Typing indicator (typing chat bubble) (#8215)

Content.Server/Chat/TypingIndicator/TypingIndicatorSystem.cs

@@ -0,0 +1,63 @@
+using Content.Shared.ActionBlocker;
+using Content.Shared.Chat.TypingIndicator;
+using Robust.Server.GameObjects;
+
+namespace Content.Server.Chat.TypingIndicator;
+
+// Server-side typing system
+// It receives networked typing events from clients
+// And sync typing indicator using appearance component
+public sealed class TypingIndicatorSystem : SharedTypingIndicatorSystem
+{
+    [Dependency] private readonly ActionBlockerSystem _actionBlocker = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+        SubscribeLocalEvent<PlayerAttachedEvent>(OnPlayerAttached);
+        SubscribeLocalEvent<TypingIndicatorComponent, PlayerDetachedEvent>(OnPlayerDetached);
+        SubscribeNetworkEvent<TypingChangedEvent>(OnClientTypingChanged);
+    }
+
+    private void OnPlayerAttached(PlayerAttachedEvent ev)
+    {
+        // when player poses entity we want to make sure that there is typing indicator
+        EnsureComp<TypingIndicatorComponent>(ev.Entity);
+        // we also need appearance component to sync visual state
+        EnsureComp<ServerAppearanceComponent>(ev.Entity);
+    }
+
+    private void OnPlayerDetached(EntityUid uid, TypingIndicatorComponent component, PlayerDetachedEvent args)
+    {
+        // player left entity body - hide typing indicator
+        SetTypingIndicatorEnabled(uid, false);
+    }
+
+    private void OnClientTypingChanged(TypingChangedEvent ev)
+    {
+        // make sure that this entity still exist
+        if (!Exists(ev.Uid))
+        {
+            Logger.Warning($"Client attached entity {ev.Uid} from TypingChangedEvent doesn't exist on server.");
+            return;
+        }
+
+        // check if this entity can speak or emote
+        if (!_actionBlocker.CanSpeak(ev.Uid) && !_actionBlocker.CanEmote(ev.Uid))
+        {
+            // nah, make sure that typing indicator is disabled
+            SetTypingIndicatorEnabled(ev.Uid, false);
+            return;
+        }
+
+        SetTypingIndicatorEnabled(ev.Uid, ev.IsTyping);
+    }
+
+    private void SetTypingIndicatorEnabled(EntityUid uid, bool isEnabled, AppearanceComponent? appearance = null)
+    {
+        if (!Resolve(uid, ref appearance, false))
+            return;
+
+        appearance.SetData(TypingIndicatorVisuals.IsTyping, isEnabled);
+    }
+}