static NSString *kMail = @"Mail";
static NSString *kPassword = @"Password";

static NSString *kLoginOk = @"loginOk";

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    self.registrationFieldView.hidden = YES;

    // Проверка пользователя в сети
    NSUserDefaults *user = [NSUserDefaults standardUserDefaults];
    if ([user objectForKey:kMail] != nil || [user objectForKey:kPassword] != nil) {
        [self performSegueWithIdentifier:kLoginOk sender:self];
    }
    NSLog(@"%@, %@", [user objectForKey:kMail], [user objectForKey:kPassword]);

}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (IBAction)loginAndRegSegmenSwitch:(id)sender {
    UISegmentedControl *seg = (UISegmentedControl *)sender;
    NSInteger select = seg.selectedSegmentIndex;
    if (select == loginSegment) {
        self.registrationFieldView.hidden = YES;
    } else {
        self.registrationFieldView.hidden = NO;
    }
}

// форма логина и проверка на наличие пустых полей
- (IBAction)logInButton:(UIButton *)sender {
    // проверка на заполнение полей
    if (![self.mailLoginTextField.text isEqualToString:@""] || ![self.passwordLoginTextField.text isEqualToString:@""]) {
        // хранение данных о пользователе
        NSUserDefaults *userInfo = [NSUserDefaults standardUserDefaults];
        [userInfo setObject:self.mailLoginTextField.text forKey:kMail];
        [userInfo setObject:self.passwordLoginTextField.text forKey:kPassword];
        [self performSegueWithIdentifier:kLoginOk sender:self];
        [userInfo synchronize];
    } else {
            if ([self.mailLoginTextField.text isEqualToString:@""] && [self.passwordLoginTextField.text isEqualToString:@""]) {
                [self title:@"Заплоните поля" message:@"Поля  \"Mail\" и \"Password\" пустые"];
            } else {
                if ([self.mailLoginTextField.text isEqualToString:@""]) {
                    [self title:@"Заплоните поле" message:@"Поле \"Mail\" пустое"];
                } else if ([self.passwordLoginTextField.text isEqualToString:@""]) {
                    [self title:@"Заплоните поле" message:@"Поле \"Password\" пустое"];
                }
            }
    }
}