How do I reorganize this project?

Question

How do I reorganize this project?

class Service : IChargeable, IExtendable<br />
{

}

interface IChargeable
{
decimal? ChargeableAmount { 
    get; 
    }
}

interface IExtendable
{
bool IsExtendable { 
    get; 
    }
}

class DayService : Service { } 
class NightService : Service { } 
class TwentFourService : Service { }

The problem is that these services are paid at different rates, depending on whether they can expand or depending on their type.
A percentage of the paid amount is charged if the service is extended. Service Charge - ChargeableAmount * Seasonal rate that is different for each service.

. SeasonalRate, ServiceType, SeasonalRate? , , , .

SeasonalRates ServiceClass ( )? , SeasonalRates ServiceTypes?
SeasonalRate, , , DiscountRate, ZipCodeRate ..
ServiceType, ?

: ServiceType. , SeasonalRates

/ , , , :

interface IVisitable
{
    Accept(IVisitor visitor);
}
interface IVisitor
{
    Visit(IVisitable visitable);
}
interface IRate
{
    Rate { get; }
}

class Service : IVisitable
{
    public virtual Accept(IVisitor visitor);
}
class Visitor : IVisitor
{
    public virtual Visit(IVisitable visitable) { }
    public virtual Visit(DayService visitable) { }
    public virtual Visit(NightService visitable) { }
}
class RateVisitor : Visitor, IRateVisitor
{
    decimal? _Rate;

    override Visit(IVisitable visitable) { };
    override Visit(DayService visitable) { // Logic Goes here, sets the _Rate Variable };
    // Overrides for other services

    public virtual Rate 
    {
        return this._Rate;
    }
} 

Answer 1

, : -? .

:

class Service : IChargeable, IExtendable
{

}

interface IChargeable {  
    decimal? ChargeableAmount { get; }  
}

interface IExtendable {  
    bool IsExtendable { get; }  
}

class RatedService: Service {  
    RateStrategy strategy;  
}

interface RateStrategy {  
    decimal SeasonalRate { get; }  
}

class DiscountRate: RateStrategy {}  
class ZipCodeRate: RateStrategy {}  

class DayService : RatedService { }  
class NightService : RatedService { }  
class TwentFourService : RatedService { }

Answer 2

. , , .

, . ( ?) :

SeasonalRate, DiscountRate, ZipCodeRate ..

, , Visitor, :

DayService, NightService, TwentyFourService ..

, - ?

. , , .

public interface IRate { 
  decimal GetRate(Service s);
}

, . , (IChargeable, IExtendable ..), , , Rate.

, :

public interface IThumbnail {
  string ThumbnailFile { get; }
  int ThumbnailSize { get; }
  Image GetThumbnail();
}
public interface IThumbnailProvider { 
  Image GetThumbnail(Service s);
}

public class Thumbnail : IThumbnailProvider { 
    public Image GetThumbnail(Service s) { 
       if(s.ThumbnailFile != null) {
           // get the image
       }
    }
}

public interface ISeasonal {
  SeasonType Season { get; }
}

public class SeasonalRate : IRate {
  public decimal GetRate(Service s) { 
    if(s.Season != SeasonType.None) {
       // return seasonal rate based on s.Season
    } else {
       // throw an exception or do something else
    }
}

public abstract class Service : IChargeable, IExtendable, ISeasonal, IThumbnail { 
  // default implementation for ISeasonal
  protected SeasonType _season = SeasonType.None;
  public SeasonType Season { get { return _season; } }


  // default implementation for IThumbnail
  protected string _thumbFile = null;
  protected int _thumbSize = 32;
  public string ThumbnailFile { get { return _thumbFile; } }
  public int ThumbnailSize { get { return _thumbnailSize; } }
  public Image GetThumbnail() {
     return null; // 
  } 
}

public class DayService : Service { 
  private IRate _confirmedRate;
  private IThumbnailProvider _fileServer;
  public decimal GetRate() { return confirmedRate.GetRate(this); }
  public Image GetThumbnail() { return fileServer.GetThumbnail(); }

  // constructor
  public DayService(IThumbnailProvider fileServer, IRate confirmedRate) { 
        this._season = SeasonType.Day; 
        this._filename = "sunny.jpg"; 
        this._fileServer = fileServer;
        this._confirmedRate = confirmedRate;
  }
} 

Rate , , , - .

, NightService , GetThumbnail. .