using System;

using System.Collections.Generic;

​

    // Mediator interface

    public interface IChatMediator

    {

        void AddUser(IUser user);

        void SendMessage(string message, IUser sender);

    }

    // Cocrete Mediator

    public class ChatMediator : IChatMediator

    {

        List<IUser> users;

​

        public ChatMediator()

        {

            users = new List<IUser>();

        }

​

        public void AddUser(IUser user)

        {

            users.Add(user);

        }

​

        public void SendMessage(string message, IUser sender)

        {

            foreach(IUser user in users)

            {

                // Sender will not receive the message

                if (user != sender)  

                    user.ReceiveMessage(message);

            }

        }

    }

    // Colleague interface

    public interface IUser

    {

        void SendMessage(string message);

        void ReceiveMessage(string message);

    }

    // Concrete Colleague 1

    public class traveller : IUser

    {

        string name;

        IChatMediator chatMediator;

​

        public traveller(IChatMediator chatMediator, string name)

        {

            this.name = name;

            this.chatMediator = chatMediator;

        }

​

        public void SendMessage(string message)

        {

            chatMediator.SendMessage(message, this);

        }

​

        public void ReceiveMessage(string message)

        {

            Console.WriteLine("User Type: Passenger -- " + name + "; received message: " + message);

        }

    }

    // Concrete Colleague 2

    public class admin : IUser

    {

        string name;

        IChatMediator chatMediator;

​

        public admin(IChatMediator chatMediator, string name)

        {

            this.name = name;

            this.chatMediator = chatMediator;

        }

​

        public void SendMessage(string message)

        {

            chatMediator.SendMessage(message, this);

        }

​

        public void ReceiveMessage(string message)

        {

            Console.WriteLine("User Type: Admin -- " + name + "; received message: " + message);

        }

    }

   public  class Program

    {

       public  static void Main(string[] args)

        {

           Console.WriteLine("---------------WELCOME TO TOUR INDIA--------------");

            IChatMediator chatMediator = new ChatMediator();

            // create users and add them to chat mediator's user list

            IUser Sumanth = new traveller(chatMediator, "Sumanth");

            IUser Nishanth = new admin(chatMediator, "Nishanth");

            IUser SumanthNishanth = new admin(chatMediator, "SumanthNishanth");

            chatMediator.AddUser(Sumanth);

           Console.WriteLine();

            chatMediator.AddUser(Nishanth);

           Console.WriteLine();

            chatMediator.AddUser(SumanthNishanth);

            // send message

            SumanthNishanth.SendMessage("WELCOME TO TOUR INDIA PORTAL");

        }

    } 

​