-(void)authenticateLocalPlayer{
    GKLocalPlayer *localPlayer = [GKLocalPlayer localPlayer];

    localPlayer.authenticateHandler = ^(UIViewController *viewController, NSError *error){
        if (viewController != nil) {
            [[CCDirector sharedDirector] presentViewController:viewController animated:YES completion:nil];

        }
        else{
            if ([GKLocalPlayer localPlayer].authenticated) {
                _gameCenterEnabled = YES;


                // Get the default leaderboard identifier.
                [[GKLocalPlayer localPlayer]   loadDefaultLeaderboardIdentifierWithCompletionHandler:^(NSString *leaderboardIdentifier, NSError *error) {

                    if (error != nil) {
                        NSLog(@"%@", [error localizedDescription]);
                    }
                    else{
                        _leaderboardIdentifier = leaderboardIdentifier;
                    }
                }];
            }

            else{
                _gameCenterEnabled = NO;
            }
        }
    };
}

-(void)reportScore{
    GKScore *score = [[GKScore alloc] initWithLeaderboardIdentifier:_leaderboardIdentifier];
    score.value = _points;

    CCLOG(@"Score: %i ",_points);

    [GKScore reportScores:@[score] withCompletionHandler:^(NSError *error) {
        if (error != nil) {
            NSLog(@"%@", [error localizedDescription]);
        }
    }];

}

- (void)restart {
    CCScene *scene = [CCBReader loadAsScene:@"MainScene"];
    [[CCDirector sharedDirector] replaceScene:scene];
}