Classes to circunvent the problem of SKAN V4 bein zerod out by the +[AAAttribution attributionTokenWithError:] method as presented by this article https://www.singular.net/blog/skan-4-cv-reset-bug/

WLSConversionValueUtils.h

//
//  WLSConversionValueUtils.h
//  Unity-iPhone
//
//  Created by Guthyerrz Silva on 03/08/23.
//

#ifndef WLSSKAdNetworkCVUtils_h
#define WLSSKAdNetworkCVUtils_h

#import <StoreKit/SKAdNetwork.h>

typedef NS_ENUM(NSInteger, WLSSKANCoarseConversionValue) {
    WLSSKANCoarseConversionValueLow = 0,
    WLSSKANCoarseConversionValueMedium,
    WLSSKANCoarseConversionValueHigh,
} ;


@interface WLSConversionValueUtils : NSObject


+ (void)sendUpdatedConversionValue:(NSInteger)conversionValue
             coarseConversionValue:(WLSSKANCoarseConversionValue)coarseConversionValue
                        lockWindow:(BOOL)lockWindow
                 completionHandler:(void (^)(NSError *error))completionHandler;
@end

#endif /* WLSSKAdNetworkUtils_h */

WLSConversionValueUtils.m

//
//  WLSConversionValueUtils.m
//  Unity-iPhone
//
//  Created by Guthyerrz Silva on 03/08/23.
//

#import <Foundation/Foundation.h>
#import "WLSConversionValueUtils.h"
#import <objc/runtime.h>
#import <StoreKit/SKAdNetwork.h>


#define CV_KEY @"WLSSKAdNetworkCVUtils_CV_KEY"
#define COARSE_CV_KEY @"WLSSKAdNetworkCVUtils_COARSE_CV_KEY"
#define LOCK_WINDOW_KEY @"WLSSKAdNetworkCVUtils_LOCK_WINDOW_KEY"

@implementation WLSConversionValueUtils

static NSInteger conversionValue = 0;
static WLSSKANCoarseConversionValue coarseCV = WLSSKANCoarseConversionValueLow;
static BOOL lockWindow = false;


+ (void)load {
    static dispatch_once_t onceToken;
    
    dispatch_once(&onceToken, ^{
        [WLSConversionValueUtils loadVariables];
        Class originalClass = [SKAdNetwork class];
        Class newClass = [self class];
        
        SEL swizzledSelector = @selector(wlsUpdatePostbackConversionValue:coarseValue:lockWindow:completionHandler:);
        SEL originalSelector = @selector(updatePostbackConversionValue:coarseValue:lockWindow:completionHandler:);

        Method originalMethod = class_getClassMethod(originalClass, originalSelector);
        Method swizzledMethod = class_getClassMethod(newClass, swizzledSelector);
        
        method_exchangeImplementations(originalMethod,swizzledMethod);
        
        swizzledSelector = @selector(wlsUpdatePostbackConversionValue:coarseValue:completionHandler:);
        originalSelector = @selector(updatePostbackConversionValue:coarseValue:completionHandler:);

        originalMethod = class_getClassMethod(originalClass, originalSelector);
        swizzledMethod = class_getClassMethod(newClass, swizzledSelector);
        
        method_exchangeImplementations(originalMethod,swizzledMethod);
        
        
        swizzledSelector = @selector(wlsUpdatePostbackConversionValue:completionHandler:);
        originalSelector = @selector(updatePostbackConversionValue:completionHandler:);

        originalMethod = class_getClassMethod(originalClass, originalSelector);
        swizzledMethod = class_getClassMethod(newClass, swizzledSelector);
        
        method_exchangeImplementations(originalMethod,swizzledMethod);
        
        swizzledSelector = @selector(wlsUpdateConversionValue:);
        originalSelector = @selector(updateConversionValue:);

        originalMethod = class_getClassMethod(originalClass, originalSelector);
        swizzledMethod = class_getClassMethod(newClass, swizzledSelector);
        
        method_exchangeImplementations(originalMethod,swizzledMethod);
        
        
    });
}

+(void)sendUpdatedConversionValue:(NSInteger)conversionValue
            coarseConversionValue:(WLSSKANCoarseConversionValue)coarse
                       lockWindow:(BOOL)lockWindow
                completionHandler:(void (^)(NSError *))completionHandler{
    [WLSConversionValueUtils saveConversionValue:conversionValue
                         coarseConversionValue:coarse
                                    lockWindow:lockWindow];
    
    if (@available(iOS 16.1, *)) {
        SKAdNetworkCoarseConversionValue coarseCV = [WLSConversionValueUtils mapToSKAdNetworkCoarseCV:coarse];
        
        [WLSConversionValueUtils wlsUpdatePostbackConversionValue:conversionValue
                                       coarseValue:coarseCV
                                        lockWindow:lockWindow
                                 completionHandler:completionHandler];
    } else if(@available (iOS 15.4,*)) {
        [WLSConversionValueUtils wlsUpdatePostbackConversionValue:conversionValue
                                 completionHandler:completionHandler];
    } else if(@available (iOS 14.0,*)){
        [WLSConversionValueUtils wlsUpdateConversionValue:conversionValue];
    }
    
}

+ (void)wlsUpdatePostbackConversionValue:(NSInteger)fineValue coarseValue:(SKAdNetworkCoarseConversionValue)coarseValue lockWindow:(BOOL)lock completionHandler:(nullable void (^)(NSError *__nullable error))completion API_AVAILABLE(ios(16.1)){
    SKAdNetworkCoarseConversionValue coarse = [WLSConversionValueUtils mapToSKAdNetworkCoarseCV:coarseCV];
    [WLSConversionValueUtils wlsUpdatePostbackConversionValue:conversionValue coarseValue:coarse lockWindow:lockWindow completionHandler:completion];
}

+ (void)wlsUpdatePostbackConversionValue:(NSInteger)fineValue completionHandler:(nullable void (^)(NSError *__nullable error))completion API_AVAILABLE(ios(15.4)){
    [WLSConversionValueUtils wlsUpdatePostbackConversionValue:conversionValue completionHandler:completion];
}

+ (void)wlsUpdateConversionValue:(NSInteger)fineValue API_DEPRECATED("Use updatePostbackConversionValue:completionHandler: instead", ios(14.0, 15.4)){
    [WLSConversionValueUtils wlsUpdateConversionValue:conversionValue];
}


+ (void)wlsUpdatePostbackConversionValue:(NSInteger)fineValue coarseValue:(SKAdNetworkCoarseConversionValue)coarseValue completionHandler:(nullable void (^)(NSError *__nullable error))completion API_AVAILABLE(ios(16.1)){
    SKAdNetworkCoarseConversionValue coarse = [WLSConversionValueUtils mapToSKAdNetworkCoarseCV:coarseCV];
    [WLSConversionValueUtils wlsUpdatePostbackConversionValue:conversionValue coarseValue:coarse completionHandler:completion];
}


+(void) loadVariables{
    NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
    conversionValue = [userDefaults integerForKey:CV_KEY];
    coarseCV = (WLSSKANCoarseConversionValue) [userDefaults integerForKey:COARSE_CV_KEY];
    lockWindow = [userDefaults boolForKey:LOCK_WINDOW_KEY];
}

+(void)saveConversionValue:(NSInteger)fineValue
     coarseConversionValue:(WLSSKANCoarseConversionValue)coarse
                lockWindow:(BOOL)lk{
    NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
    [userDefaults setInteger:fineValue forKey:CV_KEY];
    [userDefaults setInteger:coarse forKey:COARSE_CV_KEY];
    [userDefaults setBool:lk forKey:LOCK_WINDOW_KEY];
    
    conversionValue = fineValue;
    coarseCV = coarse;
    lockWindow = lk;
}

+ (SKAdNetworkCoarseConversionValue)mapToSKAdNetworkCoarseCV:(WLSSKANCoarseConversionValue)coarseConversionValue  API_AVAILABLE(ios(16.0)){
    SKAdNetworkCoarseConversionValue coarseCV = SKAdNetworkCoarseConversionValueLow;

    switch (coarseConversionValue) {
        case WLSSKANCoarseConversionValueMedium:
            coarseCV = SKAdNetworkCoarseConversionValueMedium;
            break;

        case WLSSKANCoarseConversionValueHigh:
            coarseCV = SKAdNetworkCoarseConversionValueHigh;
            break;

        default:
            //Use SKAdNetworkCoarseConversionValueLow (for WLSSKANCoarseConversionValueLow or any other value)
            break;
    }

    return coarseCV;
}

@end