Ambient music rules refactor (#29921)

* refactor

* dutypo

Content.Shared/Random/Rules/GridInRange.cs

@@ -0,0 +1,39 @@
+using System.Numerics;
+using Robust.Shared.Map;
+
+namespace Content.Shared.Random.Rules;
+
+/// <summary>
+/// Returns true if on a grid or in range of one.
+/// </summary>
+public sealed partial class GridInRangeRule : RulesRule
+{
+    [DataField]
+    public float Range = 10f;
+
+    public override bool Check(EntityManager entManager, EntityUid uid)
+    {
+        if (!entManager.TryGetComponent(uid, out TransformComponent? xform))
+        {
+            return false;
+        }
+
+        if (xform.GridUid != null)
+        {
+            return !Inverted;
+        }
+
+        var transform = entManager.System<SharedTransformSystem>();
+        var mapManager = IoCManager.Resolve<IMapManager>();
+
+        var worldPos = transform.GetWorldPosition(xform);
+        var gridRange = new Vector2(Range, Range);
+
+        foreach (var _ in mapManager.FindGridsIntersecting(xform.MapID, new Box2(worldPos - gridRange, worldPos + gridRange)))
+        {
+            return !Inverted;
+        }
+
+        return false;
+    }
+}