Console.cs

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using System;
using System.Text;
using System.Threading;
using System.Threading.Tasks;

namespace Tgstation.Server.Host.IO
{
    sealed class Console : IConsole
    {
        public bool Available => Environment.UserInteractive;

        void CheckAvailable()
        {
            if (!Available)
                throw new InvalidOperationException("Console unavailable");
        }

        public Task PressAnyKeyAsync(CancellationToken cancellationToken) => Task.Factory.StartNew(() =>
        {
            CheckAvailable();
            System.Console.Read();
        }, cancellationToken, TaskCreationOptions.LongRunning, TaskScheduler.Current);

        public Task<string> ReadLineAsync(bool usePasswordChar, CancellationToken cancellationToken) => Task.Factory.StartNew(() =>
        {
            //TODO Make this better: https://stackoverflow.com/questions/9479573/how-to-interrupt-console-readline
            CheckAvailable();
            if (!usePasswordChar)
                return System.Console.ReadLine();

            var passwordBuilder = new StringBuilder();
            do
            {
                var keyDescription = System.Console.ReadKey(true);
                if (keyDescription.Key == ConsoleKey.Enter)
                    break;
                else if (keyDescription.Key == ConsoleKey.Backspace)
                {
                    if (passwordBuilder.Length > 0)
                    {
                        --passwordBuilder.Length;
                        System.Console.Write("\b \b");
                    }
                }
                else if (keyDescription.KeyChar != '\u0000') // KeyChar == '\u0000' if the key pressed does not correspond to a printable character, e.g. F1, Pause-Break, etc
                {
                    passwordBuilder.Append(keyDescription.KeyChar);
                    System.Console.Write('*');
                }
            }
            while (!cancellationToken.IsCancellationRequested);
            cancellationToken.ThrowIfCancellationRequested();
            System.Console.WriteLine();
            return passwordBuilder.ToString();
        }, cancellationToken, TaskCreationOptions.LongRunning, TaskScheduler.Current);

        public Task WriteAsync(string text, bool newLine, CancellationToken cancellationToken) => Task.Factory.StartNew(() =>
        {
            CheckAvailable();
            if (text == null)
            {
                if (!newLine)
                    throw new InvalidOperationException("Cannot write null text without a new line!");
                System.Console.WriteLine();
            }
            else if (newLine)
                System.Console.WriteLine(text);
            else
                System.Console.Write(text);
        }, cancellationToken, TaskCreationOptions.LongRunning, TaskScheduler.Current);
    }
}