public class User
{
    public string Login {get; set;}
    public string Password {get; set;}
    public string Email {get; set;}
}

public class UserRegisterInput
{
    public string Login {get; set;}
    public string Password {get; set;}
    public string PasswordConfirm{get;set;}
    public string Email {get; set;}
    public bool IsTermsAccepted{get; set;}
}

public interface IUserRepository
{
    User GetUserByEmail(string email);
    User GetUserByLogin(string login);
    User Create(User user);
}

public interface IUserServices
{
    User Register(UserRegisterInput input);
}

public class UserServices : IUserServices
{
    private IUserRepository _userRepository;
    public UserServices(IUserRepository userRepository, IValidatorFactory validatorFactory)
    {
        _userRepository = userRepository;
        _validatorFactory = validatorFactory;
    }

    public User Register(UserRegisterInput input)
    {
        var validationResult = validatorFactory.Validate(input);
        if (!validationResult.IsValid)
            return null;

        var user = new User {Login = input.Login, Password = input.Password, Email = input.Email}
        return _userRepository.Create(user);
    }
}