Task01

using System;

namespace Task01
{
    internal class Program
    {
        static void Main(string[] args)
        {
            bool quit = false;

            DateTime now;

            while (!quit)
            {
                string choice;

                Console.WriteLine(
                    "1.\tRun example.\n" +
                    "2.\tChange text color.\n" +
                    "3.\tChange background color.\n" +
                    "4.\tChange title.\n" +
                    "5.\tChange console size.\n" +
                    "6.\tMake beep sound.\n" +
                    "7.\tShow current time.\n" +
                    "8.\tShow count of days until ...\n" +
                    "9.\tQuit the program.\n"
                );

                choice = Console.ReadLine();

                Console.Clear();

                now = DateTime.Now;

                bool innerQuit;

                switch (choice)
                {
                    case "1":
                        Console.WriteLine("Input your name: ");
                        string name = Console.ReadLine();
                        Console.WriteLine("Hello, {0}", name);

                        Console.WriteLine("Today is {0}, {1:D2}.{2:D2}.{3:D2}\n", now.DayOfWeek, now.Day, now.Month, now.Year);
                        break;
                    case "2":
                        do
                        {
                            innerQuit = true;

                            Console.WriteLine(
                                "1.\tChange text color to Green.\n" +
                                "2.\tChange text color to Yellow.\n" +
                                "3.\tChange text color to Red.\n" +
                                "4.\tChange text color to Blue.\n" +
                                "5.\tChange text color to Gray.\n" +
                                "6.\tChange text color to White.\n" +
                                "7.\tChange text color to Black.\n" +
                                "8.\tRun to default.\n" +
                                "9.\tQuit text color settings.\n"
                            );

                            choice = Console.ReadLine();

                            switch (choice)
                            {
                                case "1":
                                    Console.ForegroundColor = ConsoleColor.Green;
                                    break;
                                case "2":
                                    Console.ForegroundColor = ConsoleColor.Yellow;
                                    break;
                                case "3":
                                    Console.ForegroundColor = ConsoleColor.Red;
                                    break;
                                case "4":
                                    Console.ForegroundColor = ConsoleColor.Blue;
                                    break;
                                case "5":
                                    Console.ForegroundColor = ConsoleColor.Gray;
                                    break;
                                case "6":
                                    Console.ForegroundColor = ConsoleColor.White;
                                    break;
                                case "7":
                                    Console.ForegroundColor = ConsoleColor.Black;
                                    break;
                                case "8":
                                    Console.ResetColor();
                                    break;
                                case "9":
                                    break;
                                default:
                                    innerQuit = false;
                                    break;
                            }
                        } while (!innerQuit);

                        break;
                    case "3":
                        do
                        {
                            innerQuit = true;

                            Console.WriteLine(
                                "1.\tChange background color to Green.\n" +
                                "2.\tChange background color to Yellow.\n" +
                                "3.\tChange background color to Red.\n" +
                                "4.\tChange background color to Blue.\n" +
                                "5.\tChange background color to Gray.\n" +
                                "6.\tChange background color to White.\n" +
                                "7.\tChange background color to Black.\n" +
                                "8.\tRun to default.\n" +
                                "9.\tQuit background color settings.\n"
                            );

                            choice = Console.ReadLine();

                            switch (choice)
                            {
                                case "1":
                                    Console.BackgroundColor = ConsoleColor.Green;
                                    break;
                                case "2":
                                    Console.BackgroundColor = ConsoleColor.Yellow;
                                    break;
                                case "3":
                                    Console.BackgroundColor = ConsoleColor.Red;
                                    break;
                                case "4":
                                    Console.BackgroundColor = ConsoleColor.Blue;
                                    break;
                                case "5":
                                    Console.BackgroundColor = ConsoleColor.Gray;
                                    break;
                                case "6":
                                    Console.BackgroundColor = ConsoleColor.White;
                                    break;
                                case "7":
                                    Console.BackgroundColor = ConsoleColor.Black;
                                    break;
                                case "8":
                                    Console.ResetColor();
                                    break;
                                case "9":
                                    break;
                                default:
                                    innerQuit = false;
                                    break;
                            }
                        } while (!innerQuit);

                        break;
                    case "4":
                        while (true)
                        {
                            Console.WriteLine("Enter text to change title: ");
                            string str = Console.ReadLine();
                            if (!string.IsNullOrEmpty(str))
                            {
                                Console.Title = str;
                                break;
                            }
                            else
                            {
                                Console.WriteLine("String must not be empty. Repeat please.");
                            }
                        }
                        break;
                    case "5":
                        while (true)
                        {
                            int borderX = -1, borderY = -1;

                            Console.Write("Enter width (1 - {0}): ", Console.LargestWindowWidth);

                            if (int.TryParse(Console.ReadLine(), out borderX) && borderX >= 1 && borderX <= Console.LargestWindowWidth)
                            {
                                Console.Write("Enter height (1 - {0}): ", Console.LargestWindowHeight);

                                if (int.TryParse(Console.ReadLine(), out borderY) && borderY >= 1 && borderY <= Console.LargestWindowHeight)
                                {
                                    Console.SetWindowSize(borderX, borderY);
                                    break;
                                }
                            }

                            Console.WriteLine("Width and height must be valid integers within the specified range.");
                        }
                        break;
                    case "6":
                        Console.Beep();
                        break;
                    case "7":
                        Console.WriteLine("Date: " + now.ToShortDateString());
                        Console.WriteLine("Time: " + now.ToShortTimeString() + "\n");
                        break;
                    case "8":
                        DateTime newYear = new DateTime(now.Year + 1, 1, 1);
                        TimeSpan daysLeft = newYear - now;
                        string newYearMessage = daysLeft.Days == 1 ? "day" : "days";
                        Console.WriteLine("{0} {1} until new year", daysLeft.Days, newYearMessage);

                        DateTime birthday = new DateTime(now.Year + 1, 1, 6);
                        daysLeft = birthday - now;
                        string birthdayMessage = daysLeft.Days == 1 ? "day" : "days";
                        Console.WriteLine("{0} {1} until my birthday", daysLeft.Days, birthdayMessage);

                        DateTime kaiDay = new DateTime(now.Year + 1, 5, 27);
                        daysLeft = kaiDay - now;
                        string kaiDayMessage = daysLeft.Days == 1 ? "day" : "days";
                        Console.WriteLine("{0} {1} until KAI day", daysLeft.Days, kaiDayMessage);

                        Console.WriteLine("Days until victory: not long left\n");
                        break;
                    case "9":
                        Console.WriteLine("Closure -_-");
                        quit = true;
                        break;
                }
            }
        }
    }
}