NFC Reader

API_AVAILABLE(ios(13.0))
@interface ALNFCScanViewController () <ALNFCDetectorDelegate, ALScanPluginDelegate>

@property (nonatomic, strong) ALNFCDetector *nfcDetector;
@property (nonatomic, strong, nullable) ALScanView *scanView;
@property (nonatomic, strong) ALScanViewPlugin *scanViewPlugin;
@property (nonatomic, strong) ALScanViewConfig *scanViewConfig;

@property (nonatomic, strong, nullable) UIView *hintView;

// keep the last values we read from the MRZ, so we can retry reading NFC if
// NFC failed for reasons other than getting these details wrong
@property (nonatomic, copy) NSString *passportNumberForNFC;

@property (nonatomic, strong) NSDate *dateOfBirth;

@property (nonatomic, strong) NSDate *dateOfExpiry;

@end


@implementation ALNFCScanViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    BOOL NFCEnabled = [self checkNFCCapability];
    if (!NFCEnabled) {
        return;
    }

    if (@available(iOS 13.0, *)) {
        self.nfcDetector = [[ALNFCDetector alloc] initWithDelegate:self];
    }

    NSString *jsonFilePath = [[NSBundle mainBundle] pathForResource:@"mrz_nfc_config"
                                                             ofType:@"json"];
    NSString *configStr = [NSString stringWithContentsOfFile:jsonFilePath
                                                    encoding:NSUTF8StringEncoding
                                                       error:NULL];
    id JSONConfigObj = [configStr asJSONObject];

    // instead of directly creating a scan view plugin, we can let a factory determine
    // whether the result is a plain ALScanViewPlugin or an ALViewPluginComposite.
    self.scanViewPlugin = (ALScanViewPlugin *)[ALScanViewPluginFactory withJSONDictionary:JSONConfigObj];

    self.scanViewConfig = [[ALScanViewConfig alloc] initWithJSONDictionary:JSONConfigObj error:nil];

    // Tweak the MRZ tolerances here if necessary.
    // [self configureScanViewConfig];

    self.scanViewPlugin.scanPlugin.delegate = self;

    self.scanView = [[ALScanView alloc] initWithFrame:CGRectZero
                                       scanViewPlugin:self.scanViewPlugin
                                       scanViewConfig:self.scanViewConfig
                                                error:nil];

    // add the scan view to the view hierarchy and position it correctly using
    // Autolayout.
    [self installScanView:self.scanView];

    [self.scanView startCamera];

    [self.view addSubview:self.scanView];
    [self.view sendSubviewToBack:self.scanView];
}

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    [self.scanViewPlugin startWithError:nil];
}

- (BOOL)checkNFCCapability {
    // NOTE: Apart from the iOS version + device requirement, also make sure to
    // check that the app was provisioned with the Near Field Communications
    // Tag Reading capability.
    if (@available(iOS 13.0, *)) {
        if ([ALNFCDetector readingAvailable]) {
        return YES;
        }
    }

    // NFC not supported!
    return NO;
}

// MARK: - ALScanPluginDelegate

- (void)scanPlugin:(ALScanPlugin *)scanPlugin resultReceived:(ALScanResult *)scanResult {

    // get passport number, date of birth, date of expiry

    ALMrzResult *mrzResult = scanResult.pluginResult.mrzResult;

    NSDate *dateOfBirth = [self.class formattedStringToDate:mrzResult.dateOfBirthObject];
    NSDate *dateOfExpiry = [self.class formattedStringToDate:mrzResult.dateOfExpiryObject];

    NSMutableString *passportNumberForNFC = [[mrzResult.documentNumber stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]] mutableCopy];
    NSRange passportNumberRange = [mrzResult.mrzString rangeOfString:passportNumberForNFC];
    if (passportNumberRange.location != NSNotFound) {
        if ([mrzResult.mrzString characterAtIndex:NSMaxRange(passportNumberRange)] == '<') {
            [passportNumberForNFC appendString:@"<"];
        }
    }

    if (passportNumberForNFC.length > 0) {
        [self.scanViewPlugin stop];
        self.hintView.hidden = YES;

        __weak __block typeof(self) weakSelf = self;
        dispatch_async(dispatch_get_main_queue(), ^{
            [weakSelf.nfcDetector startNfcDetectionWithPassportNumber:passportNumberForNFC
                                                          dateOfBirth:dateOfBirth
                                                       expirationDate:dateOfExpiry];
        });
    }

    self.dateOfBirth = dateOfBirth;
    self.dateOfExpiry = dateOfExpiry;
    self.passportNumberForNFC = passportNumberForNFC;
}

// MARK: - ALNFCDetectorDelegate

/// This method is called after all the data has been read from the NFC chip. To display
/// data as it is read instead of waiting until everything has been read, we could also
/// implement nfcSucceededWithDataGroup1: or nfcSucceededWithDataGroup2:
/// - Parameter nfcResult: NFCResult object
- (void)nfcSucceededWithResult:(ALNFCResult * _Nonnull)nfcResult API_AVAILABLE(ios(13.0)) {

    // First name: nfcResult.dataGroup1.firstName
    // Last name: nfcResult.dataGroup1.lastName
    // Date of Birth: nfcResult.dataGroup1.dateOfBirth
    // Date of Expiry: nfcResult.dataGroup1.dateOfExpiry
    // Document Number: nfcResult.dataGroup1.documentNumber
    // Issuing State Code: nfcResult.dataGroup1.issuingStateCode
    // Gender: nfcResult.dataGroup1.gender
    // Nationality: nfcResult.dataGroup1.nationality
    // Face Image: nfcResult.dataGroup2.faceImage
}

- (void)nfcFailedWithError:(NSError *)error API_AVAILABLE(ios(13.0)) {

    NSLog(@"NFC failed with error code: %ld, document number: %@", (long)error.code, self.passportNumberForNFC);
    // In most cases we don't really need to do anything special here since the NFC UI already shows
    // that it failed. We shouldn't get ALNFCTagErrorNFCNotSupported either because we check +readingAvailable
    // before even showing NFC, so this is just an example of how else that situation could be handled.

    if (error.code == ALNFCTagErrorNFCNotSupported) {
        [self showAlertWithTitle:@"NFC Not Supported"
                         message:@"NFC passport reading is not supported on this device."
                      completion:nil];
    }
    if (error.code == ALNFCTagErrorResponseError || // error ALNFCTagErrorResponseError can mean the MRZ key was wrong
        error.code == ALNFCTagErrorUnexpectedError) { // error ALNFCTagErrorUnexpectedError can mean the user pressed the
        // 'Cancel' button while scanning. It could also mean the phone lost the connection with the NFC chip because it was moved.
        [self.scanViewPlugin startWithError:nil];
    } else {
        // the MRZ details are correct, but something else went wrong. We can try reading the NFC chip again without rescanning the MRZ.
        [self.nfcDetector startNfcDetectionWithPassportNumber:self.passportNumberForNFC
                                                  dateOfBirth:self.dateOfBirth
                                               expirationDate:self.dateOfExpiry];
    }
}

@end