using System;

​

public class Program

{

    public static void Main()

    {

        var orderDiscount = OrderDiscountFactory.GetOrderDiscount();

        var p = 100;

        var q = 10;

        var discount = orderDiscount.CheckForDiscount(p, q);

        Console.WriteLine(discount);

        Console.WriteLine("Price is: {0}", p * q * (1 - discount ));

    }   

}

​

public static class OrderDiscountFactory

{

    public static OrderDiscount GetOrderDiscount() 

    {

        var orderDiscount = new OneThousandDollarBikeDiscount();

        //Chain on Next discounts

        orderDiscount.SetNext(new TwoThousandDollarBikeDiscount())

            .SetNext(new FiveThousandDollarBikeDiscount())

            .SetNext(new OverTenDiscount());

        return orderDiscount;

    }

}

​

public abstract class OrderDiscount

{

    protected OrderDiscount next;

    public OrderDiscount SetNext(OrderDiscount nextDiscount)

    {

        next = nextDiscount;

        return nextDiscount;

    }

​

    public double CheckForDiscount(int price, int quantity)

    {

        double discount = 0;

        discount = GetDiscount(price, quantity);

        if (next != null)

        {

            discount += next.CheckForDiscount(price, quantity);

        }

​

        return discount;

    }

​

    abstract protected double GetDiscount(int price, int quantity);

}

​

// 1000  quantity >= 20   10% off

public class OneThousandDollarBikeDiscount : OrderDiscount

{

    protected override double GetDiscount(int price, int quantity)

    {

        double discount = 0;

        Console.WriteLine("Testing $1000");

        if (price == 1000 && quantity >= 20)

        {

            discount = .1;

        }

​

        return discount;

    }

}

​

// 2000  quantity >= 10   20% off

public class TwoThousandDollarBikeDiscount : OrderDiscount

{

    protected override double GetDiscount(int price, int quantity)

    {

        double discount = 0;

        Console.WriteLine("Testing $2000");

        if (price == 2000 && quantity >= 10)

        {

            discount = .2;

        }

​

        return discount;

    }

}

​

// 5000  quantity >= 5    20% off

public class FiveThousandDollarBikeDiscount : OrderDiscount

{

    protected override double GetDiscount(int price, int quantity)

    {

        double discount = 0;

        Console.WriteLine("Testing $5000");

        if (price == 5000 && quantity >= 5)

        {

            discount = .2;

        }

​

        return discount;

    }

}

​

// 10 or over items you get 1% off

public class OverTenDiscount : OrderDiscount

{

    protected override double GetDiscount(int price, int quantity)

    {

        double discount = 0;

        Console.WriteLine("Checking Over Ten Discount");

        if (quantity >= 10)

        {

            discount = .01;

        }

​

        return discount;

    }

}