Guidebook links (#17162)

* Guidebook links

* warning!

Content.Client/Guidebook/Controls/GuidebookWindow.xaml.cs

@@ -1,7 +1,11 @@
+using System.Diagnostics.CodeAnalysis;
 using System.Linq;
+using Content.Client.Guidebook.RichText;
 using Content.Client.UserInterface.Controls;
 using Content.Client.UserInterface.Controls.FancyTree;
+using JetBrains.Annotations;
 using Robust.Client.AutoGenerated;
+using Robust.Client.UserInterface;
 using Robust.Client.UserInterface.Controls;
 using Robust.Client.UserInterface.XAML;
 using Robust.Shared.ContentPack;
@@ -9,7 +13,7 @@ using Robust.Shared.ContentPack;
 namespace Content.Client.Guidebook.Controls;
 
 [GenerateTypedNameReferences]
-public sealed partial class GuidebookWindow : FancyWindow
+public sealed partial class GuidebookWindow : FancyWindow, ILinkClickHandler
 {
     [Dependency] private readonly IResourceManager _resourceManager = default!;
     [Dependency] private readonly DocumentParsingManager _parsingMan = default!;
@@ -139,4 +143,20 @@ public sealed partial class GuidebookWindow : FancyWindow
 
         return item;
     }
+
+    public void HandleClick(string link)
+    {
+        if (!_entries.TryGetValue(link, out var entry))
+            return;
+
+        if (Tree.TryGetIndexFromMetadata(entry, out var index))
+        {
+            Tree.ExpandParentEntries(index.Value);
+            Tree.SetSelectedIndex(index);
+        }
+        else
+        {
+            ShowGuide(entry);
+        }
+    }
 }

Content.Client/Guidebook/Richtext/TextLinkTag.cs

@@ -0,0 +1,70 @@
+using System.Diagnostics.CodeAnalysis;
+using JetBrains.Annotations;
+using Robust.Client.UserInterface;
+using Robust.Client.UserInterface.Controls;
+using Robust.Client.UserInterface.RichText;
+using Robust.Shared.Input;
+using Robust.Shared.Utility;
+
+namespace Content.Client.Guidebook.RichText;
+
+[UsedImplicitly]
+public sealed class TextLinkTag : IMarkupTag
+{
+    public string Name => "textlink";
+
+    public Control? Control;
+
+    /// <inheritdoc/>
+    public bool TryGetControl(MarkupNode node, [NotNullWhen(true)] out Control? control)
+    {
+        if (!node.Value.TryGetString(out var text)
+            || !node.Attributes.TryGetValue("link", out var linkParameter)
+            || !linkParameter.TryGetString(out var link))
+        {
+            control = null;
+            return false;
+        }
+
+        var label = new Label();
+        label.Text = text;
+
+        label.MouseFilter = Control.MouseFilterMode.Stop;
+        label.FontColorOverride = Color.CornflowerBlue;
+        label.DefaultCursorShape = Control.CursorShape.Hand;
+
+        label.OnMouseEntered += _ => label.FontColorOverride = Color.LightSkyBlue;
+        label.OnMouseExited += _ => label.FontColorOverride = Color.CornflowerBlue;
+        label.OnKeyBindDown += args => OnKeybindDown(args, link);
+
+        control = label;
+        Control = label;
+        return true;
+    }
+
+    private void OnKeybindDown(GUIBoundKeyEventArgs args, string link)
+    {
+        if (args.Function != EngineKeyFunctions.UIClick)
+            return;
+
+        if (Control == null)
+            return;
+
+        var current = Control;
+        while (current != null)
+        {
+            current = current.Parent;
+
+            if (current is not ILinkClickHandler handler)
+                continue;
+            handler.HandleClick(link);
+            return;
+        }
+        Logger.Warning($"Warning! No valid ILinkClickHandler found.");
+    }
+}
+
+public interface ILinkClickHandler
+{
+    public void HandleClick(string link);
+}

Content.Client/UserInterface/Controls/FancyTree/FancyTree.xaml.cs

@@ -1,3 +1,4 @@
+using System.Diagnostics.CodeAnalysis;
 using Content.Client.Resources;
 using Robust.Client.AutoGenerated;
 using Robust.Client.Graphics;
@@ -203,6 +204,31 @@ public sealed partial class FancyTree : Control
         }
     }
 
+    public bool TryGetIndexFromMetadata(object metadata, [NotNullWhen(true)] out int? index)
+    {
+        index = null;
+        foreach (var item in Items)
+        {
+            if (item.Metadata?.Equals(metadata) ?? false)
+            {
+                index = item.Index;
+                break;
+            }
+        }
+        return index != null;
+    }
+
+    public void ExpandParentEntries(int index)
+    {
+        Control? current = Items[index];
+        while (current != null)
+        {
+            if (current is TreeItem item)
+                item.SetExpanded(true);
+            current = current.Parent;
+        }
+    }
+
     public void Clear()
     {
         foreach (var item in Items)