[ads] Support NTT grace period on iOS (#28892)

ios/brave-ios/Sources/Brave/Frontend/Browser/HomePanel/NTPDataSource.swift

@@ -123,6 +123,10 @@ public class NTPDataSource {
       let newTabPageAd = rewards?.ads.maybeGetPrefetchedNewTabPageAd()
     else { return nil }
 
+    if !hasGracePeriodEnded(sponsoredImageData) {
+      return nil
+    }
+
     let isSponsoredVideoAllowed =
       Preferences.NewTabPage.backgroundMediaType == .sponsoredImagesAndVideos
 
@@ -230,6 +234,22 @@ public class NTPDataSource {
       replaceFavoritesIfNeeded?(superReferralImageData.topSites)
     }
   }
+
+  private func hasGracePeriodEnded(_ sponsoredImageData: NTPSponsoredImageData) -> Bool {
+    if BraveRewards.Configuration.current().isDebug == true {
+      // If debug mode is enabled, consider it ended.
+      return true
+    }
+
+    guard let gracePeriod = sponsoredImageData.gracePeriod?.doubleValue,
+      let installDate = Preferences.P3A.installationDate.value
+    else {
+      // If either the grace period or install date is not set, consider it ended.
+      return true
+    }
+
+    return Date.now.timeIntervalSince(installDate) > gracePeriod
+  }
 }
 
 extension NTPDataSource: PreferencesObserver {

ios/browser/api/ntp_background_images/ntp_sponsored_image.h

@@ -16,12 +16,14 @@ NS_ASSUME_NONNULL_BEGIN
 OBJC_EXPORT
 @interface NTPSponsoredImageData : NSObject
 @property(readonly) NSArray<NTPSponsoredImageCampaign*>* campaigns;
+@property(readonly, nullable) NSNumber* gracePeriod;
 @property(readonly) BOOL isSuperReferral;
 @property(readonly, nullable) NSString* themeName;
 @property(readonly, nullable) NSArray<NTPSponsoredImageTopSite*>* topSites;
 - (instancetype)init NS_UNAVAILABLE;
 - (instancetype)
     initWithCampaigns:(NSArray<NTPSponsoredImageCampaign*>*)campaigns
+          gracePeriod:(nullable NSNumber*)gracePeriod
       isSuperReferral:(BOOL)isSuperReferral
             themeName:(nullable NSString*)themeName
              topSites:(nullable NSArray<NTPSponsoredImageTopSite*>*)topSites

ios/browser/api/ntp_background_images/ntp_sponsored_image.mm

@@ -16,6 +16,7 @@
 
 @interface NTPSponsoredImageData ()
 @property(nonatomic, copy) NSArray<NTPSponsoredImageCampaign*>* campaigns;
+@property(nonatomic, nullable) NSNumber* gracePeriod;
 @property(nonatomic) BOOL isSuperReferral;
 @property(nonatomic, copy, nullable) NSString* themeName;
 @property(nonatomic, copy, nullable)
@@ -26,11 +27,13 @@
 
 - (instancetype)
     initWithCampaigns:(NSArray<NTPSponsoredImageCampaign*>*)campaigns
+          gracePeriod:(nullable NSNumber*)gracePeriod
       isSuperReferral:(BOOL)isSuperReferral
             themeName:(nullable NSString*)themeName
              topSites:(nullable NSArray<NTPSponsoredImageTopSite*>*)topSites {
   if ((self = [super init])) {
     self.campaigns = campaigns;
+    self.gracePeriod = gracePeriod;
     self.isSuperReferral = isSuperReferral;
     self.themeName = themeName;
     self.topSites = topSites;
@@ -45,6 +48,10 @@
     [campaigns addObject:[[NTPSponsoredImageCampaign alloc]
                              initWithCampaign:campaign]];
   }
+  NSNumber* gracePeriod = nil;
+  if (data.grace_period) {
+    gracePeriod = [NSNumber numberWithFloat:data.grace_period->InSecondsF()];
+  }
   auto isSuperReferral = data.IsSuperReferral();
   NSString* themeName = nil;
   NSMutableArray<NTPSponsoredImageTopSite*>* topSites = nil;
@@ -57,6 +64,7 @@
     }
   }
   return [self initWithCampaigns:campaigns
+                     gracePeriod:gracePeriod
                  isSuperReferral:isSuperReferral
                        themeName:themeName
                         topSites:topSites];