public User Login(LoginInputModel inputModel)
{
if (inputModel == null || inputModel.Username == null || inputModel.Password == null)
{
throw new UnauthorizedAccessException("Username or Password is non-existing");
}
User foundUser = GetAllUsers().FirstOrDefault(u => u.Username.Equals(inputModel.Username));
if (foundUser == null)
{
throw new UnauthorizedAccessException("No user registered with such a name");
}
AuthenticationHelper.ValidateLogin(foundUser, inputModel);
return(foundUser);
}