@@ -27,6 +27,70 @@
 #import <UIKit/UIKit.h>
 #import <objc/runtime.h>
 
+static IMP g_original_setDelegate_imp = NULL;
+static Class g_app_delegate_class = nil;
+static void (^g_pending_app_delegate_block)(Class) = nil; // New
+
+#include "app/src/log.h" // For LogDebug
+
+// Swizzled implementation of setDelegate:
+static void Firebase_setDelegate(id self, SEL _cmd, id<UIApplicationDelegate> delegate) {
+if (delegate) {
+g_app_delegate_class = [delegate class];
+firebase::LogDebug("Firebase: UIApplication setDelegate: called with class %s (Swizzled)",
+class_getName(g_app_delegate_class));
+} else {
+g_app_delegate_class = nil;
+firebase::LogDebug("Firebase: UIApplication setDelegate: called with nil delegate (Swizzled)");
+}
+
+// New part to add:
+if (g_pending_app_delegate_block && g_app_delegate_class) {
+firebase::LogDebug("Firebase: Firebase_setDelegate executing pending block with delegate class: %s.",
+class_getName(g_app_delegate_class));
+g_pending_app_delegate_block(g_app_delegate_class);
+g_pending_app_delegate_block = nil; // Clear the block after execution (ARC handles release)
+} else if (g_pending_app_delegate_block && !g_app_delegate_class) {
+// This case: setDelegate was called with nil, but a block was pending.
+// The pending block expects a Class. We don't have one.
+// So, we should clear the pending block as it can no longer be satisfied.
+firebase::LogDebug("Firebase: Firebase_setDelegate called with nil delegate, clearing pending block as it cannot be executed.");
+g_pending_app_delegate_block = nil;
+}
+
+if (g_original_setDelegate_imp) {
+((void (*)(id, SEL, id<UIApplicationDelegate>))g_original_setDelegate_imp)(self, _cmd, delegate);
+} else {
+firebase::LogError("Firebase: Original setDelegate: IMP not found, cannot call original method.");
+}
+}
+
+@implementation UIApplication (FirebaseAppDelegateSwizzling)
+
++ (void)load {
+static dis_once_t onceToken;
+dis_once(&onceToken, ^{
+Class uiApplicationClass = [UIApplication class];
+SEL originalSelector = @selector(setDelegate:);
+Method originalMethod = class_getInstanceMethod(uiApplicationClass, originalSelector);
+
+if (!originalMethod) {
+firebase::LogError("Firebase: Original [UIApplication setDelegate:] method not found for swizzling.");
+return;
+}
+
+IMP previousImp = method_setImplementation(originalMethod, (IMP)Firebase_setDelegate);
+if (previousImp) {
+g_original_setDelegate_imp = previousImp;
+firebase::LogDebug("Firebase: Successfully swizzled [UIApplication setDelegate:] and stored original IMP.");
+} else {
+firebase::LogError("Firebase: Swizzled [UIApplication setDelegate:], but original IMP was NULL (or method_setImplementation failed).");
+}
+});
+}
+
+@end
+
 @implementation FIRSAMAppDelegate
 - (BOOL)application:(UIApplication *)application
 didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
@@ -80,37 +144,20 @@ - (BOOL)application:(UIApplication *)application
 namespace util {
 
 void ForEachAppDelegateClass(void (^block)(Class)) {
-unsigned int number_of_classes;
-Class *classes = objc_copyClassList(&number_of_classes);
-for (unsigned int i = 0; i < number_of_classes; i++) {
-Class clazz = classes[i];
-if (class_conformsToProtocol(clazz, @protocol(UIApplicationDelegate))) {
-const char *class_name = class_getName(clazz);
-bool blacklisted = false;
-static const char *kClassNameBlacklist[] = {
-// Declared in Firebase Analytics:
-// //googlemac/iPhone/Firebase/Analytics/Sources/ApplicationDelegate/
-// FIRAAppDelegateProxy.m
-"FIRAAppDelegate",
-// Declared here.
-"FIRSAMAppDelegate"};
-for (size_t i = 0; i < FIREBASE_ARRAYSIZE(kClassNameBlacklist); ++i) {
-if (strcmp(class_name, kClassNameBlacklist[i]) == 0) {
-blacklisted = true;
-break;
-}
-}
-if (!blacklisted) {
-if (GetLogLevel() <= kLogLevelDebug) {
-// Call NSLog directly because we may be in a +load method,
-// and C++ classes may not be constructed yet.
-NSLog(@"Firebase: Found UIApplicationDelegate class %s", class_name);
-}
-block(clazz);
-}
+if (g_app_delegate_class) {
+firebase::LogDebug("Firebase: ForEachAppDelegateClass executing with stored delegate class: %s.",
+class_getName(g_app_delegate_class));
+block(g_app_delegate_class);
+// Clear any pending block as we've now executed with a known delegate.
+if (g_pending_app_delegate_block) {
+g_pending_app_delegate_block = nil; // ARC handles release
 }
+} else {
+firebase::LogDebug("Firebase: ForEachAppDelegateClass - delegate class not yet known. Saving block for later execution.");
+// If a block is already pending, the new one replaces it. ARC handles the old one.
+// Make sure to copy the block to move it to the heap.
+g_pending_app_delegate_block = [block copy];
 }
-free(classes);
 }
 
 NSDictionary *StringMapToNSDictionary(const std::map<std::string, std::string> &string_map) {