Achievement manager

AchievementManager.h

@interface AchievementManager : NSObject

+(AchievementManager*) sharedManager;

/** Local copy of current achievements progress */
@property(nonatomic, retain) NSMutableDictionary *achievementsDictionary;

/** Must be called right after Game Center authentication */
-(void) loadAchievements;

/** Report an achievement if necessary (i.E if better than current progress) */
-(void) reportAchievementIdentifier:(NSString*) identifier percentComplete:(float) percent;

/** Increment an achievement if necessary (i.e if current is < 100%) */
-(void) incrementAchievementIdentifier:(NSString*) identifier percentIncrement:(float) percent;

@end

AchievementManager.m

@implementation AchievementManager

static AchievementManager* _sharedManager = nil;

+(AchievementManager*) sharedManager {
    @synchronized([AchievementManager class])
	{
		if (!_sharedManager)
			_sharedManager = [[self alloc] init];
        
		return _sharedManager;
	}
    
	return nil;
}

@synthesize achievementsDictionary;

-(id) init {
    if(self = [super init]) {
        achievementsDictionary = [[NSMutableDictionary alloc] init];
    }
    return self;
}

- (void) loadAchievements
{
    CCLOG(@"[ACHIEVEMENT] loadAchievements");
    [GKAchievement loadAchievementsWithCompletionHandler:^(NSArray *achievements, NSError *error)
     {
         if (error == nil)
         {
             for (GKAchievement* achievement in achievements)
                 [achievementsDictionary setObject: achievement forKey: achievement.identifier];
         }
     }];
}

- (GKAchievement*) getAchievementForIdentifier: (NSString*) identifier
{
    GKAchievement *achievement = [achievementsDictionary objectForKey:identifier];
    if (achievement == nil)
    {
        achievement = [[GKAchievement alloc] initWithIdentifier:identifier];
        [achievementsDictionary setObject:achievement forKey:achievement.identifier];
    }
    return achievement;
}

-(void) reportAchievementIdentifier: (NSString*) identifier percentComplete: (float) percent {
    GKAchievement *achievement = [self getAchievementForIdentifier:identifier];
    if (achievement && percent > achievement.percentComplete)
    {
        CCLOG(@"[ACHIEVEMENT] reportAchievementIdentifier: '%@' percentComplete: %f", identifier, percent);
        achievement.percentComplete = percent;
        achievement.showsCompletionBanner = YES;
        
        [achievement reportAchievementWithCompletionHandler:^(NSError *error) {
            if (error != nil)
            {
                CCLOGERROR(@"[ACHIEVEMENT] Error in reporting achievements: %@", error);
            }
        }];
    }
}

-(void) incrementAchievementIdentifier: (NSString*) identifier percentIncrement: (float) percent {
    GKAchievement *achievement = [self getAchievementForIdentifier:identifier];
    if(achievement.percentComplete < 100) {
        CCLOG(@"[ACHIEVEMENT] incrementAchievementIdentifier: '%@' percentIncrement: %f", identifier, percent);
        achievement.percentComplete += percent;
        achievement.showsCompletionBanner = YES;
        
        [achievement reportAchievementWithCompletionHandler:^(NSError *error) {
            if (error != nil)
            {
                CCLOGERROR(@"[ACHIEVEMENT] Error in reporting achievements: %@", error);
            }
        }];
    }
}

@end