FacebookManger.m

#import <FacebookSDK/FacebookSDK.h>
#import "FacebookManager.h"

@implementation FacebookManager

static FacebookManager* _FacebookManager;
+ (FacebookManager*)sharedManager;
{
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        _FacebookManager = [[FacebookManager alloc] init];
    });
    
    return _FacebookManager;
}

- (BOOL)isLogin
{
    return _session != nil && [_session isOpen];
}

- (BOOL)isEmptyCache
{
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    NSString *userName = [defaults stringForKey:KEY_DEFAULT_FACEBOOK_USERNAME];
    
    return (userName == NULL) ? YES : NO;
}

- (void)login
{
    FBSessionTokenCachingStrategy* tokenCachingStrategy = [[FBSessionTokenCachingStrategy alloc] initWithUserDefaultTokenInformationKeyName:KEY_DEFAULT_FACEBOOK_TOKEN];
    
    _session = [[FBSession alloc] initWithAppID: nil permissions:@[@"basic_info",@"user_birthday"] defaultAudience: FBSessionDefaultAudienceFriends urlSchemeSuffix: nil tokenCacheStrategy: tokenCachingStrategy];
    [_session openWithCompletionHandler:^(FBSession *session, FBSessionState status, NSError *error) {
        if (status == FBSessionStateOpen) {
            FBRequest *me = [[FBRequest alloc] initWithSession:_session
                                                     graphPath:@"me"];
            [me startWithCompletionHandler:^(FBRequestConnection *connection,
                                             NSDictionary<FBGraphUser> *user,
                                             NSError *error) {
                if (error) {
                    NSLog(@"Couldn't get info : %@", error.localizedDescription);
                    return;
                }
                
                NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
                NSString *userName = user.username;
                
                [defaults setObject:userName forKey:KEY_DEFAULT_FACEBOOK_USERNAME];
                [defaults synchronize];
            }];
        } else if (status == FBSessionStateClosed) {
            NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
            [defaults removeObjectForKey: KEY_DEFAULT_FACEBOOK_USERNAME];
            [defaults synchronize];
        }
    }];
}

- (BOOL)logout
{
    if (_session != nil) {
        [_session closeAndClearTokenInformation];
        _session = nil;
        
        return YES;
    }
    
    return NO;
}

@end