// Chapter 8 Notes

// Delegates and Events
/* 
 Delegate is going to allow us to pass methods as a parameters, return method send to variable<store>
 Events notifications between objects <publisher - publish any changes to an object><subscriber - get those changes>
*/


// Program Code
// Define a delegate for the event handler
using System.Runtime.CompilerServices;

public delegate void ContactAddedEventHandler(object sender, ContactEventArgs e); // param 2 args
//public delegate void ContactDeletedEventHandler(object sender, ContactEventArgs e); // param 2 args


// Custom events arguments
// optionally > pass any data related to the event
public class ContactEventArgs : EventArgs
{
    // Args
    public string FirstName // "Philip"
    {
    get; }
    public string LastName // "Matusiak"
    {
    get; }
    public int Age // 21
    {
    get; }

    // Constructor Statement ClassName()
    // local var getter = param definition
    public ContactEventArgs(string firstName, string lastName, int age)
    {
        // getter = param
        FirstName = firstName;
        LastName = lastName;
        Age = age;

    } // constructor

} // ContactEventArgs

// Contact Class
// manage data model, contacts and trigger<chapter8>
public class Contacts
{
    // Event declaration
    // access objectType ClassType varName
    public event ContactAddedEventHandler ContactAdded;
    //public string contactAdded; // access type name

    // Method to add a new contact
    public void AddContact(string firstName, string lastName, int age)
    {
        // Add contact logic
        // 2 string types and the int type FAIL don't match
        Console.WriteLine("Do add logic here...");
        Console.WriteLine(firstName);
        Console.WriteLine(lastName);
        Console.WriteLine(age);

        // Trigger the event
        // some type of onName function
        // protected method
        OnContactAdded(new ContactEventArgs(firstName, lastName, age));

    } // AddContact


    // Method to raise the event onName
    protected virtual void OnContactAdded(ContactEventArgs e)
    {
        // kick off or Invoke or publish to Any subscribers listening to this event
        ContactAdded?.Invoke(this, e);  // new Action(()=>ops)
    } // OnContactAdded


} // Contacts

// Program Class
class Program
{

    static void Main(string[] args)
    {
        // Welcome to my app
        Console.WriteLine("=== Welcome to my App");
    
        // Create an Instance of the Contacts Class
        Contacts contacts = new Contacts();

        // Tuple immutable, indexed, defined
        contacts.AddContact("Bob", "Smith", 21);

        // Subscriber > to a specific event
        contacts.ContactAdded += Contacts_ContactAdded;

        // optionally > unsubscribe
        contacts.ContactAdded -= Contacts_ContactAdded;

        // Footer
        Console.WriteLine("=== Footer ===");

    } // Main

    //  // Event Handler Method for the Program
    /*    
    * private static void Contacts_ContactAdded(object sender, ContactEventArgs e)
    */
    // Anonymous Object
    private static void Contacts_ContactAdded(object sender, object e) // replacing ClassType with refType
    {
        // Anonymous Type
        var addedContact = e as dynamic; // replace e with anonymous definition

        /*    
        * Console.WriteLine($"New contact(s) added: {e.FirstName} {e.LastName} {e.Age}.");
        */


        } // Contacts_ContactedAdded


} // Program Class