IListener and IRadio purge (#11980)

Content.Server/Speech/EntitySystems/ListeningSystem.cs

@@ -0,0 +1,61 @@
+using Content.Server.Chat.Systems;
+using Content.Server.Speech.Components;
+
+namespace Content.Server.Speech.EntitySystems;
+
+/// <summary>
+///     This system redirects local chat messages to listening entities (e.g., radio microphones).
+/// </summary>
+public sealed class ListeningSystem : EntitySystem
+{
+    [Dependency] private readonly SharedTransformSystem _xforms = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+        SubscribeLocalEvent<EntitySpokeEvent>(OnSpeak);
+    }
+
+    private void OnSpeak(EntitySpokeEvent ev)
+    {
+        PingListeners(ev.Source, ev.Message, ev.ObfuscatedMessage);
+    }
+
+    public void PingListeners(EntityUid source, string message, string? obfuscatedMessage)
+    {
+        // TODO whispering / audio volume? Microphone sensitivity?
+        // for now, whispering just arbitrarily reduces the listener's max range.
+
+        var xformQuery = GetEntityQuery<TransformComponent>();
+        var sourceXform = xformQuery.GetComponent(source);
+        var sourcePos = _xforms.GetWorldPosition(sourceXform, xformQuery);
+
+        var attemptEv = new ListenAttemptEvent(source);
+        var ev = new ListenEvent(message, source);
+        var obfuscatedEv = obfuscatedMessage == null ? null : new ListenEvent(obfuscatedMessage, source);
+
+        foreach (var (listener, xform) in EntityQuery<ActiveListenerComponent, TransformComponent>())
+        {
+            if (xform.MapID != sourceXform.MapID)
+                return;
+
+            // range checks
+            // TODO proper speech occlusion
+            var distance = (sourcePos - _xforms.GetWorldPosition(xform, xformQuery)).LengthSquared;
+            if (distance > listener.Range * listener.Range)
+                continue;
+
+            RaiseLocalEvent(listener.Owner, attemptEv);
+            if (attemptEv.Cancelled)
+            {
+                attemptEv.Uncancel();
+                continue;
+            }
+
+            if (obfuscatedEv != null && distance > ChatSystem.WhisperRange)
+                RaiseLocalEvent(listener.Owner, obfuscatedEv);
+            else
+                RaiseLocalEvent(listener.Owner, ev);
+        }
+    }
+}