using System;

using System.Collections.Generic;

​

public class Customer{

  public string Name {get;set;}

  public string Email {get;set;}

}

​

public interface IProduct{

  int ID {get;set;}

  string Name {get;set;}

  bool HasOrderCompleted {get;}

  void ShipItem(Customer customer);

}

​

​

​

class PhysicalProduct:IProduct{ 

  public int ID {get;set;}

  public string Name {get;set;}

  public bool HasOrderCompleted {get;private set;}

  public void ShipItem(Customer customer){

     if(this.HasOrderCompleted==false){

         Console.WriteLine("Physical Product {0} shipped to {1}",this.Name,customer.Name);

         this.HasOrderCompleted = true;

     }   

  } 

}

​

class DigitalProduct:IProduct{

  public int ID {get;set;}

  public string Name {get;set;}

  public bool HasOrderCompleted {get;private set;}

  public int DownloadsRemaining {get;set;}=5;

  public void ShipItem(Customer customer){

    if(this.HasOrderCompleted==false){

         Console.WriteLine("Digital Product {0} Mailed to {1}",this.Name,customer.Email);

         this.HasOrderCompleted = true;

         this.DownloadsRemaining--;

     }

  }

}

class ServiceProduct{

  public int ID {get;set;}

  public string Name {get;set;}

  public bool HasOrderCompleted {get;private set;}

  public decimal Hours {get;set;}

  public void SubscribeService(Customer customer){

    Console.WriteLine("{0} Subscribed {1} for {2} hours",customer.Name,this.Name,this.Hours);

  }

}

public class Program

{

    public static void Main()

    {

        var products = GetProducts();

        var customer = new Customer(){Name="Shahanad",Email="shahanad987@gmail.com"};

        foreach(var product in products){

            product.ShipItem(customer);

            if(product is DigitalProduct){

              DigitalProduct digital = (DigitalProduct)product;

              Console.WriteLine("Downloads Remaining = {0}",digital.DownloadsRemaining);

            }

        }

    }

    public static List<IProduct> GetProducts(){

         var Products = new List<IProduct>();

         Products.Add(new PhysicalProduct(){ID=1,Name="Nike Bag"});

         Products.Add(new DigitalProduct(){ID=1,Name="DataStructure & Algorithms PDF"});

         return Products;

    }

}