Terminal.Gui/UICatalog/Scenarios/TreeViewFileSystem.cs

using System.IO;
using System.IO.Abstractions;
using System.Linq;
using System.Text;
using Terminal.Gui;

namespace UICatalog.Scenarios;

[ScenarioMetadata ("File System Explorer", "Hierarchical file system explorer demonstrating TreeView.")]
[ScenarioCategory ("Controls")] [ScenarioCategory ("TreeView")] [ScenarioCategory ("Files and IO")]
public class TreeViewFileSystem : Scenario {
	/// <summary>
	/// A tree view where nodes are files and folders
	/// </summary>
	TreeView<IFileSystemInfo> _treeViewFiles;

	MenuItem _miShowLines;
	MenuItem _miPlusMinus;
	MenuItem _miArrowSymbols;
	MenuItem _miNoSymbols;
	MenuItem _miColoredSymbols;
	MenuItem _miInvertSymbols;

	MenuItem _miBasicIcons;
	MenuItem _miUnicodeIcons;
	MenuItem _miNerdIcons;

	MenuItem _miFullPaths;
	MenuItem _miLeaveLastRow;
	MenuItem _miHighlightModelTextOnly;
	MenuItem _miCustomColors;
	MenuItem _miCursor;
	MenuItem _miMultiSelect;

	DetailsFrame _detailsFrame;
	FileSystemIconProvider _iconProvider = new ();

	public override void Setup ()
	{
		Win.Title = GetName ();
		Win.Y = 1; // menu
		Win.Height = Dim.Fill ();

		var menu = new MenuBar (new MenuBarItem [] {
			new ("_File", new MenuItem [] {
				new ("_Quit", $"{Application.QuitKey}", () => Quit ())
			}),
			new ("_View", new MenuItem [] {
				_miFullPaths = new MenuItem ("_Full Paths", "", () => SetFullName ()) { Checked = false, CheckType = MenuItemCheckStyle.Checked },
				_miMultiSelect = new MenuItem ("_Multi Select", "", () => SetMultiSelect ()) { Checked = true, CheckType = MenuItemCheckStyle.Checked }
			}),
			new ("_Style", new MenuItem [] {
				_miShowLines = new MenuItem ("_Show Lines", "", () => ShowLines ()) {
					Checked = true, CheckType = MenuItemCheckStyle.Checked
				},
				null /*separator*/,
				_miPlusMinus = new MenuItem ("_Plus Minus Symbols", "+ -", () => SetExpandableSymbols ((Rune)'+', (Rune)'-')) { Checked = true, CheckType = MenuItemCheckStyle.Radio },
				_miArrowSymbols = new MenuItem ("_Arrow Symbols", "> v", () => SetExpandableSymbols ((Rune)'>', (Rune)'v')) { Checked = false, CheckType = MenuItemCheckStyle.Radio },
				_miNoSymbols = new MenuItem ("_No Symbols", "", () => SetExpandableSymbols (default, null)) { Checked = false, CheckType = MenuItemCheckStyle.Radio },
				null /*separator*/,
				_miColoredSymbols = new MenuItem ("_Colored Symbols", "", () => ShowColoredExpandableSymbols ()) { Checked = false, CheckType = MenuItemCheckStyle.Checked },
				_miInvertSymbols = new MenuItem ("_Invert Symbols", "", () => InvertExpandableSymbols ()) { Checked = false, CheckType = MenuItemCheckStyle.Checked },
				null /*separator*/,
				_miBasicIcons = new MenuItem ("_Basic Icons", null, SetNoIcons) { Checked = false, CheckType = MenuItemCheckStyle.Radio },
				_miUnicodeIcons = new MenuItem ("_Unicode Icons", null, SetUnicodeIcons) { Checked = false, CheckType = MenuItemCheckStyle.Radio },
				_miNerdIcons = new MenuItem ("_Nerd Icons", null, SetNerdIcons) { Checked = false, CheckType = MenuItemCheckStyle.Radio },
				null /*separator*/,
				_miLeaveLastRow = new MenuItem ("_Leave Last Row", "", () => SetLeaveLastRow ()) { Checked = true, CheckType = MenuItemCheckStyle.Checked },
				_miHighlightModelTextOnly = new MenuItem ("_Highlight Model Text Only", "", () => SetCheckHighlightModelTextOnly ()) { Checked = false, CheckType = MenuItemCheckStyle.Checked },
				null /*separator*/,
				_miCustomColors = new MenuItem ("C_ustom Colors Hidden Files", "Yellow/Red", () => SetCustomColors ()) { Checked = false, CheckType = MenuItemCheckStyle.Checked },
				null /*separator*/,
				_miCursor = new MenuItem ("Curs_or (MultiSelect only)", "", () => SetCursor ()) { Checked = false, CheckType = MenuItemCheckStyle.Checked }
			})
		});
		Application.Top.Add (menu);

		_treeViewFiles = new TreeView<IFileSystemInfo> () {
			X = 0,
			Y = 0,
			Width = Dim.Percent (50),
			Height = Dim.Fill ()
		};
		_treeViewFiles.DrawLine += TreeViewFiles_DrawLine;

		_detailsFrame = new DetailsFrame (_iconProvider) {
			X = Pos.Right (_treeViewFiles),
			Y = 0,
			Width = Dim.Fill (),
			Height = Dim.Fill ()
		};

		Win.Add (_detailsFrame);
		_treeViewFiles.MouseClick += TreeViewFiles_MouseClick;
		_treeViewFiles.KeyDown += TreeViewFiles_KeyPress;
		_treeViewFiles.SelectionChanged += TreeViewFiles_SelectionChanged;

		SetupFileTree ();

		Win.Add (_treeViewFiles);
		_treeViewFiles.GoToFirst ();
		_treeViewFiles.Expand ();

		SetupScrollBar ();

		_treeViewFiles.SetFocus ();

		UpdateIconCheckedness ();
	}

	void SetNoIcons ()
	{
		_iconProvider.UseUnicodeCharacters = false;
		_iconProvider.UseNerdIcons = false;
		UpdateIconCheckedness ();
	}

	void SetUnicodeIcons ()
	{
		_iconProvider.UseUnicodeCharacters = true;
		UpdateIconCheckedness ();
	}

	void SetNerdIcons ()
	{
		_iconProvider.UseNerdIcons = true;
		UpdateIconCheckedness ();
	}

	void UpdateIconCheckedness ()
	{
		_miBasicIcons.Checked = !_iconProvider.UseNerdIcons && !_iconProvider.UseUnicodeCharacters;
		_miUnicodeIcons.Checked = _iconProvider.UseUnicodeCharacters;
		_miNerdIcons.Checked = _iconProvider.UseNerdIcons;
		_treeViewFiles.SetNeedsDisplay ();
	}

	void TreeViewFiles_SelectionChanged (object sender, SelectionChangedEventArgs<IFileSystemInfo> e) => ShowPropertiesOf (e.NewValue);

	void TreeViewFiles_DrawLine (object sender, DrawTreeViewLineEventArgs<IFileSystemInfo> e)
	{
		// Render directory icons in yellow
		if (e.Model is IDirectoryInfo d) {
			if (_iconProvider.UseNerdIcons || _iconProvider.UseUnicodeCharacters) {
				if (e.IndexOfModelText > 0 && e.IndexOfModelText < e.RuneCells.Count) {
					var cell = e.RuneCells [e.IndexOfModelText];
					cell.ColorScheme = new ColorScheme (
						new Attribute (
							Color.BrightYellow,
							cell.ColorScheme.Normal.Background)
					);
				}
			}
		}
	}

	void TreeViewFiles_KeyPress (object sender, Key obj)
	{
		if (obj.KeyCode == (KeyCode.R | KeyCode.CtrlMask)) {

			var selected = _treeViewFiles.SelectedObject;

			// nothing is selected
			if (selected == null) {
				return;
			}

			int? location = _treeViewFiles.GetObjectRow (selected);

			//selected object is offscreen or somehow not found
			if (location == null || location < 0 || location > _treeViewFiles.Frame.Height) {
				return;
			}

			ShowContextMenu (new Point (
					5 + _treeViewFiles.Frame.X,
					location.Value + _treeViewFiles.Frame.Y + 2),
				selected);
		}
	}

	void TreeViewFiles_MouseClick (object sender, MouseEventEventArgs obj)
	{
		// if user right clicks
		if (obj.MouseEvent.Flags.HasFlag (MouseFlags.Button3Clicked)) {

			var rightClicked = _treeViewFiles.GetObjectOnRow (obj.MouseEvent.Y);

			// nothing was clicked
			if (rightClicked == null) {
				return;
			}

			ShowContextMenu (new Point (
					obj.MouseEvent.X + _treeViewFiles.Frame.X,
					obj.MouseEvent.Y + _treeViewFiles.Frame.Y + 2),
				rightClicked);
		}
	}

	void ShowContextMenu (Point screenPoint, IFileSystemInfo forObject)
	{
		var menu = new ContextMenu ();
		menu.Position = screenPoint;

		menu.MenuItems = new MenuBarItem (new [] { new MenuItem ("Properties", null, () => ShowPropertiesOf (forObject)) });

		Application.Invoke (menu.Show);
	}

	class DetailsFrame : FrameView {
		IFileSystemInfo fileInfo;
		FileSystemIconProvider _iconProvider;

		public DetailsFrame (FileSystemIconProvider iconProvider)
		{
			Title = "Details";
			Visible = true;
			CanFocus = true;
			_iconProvider = iconProvider;
		}

		public IFileSystemInfo FileInfo {
			get => fileInfo;
			set {
				fileInfo = value;
				StringBuilder sb = null;

				if (fileInfo is IFileInfo f) {
					Title = $"{_iconProvider.GetIconWithOptionalSpace (f)}{f.Name}".Trim ();
					sb = new StringBuilder ();
					sb.AppendLine ($"Path:\n {f.FullName}\n");
					sb.AppendLine ($"Size:\n {f.Length:N0} bytes\n");
					sb.AppendLine ($"Modified:\n {f.LastWriteTime}\n");
					sb.AppendLine ($"Created:\n {f.CreationTime}");
				}

				if (fileInfo is IDirectoryInfo dir) {
					Title = $"{_iconProvider.GetIconWithOptionalSpace (dir)}{dir.Name}".Trim ();
					sb = new StringBuilder ();
					sb.AppendLine ($"Path:\n {dir?.FullName}\n");
					sb.AppendLine ($"Modified:\n {dir.LastWriteTime}\n");
					sb.AppendLine ($"Created:\n {dir.CreationTime}\n");
				}
				Text = sb.ToString ();
			}
		}
	}

	void ShowPropertiesOf (IFileSystemInfo fileSystemInfo) => _detailsFrame.FileInfo = fileSystemInfo;

	void SetupScrollBar ()
	{
		// When using scroll bar leave the last row of the control free (for over-rendering with scroll bar)
		_treeViewFiles.Style.LeaveLastRow = true;

		var scrollBar = new ScrollBarView (_treeViewFiles, true);

		scrollBar.ChangedPosition += (s, e) => {
			_treeViewFiles.ScrollOffsetVertical = scrollBar.Position;
			if (_treeViewFiles.ScrollOffsetVertical != scrollBar.Position) {
				scrollBar.Position = _treeViewFiles.ScrollOffsetVertical;
			}
			_treeViewFiles.SetNeedsDisplay ();
		};

		scrollBar.OtherScrollBarView.ChangedPosition += (s, e) => {
			_treeViewFiles.ScrollOffsetHorizontal = scrollBar.OtherScrollBarView.Position;
			if (_treeViewFiles.ScrollOffsetHorizontal != scrollBar.OtherScrollBarView.Position) {
				scrollBar.OtherScrollBarView.Position = _treeViewFiles.ScrollOffsetHorizontal;
			}
			_treeViewFiles.SetNeedsDisplay ();
		};

		_treeViewFiles.DrawContent += (s, e) => {
			scrollBar.Size = _treeViewFiles.ContentHeight;
			scrollBar.Position = _treeViewFiles.ScrollOffsetVertical;
			scrollBar.OtherScrollBarView.Size = _treeViewFiles.GetContentWidth (true);
			scrollBar.OtherScrollBarView.Position = _treeViewFiles.ScrollOffsetHorizontal;
			scrollBar.Refresh ();
		};
	}

	void SetupFileTree ()
	{
		// setup how to build tree
		var fs = new FileSystem ();
		var rootDirs = DriveInfo.GetDrives ().Select (d => fs.DirectoryInfo.New (d.RootDirectory.FullName));
		_treeViewFiles.TreeBuilder = new FileSystemTreeBuilder ();
		_treeViewFiles.AddObjects (rootDirs);

		// Determines how to represent objects as strings on the screen
		_treeViewFiles.AspectGetter = AspectGetter;

		_iconProvider.IsOpenGetter = _treeViewFiles.IsExpanded;
	}

	string AspectGetter (IFileSystemInfo f) => (_iconProvider.GetIconWithOptionalSpace (f) + f.Name).Trim ();

	void ShowLines ()
	{
		_miShowLines.Checked = !_miShowLines.Checked;

		_treeViewFiles.Style.ShowBranchLines = (bool)_miShowLines.Checked;
		_treeViewFiles.SetNeedsDisplay ();
	}

	void SetExpandableSymbols (Rune expand, Rune? collapse)
	{
		_miPlusMinus.Checked = expand.Value == '+';
		_miArrowSymbols.Checked = expand.Value == '>';
		_miNoSymbols.Checked = expand.Value == default;

		_treeViewFiles.Style.ExpandableSymbol = expand;
		_treeViewFiles.Style.CollapseableSymbol = collapse;
		_treeViewFiles.SetNeedsDisplay ();
	}

	void ShowColoredExpandableSymbols ()
	{
		_miColoredSymbols.Checked = !_miColoredSymbols.Checked;

		_treeViewFiles.Style.ColorExpandSymbol = (bool)_miColoredSymbols.Checked;
		_treeViewFiles.SetNeedsDisplay ();
	}

	void InvertExpandableSymbols ()
	{
		_miInvertSymbols.Checked = !_miInvertSymbols.Checked;

		_treeViewFiles.Style.InvertExpandSymbolColors = (bool)_miInvertSymbols.Checked;
		_treeViewFiles.SetNeedsDisplay ();
	}

	void SetFullName ()
	{
		_miFullPaths.Checked = !_miFullPaths.Checked;

		if (_miFullPaths.Checked == true) {
			_treeViewFiles.AspectGetter = (f) => f.FullName;
		} else {
			_treeViewFiles.AspectGetter = (f) => f.Name;
		}
		_treeViewFiles.SetNeedsDisplay ();
	}

	void SetLeaveLastRow ()
	{
		_miLeaveLastRow.Checked = !_miLeaveLastRow.Checked;
		_treeViewFiles.Style.LeaveLastRow = (bool)_miLeaveLastRow.Checked;
	}

	void SetCursor ()
	{
		_miCursor.Checked = !_miCursor.Checked;
		_treeViewFiles.DesiredCursorVisibility = _miCursor.Checked == true ? CursorVisibility.Default : CursorVisibility.Invisible;
	}

	void SetMultiSelect ()
	{
		_miMultiSelect.Checked = !_miMultiSelect.Checked;
		_treeViewFiles.MultiSelect = (bool)_miMultiSelect.Checked;
	}

	void SetCustomColors ()
	{
		var hidden = new ColorScheme {
			Focus = new Attribute (Color.BrightRed, _treeViewFiles.ColorScheme.Focus.Background),
			Normal = new Attribute (Color.BrightYellow, _treeViewFiles.ColorScheme.Normal.Background)
		};

		_miCustomColors.Checked = !_miCustomColors.Checked;

		if (_miCustomColors.Checked == true) {
			_treeViewFiles.ColorGetter = (m) => {
				if (m is IDirectoryInfo && m.Attributes.HasFlag (FileAttributes.Hidden)) {
					return hidden;
				}
				if (m is IFileInfo && m.Attributes.HasFlag (FileAttributes.Hidden)) {
					return hidden;
				}
				return null;
			};
		} else {
			_treeViewFiles.ColorGetter = null;
		}
		_treeViewFiles.SetNeedsDisplay ();
	}

	void SetCheckHighlightModelTextOnly ()
	{
		_treeViewFiles.Style.HighlightModelTextOnly = !_treeViewFiles.Style.HighlightModelTextOnly;
		_miHighlightModelTextOnly.Checked = _treeViewFiles.Style.HighlightModelTextOnly;
		_treeViewFiles.SetNeedsDisplay ();
	}

	void Quit () => Application.RequestStop ();
}