xxxproject/Demo/Domain/UseCase/GroupUseCase.cs

using Demo.Data.LocalData;
using Demo.Data.Repository;
using Demo.domain.Models;
using System.Collections.Generic;
using System.Linq;

namespace Demo.Domain.UseCase
{
    public class GroupUseCase
    {
        private GroupRepositoryImpl _repositoryGroupImpl;

        public GroupUseCase(GroupRepositoryImpl repositoryGroupImpl)
        {
            _repositoryGroupImpl = repositoryGroupImpl;
        }
        public bool RemoveGroupById(int groupID)
        {
            var group = _repositoryGroupImpl.GetAllGroups.FirstOrDefault(g => g.Id == groupID);
            if (group != null)
            {
                _repositoryGroupImpl.RemoveGroupById(groupID); 
                return true;
            }
            return false; 
        }

        public List<Group> GetAllGroups() => _repositoryGroupImpl.GetAllGroup()
            .Select(it => new Group { Id = it.Id, Name = it.Name }).ToList();

        public bool AddGroup(GroupLocalEntity group)
        {
            // Если метод возвращает true, то группа добавлена успешно
            return _repositoryGroupImpl.AddGroup(group);
        }

        public bool UpdateGroupById(int groupID, GroupLocalEntity updatedGroup)
        {
            return _repositoryGroupImpl.UpdateGroupById(groupID, updatedGroup);
        }
    }
}