Strategy

using System;
using System.Collections.Generic;

//1 Identify an algorithm that the client would prefer to access through a "flex point."

//2 Declare the common interface for all variations of the algorithm.

//3 One-by-one, extract all algorithms into their own classes.They all should follow the common Strategy interface.

//4  Add a field for storing a reference to the current strategy, as well as a setter to change it, into the Context class.
//The Context should work with this object only using the Strategy interface.

//5 Context's clients must provide it with a proper strategy objects when they need the Context to perform the work in a certain way.



namespace Strategy
{

    class Context
    {
        private IStrategy _strategy;

        public Context()
        {

        }

        public Context(IStrategy strategy)
        {
            this._strategy = strategy;
        }

        public void setStrategy(IStrategy strategy)
        {
            this._strategy = strategy;
        }

        public void DoSomeBusinessLogic()
        {
            Console.Write("Context: Sorting data using the strategy (not sure how it'll do it)\n");
            var result = this._strategy.DoAlgorithm(new List<string> { "a", "b", "c", "d", "e" });

            string result_str = string.Empty;
            foreach (var element in result as List<string>)
            {
                result_str += element + ",";
            }

            Console.Write(result_str);
        }

    }

    interface IStrategy
    {
        object DoAlgorithm(object data);
    }

    class ConcreteStrategyA : IStrategy
    {
        public object DoAlgorithm(object data)
        {
            var list = data as List<string>;
            list.Sort();

            return list;
        }
    }

    class ConcreteStrategyB : IStrategy
    {
        public object DoAlgorithm(object data)
        {
            var list = data as List<string>;
            list.Sort();
            list.Reverse();

            return list;
        }
    }



    class Client
    {
        public static void ClientCode()
        {
            var context = new Context();

            Console.Write("Client: Strategy is set to normal sorting.\n");
            context.setStrategy(new ConcreteStrategyA());
            context.DoSomeBusinessLogic();
            Console.Write("\n");
            Console.Write("Client: Strategy is set to reverse sorting.\n");
            context.setStrategy(new ConcreteStrategyB());
            context.DoSomeBusinessLogic();

            Console.Write("\n");
        }
    }


    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Start Strategy!");

            Client.ClientCode();

            Console.ReadKey();
        }
    }
}