using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        GoodOldTypeCheck();

        NewTypePattern();

        TypePatternAndCollections();

        NullCheckWithTypePattern();

    }

    static void GoodOldTypeCheck() {

        object o = new Hero("Wade", "Wilson", "Deadpool", HeroType.FailedExperiment, false);

        var h = o as Hero;

        if(h != null) { Console.WriteLine($"1: o is a Hero and is called {h.HeroName}");}

    }

    static void NewTypePattern() {

        object o = new Hero("Wade", "Wilson", "Deadpool", HeroType.FailedExperiment, false);

        // +---- Type Pattern

        if(o is Hero h) {

            Console.WriteLine($"2: h is of type {h.GetType().Name}");

            Console.WriteLine($"2: o is a Hero and is called {h.HeroName}");

        }

    }

    static void TypePatternAndCollections() {

        IEnumerable<Person> pEnumerable = new Person[] {

            new ("John", "Doe"),

            new Hero("Wade", "Wilson", "Deadpool", HeroType.FailedExperiment, false)

        };

        // +--- Two Type Pattern

        // 2nd depends on First

        if(pEnumerable is IReadOnlyList<Person> pList && pList[1] is Hero h) {

            Console.WriteLine($"3: o is a Hero and is called {h.HeroName}");

        }

    }

    static void NullCheckWithTypePattern() {

        //Hero? someone = null;

        object someone = new Hero("Wade", "Wilson", "Deadpool", HeroType.FailedExperiment, false);      

        // +--- TypePattern  +--- h can be used in subsequent parts of expression

        if(someone is Hero h && h.Type == HeroType.FailedExperiment) {

            Console.WriteLine($"4: Someone is the {h.HeroName} hero and not null");

        }

        else { Console.WriteLine("4: Someone is null");}

        // +--- Constant pattern with null

        if(someone is null) { Console.WriteLine("4: Someone is null"); }

    }

    enum HeroType { NuclearAccident, FailedExperiment, Alien, Mutant, Technology, Other};

    enum HeroTypeCategory { Accident, SuperPowersFromBirth, Other };

    enum VoughtEmployeeType { TopManagement, TheSeven, LocalHero, RegularPerson };

    record Person(string FirstName, string LastName, int? Age = null, Person? Assistant = null);

    record Hero(string FirstName, string LastName, string HeroName, HeroType Type, bool CanFly, Person? Assistant = null) : Person(FirstName, LastName, Assistant: Assistant);

}

​

​

​