64
 	createAccountErr     error
 	updateAccountErr     error
 	bulkUpdateAccountErr error
 	checkMixedErr        error
-	lastMixedCheck   struct {
+	lastMixedCheck       struct {
 		accountID int64
 		platform  string
 		groupIDs  []int64

backend/internal/service/admin_service.go

@@ -2119,6 +2119,35 @@ func (s *adminServiceImpl) checkMixedChannelRisk(ctx context.Context, currentAcc
 	return nil
 }
 
+func (s *adminServiceImpl) validateGroupIDsExist(ctx context.Context, groupIDs []int64) error {
+	if len(groupIDs) == 0 {
+		return nil
+	}
+	if s.groupRepo == nil {
+		return errors.New("group repository not configured")
+	}
+
+	if batchReader, ok := s.groupRepo.(groupExistenceBatchReader); ok {
+		existsByID, err := batchReader.ExistsByIDs(ctx, groupIDs)
+		if err != nil {
+			return fmt.Errorf("check groups exists: %w", err)
+		}
+		for _, groupID := range groupIDs {
+			if groupID <= 0 || !existsByID[groupID] {
+				return fmt.Errorf("get group: %w", ErrGroupNotFound)
+			}
+		}
+		return nil
+	}
+
+	for _, groupID := range groupIDs {
+		if _, err := s.groupRepo.GetByID(ctx, groupID); err != nil {
+			return fmt.Errorf("get group: %w", err)
+		}
+	}
+	return nil
+}
+
 // CheckMixedChannelRisk checks whether target groups contain mixed channels for the current account platform.
 func (s *adminServiceImpl) CheckMixedChannelRisk(ctx context.Context, currentAccountID int64, currentAccountPlatform string, groupIDs []int64) error {
 	return s.checkMixedChannelRisk(ctx, currentAccountID, currentAccountPlatform, groupIDs)