功能：恢复商户账号分组查看

backend/internal/service/user.go

@@ -27,6 +27,14 @@ type UserListQuery struct {
 	Status     *int
 }
 
+// MerchantMemberGroup presents merchant accounts in their actual ownership
+// hierarchy: one merchant and all of its employee accounts.
+type MerchantMemberGroup struct {
+	MerchantID uint                   `json:"merchant_id"`
+	Merchant   *model.Merchant        `json:"merchant,omitempty"`
+	Members    []model.MerchantMember `json:"members"`
+}
+
 func (s *UserService) List(q UserListQuery) ([]model.User, int64, error) {
 	if q.Page < 1 {
 		q.Page = 1
@@ -123,6 +131,55 @@ func (s *UserService) ListPlatformAdmins(page, size int) ([]model.User, int64, e
 	return s.List(UserListQuery{Page: page, Size: size, Role: model.RoleAdmin})
 }
 
+// ListMerchantAccountGroups returns merchant employee accounts grouped by
+// merchant. Platform administrators are excluded from this independent view.
+func (s *UserService) ListMerchantAccountGroups(page, size int) ([]MerchantMemberGroup, int64, error) {
+	page, size = normalizePage(page, size)
+	tx := s.db.Model(&model.MerchantMember{}).
+		Joins("JOIN users ON users.id = merchant_members.user_id AND users.deleted_at IS NULL").
+		Where("users.role = ?", model.RoleMerchant)
+
+	var total int64
+	if err := tx.Distinct("merchant_members.merchant_id").Count(&total).Error; err != nil {
+		return nil, 0, err
+	}
+	var merchantIDs []uint
+	if err := tx.Distinct("merchant_members.merchant_id").
+		Order("merchant_members.merchant_id ASC").
+		Offset((page-1)*size).Limit(size).
+		Pluck("merchant_members.merchant_id", &merchantIDs).Error; err != nil {
+		return nil, 0, err
+	}
+	if len(merchantIDs) == 0 {
+		return []MerchantMemberGroup{}, total, nil
+	}
+
+	var members []model.MerchantMember
+	if err := s.db.Model(&model.MerchantMember{}).
+		Joins("JOIN users ON users.id = merchant_members.user_id AND users.deleted_at IS NULL").
+		Where("users.role = ? AND merchant_members.merchant_id IN ?", model.RoleMerchant, merchantIDs).
+		Preload("Merchant").Preload("User").
+		Order("merchant_members.merchant_id ASC, merchant_members.id ASC").
+		Find(&members).Error; err != nil {
+		return nil, 0, err
+	}
+
+	groups := make([]MerchantMemberGroup, 0, len(merchantIDs))
+	byMerchantID := make(map[uint]*MerchantMemberGroup, len(merchantIDs))
+	for _, merchantID := range merchantIDs {
+		groups = append(groups, MerchantMemberGroup{MerchantID: merchantID, Members: []model.MerchantMember{}})
+		byMerchantID[merchantID] = &groups[len(groups)-1]
+	}
+	for _, member := range members {
+		group := byMerchantID[member.MerchantID]
+		if group.Merchant == nil {
+			group.Merchant = member.Merchant
+		}
+		group.Members = append(group.Members, member)
+	}
+	return groups, total, nil
+}
+
 // CreatePlatformAdmin creates an account with platform-only privileges. It
 // deliberately does not assign the account to any merchant.
 func (s *UserService) CreatePlatformAdmin(username, password, nickname string) (*model.User, error) {