gui-cs.Terminal.Gui/Terminal.Gui/ConsoleDrivers/EscSeqUtils/EscSeqUtils.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Management;
using System.Runtime.InteropServices;
using System.Threading.Tasks;

namespace Terminal.Gui;
/// <summary>
/// Provides a platform-independent API for managing ANSI escape sequences.
/// </summary>
/// <remarks>
/// Useful resources:
/// * https://learn.microsoft.com/en-us/windows/console/console-virtual-terminal-sequences
/// * https://invisible-island.net/xterm/ctlseqs/ctlseqs.html
/// * https://vt100.net/
/// </remarks>
public static class EscSeqUtils {
	/// <summary>
	/// Escape key code (ASCII 27/0x1B).
	/// </summary>
	public static readonly char KeyEsc = (char)Key.Esc;

	/// <summary>
	/// ESC [ - The CSI (Control Sequence Introducer).
	/// </summary>
	public static readonly string CSI = $"{KeyEsc}[";

	/// <summary>
	/// ESC [ ? 1003 h - Enable  mouse event tracking.
	/// </summary>
	public static readonly string CSI_EnableAnyEventMouse = CSI + "?1003h";

	/// <summary>
	/// ESC [ ? 1006 h - Enable SGR (Select Graphic Rendition).
	/// </summary>
	public static readonly string CSI_EnableSgrExtModeMouse = CSI + "?1006h";

	/// <summary>
	/// ESC [ ? 1015 h - Enable URXVT (Unicode Extended Virtual Terminal).
	/// </summary>
	public static readonly string CSI_EnableUrxvtExtModeMouse = CSI + "?1015h";

	/// <summary>
	/// ESC [ ? 1003 l - Disable any mouse event tracking.
	/// </summary>
	public static readonly string CSI_DisableAnyEventMouse = CSI + "?1003l";

	/// <summary>
	/// ESC [ ? 1006 l - Disable SGR (Select Graphic Rendition).
	/// </summary>
	public static readonly string CSI_DisableSgrExtModeMouse = CSI + "?1006l";

	/// <summary>
	/// ESC [ ? 1015 l - Disable URXVT (Unicode Extended Virtual Terminal).
	/// </summary>
	public static readonly string CSI_DisableUrxvtExtModeMouse = CSI + "?1015l";

	/// <summary>
	/// Control sequence for enabling mouse events.
	/// </summary>
	public static string CSI_EnableMouseEvents { get; set; } =
		CSI_EnableAnyEventMouse + CSI_EnableUrxvtExtModeMouse + CSI_EnableSgrExtModeMouse;

	/// <summary>
	/// Control sequence for disabling mouse events.
	/// </summary>
	public static string CSI_DisableMouseEvents { get; set; } =
		CSI_DisableAnyEventMouse + CSI_DisableUrxvtExtModeMouse + CSI_DisableSgrExtModeMouse;

	/// <summary>
	/// ESC [ ? 1047 h - Activate xterm alternative buffer (no backscroll)
	/// </summary>
	public static readonly string CSI_ActivateAltBufferNoBackscroll = CSI + "?1047h";

	/// <summary>
	/// ESC [ ? 1047 l - Restore xterm working buffer (with backscroll)
	/// </summary>
	public static readonly string CSI_RestoreAltBufferWithBackscroll = CSI + "?1047l";

	/// <summary>
	/// ESC [ ? 1049 h - Save cursor position and activate xterm alternative buffer (no backscroll)
	/// </summary>
	public static readonly string CSI_SaveCursorAndActivateAltBufferNoBackscroll = CSI + "?1049h";

	/// <summary>
	/// ESC [ ? 1049 l - Restore cursor position and restore xterm working buffer (with backscroll)
	/// </summary>
	public static readonly string CSI_RestoreCursorAndActivateAltBufferWithBackscroll = CSI + "?1049l";

	/// <summary>
	/// Options for ANSI ESC "[xJ" - Clears part of the screen.
	/// </summary>
	public enum ClearScreenOptions {
		/// <summary>
		/// If n is 0 (or missing), clear from cursor to end of screen.
		/// </summary>
		CursorToEndOfScreen = 0,
		/// <summary>
		/// If n is 1, clear from cursor to beginning of the screen.
		/// </summary>
		CursorToBeginningOfScreen = 1,
		/// <summary>
		/// If n is 2, clear entire screen (and moves cursor to upper left on DOS ANSI.SYS).
		/// </summary>
		EntireScreen = 2,
		/// <summary>
		/// If n is 3, clear entire screen and delete all lines saved in the scrollback buffer
		/// </summary>
		EntireScreenAndScrollbackBuffer = 3
	}

	/// <summary>
	/// ESC [ x J - Clears part of the screen. See <see cref="ClearScreenOptions"/>.
	/// </summary>
	/// <param name="option"></param>
	/// <returns></returns>
	public static string CSI_ClearScreen (ClearScreenOptions option) => $"{CSI}{(int)option}J";

	#region Cursor
	//ESC [ M - RI Reverse Index – Performs the reverse operation of \n, moves cursor up one line, maintains horizontal position, scrolls buffer if necessary*

	/// <summary>
	/// ESC [ 7 - Save Cursor Position in Memory**
	/// </summary>
	public static readonly string CSI_SaveCursorPosition = CSI + "7";

	/// <summary>
	/// ESC [ 8 - DECSR Restore Cursor Position from Memory**
	/// </summary>
	public static readonly string CSI_RestoreCursorPosition = CSI + "8";

	/// <summary>
	/// ESC [ 8 ; height ; width t - Set Terminal Window Size
	/// https://terminalguide.namepad.de/seq/csi_st-8/
	/// </summary>
	public static string CSI_SetTerminalWindowSize (int height, int width) => $"{CSI}8;{height};{width}t";

	//ESC [ < n > A - CUU - Cursor Up       Cursor up by < n >
	//ESC [ < n > B - CUD - Cursor Down     Cursor down by < n >
	//ESC [ < n > C - CUF - Cursor Forward  Cursor forward (Right) by < n >
	//ESC [ < n > D - CUB - Cursor Backward Cursor backward (Left) by < n >
	//ESC [ < n > E - CNL - Cursor Next Line - Cursor down < n > lines from current position
	//ESC [ < n > F - CPL - Cursor Previous Line    Cursor up < n > lines from current position
	//ESC [ < n > G - CHA - Cursor Horizontal Absolute      Cursor moves to < n > th position horizontally in the current line
	//ESC [ < n > d - VPA - Vertical Line Position Absolute Cursor moves to the < n > th position vertically in the current column

	/// <summary>
	/// ESC [ y ; x H - CUP Cursor Position - Cursor moves to x ; y coordinate within the viewport, where x is the column of the y line
	/// </summary>
	/// <param name="x"></param>
	/// <param name="y"></param>
	/// <returns></returns>
	public static string CSI_SetCursorPosition (int x, int y) => $"{CSI}{y};{x}H";


	//ESC [ <y> ; <x> f - HVP     Horizontal Vertical Position* Cursor moves to<x>; <y> coordinate within the viewport, where <x> is the column of the<y> line
	//ESC [ s - ANSISYSSC       Save Cursor – Ansi.sys emulation	**With no parameters, performs a save cursor operation like DECSC
	//ESC [ u - ANSISYSRC       Restore Cursor – Ansi.sys emulation	**With no parameters, performs a restore cursor operation like DECRC
	//ESC [ ? 12 h - ATT160  Text Cursor Enable Blinking     Start the cursor blinking
	//ESC [ ? 12 l - ATT160  Text Cursor Disable Blinking    Stop blinking the cursor
	/// <summary>
	/// ESC [ ? 25 h - DECTCEM Text Cursor Enable Mode Show    Show the cursor
	/// </summary>
	public static readonly string CSI_ShowCursor = CSI + "?25h";

	/// <summary>
	/// ESC [ ? 25 l - DECTCEM Text Cursor Enable Mode Hide    Hide the cursor
	/// </summary>
	public static readonly string CSI_HideCursor = CSI + "?25l";
	//ESC [ ? 12 h - ATT160  Text Cursor Enable Blinking     Start the cursor blinking
	//ESC [ ? 12 l - ATT160  Text Cursor Disable Blinking    Stop blinking the cursor
	//ESC [ ? 25 h - DECTCEM Text Cursor Enable Mode Show    Show the cursor
	//ESC [ ? 25 l - DECTCEM Text Cursor Enable Mode Hide    Hide the cursor

	/// <summary>
	/// Styles for ANSI ESC "[x q" - Set Cursor Style
	/// </summary>
	public enum DECSCUSR_Style {
		/// <summary>
		/// DECSCUSR - User Shape - Default cursor shape configured by the user
		/// </summary>
		UserShape = 0,
		/// <summary>
		/// DECSCUSR - Blinking Block - Blinking block cursor shape
		/// </summary>
		BlinkingBlock = 1,
		/// <summary>
		/// DECSCUSR - Steady Block - Steady block cursor shape
		/// </summary>
		SteadyBlock = 2,
		/// <summary>
		/// DECSCUSR - Blinking Underline - Blinking underline cursor shape
		/// </summary>
		BlinkingUnderline = 3,
		/// <summary>
		/// DECSCUSR - Steady Underline - Steady underline cursor shape
		/// </summary>
		SteadyUnderline = 4,
		/// <summary>
		/// DECSCUSR - Blinking Bar - Blinking bar cursor shape
		/// </summary>
		BlinkingBar = 5,
		/// <summary>
		/// DECSCUSR - Steady Bar - Steady bar cursor shape
		/// </summary>
		SteadyBar = 6
	}

	/// <summary>
	/// ESC [ n SP q - Select Cursor Style (DECSCUSR)
	/// https://terminalguide.namepad.de/seq/csi_sq_t_space/ 
	/// </summary>
	/// <param name="style"></param>
	/// <returns></returns>
	public static string CSI_SetCursorStyle (DECSCUSR_Style style) => $"{CSI}{(int)style} q";

	#endregion

	#region Colors
	/// <summary>
	/// ESC [ (n) m - SGR - Set Graphics Rendition - Set the format of the screen and text as specified by (n)
	/// This command is special in that the (n) position can accept between 0 and 16 parameters separated by semicolons.
	/// When no parameters are specified, it is treated the same as a single 0 parameter.
	/// https://terminalguide.namepad.de/seq/csi_sm/
	/// </summary>
	public static string CSI_SetGraphicsRendition (params int [] parameters) => $"{CSI}{string.Join (";", parameters)}m";

	/// <summary>
	/// ESC[38;5;{id}m - Set foreground color (256 colors)
	/// </summary>
	public static string CSI_SetForegroundColor (int id) => $"{CSI}38;5;{id}m";

	/// <summary>
	/// ESC[48;5;{id}m - Set background color (256 colors)
	/// </summary>
	public static string CSI_SetBackgroundColor (int id) => $"{CSI}48;5;{id}m";

	/// <summary>
	/// ESC[38;2;{r};{g};{b}m	Set foreground color as RGB.
	/// </summary>
	public static string CSI_SetForegroundColorRGB (int r, int g, int b) => $"{CSI}38;2;{r};{g};{b}m";

	/// <summary>
	/// ESC[48;2;{r};{g};{b}m	Set background color as RGB.
	/// </summary>
	public static string CSI_SetBackgroundColorRGB (int r, int g, int b) => $"{CSI}48;2;{r};{g};{b}m";

	#endregion

	#region Requests
	/// <summary>
	/// ESC [ ? 6 n - Request Cursor Position Report (?) (DECXCPR)
	/// https://terminalguide.namepad.de/seq/csi_sn__p-6/
	/// </summary>
	public static readonly string CSI_RequestCursorPositionReport = CSI + "?6n";

	/// <summary>
	/// The terminal reply to <see cref="CSI_RequestCursorPositionReport"/>. ESC [ ? (y) ; (x) R
	/// </summary>
	public const string CSI_RequestCursorPositionReport_Terminator = "R";

	/// <summary>
	/// ESC [ 0 c - Send Device Attributes (Primary DA)
	///
	/// https://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h3-Application-Program-Command-functions
	/// https://www.xfree86.org/current/ctlseqs.html
	/// Windows Terminal v1.17 and below emits “\x1b[?1;0c”, indicating "VT101 with No Options".
	/// Windows Terminal v1.18+ emits: \x1b[?61;6;7;22;23;24;28;32;42c"
	/// See https://github.com/microsoft/terminal/pull/14906
	///
	/// 61 - The device conforms to level 1 of the character cell display architecture
	/// (See https://github.com/microsoft/terminal/issues/15693#issuecomment-1633304497)
	/// 6 = Selective erase
	/// 7 = Soft fonts
	/// 22 = Color text
	/// 23 = Greek character sets
	/// 24 = Turkish character sets
	/// 28 = Rectangular area operations
	/// 32 = Text macros
	/// 42 = ISO Latin-2 character set
	/// 
	/// </summary>
	public static readonly string CSI_SendDeviceAttributes = CSI + "0c";

	/// <summary>
	/// ESC [ > 0 c - Send Device Attributes (Secondary DA)
	/// Windows Terminal v1.18+ emits: "\x1b[>0;10;1c" (vt100, firmware version 1.0, vt220)
	/// </summary>
	public static readonly string CSI_SendDeviceAttributes2 = CSI + ">0c";

	/// <summary>
	/// The terminator indicating a reply to <see cref="CSI_SendDeviceAttributes"/> or <see cref="CSI_SendDeviceAttributes2"/>
	/// 
	/// </summary>
	public const string CSI_ReportDeviceAttributes_Terminator = "c";

	/// <summary>
	/// CSI 1 8 t  | yes | yes |  yes  | report window size in chars
	/// https://terminalguide.namepad.de/seq/csi_st-18/
	/// </summary>
	public static readonly string CSI_ReportTerminalSizeInChars = CSI + "18t";

	/// <summary>
	/// The terminator indicating a reply to <see cref="CSI_ReportTerminalSizeInChars"/> : ESC [ 8 ; height ; width t
	/// </summary>
	public const string CSI_ReportTerminalSizeInChars_Terminator = "t";

	/// <summary>
	/// The value of the response to <see cref="CSI_ReportTerminalSizeInChars"/> indicating value 1 and 2 are the terminal size in chars.
	/// </summary>
	public const string CSI_ReportTerminalSizeInChars_ResponseValue = "8";
	#endregion

	/// <summary>
	/// Ensures a console key is mapped to one that works correctly with ANSI escape sequences.
	/// </summary>
	/// <param name="consoleKeyInfo">The <see cref="ConsoleKeyInfo"/>.</param>
	/// <returns>The <see cref="ConsoleKeyInfo"/> modified.</returns>
	public static ConsoleKeyInfo MapConsoleKeyInfo (ConsoleKeyInfo consoleKeyInfo)
	{
		ConsoleKeyInfo newConsoleKeyInfo = consoleKeyInfo;
		ConsoleKey key;
		var keyChar = consoleKeyInfo.KeyChar;
		switch ((uint)keyChar) {
		case 0:
			if (consoleKeyInfo.Key == (ConsoleKey)64) {    // Ctrl+Space in Windows.
				newConsoleKeyInfo = new ConsoleKeyInfo (' ', ConsoleKey.Spacebar,
					(consoleKeyInfo.Modifiers & ConsoleModifiers.Shift) != 0,
					(consoleKeyInfo.Modifiers & ConsoleModifiers.Alt) != 0,
					(consoleKeyInfo.Modifiers & ConsoleModifiers.Control) != 0);
			}
			break;
		case uint n when n > 0 && n <= KeyEsc:
			if (consoleKeyInfo.Key == 0 && consoleKeyInfo.KeyChar == '\r') {
				key = ConsoleKey.Enter;
				newConsoleKeyInfo = new ConsoleKeyInfo (consoleKeyInfo.KeyChar,
					key,
					(consoleKeyInfo.Modifiers & ConsoleModifiers.Shift) != 0,
					(consoleKeyInfo.Modifiers & ConsoleModifiers.Alt) != 0,
					(consoleKeyInfo.Modifiers & ConsoleModifiers.Control) != 0);
			} else if (consoleKeyInfo.Key == 0) {
				key = (ConsoleKey)(char)(consoleKeyInfo.KeyChar + (uint)ConsoleKey.A - 1);
				newConsoleKeyInfo = new ConsoleKeyInfo ((char)key,
					key,
					(consoleKeyInfo.Modifiers & ConsoleModifiers.Shift) != 0,
					(consoleKeyInfo.Modifiers & ConsoleModifiers.Alt) != 0,
					true);
			}
			break;
		case 127: // DEL
			newConsoleKeyInfo = new ConsoleKeyInfo (consoleKeyInfo.KeyChar, ConsoleKey.Backspace,
				(consoleKeyInfo.Modifiers & ConsoleModifiers.Shift) != 0,
				(consoleKeyInfo.Modifiers & ConsoleModifiers.Alt) != 0,
				(consoleKeyInfo.Modifiers & ConsoleModifiers.Control) != 0);
			break;
		default:
			newConsoleKeyInfo = consoleKeyInfo;
			break;
		}

		return newConsoleKeyInfo;
	}

	/// <summary>
	/// A helper to resize the <see cref="ConsoleKeyInfo"/> as needed.
	/// </summary>
	/// <param name="consoleKeyInfo">The <see cref="ConsoleKeyInfo"/>.</param>
	/// <param name="cki">The <see cref="ConsoleKeyInfo"/> array to resize.</param>
	/// <returns>The <see cref="ConsoleKeyInfo"/> resized.</returns>
	public static ConsoleKeyInfo [] ResizeArray (ConsoleKeyInfo consoleKeyInfo, ConsoleKeyInfo [] cki)
	{
		Array.Resize (ref cki, cki == null ? 1 : cki.Length + 1);
		cki [cki.Length - 1] = consoleKeyInfo;
		return cki;
	}

	/// <summary>
	/// Decodes an ANSI escape sequence.
	/// </summary>
	/// <param name="escSeqRequests">The <see cref="EscSeqRequests"/> which may contain a request.</param>
	/// <param name="newConsoleKeyInfo">The <see cref="ConsoleKeyInfo"/> which may changes.</param>
	/// <param name="key">The <see cref="ConsoleKey"/> which may changes.</param>
	/// <param name="cki">The <see cref="ConsoleKeyInfo"/> array.</param>
	/// <param name="mod">The <see cref="ConsoleModifiers"/> which may changes.</param>
	/// <param name="c1Control">The control returned by the <see cref="GetC1ControlChar(char)"/> method.</param>
	/// <param name="code">The code returned by the <see cref="GetEscapeResult(char[])"/> method.</param>
	/// <param name="values">The values returned by the <see cref="GetEscapeResult(char[])"/> method.</param>
	/// <param name="terminator">The terminator returned by the <see cref="GetEscapeResult(char[])"/> method.</param>
	/// <param name="isMouse">Indicates if the escape sequence is a mouse event.</param>
	/// <param name="buttonState">The <see cref="MouseFlags"/> button state.</param>
	/// <param name="pos">The <see cref="MouseFlags"/> position.</param>
	/// <param name="isResponse">Indicates if the escape sequence is a response to a request.</param>
	/// <param name="continuousButtonPressedHandler">The handler that will process the event.</param>
	public static void DecodeEscSeq (EscSeqRequests escSeqRequests, ref ConsoleKeyInfo newConsoleKeyInfo, ref ConsoleKey key, ConsoleKeyInfo [] cki, ref ConsoleModifiers mod, out string c1Control, out string code, out string [] values, out string terminator, out bool isMouse, out List<MouseFlags> buttonState, out Point pos, out bool isResponse, Action<MouseFlags, Point> continuousButtonPressedHandler)
	{
		char [] kChars = GetKeyCharArray (cki);
		(c1Control, code, values, terminator) = GetEscapeResult (kChars);
		isMouse = false;
		buttonState = new List<MouseFlags> () { 0 };
		pos = default;
		isResponse = false;
		switch (c1Control) {
		case "ESC":
			if (values == null && string.IsNullOrEmpty (terminator)) {
				key = ConsoleKey.Escape;
				newConsoleKeyInfo = new ConsoleKeyInfo (cki [0].KeyChar, key,
					(mod & ConsoleModifiers.Shift) != 0,
					(mod & ConsoleModifiers.Alt) != 0,
					(mod & ConsoleModifiers.Control) != 0);
			} else if ((uint)cki [1].KeyChar >= 1 && (uint)cki [1].KeyChar <= 26) {
				key = (ConsoleKey)(char)(cki [1].KeyChar + (uint)ConsoleKey.A - 1);
				newConsoleKeyInfo = new ConsoleKeyInfo (cki [1].KeyChar,
					key,
					false,
					true,
					true);
			} else {
				if (cki [1].KeyChar >= 97 && cki [1].KeyChar <= 122) {
					key = (ConsoleKey)cki [1].KeyChar.ToString ().ToUpper () [0];
				} else {
					key = (ConsoleKey)cki [1].KeyChar;
				}
				newConsoleKeyInfo = new ConsoleKeyInfo ((char)key,
					(ConsoleKey)Math.Min ((uint)key, 255),
					false,
					true,
					false);
			}
			break;
		case "SS3":
			key = GetConsoleKey (terminator [0], values [0], ref mod);
			newConsoleKeyInfo = new ConsoleKeyInfo ('\0',
				key,
				(mod & ConsoleModifiers.Shift) != 0,
				(mod & ConsoleModifiers.Alt) != 0,
				(mod & ConsoleModifiers.Control) != 0);
			break;
		case "CSI":
			if (!string.IsNullOrEmpty (code) && code == "<") {
				GetMouse (cki, out buttonState, out pos, continuousButtonPressedHandler);
				isMouse = true;
				return;
			} else if (escSeqRequests != null && escSeqRequests.HasResponse (terminator)) {
				isResponse = true;
				escSeqRequests.Remove (terminator);
				return;
			}
			if (!string.IsNullOrEmpty (terminator)) {
				key = GetConsoleKey (terminator [0], values [0], ref mod);
				if (key != 0 && values.Length > 1) {
					mod |= GetConsoleModifiers (values [1]);
				}
				newConsoleKeyInfo = new ConsoleKeyInfo ('\0',
					key,
					(mod & ConsoleModifiers.Shift) != 0,
					(mod & ConsoleModifiers.Alt) != 0,
					(mod & ConsoleModifiers.Control) != 0);
			} else {
				// BUGBUG: See https://github.com/gui-cs/Terminal.Gui/issues/2803
				// This is caused by NetDriver depending on Console.KeyAvailable?
				throw new InvalidOperationException ($"CSI response, but there's no terminator");
				//newConsoleKeyInfo = new ConsoleKeyInfo ('\0',
				//	key,
				//	(mod & ConsoleModifiers.Shift) != 0,
				//	(mod & ConsoleModifiers.Alt) != 0,
				//	(mod & ConsoleModifiers.Control) != 0);
			}
			break;
		}
	}

	/// <summary>
	/// Gets all the needed information about a escape sequence.
	/// </summary>
	/// <param name="kChar">The array with all chars.</param>
	/// <returns>
	/// The c1Control returned by <see cref="GetC1ControlChar(char)"/>, code, values and terminating.
	/// </returns>
	public static (string c1Control, string code, string [] values, string terminating) GetEscapeResult (char [] kChar)
	{
		if (kChar == null || kChar.Length == 0) {
			return (null, null, null, null);
		}
		if (kChar [0] != KeyEsc) {
			throw new InvalidOperationException ("Invalid escape character!");
		}
		if (kChar.Length == 1) {
			return ("ESC", null, null, null);
		}
		if (kChar.Length == 2) {
			return ("ESC", null, null, kChar [1].ToString ());
		}
		string c1Control = GetC1ControlChar (kChar [1]);
		string code = null;
		int nSep = kChar.Count (x => x == ';') + 1;
		string [] values = new string [nSep];
		int valueIdx = 0;
		string terminating = "";
		for (int i = 2; i < kChar.Length; i++) {
			var c = kChar [i];
			if (char.IsDigit (c)) {
				values [valueIdx] += c.ToString ();
			} else if (c == ';') {
				valueIdx++;
			} else if (valueIdx == nSep - 1 || i == kChar.Length - 1) {
				terminating += c.ToString ();
			} else {
				code += c.ToString ();
			}
		}

		return (c1Control, code, values, terminating);
	}

	/// <summary>
	/// Gets the c1Control used in the called escape sequence.
	/// </summary>
	/// <param name="c">The char used.</param>
	/// <returns>The c1Control.</returns>
	public static string GetC1ControlChar (char c)
	{
		// These control characters are used in the vtXXX emulation.
		switch (c) {
		case 'D':
			return "IND"; // Index
		case 'E':
			return "NEL"; // Next Line
		case 'H':
			return "HTS"; // Tab Set
		case 'M':
			return "RI"; // Reverse Index
		case 'N':
			return "SS2"; // Single Shift Select of G2 Character Set: affects next character only
		case 'O':
			return "SS3"; // Single Shift Select of G3 Character Set: affects next character only
		case 'P':
			return "DCS"; // Device Control String
		case 'V':
			return "SPA"; // Start of Guarded Area
		case 'W':
			return "EPA"; // End of Guarded Area
		case 'X':
			return "SOS"; // Start of String
		case 'Z':
			return "DECID"; // Return Terminal ID Obsolete form of CSI c (DA)
		case '[':
			return "CSI"; // Control Sequence Introducer
		case '\\':
			return "ST"; // String Terminator
		case ']':
			return "OSC"; // Operating System Command
		case '^':
			return "PM"; // Privacy Message
		case '_':
			return "APC"; // Application Program Command
		default:
			return ""; // Not supported
		}
	}

	/// <summary>
	/// Gets the <see cref="ConsoleModifiers"/> from the value.
	/// </summary>
	/// <param name="value">The value.</param>
	/// <returns>The <see cref="ConsoleModifiers"/> or zero.</returns>
	public static ConsoleModifiers GetConsoleModifiers (string value)
	{
		switch (value) {
		case "2":
			return ConsoleModifiers.Shift;
		case "3":
			return ConsoleModifiers.Alt;
		case "4":
			return ConsoleModifiers.Shift | ConsoleModifiers.Alt;
		case "5":
			return ConsoleModifiers.Control;
		case "6":
			return ConsoleModifiers.Shift | ConsoleModifiers.Control;
		case "7":
			return ConsoleModifiers.Alt | ConsoleModifiers.Control;
		case "8":
			return ConsoleModifiers.Shift | ConsoleModifiers.Alt | ConsoleModifiers.Control;
		default:
			return 0;
		}
	}

	/// <summary>
	/// Gets the <see cref="ConsoleKey"/> depending on terminating and value.
	/// </summary>
	/// <param name="terminator">The terminator indicating a reply to <see cref="CSI_SendDeviceAttributes"/> or <see cref="CSI_SendDeviceAttributes2"/>.</param>
	/// <param name="value">The value.</param>
	/// <param name="mod">The <see cref="ConsoleModifiers"/> which may changes.</param>
	/// <returns>The <see cref="ConsoleKey"/> and probably the <see cref="ConsoleModifiers"/>.</returns>
	public static ConsoleKey GetConsoleKey (char terminator, string value, ref ConsoleModifiers mod)
	{
		ConsoleKey key;
		switch (terminator) {
		case 'A':
			key = ConsoleKey.UpArrow;
			break;
		case 'B':
			key = ConsoleKey.DownArrow;
			break;
		case 'C':
			key = ConsoleKey.RightArrow;
			break;
		case 'D':
			key = ConsoleKey.LeftArrow;
			break;
		case 'F':
			key = ConsoleKey.End;
			break;
		case 'H':
			key = ConsoleKey.Home;
			break;
		case 'P':
			key = ConsoleKey.F1;
			break;
		case 'Q':
			key = ConsoleKey.F2;
			break;
		case 'R':
			key = ConsoleKey.F3;
			break;
		case 'S':
			key = ConsoleKey.F4;
			break;
		case 'Z':
			key = ConsoleKey.Tab;
			mod |= ConsoleModifiers.Shift;
			break;
		case '~':
			switch (value) {
			case "2":
				key = ConsoleKey.Insert;
				break;
			case "3":
				key = ConsoleKey.Delete;
				break;
			case "5":
				key = ConsoleKey.PageUp;
				break;
			case "6":
				key = ConsoleKey.PageDown;
				break;
			case "15":
				key = ConsoleKey.F5;
				break;
			case "17":
				key = ConsoleKey.F6;
				break;
			case "18":
				key = ConsoleKey.F7;
				break;
			case "19":
				key = ConsoleKey.F8;
				break;
			case "20":
				key = ConsoleKey.F9;
				break;
			case "21":
				key = ConsoleKey.F10;
				break;
			case "23":
				key = ConsoleKey.F11;
				break;
			case "24":
				key = ConsoleKey.F12;
				break;
			default:
				key = 0;
				break;
			}
			break;
		default:
			key = 0;
			break;
		}

		return key;
	}

	/// <summary>
	/// A helper to get only the <see cref="ConsoleKeyInfo.KeyChar"/> from the <see cref="ConsoleKeyInfo"/> array.
	/// </summary>
	/// <param name="cki"></param>
	/// <returns>The char array of the escape sequence.</returns>
	public static char [] GetKeyCharArray (ConsoleKeyInfo [] cki)
	{
		char [] kChar = new char [] { };
		var length = 0;
		foreach (var kc in cki) {
			length++;
			Array.Resize (ref kChar, length);
			kChar [length - 1] = kc.KeyChar;
		}

		return kChar;
	}

	private static MouseFlags? lastMouseButtonPressed;
	//private static MouseFlags? lastMouseButtonReleased;
	private static bool isButtonPressed;
	//private static bool isButtonReleased;
	private static bool isButtonClicked;
	private static bool isButtonDoubleClicked;
	private static bool isButtonTripleClicked;
	private static Point point;

	/// <summary>
	/// Gets the <see cref="MouseFlags"/> mouse button flags and the position.
	/// </summary>
	/// <param name="cki">The <see cref="ConsoleKeyInfo"/> array.</param>
	/// <param name="mouseFlags">The mouse button flags.</param>
	/// <param name="pos">The mouse position.</param>
	/// <param name="continuousButtonPressedHandler">The handler that will process the event.</param>
	public static void GetMouse (ConsoleKeyInfo [] cki, out List<MouseFlags> mouseFlags, out Point pos, Action<MouseFlags, Point> continuousButtonPressedHandler)
	{
		MouseFlags buttonState = 0;
		pos = new Point ();
		int buttonCode = 0;
		bool foundButtonCode = false;
		int foundPoint = 0;
		string value = "";
		var kChar = GetKeyCharArray (cki);
		//System.Diagnostics.Debug.WriteLine ($"kChar: {new string (kChar)}");
		for (int i = 0; i < kChar.Length; i++) {
			var c = kChar [i];
			if (c == '<') {
				foundButtonCode = true;
			} else if (foundButtonCode && c != ';') {
				value += c.ToString ();
			} else if (c == ';') {
				if (foundButtonCode) {
					foundButtonCode = false;
					buttonCode = int.Parse (value);
				}
				if (foundPoint == 1) {
					pos.X = int.Parse (value) - 1;
				}
				value = "";
				foundPoint++;
			} else if (foundPoint > 0 && c != 'm' && c != 'M') {
				value += c.ToString ();
			} else if (c == 'm' || c == 'M') {
				//pos.Y = int.Parse (value) + Console.WindowTop - 1;
				pos.Y = int.Parse (value) - 1;

				switch (buttonCode) {
				case 0:
				case 8:
				case 16:
				case 24:
				case 32:
				case 36:
				case 40:
				case 48:
				case 56:
					buttonState = c == 'M' ? MouseFlags.Button1Pressed
						: MouseFlags.Button1Released;
					break;
				case 1:
				case 9:
				case 17:
				case 25:
				case 33:
				case 37:
				case 41:
				case 45:
				case 49:
				case 53:
				case 57:
				case 61:
					buttonState = c == 'M' ? MouseFlags.Button2Pressed
						: MouseFlags.Button2Released;
					break;
				case 2:
				case 10:
				case 14:
				case 18:
				case 22:
				case 26:
				case 30:
				case 34:
				case 42:
				case 46:
				case 50:
				case 54:
				case 58:
				case 62:
					buttonState = c == 'M' ? MouseFlags.Button3Pressed
						: MouseFlags.Button3Released;
					break;
				case 35:
				//// Needed for Windows OS
				//if (isButtonPressed && c == 'm'
				//	&& (lastMouseEvent.ButtonState == MouseFlags.Button1Pressed
				//	|| lastMouseEvent.ButtonState == MouseFlags.Button2Pressed
				//	|| lastMouseEvent.ButtonState == MouseFlags.Button3Pressed)) {

				//	switch (lastMouseEvent.ButtonState) {
				//	case MouseFlags.Button1Pressed:
				//		buttonState = MouseFlags.Button1Released;
				//		break;
				//	case MouseFlags.Button2Pressed:
				//		buttonState = MouseFlags.Button2Released;
				//		break;
				//	case MouseFlags.Button3Pressed:
				//		buttonState = MouseFlags.Button3Released;
				//		break;
				//	}
				//} else {
				//	buttonState = MouseFlags.ReportMousePosition;
				//}
				//break;
				case 39:
				case 43:
				case 47:
				case 51:
				case 55:
				case 59:
				case 63:
					buttonState = MouseFlags.ReportMousePosition;
					break;
				case 64:
					buttonState = MouseFlags.WheeledUp;
					break;
				case 65:
					buttonState = MouseFlags.WheeledDown;
					break;
				case 68:
				case 72:
				case 80:
					buttonState = MouseFlags.WheeledLeft;       // Shift/Ctrl+WheeledUp
					break;
				case 69:
				case 73:
				case 81:
					buttonState = MouseFlags.WheeledRight;      // Shift/Ctrl+WheeledDown
					break;
				}
				// Modifiers.
				switch (buttonCode) {
				case 8:
				case 9:
				case 10:
				case 43:
					buttonState |= MouseFlags.ButtonAlt;
					break;
				case 14:
				case 47:
					buttonState |= MouseFlags.ButtonAlt | MouseFlags.ButtonShift;
					break;
				case 16:
				case 17:
				case 18:
				case 51:
					buttonState |= MouseFlags.ButtonCtrl;
					break;
				case 22:
				case 55:
					buttonState |= MouseFlags.ButtonCtrl | MouseFlags.ButtonShift;
					break;
				case 24:
				case 25:
				case 26:
				case 59:
					buttonState |= MouseFlags.ButtonCtrl | MouseFlags.ButtonAlt;
					break;
				case 30:
				case 63:
					buttonState |= MouseFlags.ButtonCtrl | MouseFlags.ButtonShift | MouseFlags.ButtonAlt;
					break;
				case 32:
				case 33:
				case 34:
					buttonState |= MouseFlags.ReportMousePosition;
					break;
				case 36:
				case 37:
					buttonState |= MouseFlags.ReportMousePosition | MouseFlags.ButtonShift;
					break;
				case 39:
				case 68:
				case 69:
					buttonState |= MouseFlags.ButtonShift;
					break;
				case 40:
				case 41:
				case 42:
					buttonState |= MouseFlags.ReportMousePosition | MouseFlags.ButtonAlt;
					break;
				case 45:
				case 46:
					buttonState |= MouseFlags.ReportMousePosition | MouseFlags.ButtonAlt | MouseFlags.ButtonShift;
					break;
				case 48:
				case 49:
				case 50:
					buttonState |= MouseFlags.ReportMousePosition | MouseFlags.ButtonCtrl;
					break;
				case 53:
				case 54:
					buttonState |= MouseFlags.ReportMousePosition | MouseFlags.ButtonCtrl | MouseFlags.ButtonShift;
					break;
				case 56:
				case 57:
				case 58:
					buttonState |= MouseFlags.ReportMousePosition | MouseFlags.ButtonCtrl | MouseFlags.ButtonAlt;
					break;
				case 61:
				case 62:
					buttonState |= MouseFlags.ReportMousePosition | MouseFlags.ButtonCtrl | MouseFlags.ButtonShift | MouseFlags.ButtonAlt;
					break;
				}
			}
		}

		mouseFlags = new List<MouseFlags> () { MouseFlags.AllEvents };

		if (lastMouseButtonPressed != null && !isButtonPressed && !buttonState.HasFlag (MouseFlags.ReportMousePosition)
			&& !buttonState.HasFlag (MouseFlags.Button1Released)
			&& !buttonState.HasFlag (MouseFlags.Button2Released)
			&& !buttonState.HasFlag (MouseFlags.Button3Released)
			&& !buttonState.HasFlag (MouseFlags.Button4Released)) {

			lastMouseButtonPressed = null;
			isButtonPressed = false;
		}

		if (!isButtonClicked && !isButtonDoubleClicked && ((buttonState == MouseFlags.Button1Pressed || buttonState == MouseFlags.Button2Pressed ||
			  buttonState == MouseFlags.Button3Pressed || buttonState == MouseFlags.Button4Pressed) && lastMouseButtonPressed == null) ||
			  isButtonPressed && lastMouseButtonPressed != null && buttonState.HasFlag (MouseFlags.ReportMousePosition)) {

			mouseFlags [0] = buttonState;
			lastMouseButtonPressed = buttonState;
			isButtonPressed = true;

			if ((mouseFlags [0] & MouseFlags.ReportMousePosition) == 0) {
				point = new Point () {
					X = pos.X,
					Y = pos.Y
				};

				Application.MainLoop.AddIdle (() => {
					Task.Run (async () => await ProcessContinuousButtonPressedAsync (buttonState, continuousButtonPressedHandler));
					return false;
				});
			} else if (mouseFlags [0] == MouseFlags.ReportMousePosition) {
				isButtonPressed = false;
			}

		} else if (isButtonDoubleClicked && (buttonState == MouseFlags.Button1Pressed || buttonState == MouseFlags.Button2Pressed ||
			buttonState == MouseFlags.Button3Pressed || buttonState == MouseFlags.Button4Pressed)) {

			mouseFlags [0] = GetButtonTripleClicked (buttonState);
			isButtonDoubleClicked = false;
			isButtonTripleClicked = true;

		} else if (isButtonClicked && (buttonState == MouseFlags.Button1Pressed || buttonState == MouseFlags.Button2Pressed ||
			buttonState == MouseFlags.Button3Pressed || buttonState == MouseFlags.Button4Pressed)) {

			mouseFlags [0] = GetButtonDoubleClicked (buttonState);
			isButtonClicked = false;
			isButtonDoubleClicked = true;
			Application.MainLoop.AddIdle (() => {
				Task.Run (async () => await ProcessButtonDoubleClickedAsync ());
				return false;
			});

		}
		//else if (isButtonReleased && !isButtonClicked && buttonState == MouseFlags.ReportMousePosition) {
		//	mouseFlag [0] = GetButtonClicked ((MouseFlags)lastMouseButtonReleased);
		//	lastMouseButtonReleased = null;
		//	isButtonReleased = false;
		//	isButtonClicked = true;
		//	Application.MainLoop.AddIdle (() => {
		//		Task.Run (async () => await ProcessButtonClickedAsync ());
		//		return false;
		//	});

		//} 
		else if (!isButtonClicked && !isButtonDoubleClicked && (buttonState == MouseFlags.Button1Released || buttonState == MouseFlags.Button2Released ||
			  buttonState == MouseFlags.Button3Released || buttonState == MouseFlags.Button4Released)) {

			mouseFlags [0] = buttonState;
			isButtonPressed = false;

			if (isButtonTripleClicked) {
				isButtonTripleClicked = false;
			} else if (pos.X == point.X && pos.Y == point.Y) {
				mouseFlags.Add (GetButtonClicked (buttonState));
				isButtonClicked = true;
				Application.MainLoop.AddIdle (() => {
					Task.Run (async () => await ProcessButtonClickedAsync ());
					return false;
				});
			}

			point = pos;

			//if ((lastMouseButtonPressed & MouseFlags.ReportMousePosition) == 0) {
			//	lastMouseButtonReleased = buttonState;
			//	isButtonPressed = false;
			//	isButtonReleased = true;
			//} else {
			//	lastMouseButtonPressed = null;
			//	isButtonPressed = false;
			//}

		} else if (buttonState == MouseFlags.WheeledUp) {

			mouseFlags [0] = MouseFlags.WheeledUp;

		} else if (buttonState == MouseFlags.WheeledDown) {

			mouseFlags [0] = MouseFlags.WheeledDown;

		} else if (buttonState == MouseFlags.WheeledLeft) {

			mouseFlags [0] = MouseFlags.WheeledLeft;

		} else if (buttonState == MouseFlags.WheeledRight) {

			mouseFlags [0] = MouseFlags.WheeledRight;

		} else if (buttonState == MouseFlags.ReportMousePosition) {
			mouseFlags [0] = MouseFlags.ReportMousePosition;

		} else {
			mouseFlags [0] = buttonState;
			//foreach (var flag in buttonState.GetUniqueFlags()) {
			//	mouseFlag [0] |= flag;
			//}
		}

		mouseFlags [0] = SetControlKeyStates (buttonState, mouseFlags [0]);
		//buttonState = mouseFlags;

		//System.Diagnostics.Debug.WriteLine ($"buttonState: {buttonState} X: {pos.X} Y: {pos.Y}");
		//foreach (var mf in mouseFlags) {
		//	System.Diagnostics.Debug.WriteLine ($"mouseFlags: {mf} X: {pos.X} Y: {pos.Y}");
		//}
	}

	private static async Task ProcessContinuousButtonPressedAsync (MouseFlags mouseFlag, Action<MouseFlags, Point> continuousButtonPressedHandler)
	{
		while (isButtonPressed) {
			await Task.Delay (100);
			//var me = new MouseEvent () {
			//	X = point.X,
			//	Y = point.Y,
			//	Flags = mouseFlag
			//};

			var view = Application.WantContinuousButtonPressedView;
			if (view == null)
				break;
			if (isButtonPressed && lastMouseButtonPressed != null && (mouseFlag & MouseFlags.ReportMousePosition) == 0) {
				Application.MainLoop.Invoke (() => continuousButtonPressedHandler (mouseFlag, point));
			}
		}
	}

	private static async Task ProcessButtonClickedAsync ()
	{
		await Task.Delay (300);
		isButtonClicked = false;
	}

	private static async Task ProcessButtonDoubleClickedAsync ()
	{
		await Task.Delay (300);
		isButtonDoubleClicked = false;
	}

	private static MouseFlags GetButtonClicked (MouseFlags mouseFlag)
	{
		MouseFlags mf = default;
		switch (mouseFlag) {
		case MouseFlags.Button1Released:
			mf = MouseFlags.Button1Clicked;
			break;

		case MouseFlags.Button2Released:
			mf = MouseFlags.Button2Clicked;
			break;

		case MouseFlags.Button3Released:
			mf = MouseFlags.Button3Clicked;
			break;
		}
		return mf;
	}

	private static MouseFlags GetButtonDoubleClicked (MouseFlags mouseFlag)
	{
		MouseFlags mf = default;
		switch (mouseFlag) {
		case MouseFlags.Button1Pressed:
			mf = MouseFlags.Button1DoubleClicked;
			break;

		case MouseFlags.Button2Pressed:
			mf = MouseFlags.Button2DoubleClicked;
			break;

		case MouseFlags.Button3Pressed:
			mf = MouseFlags.Button3DoubleClicked;
			break;
		}
		return mf;
	}

	private static MouseFlags GetButtonTripleClicked (MouseFlags mouseFlag)
	{
		MouseFlags mf = default;
		switch (mouseFlag) {
		case MouseFlags.Button1Pressed:
			mf = MouseFlags.Button1TripleClicked;
			break;

		case MouseFlags.Button2Pressed:
			mf = MouseFlags.Button2TripleClicked;
			break;

		case MouseFlags.Button3Pressed:
			mf = MouseFlags.Button3TripleClicked;
			break;
		}
		return mf;
	}

	private static MouseFlags SetControlKeyStates (MouseFlags buttonState, MouseFlags mouseFlag)
	{
		if ((buttonState & MouseFlags.ButtonCtrl) != 0 && (mouseFlag & MouseFlags.ButtonCtrl) == 0)
			mouseFlag |= MouseFlags.ButtonCtrl;

		if ((buttonState & MouseFlags.ButtonShift) != 0 && (mouseFlag & MouseFlags.ButtonShift) == 0)
			mouseFlag |= MouseFlags.ButtonShift;

		if ((buttonState & MouseFlags.ButtonAlt) != 0 && (mouseFlag & MouseFlags.ButtonAlt) == 0)
			mouseFlag |= MouseFlags.ButtonAlt;
		return mouseFlag;
	}

	// TODO: Move this out of here and into ConsoleDriver or somewhere else.
	/// <summary>
	/// Get the terminal that holds the console driver.
	/// </summary>
	/// <param name="process">The process.</param>
	/// <returns>If supported the executable console process, null otherwise.</returns>
	public static Process GetParentProcess (Process process)
	{
		if (!RuntimeInformation.IsOSPlatform (OSPlatform.Windows)) {
			return null;
		}

		string query = "SELECT ParentProcessId FROM Win32_Process WHERE ProcessId = " + process.Id;
		using (ManagementObjectSearcher mos = new ManagementObjectSearcher (query)) {
			foreach (ManagementObject mo in mos.Get ()) {
				if (mo ["ParentProcessId"] != null) {
					try {
						var id = Convert.ToInt32 (mo ["ParentProcessId"]);
						return Process.GetProcessById (id);
					} catch {
					}
				}
			}
		}
		return null;
	}
}