NSMutableArray *_displayedErrors;
void errorAlert(NSString *text) {
    if (!_displayedErrors) {
        _displayedErrors = [[NSMutableArray alloc] init];
    }

    if (text == nil) {
        text = @"Unknown error";
    }

    if ([_displayedErrors containsObject:text]) {
        return;
    }

    [_displayedErrors addObject:text];
    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
        [_displayedErrors removeObject:text];
    });

    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Error".localized message:text delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
    [alertView show];
}