/// Initialize VGSCollect instance
var vgsCollect = VGSCollect(id: "vauiltId", environment: .sandbox)

/// VGS UI Elements
var cardNumberField = VGSCardTextField()
var cardHolderNameField = VGSTextField()
var expCardDateField = VGSTextField()
var cvcField = VGSTextField()

/// Native UI Elements
@IBOutlet weak var stackView: UIStackView!

override func viewDidLoad() {
    super.viewDidLoad()

    /// Create card number field configuration
    let cardConfiguration = VGSConfiguration(collector: vgsCollect,
                                         fieldName: "card_number")
    cardConfiguration.type = .cardNumber
    cardConfiguration.isRequiredValidOnly = true

    /// Setup configuration to card number field
    cardNumberField.configuration = cardConfiguration
    cardNumberField.placeholder = "Card Number"
    stackView.addArrangedSubview(cardNumberField)

    /// Setup next textfields...
}
...

override func viewDidLoad() {
    super.viewDidLoad()
	
    ...  
	
    /// Observing text fields
    vgsCollect.observeStates = { textFields in

        textFields.forEach({ textField in
            print(textdField.state.description)
            if textdField.state.isValid {
                textField.borderColor = .grey
            } else {
                textField.borderColor = .red
            }

            /// CardState is available for VGSCardTextField
            if let cardState = textField.state as? CardState {
                print(cardState.bin)
                print(cardState.last4)
                print(cardState.brand.stringValue)
            }
        })
    }
}

// ...

// MARK: - Send data    
func sendData() {

    /// handle fields validation before send data
    guard cardNumberField.state.isValid else {
	print("cardNumberField input is not valid")
    }

    /// extra information will be sent together with all sensitive card information
    var extraData = [String: Any]()
    extraData["customKey"] = "Custom Value"

    /// send data to your Vault
    vgsCollect.sendData(path: "/post", extraData: extraData) { [weak self](response) in
      switch response {
        case .success(let code, let data, let response):
          // parse data
        case .failure(let code, let data, let response, let error):
          // handle failed request
          switch code {
            // handle error codes
          }
      }
    }
}

class ViewController: UIViewController {
	 
    var vgsCollect = VGSCollect(id: "vauiltId", environment: .sandbox)

    /// Init VGSCardIOScanController
    var scanController = VGSCardIOScanController()

    /// Init VGSTextFields...

    override func viewDidLoad() {
        super.viewDidLoad()

        /// set VGSCardIOScanDelegate
        canController.delegate = self
    }

    /// Present scan controller 
    func scanData() {
        scanController.presentCardScanner(on: self,
				animated: true,
			      completion: nil)
    }

    // MARK: - Send data  
    func sendData() {
        /// Send data from VGSTextFields to your Vault
        vgsCollect.sendData{...}
    }
}
...

// ...

/// Implement VGSCardIOScanControllerDelegate methods
extension ViewController: VGSCardIOScanControllerDelegate {

    ///Asks VGSTextField where scanned data with type need to be set.
    func textFieldForScannedData(type: CradIODataType) -> VGSTextField? {
	switch type {
	case .expirationDate:
	    return expCardDateField
	case .cvc:
	    return cvcField
	case .cardNumber:
	    return cardNumberField
	default:
	    return nil
	}
    }

    /// When user press Done button on CardIO screen
    func userDidFinishScan() {
	scanController.dismissCardScanner(animated: true, completion: { [weak self] in
	    /// self?.sendData()
	})
    }
}

class FilePickerViewController: UIViewController, VGSFilePickerControllerDelegate {

  var vgsCollect = VGSCollect(id: "vailtId", environment: .sandbox)
  
  /// Create strong referrence of VGSFilePickerController
  var pickerController: VGSFilePickerController?

  override func viewDidLoad() {
      super.viewDidLoad()

      /// create picker configuration
      let filePickerConfig = VGSFilePickerConfiguration(collector: vgsCollect,
      							fieldName: "secret_doc",
						       fileSource: .photoLibrary)

      /// init picket controller with configuration
      pickerController = VGSFilePickerController(configuration: filePickerConfig)

      /// handle picker delegates
      pickerController?.delegate = self
  }

  /// Present picker controller
  func presentFilePicker() {
      pickerController?.presentFilePicker(on: self, animated: true, completion: nil)
  }
}
...

// ...  

// MARK: - VGSFilePickerControllerDelegate
/// Check file info, selected by user
func userDidPickFileWithInfo(_ info: VGSFileInfo) {
	let fileInfo = """
		    File info:
		    - fileExtension: \(info.fileExtension ?? "unknown")
		    - size: \(info.size)
		    - sizeUnits: \(info.sizeUnits ?? "unknown")
		    """
	print(fileInfo)
	pickerController?.dismissFilePicker(animated: true,
					  completion: { [weak self] in
					  
		self?.sendFile()
	})
}

// Handle cancel file selection
func userDidSCancelFilePicking() {
	pickerController?.dismissFilePicker(animated: true)
}

// Handle errors on picking the file
func filePickingFailedWithError(_ error: VGSError) {
	pickerController?.dismissFilePicker(animated: true)
}

// ...

// MARK: - Send File	
/// Send file and extra data
func sendFile() {

	/// add extra data to send request	
	let extraData = ["document_holder": "Joe B"]

  /// send file to your Vault
  vgsCollect.sendFile(path: "/post", extraData: extraData) { [weak self](response) in
    switch response {
      case .success(let code, let data, let response):
        /// remove file from VGSCollect storage
        self?.vgsCollect.cleanFiles()
      case .failure(let code, let data, let response, let error):
        // handle failed request
        switch code {
          // handle error codes
        }
    }
  }
}