Command

//
//Full Tutorial on https://indiedevart.wordpress.com/
//

using System;

namespace Command.Pattern
{
    class Program
    {
        static void Main()
        {
            // Create receiver, command, and invoker
            IEnemy receiver = new Goblin();
            ICommand command = new Heal(receiver);
            Field invoker = new Field();

            // Set and execute command
            invoker.SetCommand(command);
            invoker.EnterField();
            invoker.ExitField();

            Console.ReadKey();
        }
    }

    interface ICommand
    {

        void Execute();
        void UnDo();

    }

    class Heal : ICommand
    {
         IEnemy _receiver;
        // Constructor
        public Heal(IEnemy receiver)
        {
            _receiver = receiver;
        }

        public void Execute()
        {
            Console.WriteLine(_receiver.Heal());
        }
        public void UnDo()
        {
            Console.WriteLine(_receiver.Damage());
        }
    }
    class Buff : ICommand
    {
        IEnemy _receiver;
        // Constructor
        public Buff(IEnemy receiver)
        {
            _receiver = receiver;
        }

        public void Execute()
        {
            Console.WriteLine(_receiver.BuffON());
        }
        public void UnDo()
        {
            Console.WriteLine(_receiver.BuffOFF());
        }
    }

    interface IEnemy
    {
        string Damage();
        string Heal();
        string BuffON();
        string BuffOFF();
    }
    class Goblin : IEnemy
    {
        public string BuffOFF()
        {
            return "Goblin enters the field-Buff is ON";
        }

        public string BuffON()
        {
            return "Goblin exits the field-Buff is OFF";
        }

        public string Damage()
        {
            return "Goblin exits the field- takes damage";
        }

        public string Heal()
        {
            return "Goblin enters the field- heals";
        }
    }
    class Dragon : IEnemy
    {
        public string BuffOFF()
        {
            return "Goblin enters the field-Buff is ON";
        }

        public string BuffON()
        {
            return "Goblin exits the field-Buff is OFF";
        }

        public string Damage()
        {
            return "Goblin exits the field- takes damage";
        }

        public string Heal()
        {
            return "Goblin enters the field- heals";
        }
    }
    class Field
    {
        private ICommand _command;

        public void SetCommand(ICommand command)
        {
            this._command = command;
        }

        public void EnterField()
        {
            _command.Execute();
        }
        public void ExitField()
        {
            _command.UnDo();
        }
    }
}