Firebase initialization and register for remote notifications

firebase-init-notification-setup.m

[FIRApp configure];

if( floor(NSFoundationVersionNumber) <= NSFoundationVersionNumber_iOS_9_x_Max )
  {
    // iOS 9
    UIUserNotificationType allNotificationTypes = ( UIUserNotificationTypeSound | UIUserNotificationTypeAlert | UIUserNotificationTypeBadge );
    UIUserNotificationSettings *settings = [UIUserNotificationSettings settingsForTypes:allNotificationTypes categories:nil];
    [[UIApplication sharedApplication] registerUserNotificationSettings:settings];
  }else
  {
    // iOS 10 or later
#if defined(__IPHONE_10_0) && __IPHONE_OS_VERSION_MAX_ALLOWED >= __IPHONE_10_0
    UNAuthorizationOptions authOptions = UNAuthorizationOptionAlert | UNAuthorizationOptionSound | UNAuthorizationOptionBadge;
    [[UNUserNotificationCenter currentNotificationCenter] requestAuthorizationWithOptions:authOptions completionHandler:^(BOOL granted, NSError * _Nullable error) {
    }];
    
    // For iOS 10 display notification (sent via APNS)
    [[UNUserNotificationCenter currentNotificationCenter] setDelegate:self];
    // For iOS 10 data message (sent via FCM)
    [[FIRMessaging messaging] setRemoteMessageDelegate:self];
#endif
  }
  
  [[UIApplication sharedApplication] registerForRemoteNotifications];