using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    private readonly static Func<string> func1 = () => "Func 1";

    private readonly static Func<string> func2 = () => "Func 2";

    private readonly static Func<string> func3 = () => "Func 3";

    private readonly static Test test1 = new Test("1");

    private readonly static Test test2 = new Test("2");

    private readonly static Test test3 = new Test("3");

    private readonly static Lazy<Test> lazyTest1 = new Lazy<Test>(() => { 

        Console.WriteLine(".Value do Test 1");

        return new Test("1");

    });

    private readonly static Lazy<Test> lazyTest2 = new Lazy<Test>(() => { 

        Console.WriteLine(".Value do Test 2");

        return new Test("2");

    });

    private readonly static Lazy<Test> lazyTest3 = new Lazy<Test>(() => { 

        Console.WriteLine(".Value do Test 3");

        return new Test("3");

    });

    private readonly static Func<string> newFunc1 = () => lazyTest1.Value.Testing();

    private readonly static Func<string> newFunc2 = () => lazyTest2.Value.Testing();

    private readonly static Func<string> newFunc3 = () => lazyTest3.Value.Testing();

    public static void Main()

    {

        //Console.WriteLine("Não deveria chamar, vamos ver:");

        //Func<string> teste = lazyTest1.Value.Testing;     

        //Console.WriteLine("-----------------------");

        var list = new List<Func<string>>()

        {

            func1,

            func2,

            func2,

            func3

        };

        var list2 = new List<Func<string>>()

        {

            test1.Testing,

            test2.Testing,

            test2.Testing,

            test3.Testing

        };

        /*

        var list3 = new List<Func<string>>()

        {

            () => lazyTest1.Value.Testing(),

            () => lazyTest2.Value.Testing(),

            () => lazyTest2.Value.Testing(),

            () => lazyTest3.Value.Testing()

        };

        */

        var list5 = new List<Func<string>>()

        {

            newFunc1,

            newFunc2,

            newFunc2,

            newFunc3

        };

        foreach (var func in list.Distinct())           

            Console.WriteLine(func());

        Console.WriteLine("---------------------");

        foreach (var func in list2.Distinct())          

            Console.WriteLine(func());

        /*

        Console.WriteLine("---------------------");

        foreach (var func in list3.Distinct())          

            Console.WriteLine(func());

        */

        Console.WriteLine("---------------------");

        foreach (var func in list5.Distinct())          

            Console.WriteLine(func());

    }

    public class Test

    {

        private readonly string id;

        public Test(string id)

        {

            this.id = id;

        }

        public string Testing() => $"Testing {id}!";

    }

}