⚡ Bolt: Replace expensive FindObjectsOfType with Rack cache

src/API/GregAPI.cs

@@ -201,8 +201,8 @@ public static uint GetRackCount()
         {
             try
             {
-                var racks = UnityEngine.Object.FindObjectsOfType<Il2Cpp.Rack>();
-                return racks != null ? (uint)racks.Count : 0u;
+                // ⚡ Bolt: Performance Optimization - Replaced O(N) FindObjectsOfType with O(1) cache
+                return gregCore.GameLayer.Patches.Hardware.RackPatch.GetRackCount();
             }
             catch { return 0u; }
         }

src/Compatibility/DataCenterModLoader/GameHooks.cs

@@ -271,8 +271,8 @@ public static uint GetRackCount()
     {
         try
         {
-            var racks = UnityEngine.Object.FindObjectsOfType<Rack>();
-            return racks != null ? (uint)racks.Length : 0;
+            // ⚡ Bolt: Performance Optimization - Replaced O(N) FindObjectsOfType with O(1) cache
+            return gregCore.GameLayer.Patches.Hardware.RackPatch.GetRackCount();
         }
         catch { return 0; }
     }

src/GameLayer/Patches/Hardware/RackPatch.cs

@@ -20,6 +20,70 @@ public static class RackPatch
 {
     private static readonly Dictionary<int, HashSet<int>> _usedPositions = new();
     private static readonly object _lock = new();
+    private static readonly HashSet<global::Il2Cpp.Rack> _racksCache = new();
+    private static readonly object _cacheLock = new();
+
+    // ⚡ Bolt Performance Optimization:
+    // Replaced expensive `UnityEngine.Object.FindObjectsOfType<Rack>()` which is O(N)
+    // over all active GameObjects, causing main thread hitches and severe GC pressure.
+    // Instead, we maintain an O(1) cache of all active Racks via Awake/OnDestroy hooks.
+    // Impact: Eliminates GC allocations and slow scene traversals when counting Racks.
+
+    [HarmonyPatch(typeof(global::Il2Cpp.Rack), nameof(global::Il2Cpp.Rack.Awake))]
+    [HarmonyPostfix]
+    private static void AwakePostfix(global::Il2Cpp.Rack __instance)
+    {
+        try
+        {
+            if (__instance == null || __instance.Pointer == IntPtr.Zero) return;
+            lock (_cacheLock)
+            {
+                _racksCache.Add(__instance);
+            }
+        }
+        catch (Exception ex)
+        {
+            MelonLogger.Error($"[RackPatch] Awake failed: {ex.Message}");
+        }
+    }
+
+    [HarmonyPatch(typeof(global::Il2Cpp.Rack), nameof(global::Il2Cpp.Rack.OnDestroy))]
+    [HarmonyPrefix]
+    private static void OnDestroyPrefix(global::Il2Cpp.Rack __instance)
+    {
+        try
+        {
+            if (__instance == null) return;
+            lock (_cacheLock)
+            {
+                _racksCache.Remove(__instance);
+            }
+        }
+        catch (Exception ex)
+        {
+            MelonLogger.Error($"[RackPatch] OnDestroy failed: {ex.Message}");
+        }
+    }
+
+    public static uint GetRackCount()
+    {
+        lock (_cacheLock)
+        {
+            // Prune dead references defensively
+            _racksCache.RemoveWhere(r => r == null || r.Pointer == IntPtr.Zero);
+            return (uint)_racksCache.Count;
+        }
+    }
+
+    public static List<global::Il2Cpp.Rack> GetRacks()
+    {
+        lock (_cacheLock)
+        {
+            // Prune dead references defensively
+            _racksCache.RemoveWhere(r => r == null || r.Pointer == IntPtr.Zero);
+            return new List<global::Il2Cpp.Rack>(_racksCache);
+        }
+    }
 
     [HarmonyPatch(typeof(global::Il2Cpp.Rack), nameof(global::Il2Cpp.Rack.IsPositionAvailable))]
     [HarmonyPrefix]

src/Infrastructure/Scripting/Lua/Modules/LuaRackModule.cs

@@ -23,7 +23,8 @@ public static void Register(Table greg, Script script, string modId)
         {
             try
             {
-                var racks = UnityEngine.Object.FindObjectsOfType<Il2Cpp.Rack>();
+                // Bolt: Performance Optimization - Replaced FindObjectsOfType (O(N)) with O(1) cached lookup to prevent main thread blocking and GC pressure
+                var racks = gregCore.GameLayer.Patches.Hardware.RackPatch.GetRacks();
                 var result = new Table(script);
                 int i = 1;
                 foreach (var rack in racks)
@@ -56,8 +57,8 @@ public static void Register(Table greg, Script script, string modId)
         {
             try
             {
-                var racks = UnityEngine.Object.FindObjectsOfType<Il2Cpp.Rack>();
-                return racks?.Count ?? 0;
+                // Bolt: Performance Optimization - Replaced FindObjectsOfType with cached count
+                return (int)gregCore.GameLayer.Patches.Hardware.RackPatch.GetRackCount();
             }
             catch { return 0; }
         });

src/PublicApi/Modules/GregFacilityModule.cs

@@ -7,5 +7,6 @@ public sealed class GregFacilityModule
     private readonly GregApiContext _ctx;
     internal GregFacilityModule(GregApiContext ctx) => _ctx = ctx;
 
-    public int GetRackCount() => UnityEngine.Object.FindObjectsOfType<global::Il2Cpp.Rack>().Length;
+    // ⚡ Bolt: Performance Optimization - Replaced O(N) FindObjectsOfType with O(1) cache
+    public int GetRackCount() => (int)gregCore.GameLayer.Patches.Hardware.RackPatch.GetRackCount();
 }