Fixes #5153. Make Markdown work like Label

Terminal.Gui/Views/Markdown/Markdown.cs

@@ -87,10 +87,58 @@ public Markdown ()
         SetupBindingsAndCommands ();
     }
 
+    /// <inheritdoc/>
+    /// <remarks>
+    ///     If <see cref="View.CanFocus"/> is <see langword="false"/> and a valid <see cref="View.HotKey"/>
+    ///     is set, the hotkey is forwarded to the next peer in <see cref="View.SuperView"/>'s
+    ///     <see cref="View.SubViews"/> — mirroring <see cref="Label"/> so that a non-focusable
+    ///     <see cref="Markdown"/> describing a focusable view (e.g. a <see cref="TextField"/>) moves
+    ///     focus to that view when its hotkey is pressed.
+    /// </remarks>
+    protected override bool OnActivating (CommandEventArgs args)
+    {
+        // If Markdown can't focus, forward HotKey to the next peer in the SubView list
+        if (CanFocus || !HotKey.IsValid)
+        {
+            return base.OnActivating (args);
+        }
+        int me = SuperView?.SubViews.IndexOf (this) ?? -1;
+
+        if (me == -1 || !(me < SuperView?.SubViews.Count - 1))
+        {
+            return base.OnActivating (args);
+        }
+        bool handled = SuperView?.SubViews.ElementAt (me + 1).InvokeCommand (Command.HotKey) == true;
+
+        if (!handled)
+        {
+            return base.OnActivating (args);
+        }
+        args.Handled = true;
+
+        return true;
+    }
+
     /// <summary>Gets or sets the Markdown-formatted text displayed by this view.</summary>
     /// <value>The raw Markdown string. Setting this property triggers reparsing, re-layout, and a redraw.</value>
     public override string Text { get => _markdown; set => SetMarkdown (value); }
 
+    /// <inheritdoc/>
+    /// <remarks>
+    ///     Unlike <see cref="Label"/>, <see cref="Markdown"/> derives <see cref="View.HotKey"/>
+    ///     from <see cref="Text"/> (the raw markdown) rather than <see cref="View.Title"/>,
+    ///     because <see cref="Text"/> does not flow through <c>Title</c>.
+    /// </remarks>
+    public override Rune HotKeySpecifier
+    {
+        get => base.HotKeySpecifier;
+        set
+        {
+            TitleTextFormatter.HotKeySpecifier = TextFormatter.HotKeySpecifier = value;
+            UpdateHotKeyFromMarkdown ();
+        }
+    }
+
     /// <summary>Gets or sets the Markdig <see cref="Markdig.MarkdownPipeline"/> used for parsing.</summary>
     /// <value>
     ///     A custom pipeline, or <see langword="null"/> to use the default pipeline
@@ -266,13 +314,36 @@ private void SetMarkdown (string value)
         }
 
         _markdown = value;
+        UpdateHotKeyFromMarkdown ();
         _scrollToTopPending = true;
         InvalidateParsedAndLayout ();
 
         OnMarkdownChanged ();
         MarkdownChanged?.Invoke (this, EventArgs.Empty);
     }
 
+    private void UpdateHotKeyFromMarkdown ()
+    {
+        if (HotKeySpecifier == new Rune ('\xFFFF'))
+        {
+            HotKey = Key.Empty;
+
+            return;
+        }
+
+        if (TextFormatter.FindHotKey (_markdown, HotKeySpecifier, out _, out Key hotKey))
+        {
+            if (HotKey != hotKey)
+            {
+                HotKey = hotKey;
+            }
+
+            return;
+        }
+
+        HotKey = Key.Empty;
+    }
+
     private void InvalidateParsedAndLayout ()
     {
         _parsed = false;

Tests/UnitTestsParallelizable/Views/Markdown/MarkdownViewTests.cs

@@ -1,5 +1,6 @@
 using System.Collections;
 using System.Reflection;
+using System.Text;
 using JetBrains.Annotations;
 using UnitTests;
 
@@ -1903,5 +1904,144 @@ public void GetContentHeight_Table_With_Wide_Code_Block_Does_Not_Overestimate ()
         hostCode.Dispose ();
         hostNoCode.Dispose ();
     }
-}
 
+    // Copilot
+    [Fact]
+    public void CanFocus_False_Text_HotKeySpecifier_SetsFocus_Next ()
+    {
+        using IApplication app = Application.Create ();
+        Runnable<bool> runnable = new ();
+        View otherView = new () { CanFocus = true };
+        Terminal.Gui.Views.Markdown markdown = new ()
+        {
+            CanFocus = false,
+            Width = 20,
+            Height = 1,
+            Text = "_Markdown"
+        };
+        View nextView = new () { CanFocus = true };
+
+        markdown.HotKeySpecifier = (Rune)'_';
+
+        app.Begin (runnable);
+        runnable.Add (otherView, markdown, nextView);
+        otherView.SetFocus ();
+
+        Assert.Equal (Key.M, markdown.HotKey);
+        Assert.True (otherView.HasFocus);
+        Assert.False (markdown.HasFocus);
+        Assert.False (nextView.HasFocus);
+
+        app.Keyboard.RaiseKeyDownEvent (markdown.HotKey);
+
+        Assert.False (otherView.HasFocus);
+        Assert.False (markdown.HasFocus);
+        Assert.True (nextView.HasFocus);
+    }
+
+    // Copilot
+    [Fact]
+    public void CanFocus_False_LeftButtonClicked_SetsFocus_Next ()
+    {
+        using IApplication app = Application.Create ();
+        Runnable<bool> runnable = new ();
+        View otherView = new ()
+        {
+            X = 0,
+            Y = 0,
+            Width = 1,
+            Height = 1,
+            CanFocus = true
+        };
+        Terminal.Gui.Views.Markdown markdown = new ()
+        {
+            X = 0,
+            Y = 1,
+            Width = 20,
+            Height = 1,
+            CanFocus = false,
+            Text = "_Markdown"
+        };
+        View nextView = new ()
+        {
+            X = Pos.Right (markdown),
+            Y = Pos.Top (markdown),
+            Width = 1,
+            Height = 1,
+            CanFocus = true
+        };
+
+        markdown.HotKeySpecifier = (Rune)'_';
+
+        app.Begin (runnable);
+        runnable.Add (otherView, markdown, nextView);
+        otherView.SetFocus ();
+
+        Assert.Equal (Key.M, markdown.HotKey);
+        Assert.True (otherView.HasFocus);
+        Assert.False (markdown.HasFocus);
+        Assert.False (nextView.HasFocus);
+
+        app.Mouse.RaiseMouseEvent (new Mouse { ScreenPosition = markdown.Frame.Location, Flags = MouseFlags.LeftButtonClicked });
+
+        Assert.False (markdown.HasFocus);
+        Assert.True (nextView.HasFocus);
+    }
+
+    // Copilot
+    [Fact]
+    public void CanFocus_True_Text_HotKeySpecifier_SetsFocus_OnMarkdown ()
+    {
+        using IApplication app = Application.Create ();
+        Runnable<bool> runnable = new ();
+        View otherView = new () { CanFocus = true };
+        Terminal.Gui.Views.Markdown markdown = new ()
+        {
+            CanFocus = true,
+            Width = 20,
+            Height = 1,
+            Text = "_Markdown"
+        };
+        View nextView = new () { CanFocus = true };
+
+        markdown.HotKeySpecifier = (Rune)'_';
+
+        app.Begin (runnable);
+        runnable.Add (otherView, markdown, nextView);
+        otherView.SetFocus ();
+
+        Assert.Equal (Key.M, markdown.HotKey);
+
+        app.Keyboard.RaiseKeyDownEvent (markdown.HotKey);
+
+        Assert.False (otherView.HasFocus);
+        Assert.True (markdown.HasFocus);
+        Assert.False (nextView.HasFocus);
+    }
+
+    // Copilot
+    [Fact]
+    public void CanFocus_False_Text_HotKeySpecifier_NoNextPeer_DoesNotFocusMarkdown ()
+    {
+        using IApplication app = Application.Create ();
+        Runnable<bool> runnable = new ();
+        Terminal.Gui.Views.Markdown markdown = new ()
+        {
+            CanFocus = false,
+            Width = 20,
+            Height = 1,
+            Text = "_Markdown"
+        };
+
+        markdown.HotKeySpecifier = (Rune)'_';
+
+        app.Begin (runnable);
+        runnable.Add (markdown);
+
+        Assert.Equal (Key.M, markdown.HotKey);
+
+        app.Keyboard.RaiseKeyDownEvent (markdown.HotKey);
+
+        Assert.False (markdown.HasFocus);
+    }
+}