public List<Message> GetMessages(String chatHash, Int32? count, Int32? lastMessageId, String order)
        {
            if (String.IsNullOrEmpty(chatHash))
                return null;

            if (lastMessageId.HasValue)
            {
                if (String.IsNullOrEmpty(order) || (order == "DESC"))
                {
                    if (count.HasValue)
                        return _messageRepository.GetAll()
                                .Where(x => (x.Chat.Hash == chatHash) && (x.Id > lastMessageId.Value))
                                .Include(x => x.Attachments).Include(x => x.User)
                                .OrderByDescending(x => x.Id)
                                .Take(count.Value)
                                .ToList();

                    return _messageRepository.GetAll()
                            .Where(x => (x.Chat.Hash == chatHash) && (x.Id > lastMessageId.Value))
                            .Include(x => x.Attachments).Include(x => x.User)
                            .OrderByDescending(x => x.Id)
                            .ToList();
                }

                if (count.HasValue)
                    return _messageRepository.GetAll()
                            .Where(x => (x.Chat.Hash == chatHash) && (x.Id > lastMessageId.Value))
                            .Include(x => x.Attachments).Include(x => x.User)
                            .Take(count.Value)
                            .ToList();

                return _messageRepository.GetAll()
                        .Where(x => (x.Chat.Hash == chatHash) && (x.Id > lastMessageId.Value))
                        .Include(x => x.Attachments).Include(x => x.User)
                        .ToList();
            }

            if (count.HasValue)
                return _messageRepository.GetAll()
                        .Where(x => x.Chat.Hash == chatHash)
                        .Include(x => x.Attachments).Include(x => x.User)
                        .OrderByDescending(x => x.Id)
                        .Take(count.Value)
                        .ToList();

            return _messageRepository.GetAll()
                    .Where(x => x.Chat.Hash == chatHash)
                    .Include(x => x.Attachments).Include(x => x.User)
                    .ToList();
        }