using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Chain_of_Responsibility
{
    /// <summary>

    /// MainApp startup class for Structural

    /// Chain of Responsibility Design Pattern.

    /// </summary>
    /// 
    
    //Definition
    //Avoid coupling the sender of a request to its receiver by giving more than one object a chance to handle the request.
    //Chain the receiving objects and pass the request along the chain until an object handles it.

    class MainApp
    {
        /// <summary>

        /// Entry point into console application.

        /// </summary>

        static void Main()
        {
            // Setup Chain of Responsibility

            Handler h1 = new ConcreteHandler1();
            Handler h2 = new ConcreteHandler2();
            Handler h3 = new ConcreteHandler3();
            h1.SetSuccessor(h2);
            h2.SetSuccessor(h3);

            // Generate and process request

            int[] requests = { 2, 5, 14, 22, 18, 3, 27, 20 };

            foreach (int request in requests)
            {
                h1.HandleRequest(request);
            }

            // Wait for user

            Console.ReadKey();
        }
    }

    /// <summary>

    /// The 'Handler' abstract class

    /// </summary>

    abstract class Handler
    {
        protected Handler successor;

        public void SetSuccessor(Handler successor)
        {
            this.successor = successor;
        }

        public abstract void HandleRequest(int request);
    }

    /// <summary>

    /// The 'ConcreteHandler1' class

    /// </summary>

    class ConcreteHandler1 : Handler
    {
        public override void HandleRequest(int request)
        {
            if (request >= 0 && request < 10)
            {
                Console.WriteLine("{0} handled request {1}",
                  this.GetType().Name, request);
            }
            else if (successor != null)
            {
                successor.HandleRequest(request);
            }
        }
    }

    /// <summary>

    /// The 'ConcreteHandler2' class

    /// </summary>

    class ConcreteHandler2 : Handler
    {
        public override void HandleRequest(int request)
        {
            if (request >= 10 && request < 20)
            {
                Console.WriteLine("{0} handled request {1}",
                  this.GetType().Name, request);
            }
            else if (successor != null)
            {
                successor.HandleRequest(request);
            }
        }
    }

    /// <summary>

    /// The 'ConcreteHandler3' class

    /// </summary>

    class ConcreteHandler3 : Handler
    {
        public override void HandleRequest(int request)
        {
            if (request >= 20 && request < 30)
            {
                Console.WriteLine("{0} handled request {1}",
                  this.GetType().Name, request);
            }
            else if (successor != null)
            {
                successor.HandleRequest(request);
            }
        }
    }
}