using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var strategies = new List<IHourlyQuaddieStrategy>()

        {

            new CaulfieldHourlyQuaddieStrategy(),

            new MetroThoroughbredHourlyQuaddieStrategy(),

            new CountryThoroughbredHourlyQuaddieStrategy(),

            new InternationalThoroughbredHourlyQuaddieStrategy()

        };

    }

}

​

public class CaulfieldHourlyQuaddieStrategy : IHourlyQuaddieStrategy

{

    public IEnumerable<Race> SelectApplicableRaces(IEnumerable<Race> races)

        => races.Where(race => race.VenueName == "Caulfield").ToList();

}

​

public class MetroThoroughbredHourlyQuaddieStrategy : SimpleHourlyQuaddieStrategy, IHourlyQuaddieStrategy

{

    public MetroThoroughbredHourlyQuaddieStrategy() : base(RacingType.Thoroughbred, Location.Local, CountryType.Metro)

    { }

}

​

public class CountryThoroughbredHourlyQuaddieStrategy : SimpleHourlyQuaddieStrategy

{

    public CountryThoroughbredHourlyQuaddieStrategy() : base(RacingType.Thoroughbred, Location.Local, CountryType.Country)

    { }

}

​

public class InternationalThoroughbredHourlyQuaddieStrategy : SimpleHourlyQuaddieStrategy

{

    public InternationalThoroughbredHourlyQuaddieStrategy() : base(RacingType.Thoroughbred, Location.International, CountryType.All)

    { }

}

​

public abstract class SimpleHourlyQuaddieStrategy : IHourlyQuaddieStrategy

{

    private readonly RacingType racingType;

    private readonly Location location;

    private readonly CountryType countryType;

    public SimpleHourlyQuaddieStrategy(RacingType racingType = RacingType.All, Location location = Location.All, CountryType countryType = CountryType.All)

    {

        this.racingType = racingType;

        this.location = location;

        this.countryType = countryType;

    }

    public IEnumerable<Race> SelectApplicableRaces(IEnumerable<Race> races)

    {

        if(this.racingType != RacingType.All)

            races = races.Where(race => race.RacingType == this.racingType);

        if(this.location != Location.All)

            races = races.Where(race => race.Location == this.location);

        if(this.countryType != CountryType.All)

            races = races.Where(race => race.CountryType == this.countryType);

        return races.ToList();

    }

}

​

public enum RacingType { All, Thoroughbred, Harness, Greyhounds }

public enum Location { All, International, Local }

public enum CountryType { All, Country, Metro }

​

public class Race 

{ 

    public RacingType RacingType { get; set; }

    public Location Location { get; set; }

    public CountryType CountryType { get; set; }

    public string VenueName { get; set; }

}

​

public interface IHourlyQuaddieStrategy

{

    IEnumerable<Race> SelectApplicableRaces(IEnumerable<Race> races);

}