Add guidebook protodata tag: embed prototype values in guidebook text (#27570)

* First clumsy implementation of guidebook protodata

* Support for Properties, format strings

* Better null

* Rename file

* Documentation and some cleanup

* Handle errors better

* Added note about client-side components

* A couple of examples

* DataFields

* Use attributes like a sane person

* Outdated doc

* string.Empty

* No IComponent?

* No casting

* Use EntityManager.ComponentFactory

* Use FrozenDictionary

* Cache tagged component fields

* Iterate components and check if they're tagged

Content.Client/Guidebook/GuidebookDataSystem.cs

@@ -0,0 +1,45 @@
+using Content.Shared.Guidebook;
+
+namespace Content.Client.Guidebook;
+
+/// <summary>
+/// Client system for storing and retrieving values extracted from entity prototypes
+/// for display in the guidebook (<see cref="RichText.ProtodataTag"/>).
+/// Requests data from the server on <see cref="Initialize"/>.
+/// Can also be pushed new data when the server reloads prototypes.
+/// </summary>
+public sealed class GuidebookDataSystem : EntitySystem
+{
+    private GuidebookData? _data;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+
+        SubscribeNetworkEvent<UpdateGuidebookDataEvent>(OnServerUpdated);
+
+        // Request data from the server
+        RaiseNetworkEvent(new RequestGuidebookDataEvent());
+    }
+
+    private void OnServerUpdated(UpdateGuidebookDataEvent args)
+    {
+        // Got new data from the server, either in response to our request, or because prototypes reloaded on the server
+        _data = args.Data;
+        _data.Freeze();
+    }
+
+    /// <summary>
+    /// Attempts to retrieve a value using the given identifiers.
+    /// See <see cref="GuidebookData.TryGetValue"/> for more information.
+    /// </summary>
+    public bool TryGetValue(string prototype, string component, string field, out object? value)
+    {
+        if (_data == null)
+        {
+            value = null;
+            return false;
+        }
+        return _data.TryGetValue(prototype, component, field, out value);
+    }
+}

Content.Client/Guidebook/Richtext/ProtodataTag.cs

@@ -0,0 +1,49 @@
+using System.Globalization;
+using Robust.Client.UserInterface.RichText;
+using Robust.Shared.Utility;
+
+namespace Content.Client.Guidebook.RichText;
+
+/// <summary>
+/// RichText tag that can display values extracted from entity prototypes.
+/// In order to be accessed by this tag, the desired field/property must
+/// be tagged with <see cref="Shared.Guidebook.GuidebookDataAttribute"/>.
+/// </summary>
+public sealed class ProtodataTag : IMarkupTag
+{
+    [Dependency] private readonly ILogManager _logMan = default!;
+    [Dependency] private readonly IEntityManager _entMan = default!;
+
+    public string Name => "protodata";
+    private ISawmill Log => _log ??= _logMan.GetSawmill("protodata_tag");
+    private ISawmill? _log;
+
+    public string TextBefore(MarkupNode node)
+    {
+        // Do nothing with an empty tag
+        if (!node.Value.TryGetString(out var prototype))
+            return string.Empty;
+
+        if (!node.Attributes.TryGetValue("comp", out var component))
+            return string.Empty;
+        if (!node.Attributes.TryGetValue("member", out var member))
+            return string.Empty;
+        node.Attributes.TryGetValue("format", out var format);
+
+        var guidebookData = _entMan.System<GuidebookDataSystem>();
+
+        // Try to get the value
+        if (!guidebookData.TryGetValue(prototype, component.StringValue!, member.StringValue!, out var value))
+        {
+            Log.Error($"Failed to find protodata for {component}.{member} in {prototype}");
+            return "???";
+        }
+
+        // If we have a format string and a formattable value, format it as requested
+        if (!string.IsNullOrEmpty(format.StringValue) && value is IFormattable formattable)
+            return formattable.ToString(format.StringValue, CultureInfo.CurrentCulture);
+
+        // No format string given, so just use default ToString
+        return value?.ToString() ?? "NULL";
+    }
+}