public UserContractUpdatedReturnDto ChangeUserContract(int userId, int newContractId)
{
if (!_userOperations.UserExists(userId) || !_contractOperations.ContractExists(newContractId))
{
return(null);
}
var user = _userOperations.GetUserById(userId);
var contract = _contractOperations.GetContractById(newContractId);
if (contract.HasAssociatedUser())
{
return(null);
}
var updatedUser = _userOperations.ChangeUserContract(user, contract);
return(updatedUser == null ? null : Mapper.Map <UserContractUpdatedReturnDto>(updatedUser));
}