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

//Provide a unified interface to a set of interfaces in a subsystem. Façade defines a higher-level interface that makes the subsystem easier to use.

namespace Facade
{
    /// <summary>

    /// MainApp startup class for Structural

    /// Facade Design Pattern.

    /// </summary>

    class MainApp
    {
        /// <summary>

        /// Entry point into console application.

        /// </summary>

        public static void Main()
        {
            Facade facade = new Facade();

            facade.MethodA();
            facade.MethodB();

            // Wait for user

            Console.ReadKey();
        }
    }

    /// <summary>

    /// The 'Subsystem ClassA' class

    /// </summary>

    class SubSystemOne
    {
        public void MethodOne()
        {
            Console.WriteLine(" SubSystemOne Method");
        }
    }

    /// <summary>

    /// The 'Subsystem ClassB' class

    /// </summary>

    class SubSystemTwo
    {
        public void MethodTwo()
        {
            Console.WriteLine(" SubSystemTwo Method");
        }
    }

    /// <summary>

    /// The 'Subsystem ClassC' class

    /// </summary>

    class SubSystemThree
    {
        public void MethodThree()
        {
            Console.WriteLine(" SubSystemThree Method");
        }
    }

    /// <summary>

    /// The 'Subsystem ClassD' class

    /// </summary>

    class SubSystemFour
    {
        public void MethodFour()
        {
            Console.WriteLine(" SubSystemFour Method");
        }
    }

    /// <summary>

    /// The 'Facade' class

    /// </summary>

    class Facade
    {
        private SubSystemOne _one;
        private SubSystemTwo _two;
        private SubSystemThree _three;
        private SubSystemFour _four;

        public Facade()
        {
            _one = new SubSystemOne();
            _two = new SubSystemTwo();
            _three = new SubSystemThree();
            _four = new SubSystemFour();
        }

        public void MethodA()
        {
            Console.WriteLine("\nMethodA() ---- ");
            _one.MethodOne();
            _two.MethodTwo();
            _four.MethodFour();
        }

        public void MethodB()
        {
            Console.WriteLine("\nMethodB() ---- ");
            _two.MethodTwo();
            _three.MethodThree();
        }
    }
}