public async Task<ICollection<BirthdayPresentEventDataTransferModel>> GetAllVisibleActive(UserBriefDataTransferModel model)
        {
            var activeEvents = await this.birthdayPresentEvents.All()
                .Where(x => !x.BirthdayGuy.UserName.Equals(model.UserName) && x.IsActive)
                .ProjectTo<BirthdayPresentEventDataTransferModel>()
                .ToListAsync();

            return activeEvents;
        }
        public async Task<ICollection<BirthdayPresentEventStatistics>> GetStatistics(UserBriefDataTransferModel model)
        {
            var unactiveEvents = await this.GetAllVisibleUnactive(model);
            var allUsers = await this.users.All().Select(x => x.UserName).ToListAsync();

            return this.BuildStatistics(ref unactiveEvents,ref allUsers);
        }