Replace conditional with polymorphism refactoring or similar?

Question

I have tried to ask a variant of this question before. I got some helpful answers, but still nothing that felt quite right to me. It seems to me this shouldn\'t really be that h

Answer 1

I would go with a strategy pattern derivative. This adds additional classes, but is more maintainable over the long haul. Also, keep in mind that there are still opporunities for refactoring here:

public class Conditional
{
    private int _numberOfManuals;
    private string _serviceType;
    public const int SMALL = 2;
    public const int MEDIUM = 8;
    public int NumberOfManuals { get { return _numberOfManuals; } }
    public string ServiceType { get { return _serviceType; } }
    private Dictionary resultStrategy;

    public Conditional(int numberOfManuals, string serviceType)
    {
        _numberOfManuals = numberOfManuals;
        _serviceType = serviceType;
        resultStrategy = new Dictionary
        {
              { SMALL, new SmallResult() },
              { MEDIUM, new MediumResult() },
              { MEDIUM + 1, new LargeResult() }
        };
    }

    public int GetHours()
    {
        return resultStrategy.Where(k => _numberOfManuals <= k.Key).First().Value.GetResult(this);
    }
}

public interface IResult
{
    int GetResult(Conditional conditional);
}

public class SmallResult : IResult
{
    public int GetResult(Conditional conditional)
    {
        return conditional.ServiceType.IsWriting() ? WritingResult(conditional) : AnalysisResult(conditional); ;
    }

    private int WritingResult(Conditional conditional)
    {
        return 30 * conditional.NumberOfManuals;
    }

    private int AnalysisResult(Conditional conditional)
    {
        return 10;
    }
}

public class MediumResult : IResult
{
    public int GetResult(Conditional conditional)
    {
        return conditional.ServiceType.IsWriting() ? WritingResult(conditional) : AnalysisResult(conditional); ;
    }

    private int WritingResult(Conditional conditional)
    {
        return (Conditional.SMALL * 30) + (20 * conditional.NumberOfManuals - Conditional.SMALL);

    }

    private int AnalysisResult(Conditional conditional)
    {
        return 20;
    }
}

public class LargeResult : IResult
{
    public int GetResult(Conditional conditional)
    {
        return conditional.ServiceType.IsWriting() ? WritingResult(conditional) : AnalysisResult(conditional); ;
    }

    private int WritingResult(Conditional conditional)
    {
        return (Conditional.SMALL * 30) + (20 * (Conditional.MEDIUM - Conditional.SMALL)) + (10 * conditional.NumberOfManuals - Conditional.MEDIUM);

    }

    private int AnalysisResult(Conditional conditional)
    {
        return 30;
    }
}

public static class ExtensionMethods
{
    public static bool IsWriting(this string value)
    {
        return value == "writing";
    }
}