feat(readline): optimize key handling and input management (#15)

.gitignore

@@ -5,4 +5,5 @@ obj/
 riderModule.iml
 /_ReSharper.Caches/
 NeonShell.sln.DotSettings.user
-publish
+publish
+global.json

Commands/CdCommand.cs

@@ -30,4 +30,4 @@ public void Execute(ShellContext context, string[] args)
             AnsiConsole.MarkupLine($"[[[red]-[/]]] - No such directory: {fullPath}");
         }
     }
-}
+}

Program.cs

@@ -2,9 +2,8 @@
 using Spectre.Console;
 using NShell.Shell;
 using NShell.Shell.Commands;
-using NShell.Shell.History;
-using NShell.Shell.Keyboard;
 using NShell.Shell.Plugins;
+using NShell.Shell.Readline;
 using static NShell.Animation.GlitchOutput;
 
 public class Program
@@ -37,21 +36,40 @@ public static async Task Main(string[] args)
 
         AnsiConsole.Markup("[bold cyan][[*]] - Booting NShell...[/]\n");
         ShellContext context = new();
-        HistoryManager history = new();
         PluginLoader plugins = new();
         AnsiConsole.Markup("[bold cyan][[*]] - Loading command(s)...[/]\n");
         CommandParser parser = new();
         AnsiConsole.Markup("[bold cyan][[*]] - Loading plugin(s)...[/]\n");
         plugins.LoadPlugins();
 
         AppDomain.CurrentDomain.ProcessExit += (_, _) => {
-            history.Save();
+            ReadLine.History.Save();
         };
 
         await GlitchedPrint("[+] - System Online", TimeSpan.FromMilliseconds(20));
-        Console.WriteLine();
+        string inputBuffer;
 
-        KeyboardHandler.Handler(history, context, parser);
-
+        while (true)
+        {
+            Environment.SetEnvironmentVariable("LS_COLORS", context.GetLsColors());
+            context.SetTheme(context.CurrentTheme);
+            AnsiConsole.Markup(context.GetPrompt());
+            ReadLine.History.ResetIndex();
+            ReadLine.Handler.UpdateInitCursorPos(Console.CursorLeft);
+
+            inputBuffer = ReadLine.GetText();
+
+            if (string.IsNullOrWhiteSpace(inputBuffer)) continue;
+            ReadLine.History.Add(inputBuffer);
+
+            try
+            {
+                parser.TryExecute(inputBuffer, context);
+            }
+            catch (Exception ex)
+            {
+                AnsiConsole.MarkupLine($"[[[red]-[/]]] - Shell crash: [yellow]{ex.Message}[/]");
+            }
+        }
     }
 }

Shell/Readline/KeyAction.cs

@@ -0,0 +1,126 @@
+using System.Diagnostics;
+
+namespace NShell.Shell.Readline;
+
+/// <summary>
+/// <c>KeyHandler</c> is a class that handle all about key input.
+/// define different key handling methods
+/// </summary>
+public partial class KeyHandler
+{
+	public void HandleNormalChar()
+	{
+		_inputBuffer.Insert(_currentCursorPos4Input, _currentKey.KeyChar);
+		_inputLength++;
+		Console.Write((string?)_inputBuffer.ToString(_currentCursorPos4Input, _inputLength - _currentCursorPos4Input));
+		_currentCursorPos4Input++;
+		_currentCursorPos4Console++;
+		Console.SetCursorPosition(_currentCursorPos4Console, Console.CursorTop);
+	}
+
+	public void HandleBackspaceChar()
+	{
+		if (IsStartOfLine())
+			return;
+		_inputBuffer = _inputBuffer.Remove(_currentCursorPos4Input - 1, 1);
+		_inputLength--;
+		_currentCursorPos4Input--;
+		_currentCursorPos4Console--;
+		Console.SetCursorPosition(_currentCursorPos4Console, Console.CursorTop);
+		Console.Write(_inputBuffer.ToString(_currentCursorPos4Input, _inputLength - _currentCursorPos4Input) + " ");
+		Console.SetCursorPosition(_currentCursorPos4Console, Console.CursorTop);
+	}
+
+	public void HandleDeleteChar()
+	{
+		if (IsEndOfLine())
+			return;
+		_inputBuffer.Remove(_currentCursorPos4Input, 1);
+		_inputLength--;
+		Console.Write(_inputBuffer.ToString(_currentCursorPos4Input, _inputLength - _currentCursorPos4Input) + " ");
+		Console.SetCursorPosition(_currentCursorPos4Console, Console.CursorTop);
+	}
+
+	public void HandleTab()
+	{
+		// TODO: Implement tab completion
+	}
+
+	public void PreviousHistory()
+	{
+		var prev = _history.GetPrevious();
+		if (prev != null)
+		{
+			Console.Write(new string('\b', _inputLength) + new string(' ', _inputLength) + new string('\b', _inputLength));
+			_inputBuffer.Clear();
+			_inputLength = prev.Length;
+			_inputBuffer.Append(prev);
+			Console.Write((object?)_inputBuffer);
+			_currentCursorPos4Input = _inputLength;
+			_currentCursorPos4Console = _initCursorPos4Console + _inputLength;
+			Console.SetCursorPosition(_currentCursorPos4Console, Console.CursorTop);
+		}
+	}
+
+	public void NextHistory()
+	{
+		var next = _history.GetNext();
+		if (next != null)
+		{
+			Console.Write(new string('\b', _inputLength) + new string(' ', _inputLength) + new string('\b', _inputLength));
+			_inputBuffer.Clear();
+			_inputLength = next.Length;
+			_inputBuffer.Append(next);
+			Console.Write((object?)_inputBuffer);
+			_currentCursorPos4Input = _inputLength;
+			_currentCursorPos4Console = _initCursorPos4Console + _inputLength;
+			Console.SetCursorPosition(_currentCursorPos4Console, Console.CursorTop);
+		}
+	}
+
+	private void MoveCursorToEnd()
+	{
+		_currentCursorPos4Input = _inputLength;
+		_currentCursorPos4Console = _initCursorPos4Console + _inputLength;
+		Console.SetCursorPosition(_currentCursorPos4Console,Console.CursorTop);
+	}
+
+	private void MoveCursorToStart()
+	{
+		_currentCursorPos4Input = 0;
+		_currentCursorPos4Console = _initCursorPos4Console;
+		Console.SetCursorPosition(_currentCursorPos4Console, Console.CursorTop);
+	}
+
+	private void MoveCursorWordLeft()
+	{
+		Debug.Write("MoveCursorWordLeft");
+	}
+
+	private void MoveCursorWordRight()
+	{
+		Debug.Write("MoveCursorWordRight");
+	}
+
+	private void MoveCursorLeft()
+	{
+		if (_currentCursorPos4Input == 0)
+			return;
+		_currentCursorPos4Console--;
+		_currentCursorPos4Input--;
+		Console.SetCursorPosition(_currentCursorPos4Console,Console.CursorTop);
+	}
+
+	private void MoveCursorRight()
+	{
+		if (_currentCursorPos4Input == _inputLength)
+			return;
+		_currentCursorPos4Console++;
+		_currentCursorPos4Input++;
+		Console.SetCursorPosition(_currentCursorPos4Console,Console.CursorTop);
+	}
+
+	private bool IsEndOfLine() => _currentCursorPos4Input ==  _inputLength;
+
+	private bool IsStartOfLine() => _currentCursorPos4Input == 0;
+}

Shell/Readline/KeyHandler.cs

@@ -0,0 +1,115 @@
+using System.Text;
+using NShell.Shell.History;
+using Spectre.Console;
+
+namespace NShell.Shell.Readline;
+
+/// <summary>
+/// <c>KeyHandler</c> deals with keybindings and inputs.
+/// defining key behaviors, managing input buffers, and cursor position
+/// </summary>
+public partial class KeyHandler
+{
+	// a dictionary that stores key bindings
+	private Dictionary<string, Action> _keyBindings;
+	// cursor position
+	private int _currentCursorPos4Console;
+	private int _currentCursorPos4Input;
+	private int _initCursorPos4Console;
+	// length of the string entered
+	private int _inputLength;
+	private ConsoleKeyInfo _currentKey;
+	private StringBuilder _inputBuffer;
+	private readonly HistoryManager _history;
+	public string InputBuffer { get => _inputBuffer.ToString(); }
+
+	public void LoadKeyBindings()
+	{
+		foreach (var binding in _keyBindings)
+		{
+			AnsiConsole.MarkupLine($"[green]+[/] - Loaded key binding: [yellow]{binding.Key}[/] -> [blue]{binding.Value}[/]");
+		}
+	}
+
+	// it can add custom key bindings to facilitate subsequent expansion
+	public void AddCustomKeyBinding(string key, Action handler)
+	{
+		if (_keyBindings.ContainsKey(key))
+		{
+			_keyBindings.Remove(key);
+		}
+		_keyBindings.Add(key, handler);
+	}
+
+	// it can remove custom key bindings
+	public void RemoveCustomKeyBinding(string key)
+	{
+		if (_keyBindings.ContainsKey(key))
+		{
+			_keyBindings.Remove(key);
+		}
+	}
+
+	public KeyHandler(HistoryManager history)
+	{
+		_history = history;
+		_inputBuffer = new();
+		_keyBindings = new();
+		_initCursorPos4Console = Console.CursorLeft;
+		_currentCursorPos4Console = _initCursorPos4Console;
+		_currentCursorPos4Input = 0;
+		_inputLength = 0;
+
+		_keyBindings["Backspace"] = HandleBackspaceChar;
+		_keyBindings["Delete"] = HandleDeleteChar;
+		_keyBindings["Home"] = MoveCursorToStart;
+		_keyBindings["ControlA"] = MoveCursorToStart;
+		_keyBindings["End"] = MoveCursorToEnd;
+		_keyBindings["ControlE"] = MoveCursorToEnd;
+		_keyBindings["LeftArrow"] = MoveCursorLeft;
+		_keyBindings["RightArrow"] = MoveCursorRight;
+		_keyBindings["UpArrow"] = PreviousHistory;
+		_keyBindings["DownArrow"] = NextHistory;
+
+		_keyBindings["Tab"] = HandleTab;
+		_keyBindings["ControlLeftArrow"] = MoveCursorWordLeft;
+		_keyBindings["ControlRightArrow"] = MoveCursorWordRight;
+	}
+
+	private string BuildKeyInput()
+	{
+		string result = "";
+		if (_currentKey.Modifiers.HasFlag(ConsoleModifiers.Control)) result += "Control";
+		if (_currentKey.Modifiers.HasFlag(ConsoleModifiers.Alt)) result += "Alt";
+		if (_currentKey.Modifiers.HasFlag(ConsoleModifiers.Shift)) result += "Shift";
+		result += _currentKey.Key.ToString();
+		return result;
+	}
+
+	// TODO: need to improve when input complex key (like Control+A, Alt+Shift+A)
+	public void HandleInput(ConsoleKeyInfo keyInfo)
+	{
+		_currentKey = keyInfo;
+		_keyBindings.TryGetValue(BuildKeyInput(),out var handleAction);
+		handleAction??=HandleNormalChar;
+		handleAction.Invoke();
+	}
+
+	// clear the input buffer and reset the cursor position
+	public void ResetInput()
+	{
+		_inputBuffer.Clear();
+		_currentCursorPos4Console = _initCursorPos4Console;
+		_currentCursorPos4Input = 0;
+		_inputLength = 0;
+	}
+
+	// update the initial cursor position when the prompt is being updated
+	public void UpdateInitCursorPos(int initCursorPos)
+	{
+		_initCursorPos4Console = initCursorPos;
+		_currentCursorPos4Console = _initCursorPos4Console;
+		_currentCursorPos4Input = 0;
+		_inputLength = 0;
+	}
+}

Shell/Readline/ReadLine.cs

@@ -0,0 +1,33 @@
+using NShell.Shell.History;
+
+namespace NShell.Shell.Readline;
+
+/// <summary>
+/// <c>ReadLine</c> is a simple readline library
+/// base on the tonerdo/readline project
+/// </summary>
+public class ReadLine
+{
+	public static KeyHandler Handler { get; }
+	public static HistoryManager History { get; }
+
+	static ReadLine()
+	{
+		History = new HistoryManager();
+		Handler = new KeyHandler(History);
+	}
+
+	public static string GetText()
+	{
+		ConsoleKeyInfo key = Console.ReadKey(intercept: true);
+		while (key.Key != ConsoleKey.Enter)
+		{
+			Handler.HandleInput(key);
+			key = Console.ReadKey(intercept: true);
+		}
+		string input = Handler.InputBuffer;
+		Handler.ResetInput();
+		Console.WriteLine();
+		return input;
+	}
+}

Shell/ShellContext.cs

@@ -15,7 +15,7 @@
         public string Prompt { get; private set; }
         public string LSColors { get; private set; }
 
         public ShellContext()
         {
             CurrentDirectory = Directory.GetCurrentDirectory();
             SetPromptAndColors("default");
@@ -122,7 +122,5 @@
             }
             return true;
         }
-
-
     }
 }