ansi-fahrplan/CursesWrapper.cs

using System.Diagnostics.Contracts;
using System.IO.Pipes;
using Microsoft.VisualBasic;
using Mindmagma.Curses;
using Newtonsoft.Json.Linq;

namespace SCI.CursesWrapper;

public class Helper {
	/// <summary>
	/// Create a centered NCurses window on the specified screen
	/// </summary>
	/// <param name="screen">Parent screen to attach window to</param>
	/// <param name="width">Width of columns of window</param>
	/// <param name="height">Height of rows of window</param>
	/// <param name="borders">If true, shows default borders around window</param>
	/// <returns>nint - Pointer of new window</returns>
	/// <exception cref="ArgumentOutOfRangeException">Throws exception if window is outside of screen bounds</exception>
	public static nint CreateCenteredWindow (nint screen, int width, int height, bool borders = true) {
		NCurses.GetMaxYX (screen, out int screenHeight, out int screenWidth);

		int originY = (screenHeight / 2) - (height / 2);
		int originX = (screenWidth / 2) - (width / 2);

		if (originX + width > screenWidth)   throw new ArgumentOutOfRangeException ("width");
		if (originY + height > screenHeight) throw new ArgumentOutOfRangeException ("height");

		if (originX < 0) throw new ArgumentOutOfRangeException ("originX");
		if (originY < 0) throw new ArgumentOutOfRangeException ("originY");

		nint window = NCurses.NewWindow (height, width, originY, originX);
		if (borders) NCurses.Box (window, (char) 0, (char) 0);

		return window;
	}

	/// <summary>
	/// Prints text horizontally centered to window (on a specific line);
	/// </summary>
	/// <param name="window">Parent window to print into</param>
	/// <param name="text">Text to display</param>
	/// <param name="y">Y posititon of the text</param>
	public static void PrintHCenteredText (nint window, string text, int y = 0) {
		NCurses.GetMaxYX (window, out int _, out int windowWidth);
		
		var x = windowWidth / 2 - text.Length / 2;
		NCurses.MoveWindowAddString (window, y, x, text);
	}
}

public class MessageBox {
	public enum MessageBoxButtons {
		OK,
		YesNo,
		RetryCancel,
		RetryIgnoreCancel
	}

	/// <summary>
	/// Shows a message box with specified text and returns the selected button from zero index
	/// </summary>
	/// <param name="screen">Parent screen to show message box on</param>
	/// <param name="text">Text to show</param>
	/// <param name="buttons">Type of buttons to show</param>
	/// <returns>Button pressed by user, zero indexed</returns>
	public static int Show (nint screen, string text, MessageBoxButtons buttons = MessageBoxButtons.OK) {
		NCurses.GetMaxYX (screen, out int screenHeight, out int screenWidth);

		// Set static box width, if width is larger than screen, reduce to screen size,
		// then calculate the message box and inner pad origin X coords
		var boxWidth = 50;
		if (boxWidth + 3 >= screenWidth) boxWidth = screenWidth - 3;
		int originX = (screenWidth / 2)  - (boxWidth / 2);
		var padOriginX = originX + 2; // Add one for the border and for a single character padding

		// Calculate sizes for the inner pad element
		var padWidth	   = boxWidth - 4; // Add four to the total box width due to the two character padding on both sides
		var totalTextLines = (int) Math.Ceiling ((double) text.Length / padWidth); // Get total amount of lines required to hold all text limited by box width
		var padHeight	  = totalTextLines;
		if (padHeight + 8 > screenHeight) { // If height required to show all text lines plus padding is larger than screen, reduce size of message box
			padHeight = screenHeight - 8;
		}

		// Now calculate the height and Y origin of the text box and inner pad
		var boxHeight = padHeight + 6; // Add five to the pad height due to the title bar and two character padding top and bottom
		if (boxHeight + 2 > screenHeight) boxHeight = screenHeight - 2;
		int originY = (screenHeight / 2) - (boxHeight / 2);
		var padOriginY = originY + 3; // Add one for the border, one for the title and one for a single character padding

		//if (text.Length > (totalTextRows * textCols)) text = text.Substring (0, (totalTextRows * textCols) - 1) + "$";

		// Create message box and inner Pad
		var msgBoxWindow = Helper.CreateCenteredWindow (screen, boxWidth, boxHeight, true);
		var msgTextPad   = NCurses.NewPad (padHeight, padWidth);

		NCurses.Refresh ();

		// Title, currently not in use
		Helper.PrintHCenteredText (msgBoxWindow, "Info", 1);
		NCurses.WindowRefresh (msgBoxWindow);

		NCurses.WindowAddString (msgTextPad, text);
		
		NCurses.PadRefresh (msgTextPad, 0, 0, padOriginY, padOriginX, padOriginY + padHeight, padOriginX + padWidth);

		return InputHandler (msgBoxWindow, buttons);
	}

	private static List<string> GetStringsFromButtonEnum (MessageBoxButtons buttons) {
		List<string> buttonStrings;

		switch (buttons) {
			case MessageBoxButtons.OK:
				buttonStrings = new List<string> () { "OK" };
				break;
			case MessageBoxButtons.YesNo:
				buttonStrings = new List<string> () { "Yes", "No" };
				break;
			case MessageBoxButtons.RetryCancel:
				buttonStrings = new List<string> () { "Retry", "Cancel" };
				break;
			case MessageBoxButtons.RetryIgnoreCancel:
				buttonStrings = new List<string> () { "Retry", "Ignore", "Cancel" };
				break;
			default:
				throw new Exception ("Unknown button layout for message box");
		}

		return buttonStrings;
	}

	/// <summary>
	/// Draws buttons specified by the buttons type
	/// </summary>
	/// <param name="window">Window to draw buttons on</param>
	/// <param name="buttons">Buttons to display</param>
	private static void DrawButtons (nint window, MessageBoxButtons buttons, int active = 0) {
		NCurses.GetMaxYX (window, out int windowHeight, out int windowWidth);

		var buttonStrings = GetStringsFromButtonEnum (buttons);
		var totalStringLength = buttonStrings.Count - 1;
		foreach (var str in buttonStrings) totalStringLength += str.Length + 2;

		NCurses.WindowMove (window, windowHeight - 2, (windowWidth / 2) - (totalStringLength / 2));
		
		var index = 0;
		foreach (var str in buttonStrings) {
			if (index == active) {
				NCurses.WindowAddString (window, $"[{str}]");
			} else {
				NCurses.WindowAddString (window, $" {str} ");
			}

			NCurses.WindowAddChar (window, ' ');

			index ++;
		}

		NCurses.WindowRefresh (window);
	}

	/// <summary>
	/// Handle the user selection of the buttons
	/// </summary>
	/// <param name="window">Window to draw buttons on</param>
	/// <param name="buttons">Buttons to display</param>
	/// <returns>User choice of button, zero indexed</returns>
	private static int InputHandler (nint window, MessageBoxButtons buttons) {
		DrawButtons (window, buttons);

		int index = 0;
		int maxIndex = GetStringsFromButtonEnum (buttons).Count - 1;

		int chr = 0;
		while ((chr = NCurses.GetChar ()) != 10) {
			if (chr == 260) { // Left
				index ++;
				if (index > maxIndex) index = 0;
				DrawButtons (window, buttons, index);
			} else if (chr == 261)  { // Right
				index --;
				if (index < 0) index = maxIndex;
				DrawButtons (window, buttons, index);
			}
		}

		return index;
	}
}