using System.Linq;
using System.IO;
using System;
using Lab2.MenuTest;

namespace Lab2
{
    namespace MenuTest
    {
        class Menu
        {
            public string Title { get; }
            public Dictionary<string, Action> Commands { get; } = new();
            public Menu(string title) => Title = title;

            public void ProcessMenu()
            {
                Console.WriteLine($"{Title}:");
                for(int index = 0; index < Commands.Count; ++index)
                    Console.WriteLine($"{index} - {Commands.ElementAt(index).Key}");

                Console.Write("Enter a command: ");
                var command = int.Parse(Console.ReadLine());
                if(command < Commands.Count && command >= 0)
                {
                    Commands.ElementAt(command).Value.Invoke();
                }
                else
                {
                    Console.WriteLine($"Invalid command: {command}");
                }
            }
        }

        class MainWindow
        {
            private Menu? CurrentMenu { get; set; } = null;
            public MainWindow()
            {
                var mainMenu = new Menu("Main menu");
                var helloworldMenu = new Menu("Helloworld");

                mainMenu.Commands.Add("Exit", () => { System.Environment.Exit(0); });
                mainMenu.Commands.Add("To hello world", () => { SetCurrentMenu(helloworldMenu); });
                helloworldMenu.Commands.Add("Print", () => { Console.WriteLine("Hello, world"); });
                helloworldMenu.Commands.Add("To main menu", () => { SetCurrentMenu(mainMenu); });
                SetCurrentMenu(mainMenu);
            }

            private void SetCurrentMenu(Menu menu) => CurrentMenu = menu;
            public void ProcessEvents() => CurrentMenu?.ProcessMenu();
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            var window = new MainWindow();
            while(true)
                window.ProcessEvents();
        }
    }
}