Terminal.Gui/UICatalog/Scenarios/CharacterMap.cs

#define DRAW_CONTENT

//#define BASE_DRAW_CONTENT
using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Net.Http;
using System.Reflection;
using System.Text;
using System.Text.Json;
using System.Text.Unicode;
using System.Threading.Tasks;
using Terminal.Gui;
using static Terminal.Gui.SpinnerStyle;

namespace UICatalog.Scenarios;

/// <summary>
///     This Scenario demonstrates building a custom control (a class deriving from View) that: - Provides a
///     "Character Map" application (like Windows' charmap.exe). - Helps test unicode character rendering in Terminal.Gui -
///     Illustrates how to use ScrollView to do infinite scrolling
/// </summary>
[ScenarioMetadata ("Character Map", "Unicode viewer demonstrating the ScrollView control.")]
[ScenarioCategory ("Text and Formatting")]
[ScenarioCategory ("Controls")]
[ScenarioCategory ("ScrollView")]
public class CharacterMap : Scenario
{
    public Label _errorLabel;
    private TableView _categoryList;
    private CharMap _charMap;

    // Don't create a Window, just return the top-level view
    public override void Init ()
    {
        Application.Init ();
        Application.Top.ColorScheme = Colors.ColorSchemes ["Base"];
    }

    public override void Setup ()
    {
        _charMap = new CharMap { X = 0, Y = 1, Height = Dim.Fill () };
        Application.Top.Add (_charMap);

        var jumpLabel = new Label
        {
            X = Pos.Right (_charMap) + 1,
            Y = Pos.Y (_charMap),
            HotKeySpecifier = (Rune)'_',
            Text = "_Jump To Code Point:"
        };
        Application.Top.Add (jumpLabel);

        var jumpEdit = new TextField
        {
            X = Pos.Right (jumpLabel) + 1, Y = Pos.Y (_charMap), Width = 10, Caption = "e.g. 01BE3"
        };
        Application.Top.Add (jumpEdit);

        _errorLabel = new Label
        {
            X = Pos.Right (jumpEdit) + 1, Y = Pos.Y (_charMap), ColorScheme = Colors.ColorSchemes ["error"], Text = "err"
        };
        Application.Top.Add (_errorLabel);

        jumpEdit.TextChanged += JumpEdit_TextChanged;

        _categoryList = new TableView { X = Pos.Right (_charMap), Y = Pos.Bottom (jumpLabel), Height = Dim.Fill () };

        _categoryList.FullRowSelect = true;

        //jumpList.Style.ShowHeaders = false;
        //jumpList.Style.ShowHorizontalHeaderOverline = false;
        //jumpList.Style.ShowHorizontalHeaderUnderline = false;
        _categoryList.Style.ShowHorizontalBottomline = true;

        //jumpList.Style.ShowVerticalCellLines = false;
        //jumpList.Style.ShowVerticalHeaderLines = false;
        _categoryList.Style.AlwaysShowHeaders = true;

        var isDescending = false;

        _categoryList.Table = CreateCategoryTable (0, isDescending);

        // if user clicks the mouse in TableView
        _categoryList.MouseClick += (s, e) =>
                                    {
                                        _categoryList.ScreenToCell (e.MouseEvent.X, e.MouseEvent.Y, out int? clickedCol);

                                        if (clickedCol != null && e.MouseEvent.Flags.HasFlag (MouseFlags.Button1Clicked))
                                        {
                                            EnumerableTableSource<UnicodeRange> table = (EnumerableTableSource<UnicodeRange>)_categoryList.Table;
                                            string prevSelection = table.Data.ElementAt (_categoryList.SelectedRow).Category;
                                            isDescending = !isDescending;

                                            _categoryList.Table = CreateCategoryTable (clickedCol.Value, isDescending);

                                            table = (EnumerableTableSource<UnicodeRange>)_categoryList.Table;

                                            _categoryList.SelectedRow = table.Data
                                                                             .Select ((item, index) => new { item, index })
                                                                             .FirstOrDefault (x => x.item.Category == prevSelection)
                                                                             ?.index
                                                                        ?? -1;
                                        }
                                    };

        int longestName = UnicodeRange.Ranges.Max (r => r.Category.GetColumns ());

        _categoryList.Style.ColumnStyles.Add (
                                              0,
                                              new ColumnStyle { MaxWidth = longestName, MinWidth = longestName, MinAcceptableWidth = longestName }
                                             );
        _categoryList.Style.ColumnStyles.Add (1, new ColumnStyle { MaxWidth = 1, MinWidth = 6 });
        _categoryList.Style.ColumnStyles.Add (2, new ColumnStyle { MaxWidth = 1, MinWidth = 6 });

        _categoryList.Width = _categoryList.Style.ColumnStyles.Sum (c => c.Value.MinWidth) + 4;

        _categoryList.SelectedCellChanged += (s, args) =>
                                             {
                                                 EnumerableTableSource<UnicodeRange> table = (EnumerableTableSource<UnicodeRange>)_categoryList.Table;
                                                 _charMap.StartCodePoint = table.Data.ToArray () [args.NewRow].Start;
                                             };

        Application.Top.Add (_categoryList);

        _charMap.SelectedCodePoint = 0;
        _charMap.SetFocus ();

        // TODO: Replace this with Dim.Auto when that's ready
        _categoryList.Initialized += _categoryList_Initialized;

        var menu = new MenuBar
        {
            Menus =
            [
                new MenuBarItem (
                                 "_File",
                                 new MenuItem []
                                 {
                                     new (
                                          "_Quit",
                                          $"{Application.QuitKey}",
                                          () => Application.RequestStop ()
                                         )
                                 }
                                ),
                new MenuBarItem (
                                 "_Options",
                                 new [] { CreateMenuShowWidth () }
                                )
            ]
        };
        Application.Top.Add (menu);
    }

    private void _categoryList_Initialized (object sender, EventArgs e) { _charMap.Width = Dim.Fill () - _categoryList.Width; }

    private EnumerableTableSource<UnicodeRange> CreateCategoryTable (int sortByColumn, bool descending)
    {
        Func<UnicodeRange, object> orderBy;
        var categorySort = string.Empty;
        var startSort = string.Empty;
        var endSort = string.Empty;

        string sortIndicator = descending ? CM.Glyphs.DownArrow.ToString () : CM.Glyphs.UpArrow.ToString ();

        switch (sortByColumn)
        {
            case 0:
                orderBy = r => r.Category;
                categorySort = sortIndicator;

                break;
            case 1:
                orderBy = r => r.Start;
                startSort = sortIndicator;

                break;
            case 2:
                orderBy = r => r.End;
                endSort = sortIndicator;

                break;
            default:
                throw new ArgumentException ("Invalid column number.");
        }

        IOrderedEnumerable<UnicodeRange> sortedRanges = descending
                                                            ? UnicodeRange.Ranges.OrderByDescending (orderBy)
                                                            : UnicodeRange.Ranges.OrderBy (orderBy);

        return new EnumerableTableSource<UnicodeRange> (
                                                        sortedRanges,
                                                        new Dictionary<string, Func<UnicodeRange, object>>
                                                        {
                                                            { $"Category{categorySort}", s => s.Category },
                                                            { $"Start{startSort}", s => $"{s.Start:x5}" },
                                                            { $"End{endSort}", s => $"{s.End:x5}" }
                                                        }
                                                       );
    }

    private MenuItem CreateMenuShowWidth ()
    {
        var item = new MenuItem { Title = "_Show Glyph Width" };
        item.CheckType |= MenuItemCheckStyle.Checked;
        item.Checked = _charMap?.ShowGlyphWidths;
        item.Action += () => { _charMap.ShowGlyphWidths = (bool)(item.Checked = !item.Checked); };

        return item;
    }

    private void JumpEdit_TextChanged (object sender, TextChangedEventArgs e)
    {
        var jumpEdit = sender as TextField;

        if (jumpEdit.Text.Length == 0)
        {
            return;
        }

        uint result = 0;

        if (jumpEdit.Text.StartsWith ("U+", StringComparison.OrdinalIgnoreCase) || jumpEdit.Text.StartsWith ("\\u"))
        {
            try
            {
                result = uint.Parse (jumpEdit.Text [2..], NumberStyles.HexNumber);
            }
            catch (FormatException)
            {
                _errorLabel.Text = "Invalid hex value";

                return;
            }
        }
        else if (jumpEdit.Text.StartsWith ("0", StringComparison.OrdinalIgnoreCase) || jumpEdit.Text.StartsWith ("\\u"))
        {
            try
            {
                result = uint.Parse (jumpEdit.Text, NumberStyles.HexNumber);
            }
            catch (FormatException)
            {
                _errorLabel.Text = "Invalid hex value";

                return;
            }
        }
        else
        {
            try
            {
                result = uint.Parse (jumpEdit.Text, NumberStyles.Integer);
            }
            catch (FormatException)
            {
                _errorLabel.Text = "Invalid value";

                return;
            }
        }

        if (result > RuneExtensions.MaxUnicodeCodePoint)
        {
            _errorLabel.Text = "Beyond maximum codepoint";

            return;
        }

        _errorLabel.Text = $"U+{result:x5}";

        EnumerableTableSource<UnicodeRange> table = (EnumerableTableSource<UnicodeRange>)_categoryList.Table;

        _categoryList.SelectedRow = table.Data
                                         .Select ((item, index) => new { item, index })
                                         .FirstOrDefault (x => x.item.Start <= result && x.item.End >= result)
                                         ?.index
                                    ?? -1;
        _categoryList.EnsureSelectedCellIsVisible ();

        // Ensure the typed glyph is selected 
        _charMap.SelectedCodePoint = (int)result;
    }
}

internal class CharMap : ScrollView
{
    private const CursorVisibility _cursor = CursorVisibility.Default;
    private const int COLUMN_WIDTH = 3;

    private ContextMenu _contextMenu = new ();
    private int _rowHeight = 1;
    private int _selected;
    private int _start;

    public CharMap ()
    {
        ColorScheme = Colors.ColorSchemes ["Dialog"];
        CanFocus = true;

        ContentSize = new Size (
                                RowWidth,
                                (MaxCodePoint / 16 + (ShowHorizontalScrollIndicator ? 2 : 1)) * _rowHeight
                               );

        AddCommand (
                    Command.ScrollUp,
                    () =>
                    {
                        if (SelectedCodePoint >= 16)
                        {
                            SelectedCodePoint -= 16;
                        }

                        return true;
                    }
                   );

        AddCommand (
                    Command.ScrollDown,
                    () =>
                    {
                        if (SelectedCodePoint < MaxCodePoint - 16)
                        {
                            SelectedCodePoint += 16;
                        }

                        return true;
                    }
                   );

        AddCommand (
                    Command.ScrollLeft,
                    () =>
                    {
                        if (SelectedCodePoint > 0)
                        {
                            SelectedCodePoint--;
                        }

                        return true;
                    }
                   );

        AddCommand (
                    Command.ScrollRight,
                    () =>
                    {
                        if (SelectedCodePoint < MaxCodePoint)
                        {
                            SelectedCodePoint++;
                        }

                        return true;
                    }
                   );

        AddCommand (
                    Command.PageUp,
                    () =>
                    {
                        int page = (Bounds.Height / _rowHeight - 1) * 16;
                        SelectedCodePoint -= Math.Min (page, SelectedCodePoint);

                        return true;
                    }
                   );

        AddCommand (
                    Command.PageDown,
                    () =>
                    {
                        int page = (Bounds.Height / _rowHeight - 1) * 16;
                        SelectedCodePoint += Math.Min (page, MaxCodePoint - SelectedCodePoint);

                        return true;
                    }
                   );

        AddCommand (
                    Command.TopHome,
                    () =>
                    {
                        SelectedCodePoint = 0;

                        return true;
                    }
                   );

        AddCommand (
                    Command.BottomEnd,
                    () =>
                    {
                        SelectedCodePoint = MaxCodePoint;

                        return true;
                    }
                   );
        KeyBindings.Add (Key.Enter, Command.Accept);

        AddCommand (
                    Command.Accept,
                    () =>
                    {
                        ShowDetails ();

                        return true;
                    }
                   );

        MouseClick += Handle_MouseClick;
    }

    /// <summary>Gets the coordinates of the Cursor based on the SelectedCodePoint in screen coordinates</summary>
    public Point Cursor
    {
        get
        {
            int row = SelectedCodePoint / 16 * _rowHeight + ContentOffset.Y + 1;

            int col = SelectedCodePoint % 16 * COLUMN_WIDTH + ContentOffset.X + RowLabelWidth + 1; // + 1 for padding

            return new Point (col, row);
        }
        set => throw new NotImplementedException ();
    }

    public static int MaxCodePoint => 0x10FFFF;

    /// <summary>
    ///     Specifies the starting offset for the character map. The default is 0x2500 which is the Box Drawing
    ///     characters.
    /// </summary>
    public int SelectedCodePoint
    {
        get => _selected;
        set
        {
            _selected = value;

            if (IsInitialized)
            {
                int row = SelectedCodePoint / 16 * _rowHeight;
                int col = SelectedCodePoint % 16 * COLUMN_WIDTH;

                int height = Bounds.Height - (ShowHorizontalScrollIndicator ? 2 : 1);

                if (row + ContentOffset.Y < 0)
                {
                    // Moving up.
                    ContentOffset = new Point (ContentOffset.X, row);
                }
                else if (row + ContentOffset.Y >= height)
                {
                    // Moving down.
                    ContentOffset = new Point (
                                               ContentOffset.X,
                                               Math.Min (row, row - height + _rowHeight)
                                              );
                }

                int width = Bounds.Width / COLUMN_WIDTH * COLUMN_WIDTH - (ShowVerticalScrollIndicator ? RowLabelWidth + 1 : RowLabelWidth);

                if (col + ContentOffset.X < 0)
                {
                    // Moving left.
                    ContentOffset = new Point (col, ContentOffset.Y);
                }
                else if (col + ContentOffset.X >= width)
                {
                    // Moving right.
                    ContentOffset = new Point (
                                               Math.Min (col, col - width + COLUMN_WIDTH),
                                               ContentOffset.Y
                                              );
                }
            }

            SetNeedsDisplay ();
            SelectedCodePointChanged?.Invoke (this, new ListViewItemEventArgs (SelectedCodePoint, null));
        }
    }

    public bool ShowGlyphWidths
    {
        get => _rowHeight == 2;
        set
        {
            _rowHeight = value ? 2 : 1;
            SetNeedsDisplay ();
        }
    }

    /// <summary>
    ///     Specifies the starting offset for the character map. The default is 0x2500 which is the Box Drawing
    ///     characters.
    /// </summary>
    public int StartCodePoint
    {
        get => _start;
        set
        {
            _start = value;
            SelectedCodePoint = value;
            SetNeedsDisplay ();
        }
    }

    private static int RowLabelWidth => $"U+{MaxCodePoint:x5}".Length + 1;
    private static int RowWidth => RowLabelWidth + COLUMN_WIDTH * 16;
    public event EventHandler<ListViewItemEventArgs> Hover;

    public override void OnDrawContent (Rect contentArea)
    {
        //if (ShowHorizontalScrollIndicator && ContentSize.Height < (int)(MaxCodePoint / 16 + 2)) {
        //	//ContentSize = new Size (CharMap.RowWidth, (int)(MaxCodePoint / 16 + 2));
        //	//ContentSize = new Size (CharMap.RowWidth, (int)(MaxCodePoint / 16) * _rowHeight + 2);
        //	var width = (Bounds.Width / COLUMN_WIDTH * COLUMN_WIDTH) - (ShowVerticalScrollIndicator ? RowLabelWidth + 1 : RowLabelWidth);
        //	if (Cursor.X + ContentOffset.X >= width) {
        //		// Snap to the selected glyph.
        //		ContentOffset = new Point (
        //			Math.Min (Cursor.X, Cursor.X - width + COLUMN_WIDTH),
        //			ContentOffset.Y == -ContentSize.Height + Bounds.Height ? ContentOffset.Y - 1 : ContentOffset.Y);
        //	} else {
        //		ContentOffset = new Point (
        //			ContentOffset.X - Cursor.X,
        //			ContentOffset.Y == -ContentSize.Height + Bounds.Height ? ContentOffset.Y - 1 : ContentOffset.Y);
        //	}
        //} else if (!ShowHorizontalScrollIndicator && ContentSize.Height > (int)(MaxCodePoint / 16 + 1)) {
        //	//ContentSize = new Size (CharMap.RowWidth, (int)(MaxCodePoint / 16 + 1));
        //	// Snap 1st column into view if it's been scrolled horizontally
        //	ContentOffset = new Point (0, ContentOffset.Y < -ContentSize.Height + Bounds.Height ? ContentOffset.Y - 1 : ContentOffset.Y);
        //}
        base.OnDrawContent (contentArea);
    }

    //public void CharMap_DrawContent (object s, DrawEventArgs a)
    public override void OnDrawContentComplete (Rect contentArea)
    {
        if (contentArea.Height == 0 || contentArea.Width == 0)
        {
            return;
        }

        var viewport = new Rect (
                                 ContentOffset,
                                 new Size (
                                           Math.Max (Bounds.Width - (ShowVerticalScrollIndicator ? 1 : 0), 0),
                                           Math.Max (Bounds.Height - (ShowHorizontalScrollIndicator ? 1 : 0), 0)
                                          )
                                );

        Rect oldClip = ClipToBounds ();

        if (ShowHorizontalScrollIndicator)
        {
            // ClipToBounds doesn't know about the scroll indicators, so if off, subtract one from height
            Driver.Clip = new Rect (
                                    Driver.Clip.Location,
                                    new Size (Driver.Clip.Width, Driver.Clip.Height - 1)
                                   );
        }

        if (ShowVerticalScrollIndicator)
        {
            // ClipToBounds doesn't know about the scroll indicators, so if off, subtract one from width
            Driver.Clip = new Rect (
                                    Driver.Clip.Location,
                                    new Size (Driver.Clip.Width - 1, Driver.Clip.Height)
                                   );
        }

        int cursorCol = Cursor.X - ContentOffset.X - RowLabelWidth - 1;
        int cursorRow = Cursor.Y - ContentOffset.Y - 1;

        Driver.SetAttribute (GetHotNormalColor ());
        Move (0, 0);
        Driver.AddStr (new string (' ', RowLabelWidth + 1));

        for (var hexDigit = 0; hexDigit < 16; hexDigit++)
        {
            int x = ContentOffset.X + RowLabelWidth + hexDigit * COLUMN_WIDTH;

            if (x > RowLabelWidth - 2)
            {
                Move (x, 0);
                Driver.SetAttribute (GetHotNormalColor ());
                Driver.AddStr (" ");

                Driver.SetAttribute (
                                     HasFocus && cursorCol + ContentOffset.X + RowLabelWidth == x
                                         ? ColorScheme.HotFocus
                                         : GetHotNormalColor ()
                                    );
                Driver.AddStr ($"{hexDigit:x}");
                Driver.SetAttribute (GetHotNormalColor ());
                Driver.AddStr (" ");
            }
        }

        int firstColumnX = viewport.X + RowLabelWidth;

        for (var y = 1; y < Bounds.Height; y++)
        {
            // What row is this?
            int row = (y - ContentOffset.Y - 1) / _rowHeight;

            int val = row * 16;

            if (val > MaxCodePoint)
            {
                continue;
            }

            Move (firstColumnX + COLUMN_WIDTH, y);
            Driver.SetAttribute (GetNormalColor ());

            for (var col = 0; col < 16; col++)
            {
                int x = firstColumnX + COLUMN_WIDTH * col + 1;

                Move (x, y);

                if (cursorRow + ContentOffset.Y + 1 == y && cursorCol + ContentOffset.X + firstColumnX + 1 == x && !HasFocus)
                {
                    Driver.SetAttribute (GetFocusColor ());
                }

                int scalar = val + col;
                var rune = (Rune)'?';

                if (Rune.IsValid (scalar))
                {
                    rune = new Rune (scalar);
                }

                int width = rune.GetColumns ();

                // are we at first row of the row?
                if (!ShowGlyphWidths || (y - ContentOffset.Y) % _rowHeight > 0)
                {
                    if (width > 0)
                    {
                        Driver.AddRune (rune);
                    }
                    else
                    {
                        if (rune.IsCombiningMark ())
                        {
                            // This is a hack to work around the fact that combining marks
                            // a) can't be rendered on their own
                            // b) that don't normalize are not properly supported in 
                            //    any known terminal (esp Windows/AtlasEngine). 
                            // See Issue #2616
                            var sb = new StringBuilder ();
                            sb.Append ('a');
                            sb.Append (rune);

                            // Try normalizing after combining with 'a'. If it normalizes, at least 
                            // it'll show on the 'a'. If not, just show the replacement char.
                            string normal = sb.ToString ().Normalize (NormalizationForm.FormC);

                            if (normal.Length == 1)
                            {
                                Driver.AddRune (normal [0]);
                            }
                            else
                            {
                                Driver.AddRune (Rune.ReplacementChar);
                            }
                        }
                    }
                }
                else
                {
                    Driver.SetAttribute (ColorScheme.HotNormal);
                    Driver.AddStr ($"{width}");
                }

                if (cursorRow + ContentOffset.Y + 1 == y && cursorCol + ContentOffset.X + firstColumnX + 1 == x && !HasFocus)
                {
                    Driver.SetAttribute (GetNormalColor ());
                }
            }

            Move (0, y);

            Driver.SetAttribute (
                                 HasFocus && cursorRow + ContentOffset.Y + 1 == y
                                     ? ColorScheme.HotFocus
                                     : ColorScheme.HotNormal
                                );

            if (!ShowGlyphWidths || (y - ContentOffset.Y) % _rowHeight > 0)
            {
                Driver.AddStr ($"U+{val / 16:x5}_ ");
            }
            else
            {
                Driver.AddStr (new string (' ', RowLabelWidth));
            }
        }

        Driver.Clip = oldClip;
    }

    public override bool OnEnter (View view)
    {
        if (IsInitialized)
        {
            Application.Driver.SetCursorVisibility (_cursor);
        }

        return base.OnEnter (view);
    }

    public override bool OnLeave (View view)
    {
        Driver.SetCursorVisibility (CursorVisibility.Invisible);

        return base.OnLeave (view);
    }

    public override void PositionCursor ()
    {
        if (HasFocus
            && Cursor.X >= RowLabelWidth
            && Cursor.X < Bounds.Width - (ShowVerticalScrollIndicator ? 1 : 0)
            && Cursor.Y > 0
            && Cursor.Y < Bounds.Height - (ShowHorizontalScrollIndicator ? 1 : 0))
        {
            Driver.SetCursorVisibility (_cursor);
            Move (Cursor.X, Cursor.Y);
        }
        else
        {
            Driver.SetCursorVisibility (CursorVisibility.Invisible);
        }
    }

    public event EventHandler<ListViewItemEventArgs> SelectedCodePointChanged;

    public static string ToCamelCase (string str)
    {
        if (string.IsNullOrEmpty (str))
        {
            return str;
        }

        TextInfo textInfo = new CultureInfo ("en-US", false).TextInfo;

        str = textInfo.ToLower (str);
        str = textInfo.ToTitleCase (str);

        return str;
    }

    private void CopyCodePoint () { Clipboard.Contents = $"U+{SelectedCodePoint:x5}"; }
    private void CopyGlyph () { Clipboard.Contents = $"{new Rune (SelectedCodePoint)}"; }

    private void Handle_MouseClick (object sender, MouseEventEventArgs args)
    {
        MouseEvent me = args.MouseEvent;

        if (me.Flags != MouseFlags.ReportMousePosition && me.Flags != MouseFlags.Button1Clicked && me.Flags != MouseFlags.Button1DoubleClicked)
        {
            return;
        }

        if (me.Y == 0)
        {
            me.Y = Cursor.Y;
        }

        if (me.Y > 0)
        { }

        if (me.X < RowLabelWidth || me.X > RowLabelWidth + 16 * COLUMN_WIDTH - 1)
        {
            me.X = Cursor.X;
        }

        int row = (me.Y - 1 - ContentOffset.Y) / _rowHeight; // -1 for header
        int col = (me.X - RowLabelWidth - ContentOffset.X) / COLUMN_WIDTH;

        if (col > 15)
        {
            col = 15;
        }

        int val = row * 16 + col;

        if (val > MaxCodePoint)
        {
            return;
        }

        if (me.Flags == MouseFlags.ReportMousePosition)
        {
            Hover?.Invoke (this, new ListViewItemEventArgs (val, null));
        }

        if (me.Flags == MouseFlags.Button1Clicked)
        {
            SelectedCodePoint = val;

            return;
        }

        if (me.Flags == MouseFlags.Button1DoubleClicked)
        {
            SelectedCodePoint = val;
            ShowDetails ();

            return;
        }

        if (me.Flags == _contextMenu.MouseFlags)
        {
            SelectedCodePoint = val;

            _contextMenu = new ContextMenu
            {
                Position = new Point (me.X + 1, me.Y + 1),
                MenuItems = new MenuBarItem (
                                             new MenuItem []
                                             {
                                                 new (
                                                      "_Copy Glyph",
                                                      "",
                                                      CopyGlyph,
                                                      null,
                                                      null,
                                                      (KeyCode)Key.C.WithCtrl
                                                     ),
                                                 new (
                                                      "Copy Code _Point",
                                                      "",
                                                      CopyCodePoint,
                                                      null,
                                                      null,
                                                      (KeyCode)Key.C.WithCtrl
                                                                  .WithShift
                                                     )
                                             }
                                            )
            };
            _contextMenu.Show ();
        }
    }

    private void ShowDetails ()
    {
        var client = new UcdApiClient ();
        var decResponse = string.Empty;

        var waitIndicator = new Dialog
        {
            Title = "Getting Code Point Information",
            X = Pos.Center (),
            Y = Pos.Center (),
            Height = 7,
            Width = 50,
            Buttons = [new Button { Text = "Cancel" }]
        };

        var errorLabel = new Label
        {
            Text = UcdApiClient.BaseUrl,
            AutoSize = false,
            X = 0,
            Y = 1,
            Width = Dim.Fill (),
            Height = Dim.Fill (1),
            TextAlignment = TextAlignment.Centered
        };
        var spinner = new SpinnerView { X = Pos.Center (), Y = Pos.Center (), Style = new Aesthetic () };
        spinner.AutoSpin = true;
        waitIndicator.Add (errorLabel);
        waitIndicator.Add (spinner);

        waitIndicator.Ready += async (s, a) =>
                               {
                                   try
                                   {
                                       decResponse = await client.GetCodepointDec (SelectedCodePoint);
                                   }
                                   catch (HttpRequestException e)
                                   {
                                       (s as Dialog).Text = e.Message;

                                       Application.Invoke (
                                                           () =>
                                                           {
                                                               spinner.Visible = false;
                                                               errorLabel.Text = e.Message;
                                                               errorLabel.ColorScheme = Colors.ColorSchemes ["Error"];
                                                               errorLabel.Visible = true;
                                                           }
                                                          );
                                   }

                                   (s as Dialog)?.RequestStop ();
                               };
        Application.Run (waitIndicator);

        if (!string.IsNullOrEmpty (decResponse))
        {
            var name = string.Empty;

            using (JsonDocument document = JsonDocument.Parse (decResponse))
            {
                JsonElement root = document.RootElement;

                // Get a property by name and output its value
                if (root.TryGetProperty ("name", out JsonElement nameElement))
                {
                    name = nameElement.GetString ();
                }

                //// Navigate to a nested property and output its value
                //if (root.TryGetProperty ("property3", out JsonElement property3Element)
                //&& property3Element.TryGetProperty ("nestedProperty", out JsonElement nestedPropertyElement)) {
                //	Console.WriteLine (nestedPropertyElement.GetString ());
                //}
                decResponse = JsonSerializer.Serialize (
                                                        document.RootElement,
                                                        new
                                                            JsonSerializerOptions { WriteIndented = true }
                                                       );
            }

            var title = $"{ToCamelCase (name)} - {new Rune (SelectedCodePoint)} U+{SelectedCodePoint:x5}";

            var copyGlyph = new Button { Text = "Copy _Glyph" };
            var copyCP = new Button { Text = "Copy Code _Point" };
            var cancel = new Button { Text = "Cancel" };

            var dlg = new Dialog { Title = title, Buttons = [copyGlyph, copyCP, cancel] };

            copyGlyph.Clicked += (s, a) =>
                                 {
                                     CopyGlyph ();
                                     dlg.RequestStop ();
                                 };

            copyCP.Clicked += (s, a) =>
                              {
                                  CopyCodePoint ();
                                  dlg.RequestStop ();
                              };
            cancel.Clicked += (s, a) => dlg.RequestStop ();

            var rune = (Rune)SelectedCodePoint;
            var label = new Label { Text = "IsAscii: ", X = 0, Y = 0 };
            dlg.Add (label);

            label = new Label { Text = $"{rune.IsAscii}", X = Pos.Right (label), Y = Pos.Top (label) };
            dlg.Add (label);

            label = new Label { Text = ", Bmp: ", X = Pos.Right (label), Y = Pos.Top (label) };
            dlg.Add (label);

            label = new Label { Text = $"{rune.IsBmp}", X = Pos.Right (label), Y = Pos.Top (label) };
            dlg.Add (label);

            label = new Label { Text = ", CombiningMark: ", X = Pos.Right (label), Y = Pos.Top (label) };
            dlg.Add (label);

            label = new Label { Text = $"{rune.IsCombiningMark ()}", X = Pos.Right (label), Y = Pos.Top (label) };
            dlg.Add (label);

            label = new Label { Text = ", SurrogatePair: ", X = Pos.Right (label), Y = Pos.Top (label) };
            dlg.Add (label);

            label = new Label { Text = $"{rune.IsSurrogatePair ()}", X = Pos.Right (label), Y = Pos.Top (label) };
            dlg.Add (label);

            label = new Label { Text = ", Plane: ", X = Pos.Right (label), Y = Pos.Top (label) };
            dlg.Add (label);

            label = new Label { Text = $"{rune.Plane}", X = Pos.Right (label), Y = Pos.Top (label) };
            dlg.Add (label);

            label = new Label { Text = "Columns: ", X = 0, Y = Pos.Bottom (label) };
            dlg.Add (label);

            label = new Label { Text = $"{rune.GetColumns ()}", X = Pos.Right (label), Y = Pos.Top (label) };
            dlg.Add (label);

            label = new Label { Text = ", Utf16SequenceLength: ", X = Pos.Right (label), Y = Pos.Top (label) };
            dlg.Add (label);

            label = new Label { Text = $"{rune.Utf16SequenceLength}", X = Pos.Right (label), Y = Pos.Top (label) };
            dlg.Add (label);

            label = new Label
            {
                Text =
                    $"Code Point Information from {UcdApiClient.BaseUrl}codepoint/dec/{SelectedCodePoint}:",
                X = 0,
                Y = Pos.Bottom (label)
            };
            dlg.Add (label);

            var json = new TextView
            {
                X = 0,
                Y = Pos.Bottom (label),
                Width = Dim.Fill (),
                Height = Dim.Fill (2),
                ReadOnly = true,
                Text = decResponse
            };
            dlg.Add (json);

            Application.Run (dlg);
        }
        else
        {
            MessageBox.ErrorQuery (
                                   "Code Point API",
                                   $"{
                                       UcdApiClient.BaseUrl
                                   }codepoint/dec/{
                                       SelectedCodePoint
                                   } did not return a result for\r\n {
                                       new Rune (SelectedCodePoint)
                                   } U+{
                                       SelectedCodePoint
                                       :x5}.",
                                   "Ok"
                                  );
        }

        // BUGBUG: This is a workaround for some weird ScrollView related mouse grab bug
        Application.GrabMouse (this);
    }
}

public class UcdApiClient
{
    public const string BaseUrl = "https://ucdapi.org/unicode/latest/";
    private static readonly HttpClient _httpClient = new ();

    public async Task<string> GetChars (string chars)
    {
        HttpResponseMessage response = await _httpClient.GetAsync ($"{BaseUrl}chars/{Uri.EscapeDataString (chars)}");
        response.EnsureSuccessStatusCode ();

        return await response.Content.ReadAsStringAsync ();
    }

    public async Task<string> GetCharsName (string chars)
    {
        HttpResponseMessage response =
            await _httpClient.GetAsync ($"{BaseUrl}chars/{Uri.EscapeDataString (chars)}/name");
        response.EnsureSuccessStatusCode ();

        return await response.Content.ReadAsStringAsync ();
    }

    public async Task<string> GetCodepointDec (int dec)
    {
        HttpResponseMessage response = await _httpClient.GetAsync ($"{BaseUrl}codepoint/dec/{dec}");
        response.EnsureSuccessStatusCode ();

        return await response.Content.ReadAsStringAsync ();
    }

    public async Task<string> GetCodepointHex (string hex)
    {
        HttpResponseMessage response = await _httpClient.GetAsync ($"{BaseUrl}codepoint/hex/{hex}");
        response.EnsureSuccessStatusCode ();

        return await response.Content.ReadAsStringAsync ();
    }
}

internal class UnicodeRange
{
    public static List<UnicodeRange> Ranges = GetRanges ();

    public string Category;
    public int End;
    public int Start;

    public UnicodeRange (int start, int end, string category)
    {
        Start = start;
        End = end;
        Category = category;
    }

    public static List<UnicodeRange> GetRanges ()
    {
        IEnumerable<UnicodeRange> ranges =
            from r in typeof (UnicodeRanges).GetProperties (BindingFlags.Static | BindingFlags.Public)
            let urange = r.GetValue (null) as System.Text.Unicode.UnicodeRange
            let name = string.IsNullOrEmpty (r.Name)
                           ? $"U+{urange.FirstCodePoint:x5}-U+{urange.FirstCodePoint + urange.Length:x5}"
                           : r.Name
            where name != "None" && name != "All"
            select new UnicodeRange (urange.FirstCodePoint, urange.FirstCodePoint + urange.Length, name);

        // .NET 8.0 only supports BMP in UnicodeRanges: https://learn.microsoft.com/en-us/dotnet/api/system.text.unicode.unicoderanges?view=net-8.0
        List<UnicodeRange> nonBmpRanges = new ()
        {
            new UnicodeRange (
                              0x1F130,
                              0x1F149,
                              "Squared Latin Capital Letters"
                             ),
            new UnicodeRange (
                              0x12400,
                              0x1240f,
                              "Cuneiform Numbers and Punctuation"
                             ),
            new UnicodeRange (0x10000, 0x1007F, "Linear B Syllabary"),
            new UnicodeRange (0x10080, 0x100FF, "Linear B Ideograms"),
            new UnicodeRange (0x10100, 0x1013F, "Aegean Numbers"),
            new UnicodeRange (0x10300, 0x1032F, "Old Italic"),
            new UnicodeRange (0x10330, 0x1034F, "Gothic"),
            new UnicodeRange (0x10380, 0x1039F, "Ugaritic"),
            new UnicodeRange (0x10400, 0x1044F, "Deseret"),
            new UnicodeRange (0x10450, 0x1047F, "Shavian"),
            new UnicodeRange (0x10480, 0x104AF, "Osmanya"),
            new UnicodeRange (0x10800, 0x1083F, "Cypriot Syllabary"),
            new UnicodeRange (
                              0x1D000,
                              0x1D0FF,
                              "Byzantine Musical Symbols"
                             ),
            new UnicodeRange (0x1D100, 0x1D1FF, "Musical Symbols"),
            new UnicodeRange (0x1D300, 0x1D35F, "Tai Xuan Jing Symbols"),
            new UnicodeRange (
                              0x1D400,
                              0x1D7FF,
                              "Mathematical Alphanumeric Symbols"
                             ),
            new UnicodeRange (0x1F600, 0x1F532, "Emojis Symbols"),
            new UnicodeRange (
                              0x20000,
                              0x2A6DF,
                              "CJK Unified Ideographs Extension B"
                             ),
            new UnicodeRange (
                              0x2F800,
                              0x2FA1F,
                              "CJK Compatibility Ideographs Supplement"
                             ),
            new UnicodeRange (0xE0000, 0xE007F, "Tags")
        };

        return ranges.Concat (nonBmpRanges).OrderBy (r => r.Category).ToList ();
    }
}