Filtering reagents (#18211)

* Making it work

* Refactoring

* Autoformat revert

* Implementing suggestions

* Changed to file scoped namespaces.

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

@@ -1,6 +1,7 @@
 using System.Diagnostics.CodeAnalysis;
 using System.Linq;
 using Content.Client.Guidebook.RichText;
+using Content.Client.UserInterface.ControlExtensions;
 using Content.Client.UserInterface.Controls;
 using Content.Client.UserInterface.Controls.FancyTree;
 using JetBrains.Annotations;
@@ -26,6 +27,11 @@ public sealed partial class GuidebookWindow : FancyWindow, ILinkClickHandler
         IoCManager.InjectDependencies(this);
 
         Tree.OnSelectedItemChanged += OnSelectionChanged;
+
+        SearchBar.OnTextChanged += _ =>
+        {
+            HandleFilter();
+        };
     }
 
     private void OnSelectionChanged(TreeItem? item)
@@ -40,6 +46,7 @@ public sealed partial class GuidebookWindow : FancyWindow, ILinkClickHandler
     {
         Placeholder.Visible = true;
         EntryContainer.Visible = false;
+        SearchContainer.Visible = false;
         EntryContainer.RemoveAllChildren();
     }
 
@@ -48,9 +55,12 @@ public sealed partial class GuidebookWindow : FancyWindow, ILinkClickHandler
         Scroll.SetScrollValue(default);
         Placeholder.Visible = false;
         EntryContainer.Visible = true;
+        SearchBar.Text = "";
         EntryContainer.RemoveAllChildren();
         using var file = _resourceManager.ContentFileReadText(entry.Text);
 
+        SearchContainer.Visible = entry.FilterEnabled;
+
         if (!_parsingMan.TryAddMarkup(EntryContainer, file.ReadToEnd()))
         {
             EntryContainer.AddChild(new Label() { Text = "ERROR: Failed to parse document." });
@@ -159,4 +169,20 @@ public sealed partial class GuidebookWindow : FancyWindow, ILinkClickHandler
             ShowGuide(entry);
         }
     }
+
+    private void HandleFilter()
+    {
+        var emptySearch = SearchBar.Text.Trim().Length == 0;
+
+        if (Tree.SelectedItem != null && Tree.SelectedItem.Metadata is GuideEntry entry && entry.FilterEnabled)
+        {
+            var foundElements = EntryContainer.GetSearchableControls();
+
+            foreach (var element in foundElements)
+            {
+                element.SetHiddenState(true, SearchBar.Text.Trim());
+            }
+        }
+
+    }
 }