Show OTP for scanned QR codes before saving

pass/Controllers/OTPScannerController.swift

@@ -0,0 +1,83 @@
+//
+//  QRScannerController.swift
+//  pass
+//
+//  Created by Yishi Lin on 10/4/17.
+//  Copyright © 2017 Yishi Lin. All rights reserved.
+//
+
+import UIKit
+import AVFoundation
+
+class OTPScannerController: QRScannerController {
+    
+    var tempPassword: Password?
+    var scannedOTP: String?
+    
+    // MARK: - AVCaptureMetadataOutputObjectsDelegate Methods
+    override func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [Any]!, from connection: AVCaptureConnection!) {
+        
+        if let metadataObj = metadataObjects.first as? AVMetadataMachineReadableCodeObject,
+            supportedCodeTypes.contains(metadataObj.type),
+            let barCodeObject = videoPreviewLayer?.transformedMetadataObject(for: metadataObj) {
+            
+            // draw a bounds on the found QR code
+            qrCodeFrameView?.frame = barCodeObject.bounds
+            
+            // check whether it is a valid result
+            if let scannedString = metadataObj.stringValue {
+                if let (accept, message) = delegate?.checkScannedOutput(line: scannedString) {
+                    if accept == true {
+                        captureSession?.stopRunning()
+                        scannedOTP = scannedString
+                        tempPassword = Password(name: "empty", plainText: scannedString)
+                        // set scannerOutput
+                        setupOneTimePasswordMessage()
+                    } else {
+                        scannerOutput.text = message
+                    }
+                } else {
+                    // no delegate, show the scanned result
+                    scannerOutput.text = scannedString
+                }
+            } else {
+                scannerOutput.text = "No string value"
+            }
+            
+        } else {
+            qrCodeFrameView?.frame = CGRect.zero
+            scannerOutput.text = "No QR code detected"
+        }
+    }
+    
+    private func setupOneTimePasswordMessage() {
+        if let password = tempPassword {
+            if password.otpType == .hotp {
+                // hotp, no need to refresh
+                let (title, content) = password.getOtpStrings()!
+                scannerOutput.text = "\(title):\(content)"
+            } else if password.otpType == .totp {
+                // totp, refresh
+                Timer.scheduledTimer(withTimeInterval: 1, repeats: true) {
+                    [weak weakSelf = self] timer in
+                    let (title, content) = password.getOtpStrings()!
+                    weakSelf?.scannerOutput.text = "\(title):\(content)"
+                }
+            }
+        }
+    }
+    
+    override func shouldPerformSegue(withIdentifier identifier: String, sender: Any?) -> Bool {
+        if identifier == "saveAddScannedOTPSegue" {
+            return tempPassword != nil
+        }
+        return true
+    }
+    
+//    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
+//        super.prepare(for: segue, sender: sender)
+//        if segue.identifier == "saveAddScannedOTPSegue" {
+//            delegate?.handleScannedOutput(line: scannedOTP)
+//        }
+//    }
+}