Throw if using secret key

RadarSDK/Radar.m

@@ -54,6 +54,13 @@ + (void)nativeSetup:(RadarInitializeOptions *)options {
 + (void)initializeWithPublishableKey:(NSString *)publishableKey options:(RadarInitializeOptions *)options {
     [[RadarLogger sharedInstance] logWithLevel:RadarLogLevelInfo type:RadarLogTypeSDKCall message:@"initialize()"];
 
+    // Check for secret key usage
+    if ([publishableKey containsString:@"_sk_"]) {
+        @throw [NSException exceptionWithName:NSInvalidArgumentException 
+                                       reason:@"Secret keys are not allowed. Please use your Radar publishable key." 
+                                     userInfo:nil];
+    }
+
     Class RadarSDKMotion = NSClassFromString(@"RadarSDKMotion");
     if (RadarSDKMotion) {
         id radarSDKMotion = [[RadarSDKMotion alloc] init];

RadarSDKTests/RadarSDKTests.m

@@ -319,6 +319,34 @@ - (void)test_Radar_initialize {
     XCTAssertEqualObjects(kPublishableKey, [RadarSettings publishableKey]);
 }
 
+- (void)test_Radar_initialize_throwsExceptionForSecretKey {
+    NSString *secretKey = @"prj_test_sk_0000000000000000000000000000000000000000";
+
+    XCTAssertThrows([Radar initializeWithPublishableKey:secretKey options:nil], 
+                    @"Should throw exception when secret key is used");
+}
+
+- (void)test_Radar_initialize_throwsCorrectExceptionTypeForSecretKey {
+    NSString *secretKey = @"prj_test_sk_0000000000000000000000000000000000000000";
+
+    @try {
+        [Radar initializeWithPublishableKey:secretKey options:nil];
+        XCTFail(@"Expected NSInvalidArgumentException to be thrown");
+    } @catch (NSException *exception) {
+        XCTAssertEqualObjects(exception.name, NSInvalidArgumentException, 
+                             @"Exception should be NSInvalidArgumentException");
+        XCTAssertTrue([exception.reason containsString:@"Secret keys are not allowed"], 
+                     @"Exception reason should mention secret keys are not allowed");
+    }
+}
+
+- (void)test_Radar_initialize_acceptsValidPublishableKey {
+    NSString *validKey = @"prj_test_pk_0000000000000000000000000000000000000000";
+
+    XCTAssertNoThrow([Radar initializeWithPublishableKey:validKey options:nil], 
+                     @"Should not throw exception for valid publishable key");
+}
+
 - (void)test_Radar_setUserId {
     NSString *userId = @"userId";
     [Radar setUserId:userId];