using System;

using FluentResults;

using System.Collections.Generic;

using CommunityToolkit.Mvvm.ComponentModel;

using CommunityToolkit.Mvvm.Messaging;

using CommunityToolkit.Mvvm.Messaging.Messages;

using CommunityToolkit.Mvvm.Input;

​

class Program

{

    public class NotificationMessage

    {

        public string Content { get; }

        public NotificationMessage(string content) => Content = content;

    }

​

    public class GetUserRequest : RequestMessage<User> { }

​

    public class User

    {

        public string Name { get; set; }

    }

    public class UserViewModel : ObservableRecipient, IRecipient<NotificationMessage>, IRecipient<GetUserRequest>

    {

        public RelayCommand DisplayUserCommand { get; }

        public UserViewModel()

        {

            IsActive = true; // Automatically registers for messages

            // Initialize the command with an action

            DisplayUserCommand = new RelayCommand(ExecuteDisplayUser);

        }

​

        public void Receive(NotificationMessage message)

        {

            Console.WriteLine($"Notification: {message.Content}");

        }

​

        public void Receive(GetUserRequest request)

        {

            request.Reply(new User { Name = "John Doe" });

        }

        private void ExecuteDisplayUser()

        {

            Console.WriteLine("DisplayUserCommand executed!");

        }

    }

    public class UserRecipient

    {

        private readonly IMessenger _messenger;

​

        public UserRecipient(IMessenger messenger)

        {

            _messenger = messenger;

​

            // Register the message handler

            _messenger.Register(this, new MessageHandler<UserRecipient, NotificationMessage>((recipient, message) =>

            {

                recipient.HandleNotification(message);

            }));

        }

​

        private void HandleNotification(NotificationMessage message)

        {

            Console.WriteLine($"Notification received: {message.Content}");

        }

    }

    static void Main(string[] args)

    {       

        // Create and register the ViewModel

        var viewModel = new UserViewModel();

​

        // Create the request

        var request = new GetUserRequest();

​

        // Send the request

        WeakReferenceMessenger.Default.Send(request);

​

        // Access the response

        var user = request.Response;

        Console.WriteLine($"User: {user.Name}");

        //------ 2

        // Create the messenger

        IMessenger messenger = WeakReferenceMessenger.Default;

​

        // Create the recipient

        var userRecipient = new UserRecipient(messenger);

​

        // Send a notification message

        messenger.Send(new NotificationMessage("You have a new message!"));

        //------ 3

​

        // Test RelayCommand without UI

        Console.WriteLine("Testing RelayCommand...");

        viewModel.DisplayUserCommand.Execute(null); 

    }

}

​

​