public async Task <ServiceResult <UserChat> > AddUserToChat(string chatId, string userId) { var chatEntity = await chatRepository.Get(chatId); if (chatEntity == null) { return(new ServiceResult <UserChat>($"No chat with id {chatId}")); } var user = await userManager.FindByIdAsync(userId); if (user == null) { return(new ServiceResult <UserChat>($"No user with id {userId}")); } var userChatEntity = await userChatRepository.Add(new UserChat { UserId = user.Id, ChatId = chatEntity.Id }); if (userChatEntity == null) { return(new ServiceResult <UserChat>($"Something went wrong)")); } return(new ServiceResult <UserChat>(userChatEntity)); }