ConsoleExtensions.cs

namespace Pastel
{
    using System;
    using System.Drawing;
    using System.Globalization;
    using System.Runtime.InteropServices;


    public static class ConsoleExtensions
    {
        private const int  STD_OUTPUT_HANDLE                     = -11;
        private const uint ENABLE_VIRTUAL_TERMINAL_PROCESSING = 0x0004;
        private const uint DISABLE_NEWLINE_AUTO_RETURN        = 0x0008;

        [DllImport("kernel32.dll")]
        private static extern bool GetConsoleMode(IntPtr hConsoleHandle, out uint lpMode);

        [DllImport("kernel32.dll")]
        private static extern bool SetConsoleMode(IntPtr hConsoleHandle, uint dwMode);

        [DllImport("kernel32.dll", SetLastError = true)]
        private static extern IntPtr GetStdHandle(int nStdHandle);

        [DllImport("kernel32.dll")]
        public static extern uint GetLastError();


        private delegate string ColorFormat(   string input, Color     color);
        private delegate string ColorFormatHex(string input, string hexColor);


        private const string _formatString       = "\u001b[{0};2;{1};{2};{3}m{4}\u001b[0m";
        private const string _foregroundModifier = "38";
        private const string _backgroundModifier = "48";


        private static readonly Func<string, int> _parseHexColor = hc => int.Parse(hc.Replace("#", ""), NumberStyles.HexNumber);

        private static readonly Func<string,  Color, string, string> _colorFormat    = (s, c, f) => string.Format(_formatString, f, c.R, c.G, c.B, s);
        private static readonly Func<string, string, string, string> _colorHexFormat = (s, c, f) => _colorFormat(s, Color.FromArgb(_parseHexColor(c)), f);

        private static readonly ColorFormat    _noColorOutputFormat    = (s, _) => s;
        private static readonly ColorFormatHex _noColorOutputHexFormat = (s, _) => s;

        private static readonly ColorFormat    _foregroundColorFormat    = (s, c) => _colorFormat(   s, c, _foregroundModifier);
        private static readonly ColorFormatHex _foregroundColorHexFormat = (s, c) => _colorHexFormat(s, c, _foregroundModifier);

        private static readonly ColorFormat    _backgroundColorFormat    = (s, c) => _colorFormat(   s, c, _backgroundModifier);
        private static readonly ColorFormatHex _backgroundColorHexFormat = (s, c) => _colorHexFormat(s, c, _backgroundModifier);


        private static ColorFormat    _foregroundColorFormatFunc;
        private static ColorFormatHex _foregroundColorHexFormatFunc;

        private static ColorFormat    _backgroundColorFormatFunc;
        private static ColorFormatHex _backgroundColorHexFormatFunc;


        static ConsoleExtensions()
        {
            if (Environment.GetEnvironmentVariable("NO_COLOR") == null)
            {
                Enable();


                if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
                {
                    var iStdOut =   GetStdHandle(STD_OUTPUT_HANDLE);

                    var enable  =   GetConsoleMode(iStdOut, out var outConsoleMode)
                                 && SetConsoleMode(iStdOut, outConsoleMode | ENABLE_VIRTUAL_TERMINAL_PROCESSING | DISABLE_NEWLINE_AUTO_RETURN);
                }
            }
            else
            {
                Disable();
            }
        }


        









        /// <summary>
        /// Enables any future console color output produced by Pastel.
        /// </summary>
        public static void Enable()
        {
            _foregroundColorFormatFunc    = _foregroundColorFormat;
            _foregroundColorHexFormatFunc = _foregroundColorHexFormat;

            _backgroundColorFormatFunc    = _backgroundColorFormat;
            _backgroundColorHexFormatFunc = _backgroundColorHexFormat;
        }

        /// <summary>
        /// Disables any future console color output produced by Pastel.
        /// </summary>
        public static void Disable()
        {
            _foregroundColorFormatFunc    = _noColorOutputFormat;
            _foregroundColorHexFormatFunc = _noColorOutputHexFormat;

            _backgroundColorFormatFunc    = _noColorOutputFormat;
            _backgroundColorHexFormatFunc = _noColorOutputHexFormat;
        }


        /// <summary>
        /// Returns a string wrapped in an ANSI foreground color code using the specified color.
        /// </summary>
        /// <param name="input">The string to color.</param>
        /// <param name="color">The color to use on the specified string.</param>
        public static string Pastel(this string input, Color color)
        {
            return _foregroundColorFormatFunc(input, color);
        }

        /// <summary>
        /// Returns a string wrapped in an ANSI foreground color code using the specified color.
        /// </summary>
        /// <param name="input">The string to color.</param>
        /// <param name="hexColor">The color to use on the specified string.<para>Supported format: [#]RRGGBB.</para></param>
        public static string Pastel(this string input, string hexColor)
        {
            return _foregroundColorHexFormatFunc(input, hexColor);
        }



        /// <summary>
        /// Returns a string wrapped in an ANSI background color code using the specified color.
        /// </summary>
        /// <param name="input">The string to color.</param>
        /// <param name="color">The color to use on the specified string.</param>
        public static string PastelBg(this string input, Color color)
        {
            return _backgroundColorFormatFunc(input, color);
        }

        /// <summary>
        /// Returns a string wrapped in an ANSI background color code using the specified color.
        /// </summary>
        /// <param name="input">The string to color.</param>
        /// <param name="hexColor">The color to use on the specified string.<para>Supported format: [#]RRGGBB.</para></param>
        public static string PastelBg(this string input, string hexColor)
        {
            return _backgroundColorHexFormatFunc(input, hexColor);
        }
    }
}