clearup yubikey reading on ios

src/App/Resources/AppResources.Designer.cs

@@ -1590,6 +1590,15 @@ namespace Bit.App.Resources {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Hold your Yubikey near the top of the device..
+        /// </summary>
+        public static string HoldYubikeyNearTop {
+            get {
+                return ResourceManager.GetString("HoldYubikeyNearTop", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Host.
         /// </summary>

src/App/Resources/AppResources.resx

@@ -1293,4 +1293,7 @@
     <value>Organization</value>
     <comment>An entity of multiple related people (ex. a team or business organization).</comment>
   </data>
+  <data name="HoldYubikeyNearTop" xml:space="preserve">
+    <value>Hold your Yubikey near the top of the device.</value>
+  </data>
 </root>

src/iOS/AppDelegate.cs

@@ -21,6 +21,7 @@ using FFImageLoading.Forms.Touch;
 using SimpleInjector;
 using XLabs.Ioc.SimpleInjectorContainer;
 using CoreNFC;
+using Bit.App.Resources;
 
 namespace Bit.iOS
 {
@@ -120,21 +121,26 @@ namespace Bit.iOS
 
                     if(listen)
                     {
-                        var del = new NFCReaderDelegate((success, message) =>
+                        _nfcSession?.InvalidateSession();
+                        _nfcSession?.Dispose();
+                        _nfcSession = null;
+                        _nfcSession = new NFCNdefReaderSession(new NFCReaderDelegate((success, message) =>
                         {
-                            Debug.WriteLine((success ? "SUCCESS! " : "ERROR! ") + message);
                             if(success)
                             {
-                                MessagingCenter.Send(Xamarin.Forms.Application.Current, "GotYubiKeyOTP", message);
+                                Device.BeginInvokeOnMainThread(() =>
+                                {
+                                    MessagingCenter.Send(Xamarin.Forms.Application.Current, "GotYubiKeyOTP", message);
+                                });
                             }
-                        });
+                        }), null, true);
-
+                        _nfcSession.AlertMessage = AppResources.HoldYubikeyNearTop;
-                        _nfcSession = new NFCNdefReaderSession(del, null, true);
                         _nfcSession.BeginSession();
                     }
                     else
                     {
                         _nfcSession?.InvalidateSession();
+                        _nfcSession?.Dispose();
                         _nfcSession = null;
                     }
                 });

src/iOS/NFCReaderDelegate.cs

@@ -34,12 +34,10 @@ namespace Bit.iOS
 
             foreach(var result in results)
             {
-                Debug.WriteLine("READ TAG: " + result);
                 var matches = _otpPattern.Matches(result);
                 if(matches.Count > 0 && matches[0].Groups.Count > 1)
                 {
                     var otp = matches[0].Groups[1].ToString();
-                    Debug.WriteLine("TAG IS MATCH: " + otp);
                     _callback.Invoke(true, otp);
                     return;
                 }