From b74b1659743d4fe1d3810b2e1ae1649a9c1558e8 Mon Sep 17 00:00:00 2001
From: dankito <git@dankito.net>
Date: Sat, 19 Feb 2022 15:15:23 +0100
Subject: [PATCH] Implemented that entered tan now can directly be set on
 TanChallenge, therefore no need of callback anymore

---
 .../banking/fints4k/android/FirstFragment.kt  |  15 +-
 .../banking/fints4k/android/Presenter.kt      |  13 +-
 .../fints4k/android/dialogs/EnterTanDialog.kt | 140 ++++++++++++++++++
 .../src/main/res/layout/dialog_enter_tan.xml  |  96 ++++++++++++
 .../AndroidApp/src/main/res/values/dimens.xml |   8 +
 .../src/main/res/values/strings.xml           |   6 +
 .../main/kotlin/AccountTransactionsView.kt    |  28 ++--
 .../WebApp/src/main/kotlin/EnterTanView.kt    |  69 +++++++++
 .../WebApp/src/main/kotlin/Presenter.kt       |  45 ++++++
 .../WebApp/src/main/kotlin/main.kt            |   4 +-
 .../fints4k iOS.xcodeproj/project.pbxproj     |   4 +
 .../fints4k iOS/fints4k iOS/ContentView.swift |   2 +-
 .../fints4k iOS/fints4k iOS/Presenter.swift   |  14 +-
 .../fints4k iOS/fints4k_iOSApp.swift          |  32 +++-
 .../service/UrlSessionWebClient.swift         |   4 +-
 .../fints4k iOS/ui/EnterTanDialog.swift       | 118 +++++++++++++++
 .../dankito/banking/fints/FinTsJobExecutor.kt |  32 ++--
 .../fints/callback/FinTsClientCallback.kt     |   2 +-
 .../fints/callback/NoOpFinTsClientCallback.kt |   4 +-
 .../callback/SimpleFinTsClientCallback.kt     |   8 +-
 .../banking/fints/model/EnterTanResult.kt     |  22 +--
 .../banking/fints/model/TanChallenge.kt       |  27 ++++
 .../dankito/banking/fints/model/TanMethod.kt  |   4 +
 .../banking/fints/webclient/IWebClient.kt     |   4 -
 .../fints/extensions/TanImageExtensions.kt    |  11 ++
 .../dankito/banking/fints/iOSFinTsClient.kt   |  30 ++++
 fints4k/src/nativeMain/kotlin/Application.kt  |  20 ++-
 .../extensions/ByteArrayExtensions.kt         |  12 ++
 28 files changed, 701 insertions(+), 73 deletions(-)
 create mode 100644 SampleApplications/AndroidApp/src/main/java/net/codinux/banking/fints4k/android/dialogs/EnterTanDialog.kt
 create mode 100644 SampleApplications/AndroidApp/src/main/res/layout/dialog_enter_tan.xml
 create mode 100644 SampleApplications/WebApp/src/main/kotlin/EnterTanView.kt
 create mode 100644 SampleApplications/WebApp/src/main/kotlin/Presenter.kt
 create mode 100644 SampleApplications/iOSApp/fints4k iOS/fints4k iOS/ui/EnterTanDialog.swift
 create mode 100644 fints4k/src/iosMain/kotlin/net/dankito/banking/fints/extensions/TanImageExtensions.kt
 create mode 100644 fints4k/src/iosMain/kotlin/net/dankito/banking/fints/iOSFinTsClient.kt
 create mode 100644 multiplatform-utils/src/iosMain/kotlin/net/dankito/utils/multiplatform/extensions/ByteArrayExtensions.kt

diff --git a/SampleApplications/AndroidApp/src/main/java/net/codinux/banking/fints4k/android/FirstFragment.kt b/SampleApplications/AndroidApp/src/main/java/net/codinux/banking/fints4k/android/FirstFragment.kt
index fe69e139..c8232c2e 100644
--- a/SampleApplications/AndroidApp/src/main/java/net/codinux/banking/fints4k/android/FirstFragment.kt
+++ b/SampleApplications/AndroidApp/src/main/java/net/codinux/banking/fints4k/android/FirstFragment.kt
@@ -10,6 +10,7 @@ import androidx.recyclerview.widget.DividerItemDecoration
 import androidx.recyclerview.widget.LinearLayoutManager
 import net.codinux.banking.fints4k.android.adapter.AccountTransactionsListRecyclerAdapter
 import net.codinux.banking.fints4k.android.databinding.FragmentFirstBinding
+import net.codinux.banking.fints4k.android.dialogs.EnterTanDialog
 
 /**
  * A simple [Fragment] subclass as the default destination in the navigation.
@@ -24,14 +25,10 @@ class FirstFragment : Fragment() {
     // onDestroyView.
     private val binding get() = _binding!!
 
-    override fun onCreateView(
-        inflater: LayoutInflater, container: ViewGroup?,
-        savedInstanceState: Bundle?
-    ): View? {
 
+    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
         _binding = FragmentFirstBinding.inflate(inflater, container, false)
         return binding.root
-
     }
 
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
@@ -43,8 +40,14 @@ class FirstFragment : Fragment() {
             adapter = accountTransactionsAdapter
         }
 
+        val presenter = Presenter() // TODO: inject
+
+        presenter.enterTanCallback = { tanChallenge ->
+            EnterTanDialog().show(tanChallenge, activity!!)
+        }
+
         // TODO: set your credentials here
-        Presenter().retrieveAccountData("", "", "", "") { response ->
+        presenter.retrieveAccountData("", "", "", "") { response ->
             if (response.successful) {
                 accountTransactionsAdapter.items = response.retrievedData.flatMap { it.bookedTransactions }
             }
diff --git a/SampleApplications/AndroidApp/src/main/java/net/codinux/banking/fints4k/android/Presenter.kt b/SampleApplications/AndroidApp/src/main/java/net/codinux/banking/fints4k/android/Presenter.kt
index 6b70dc43..3b39b8fa 100644
--- a/SampleApplications/AndroidApp/src/main/java/net/codinux/banking/fints4k/android/Presenter.kt
+++ b/SampleApplications/AndroidApp/src/main/java/net/codinux/banking/fints4k/android/Presenter.kt
@@ -8,6 +8,7 @@ import kotlinx.datetime.LocalDate
 import net.dankito.banking.fints.FinTsClientDeprecated
 import net.dankito.banking.fints.callback.SimpleFinTsClientCallback
 import net.dankito.banking.fints.model.AddAccountParameter
+import net.dankito.banking.fints.model.TanChallenge
 import net.dankito.banking.fints.response.client.AddAccountResponse
 import net.dankito.utils.multiplatform.extensions.millisSinceEpochAtSystemDefaultTimeZone
 import org.slf4j.LoggerFactory
@@ -15,7 +16,7 @@ import java.math.BigDecimal
 import java.text.DateFormat
 import java.util.*
 
-class Presenter {
+open class Presenter {
 
     companion object {
         val ValueDateFormat = DateFormat.getDateInstance(DateFormat.SHORT)
@@ -23,11 +24,17 @@ class Presenter {
         private val log = LoggerFactory.getLogger(Presenter::class.java)
     }
 
-    private val fintsClient = FinTsClientDeprecated(SimpleFinTsClientCallback())
+    private val fintsClient = FinTsClientDeprecated(SimpleFinTsClientCallback { challenge -> enterTan(challenge) })
+
+    open var enterTanCallback: ((TanChallenge) -> Unit)? = null
+
+    open protected fun enterTan(tanChallenge: TanChallenge) {
+        enterTanCallback?.invoke(tanChallenge) ?: run { tanChallenge.userDidNotEnterTan() }
+    }
 
 
 
-    fun retrieveAccountData(bankCode: String, customerId: String, pin: String, finTs3ServerAddress: String, retrievedResult: (AddAccountResponse) -> Unit) {
+    open fun retrieveAccountData(bankCode: String, customerId: String, pin: String, finTs3ServerAddress: String, retrievedResult: (AddAccountResponse) -> Unit) {
         GlobalScope.launch(Dispatchers.IO) {
             val response = fintsClient.addAccountAsync(AddAccountParameter(bankCode, customerId, pin, finTs3ServerAddress))
             log.info("Retrieved response from ${response.bank.bankName} for ${response.bank.customerName}")
diff --git a/SampleApplications/AndroidApp/src/main/java/net/codinux/banking/fints4k/android/dialogs/EnterTanDialog.kt b/SampleApplications/AndroidApp/src/main/java/net/codinux/banking/fints4k/android/dialogs/EnterTanDialog.kt
new file mode 100644
index 00000000..4140c342
--- /dev/null
+++ b/SampleApplications/AndroidApp/src/main/java/net/codinux/banking/fints4k/android/dialogs/EnterTanDialog.kt
@@ -0,0 +1,140 @@
+package net.codinux.banking.fints4k.android.dialogs
+
+import android.graphics.BitmapFactory
+import android.os.Bundle
+import android.os.Handler
+import android.text.InputFilter
+import android.text.InputType
+import android.view.KeyEvent
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.*
+import androidx.appcompat.app.AlertDialog
+import androidx.fragment.app.DialogFragment
+import androidx.fragment.app.FragmentActivity
+import net.codinux.banking.fints4k.android.Presenter
+import net.codinux.banking.fints4k.android.R
+import net.dankito.banking.fints.model.FlickerCodeTanChallenge
+import net.dankito.banking.fints.model.ImageTanChallenge
+import net.dankito.banking.fints.model.TanChallenge
+import net.dankito.utils.android.extensions.getSpannedFromHtml
+import net.dankito.utils.android.extensions.show
+
+
+open class EnterTanDialog : DialogFragment() {
+
+    companion object {
+        const val DialogTag = "EnterTanDialog"
+    }
+
+
+    protected lateinit var tanChallenge: TanChallenge
+
+
+    open fun show(tanChallenge: TanChallenge, activity: FragmentActivity) {
+        this.tanChallenge = tanChallenge
+
+        setStyle(STYLE_NORMAL, R.style.FullscreenDialogWithStatusBar)
+
+        show(activity.supportFragmentManager, DialogTag)
+    }
+
+
+    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
+        val rootView = inflater.inflate(R.layout.dialog_enter_tan, container, false)
+
+        setupUI(rootView)
+
+        return rootView
+    }
+
+    protected open fun setupUI(rootView: View) {
+        setupTanView(rootView)
+
+        setupEnteringTan(rootView)
+
+        rootView.findViewById<TextView>(R.id.txtvwMessageToShowToUser).text = tanChallenge.messageToShowToUser.getSpannedFromHtml()
+
+        rootView.findViewById<Button>(R.id.btnCancel).setOnClickListener { enteringTanDone(null) }
+
+        rootView.findViewById<Button>(R.id.btnEnteringTanDone).setOnClickListener {
+            enteringTanDone(rootView.findViewById<EditText>(R.id.edtxtEnteredTan).text.toString())
+        }
+    }
+
+    protected open fun setupTanView(rootView: View) {
+        if (tanChallenge is FlickerCodeTanChallenge) {
+//            setupFlickerCodeTanView(rootView)
+        }
+        else if (tanChallenge is ImageTanChallenge) {
+            setupImageTanView(rootView)
+        }
+    }
+
+    protected open fun setupEnteringTan(rootView: View) {
+        val edtxtEnteredTan = rootView.findViewById<EditText>(R.id.edtxtEnteredTan)
+
+        if (tanChallenge.tanMethod.isNumericTan) {
+            edtxtEnteredTan.inputType = InputType.TYPE_CLASS_NUMBER
+        }
+
+        tanChallenge.tanMethod.maxTanInputLength?.let { maxInputLength ->
+            edtxtEnteredTan.filters = arrayOf<InputFilter>(InputFilter.LengthFilter(maxInputLength))
+        }
+
+        edtxtEnteredTan.setOnKeyListener { _, keyCode, _ ->
+            if (keyCode == KeyEvent.KEYCODE_ENTER) {
+                enteringTanDone(edtxtEnteredTan.text.toString())
+                return@setOnKeyListener true
+            }
+            false
+        }
+    }
+
+    protected open fun setupImageTanView(rootView: View) {
+        val tanImageView = rootView.findViewById<ImageView>(R.id.tanImageView)
+        tanImageView.show()
+
+        val decodedImage = (tanChallenge as ImageTanChallenge).image
+        if (decodedImage.decodingSuccessful) {
+            val bitmap = BitmapFactory.decodeByteArray(decodedImage.imageBytes, 0, decodedImage.imageBytes.size)
+            tanImageView.setImageBitmap(bitmap)
+        }
+        else {
+            showDecodingTanChallengeFailedErrorDelayed(decodedImage.decodingError)
+        }
+    }
+
+
+    /**
+     * This method gets called right on start up before dialog is shown -> Alert would get displayed before dialog and
+     * therefore covered by dialog -> delay displaying alert.
+     */
+    protected open fun showDecodingTanChallengeFailedErrorDelayed(error: Exception?) {
+        val handler = Handler()
+
+        handler.postDelayed({ showDecodingTanChallengeFailedError(error) }, 500)
+    }
+
+    protected open fun showDecodingTanChallengeFailedError(error: Exception?) {
+        activity?.let { context ->
+            AlertDialog.Builder(context)
+                .setMessage(context.getString(R.string.dialog_enter_tan_error_could_not_decode_tan_image, error?.localizedMessage))
+                .setPositiveButton(android.R.string.ok) { dialog, _ -> dialog.dismiss() }
+                .show()
+        }
+    }
+
+
+    protected open fun enteringTanDone(enteredTan: String?) {
+        if (enteredTan != null) {
+            tanChallenge.userEnteredTan(enteredTan)
+        } else {
+            tanChallenge.userDidNotEnterTan()
+        }
+
+        dismiss()
+    }
+
+}
\ No newline at end of file
diff --git a/SampleApplications/AndroidApp/src/main/res/layout/dialog_enter_tan.xml b/SampleApplications/AndroidApp/src/main/res/layout/dialog_enter_tan.xml
new file mode 100644
index 00000000..4b94682a
--- /dev/null
+++ b/SampleApplications/AndroidApp/src/main/res/layout/dialog_enter_tan.xml
@@ -0,0 +1,96 @@
+<?xml version="1.0" encoding="utf-8"?>
+<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
+            android:layout_width="match_parent"
+            android:layout_height="match_parent"
+            android:padding="@dimen/dialog_enter_tan_padding"
+            android:isScrollContainer="true"
+>
+
+    <LinearLayout
+            android:orientation="vertical"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+    >
+
+        <ImageView
+                android:id="@+id/tanImageView"
+                android:layout_width="match_parent"
+                android:layout_height="350dp"
+                android:layout_gravity="center"
+                android:gravity="center_vertical"
+                android:layout_marginBottom="@dimen/dialog_enter_tan_margin_before_enter_tan"
+                android:visibility="gone"
+        />
+
+
+        <TextView
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:text="@string/dialog_enter_tan_tan_description_label"
+            />
+
+        <TextView
+            android:id="@+id/txtvwMessageToShowToUser"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content">
+
+        </TextView>
+
+        <LinearLayout
+                android:orientation="horizontal"
+                android:layout_width="match_parent"
+                android:layout_height="@dimen/dialog_enter_tan_enter_tan_height"
+                android:layout_marginBottom="@dimen/dialog_enter_tan_enter_tan_margin_bottom"
+        >
+
+            <TextView
+                    android:layout_width="wrap_content"
+                    android:layout_height="match_parent"
+                    android:layout_gravity="center_vertical"
+                    android:gravity="center_vertical"
+                    android:textStyle="bold"
+                    android:text="@string/dialog_enter_tan_enter_tan"
+            />
+
+            <EditText
+                    android:id="@+id/edtxtEnteredTan"
+                    android:layout_width="@dimen/dialog_enter_tan_enter_tan_width"
+                    android:layout_height="match_parent"
+                    android:layout_marginLeft="@dimen/dialog_enter_tan_enter_tan_margin_left"
+                    android:layout_marginStart="@dimen/dialog_enter_tan_enter_tan_margin_left"
+            />
+
+        </LinearLayout>
+
+
+        <RelativeLayout
+                android:id="@+id/lytButtonBar"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+        >
+
+            <Button
+                    android:id="@+id/btnEnteringTanDone"
+                    android:layout_width="@dimen/dialog_enter_tan_buttons_width"
+                    android:layout_height="wrap_content"
+                    android:layout_alignParentRight="true"
+                    android:layout_alignParentEnd="true"
+                    style="?android:attr/buttonBarButtonStyle"
+                    android:text="@android:string/ok"
+            />
+
+            <Button
+                    android:id="@+id/btnCancel"
+                    android:layout_width="@dimen/dialog_enter_tan_buttons_width"
+                    android:layout_height="wrap_content"
+                    android:layout_toLeftOf="@+id/btnEnteringTanDone"
+                    android:layout_toStartOf="@+id/btnEnteringTanDone"
+                    style="?android:attr/buttonBarButtonStyle"
+                    android:text="@android:string/cancel"
+            />
+
+        </RelativeLayout>
+
+    </LinearLayout>
+
+</ScrollView>
\ No newline at end of file
diff --git a/SampleApplications/AndroidApp/src/main/res/values/dimens.xml b/SampleApplications/AndroidApp/src/main/res/values/dimens.xml
index 96fb1e6c..d15ed121 100644
--- a/SampleApplications/AndroidApp/src/main/res/values/dimens.xml
+++ b/SampleApplications/AndroidApp/src/main/res/values/dimens.xml
@@ -15,4 +15,12 @@
     <dimen name="list_item_account_transaction_transaction_text_margin_left_and_right">4dp</dimen>
     <dimen name="list_item_account_transaction_other_party_name_margin_top_and_bottom">6dp</dimen>
 
+    <dimen name="dialog_enter_tan_padding">4dp</dimen>
+    <dimen name="dialog_enter_tan_margin_before_enter_tan">6dp</dimen>
+    <dimen name="dialog_enter_tan_enter_tan_height">50dp</dimen>
+    <dimen name="dialog_enter_tan_enter_tan_width">150dp</dimen>
+    <dimen name="dialog_enter_tan_enter_tan_margin_left">6dp</dimen>
+    <dimen name="dialog_enter_tan_enter_tan_margin_bottom">8dp</dimen>
+    <dimen name="dialog_enter_tan_buttons_width">120dp</dimen>
+
 </resources>
\ No newline at end of file
diff --git a/SampleApplications/AndroidApp/src/main/res/values/strings.xml b/SampleApplications/AndroidApp/src/main/res/values/strings.xml
index 43e62b1f..a42c6772 100644
--- a/SampleApplications/AndroidApp/src/main/res/values/strings.xml
+++ b/SampleApplications/AndroidApp/src/main/res/values/strings.xml
@@ -9,4 +9,10 @@
 
     <string name="hello_first_fragment">Hello first fragment</string>
     <string name="hello_second_fragment">Hello second fragment. Arg: %1$s</string>
+
+
+    <string name="dialog_enter_tan_tan_description_label">Hint from your bank:</string>
+    <string name="dialog_enter_tan_enter_tan">Enter TAN:</string>
+    <string name="dialog_enter_tan_error_could_not_decode_tan_image">Could not decode flicker code or QR code / PhotoTan. Most likely an internal error:\n%s.</string>
+
 </resources>
\ No newline at end of file
diff --git a/SampleApplications/WebApp/src/main/kotlin/AccountTransactionsView.kt b/SampleApplications/WebApp/src/main/kotlin/AccountTransactionsView.kt
index fe2e8f05..1a6807ca 100644
--- a/SampleApplications/WebApp/src/main/kotlin/AccountTransactionsView.kt
+++ b/SampleApplications/WebApp/src/main/kotlin/AccountTransactionsView.kt
@@ -1,8 +1,6 @@
 import kotlinx.coroutines.GlobalScope
 import kotlinx.coroutines.launch
-import net.dankito.banking.fints.FinTsClientDeprecated
-import net.dankito.banking.fints.model.AccountTransaction
-import net.dankito.banking.fints.model.AddAccountParameter
+import net.dankito.banking.fints.model.*
 import react.RBuilder
 import react.RComponent
 import react.Props
@@ -11,10 +9,10 @@ import react.dom.*
 import styled.styledDiv
 
 external interface AccountTransactionsViewProps : Props {
-  var client: FinTsClientDeprecated
+  var presenter: Presenter
 }
 
-data class AccountTransactionsViewState(val balance: String, val transactions: Collection<AccountTransaction>) : State
+data class AccountTransactionsViewState(val balance: String, val transactions: Collection<AccountTransaction>, val enterTanChallenge: TanChallenge? = null) : State
 
 @JsExport
 class AccountTransactionsView(props: AccountTransactionsViewProps) : RComponent<AccountTransactionsViewProps, AccountTransactionsViewState>(props) {
@@ -23,19 +21,31 @@ class AccountTransactionsView(props: AccountTransactionsViewProps) : RComponent<
   init {
     state = AccountTransactionsViewState("", listOf())
 
+    props.presenter.enterTanCallback = { setState(AccountTransactionsViewState(state.balance, state.transactions, it)) }
+
     // due to CORS your bank's servers can not be requested directly from browser -> set a CORS proxy url in main.kt
     // TODO: set your credentials here
     GlobalScope.launch {
-      val response = props.client.addAccountAsync(AddAccountParameter("", "", "", ""))
-      if (response.successful) {
-        val balance = response.retrievedData.sumOf { it.balance?.amount?.string?.replace(',', '.')?.toDoubleOrNull() ?: 0.0 } // i know, double is not an appropriate data type for amounts
+      props.presenter.retrieveAccountData("", "", "", "") { response ->
+        if (response.successful) {
+          val balance = response.retrievedData.sumOf { it.balance?.amount?.string?.replace(',', '.')?.toDoubleOrNull() ?: 0.0 } // i know, double is not an appropriate data type for amounts
 
-        setState(AccountTransactionsViewState(balance.toString() + " " + (response.retrievedData.firstOrNull()?.balance?.currency ?: ""), response.retrievedData.flatMap { it.bookedTransactions }))
+          setState(AccountTransactionsViewState(balance.toString() + " " + (response.retrievedData.firstOrNull()?.balance?.currency ?: ""), response.retrievedData.flatMap { it.bookedTransactions }, state.enterTanChallenge))
+        }
       }
     }
   }
 
   override fun RBuilder.render() {
+    state.enterTanChallenge?.let { challenge ->
+      child(EnterTanView::class) {
+        attrs {
+          presenter = props.presenter
+          tanChallenge = challenge
+        }
+      }
+    }
+
     p {
       +"Saldo: ${state.balance}"
     }
diff --git a/SampleApplications/WebApp/src/main/kotlin/EnterTanView.kt b/SampleApplications/WebApp/src/main/kotlin/EnterTanView.kt
new file mode 100644
index 00000000..29e939a4
--- /dev/null
+++ b/SampleApplications/WebApp/src/main/kotlin/EnterTanView.kt
@@ -0,0 +1,69 @@
+import io.ktor.util.encodeBase64
+import kotlinx.html.InputType
+import kotlinx.html.js.onChangeFunction
+import kotlinx.html.style
+import net.dankito.banking.fints.model.ImageTanChallenge
+import net.dankito.banking.fints.model.TanChallenge
+import org.w3c.dom.HTMLInputElement
+import react.Props
+import react.RBuilder
+import react.RComponent
+import react.State
+import react.dom.*
+
+external interface EnterTanViewProps : Props {
+  var presenter: Presenter
+  var tanChallenge: TanChallenge
+}
+
+data class EnterTanViewState(val enteredTan: String? = null) : State
+
+@JsExport
+class EnterTanView(props: EnterTanViewProps) : RComponent<EnterTanViewProps, EnterTanViewState>(props) {
+
+  override fun RBuilder.render() {
+    p {
+      +"Enter TAN:"
+    }
+
+    if (props.tanChallenge is ImageTanChallenge) {
+      val tanImage = (props.tanChallenge as ImageTanChallenge).image
+      if (tanImage.decodingSuccessful) {
+        val base64Encoded = tanImage.imageBytes.encodeBase64()
+
+        img(src = "data:${tanImage.mimeType};base64, $base64Encoded") { }
+      }
+    }
+
+    p {
+      props.tanChallenge.messageToShowToUser
+    }
+
+    div {
+      span { +"TAN:" }
+
+      input {
+        attrs {
+          type = InputType.text
+          onChangeFunction = { event ->
+            val enteredTan = (event.target as HTMLInputElement).value
+
+            setState(EnterTanViewState(enteredTan))
+          }
+        }
+      }
+
+      button {
+        span { +"Done" }
+        attrs {
+          onMouseUp = {
+            state.enteredTan?.let {
+              props.tanChallenge.userEnteredTan(it)
+            } ?: run { props.tanChallenge.userDidNotEnterTan() }
+          }
+        }
+      }
+    }
+  }
+
+}
\ No newline at end of file
diff --git a/SampleApplications/WebApp/src/main/kotlin/Presenter.kt b/SampleApplications/WebApp/src/main/kotlin/Presenter.kt
new file mode 100644
index 00000000..c2ca5974
--- /dev/null
+++ b/SampleApplications/WebApp/src/main/kotlin/Presenter.kt
@@ -0,0 +1,45 @@
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.GlobalScope
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import net.dankito.banking.fints.FinTsClientDeprecated
+import net.dankito.banking.fints.callback.SimpleFinTsClientCallback
+import net.dankito.banking.fints.model.AddAccountParameter
+import net.dankito.banking.fints.model.TanChallenge
+import net.dankito.banking.fints.response.client.AddAccountResponse
+import net.dankito.banking.fints.webclient.KtorWebClient
+import net.dankito.banking.fints.webclient.ProxyingWebClient
+import net.dankito.utils.multiplatform.log.LoggerFactory
+
+open class Presenter {
+
+  companion object {
+    private val log = LoggerFactory.getLogger(Presenter::class)
+  }
+
+
+  // to circumvent CORS we have to use a CORS proxy like the SampleApplications.CorsProxy Application.kt or
+  // https://github.com/Rob--W/cors-anywhere. Set CORS proxy's URL here
+  protected open val fintsClient = FinTsClientDeprecated(SimpleFinTsClientCallback { challenge -> enterTan(challenge) },
+    ProxyingWebClient("http://localhost:8082/", KtorWebClient()))
+
+  open var enterTanCallback: ((TanChallenge) -> Unit)? = null
+
+  open protected fun enterTan(tanChallenge: TanChallenge) {
+    enterTanCallback?.invoke(tanChallenge) ?: run { tanChallenge.userDidNotEnterTan() }
+  }
+
+
+  open fun retrieveAccountData(bankCode: String, customerId: String, pin: String, finTs3ServerAddress: String, retrievedResult: (AddAccountResponse) -> Unit) {
+    GlobalScope.launch(Dispatchers.Unconfined) {
+      val response = fintsClient.addAccountAsync(AddAccountParameter(bankCode, customerId, pin, finTs3ServerAddress))
+
+      log.info("Retrieved response from ${response.bank.bankName} for ${response.bank.customerName}")
+
+      withContext(Dispatchers.Main) {
+        retrievedResult(response)
+      }
+    }
+  }
+
+}
\ No newline at end of file
diff --git a/SampleApplications/WebApp/src/main/kotlin/main.kt b/SampleApplications/WebApp/src/main/kotlin/main.kt
index ff6d55db..5bde6fd2 100644
--- a/SampleApplications/WebApp/src/main/kotlin/main.kt
+++ b/SampleApplications/WebApp/src/main/kotlin/main.kt
@@ -11,9 +11,7 @@ fun main() {
         render(document.getElementById("root")!!) {
             child(AccountTransactionsView::class) {
                 attrs {
-                    // to circumvent CORS we have to use a CORS proxy like the SampleApplications.CorsProxy Application.kt or
-                    // https://github.com/Rob--W/cors-anywhere. Set CORS proxy's URL here
-                    client = FinTsClientDeprecated(SimpleFinTsClientCallback(), ProxyingWebClient("http://localhost:8082/", KtorWebClient()))
+                    presenter = Presenter()
                 }
             }
         }
diff --git a/SampleApplications/iOSApp/fints4k iOS/fints4k iOS.xcodeproj/project.pbxproj b/SampleApplications/iOSApp/fints4k iOS/fints4k iOS.xcodeproj/project.pbxproj
index c5d33e55..54704ab8 100644
--- a/SampleApplications/iOSApp/fints4k iOS/fints4k iOS.xcodeproj/project.pbxproj	
+++ b/SampleApplications/iOSApp/fints4k iOS/fints4k iOS.xcodeproj/project.pbxproj	
@@ -14,6 +14,7 @@
 		36266AE427BC7776008F3B00 /* Presenter.swift in Sources */ = {isa = PBXBuildFile; fileRef = 36266AE327BC7776008F3B00 /* Presenter.swift */; };
 		36266AE727BC7801008F3B00 /* ViewExtensions.swift in Sources */ = {isa = PBXBuildFile; fileRef = 36266AE627BC7801008F3B00 /* ViewExtensions.swift */; };
 		36266AEA27BC85D8008F3B00 /* UrlSessionWebClient.swift in Sources */ = {isa = PBXBuildFile; fileRef = 36266AE927BC85D8008F3B00 /* UrlSessionWebClient.swift */; };
+		36266AEC27C19146008F3B00 /* EnterTanDialog.swift in Sources */ = {isa = PBXBuildFile; fileRef = 36266AEB27C19146008F3B00 /* EnterTanDialog.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXFileReference section */
@@ -25,6 +26,7 @@
 		36266AE327BC7776008F3B00 /* Presenter.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Presenter.swift; sourceTree = "<group>"; };
 		36266AE627BC7801008F3B00 /* ViewExtensions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ViewExtensions.swift; sourceTree = "<group>"; };
 		36266AE927BC85D8008F3B00 /* UrlSessionWebClient.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = UrlSessionWebClient.swift; sourceTree = "<group>"; };
+		36266AEB27C19146008F3B00 /* EnterTanDialog.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = EnterTanDialog.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -80,6 +82,7 @@
 			isa = PBXGroup;
 			children = (
 				36266AE627BC7801008F3B00 /* ViewExtensions.swift */,
+				36266AEB27C19146008F3B00 /* EnterTanDialog.swift */,
 			);
 			path = ui;
 			sourceTree = "<group>";
@@ -183,6 +186,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				36266AEC27C19146008F3B00 /* EnterTanDialog.swift in Sources */,
 				36266AE427BC7776008F3B00 /* Presenter.swift in Sources */,
 				36266AD727BC6F72008F3B00 /* ContentView.swift in Sources */,
 				36266AEA27BC85D8008F3B00 /* UrlSessionWebClient.swift in Sources */,
diff --git a/SampleApplications/iOSApp/fints4k iOS/fints4k iOS/ContentView.swift b/SampleApplications/iOSApp/fints4k iOS/fints4k iOS/ContentView.swift
index 7d31bcf6..243c89a2 100644
--- a/SampleApplications/iOSApp/fints4k iOS/fints4k iOS/ContentView.swift	
+++ b/SampleApplications/iOSApp/fints4k iOS/fints4k iOS/ContentView.swift	
@@ -6,7 +6,7 @@ struct ContentView: View {
     
     @State var transactions: [AccountTransaction] = []
     
-    private let presenter = Presenter()
+    @EnvironmentObject private var presenter: Presenter
     
     
     var body: some View {
diff --git a/SampleApplications/iOSApp/fints4k iOS/fints4k iOS/Presenter.swift b/SampleApplications/iOSApp/fints4k iOS/fints4k iOS/Presenter.swift
index 4ed7d140..6948c644 100644
--- a/SampleApplications/iOSApp/fints4k iOS/fints4k iOS/Presenter.swift	
+++ b/SampleApplications/iOSApp/fints4k iOS/fints4k iOS/Presenter.swift	
@@ -1,13 +1,23 @@
 import SwiftUI
 import fints4k
 
-class Presenter {
+class Presenter : ObservableObject {
     
-    private let fintsClient = FinTsClientDeprecated(callback: SimpleFinTsClientCallback(), webClient: UrlSessionWebClient())
+//    var enterTanCallback: ((TanChallenge) -> Void)? = nil
+    
+    // Swift, you're so stupid! It seems to be impossible to initialize SimpleFinTsClientCallback here so that enterTanCallback gets called if set
+    private var fintsClient = iOSFinTsClient(callback: SimpleFinTsClientCallback(), webClient: UrlSessionWebClient())
     
     private let formatter = DateFormatter()
     
     
+    func setEnterTanCallback(enterTanCallback: @escaping (TanChallenge) -> Void) {
+        self.fintsClient.callback = SimpleFinTsClientCallback( enterTan: { tanChallenge in
+            enterTanCallback(tanChallenge)
+        })
+    }
+    
+    
     func retrieveTransactions(_ bankCode: String, _ customerId: String, _ pin: String, _ finTs3ServerAddress: String, _ callback: @escaping (AddAccountResponse) -> Void) {
         self.fintsClient.addAccountAsync(parameter: AddAccountParameter(bankCode: bankCode, customerId: customerId, pin: pin, finTs3ServerAddress: finTs3ServerAddress), callback: callback)
     }
diff --git a/SampleApplications/iOSApp/fints4k iOS/fints4k iOS/fints4k_iOSApp.swift b/SampleApplications/iOSApp/fints4k iOS/fints4k iOS/fints4k_iOSApp.swift
index df46a69c..7c1050c8 100644
--- a/SampleApplications/iOSApp/fints4k iOS/fints4k iOS/fints4k_iOSApp.swift	
+++ b/SampleApplications/iOSApp/fints4k iOS/fints4k iOS/fints4k_iOSApp.swift	
@@ -1,11 +1,41 @@
 
 import SwiftUI
+import fints4k
 
 @main
 struct fints4k_iOSApp: App {
+    
+    @StateObject var presenter = Presenter()
+    
+    @State private var isShowingEnterTanDialog = false
+    
+    // init with a default value
+    @State private var tanChallenge = TanChallenge(messageToShowToUser: "", challenge: "", tanMethod: TanMethod(displayName: "", securityFunction: .pinTan900, type: .entertan, hhdVersion: .hhd13, maxTanInputLength: 6, allowedTanFormat: .numeric, nameOfTanMediumRequired: false, decoupledParameters: nil), tanMediaIdentifier: nil)
+    
+    
     var body: some Scene {
         WindowGroup {
-            ContentView()
+            NavigationView {
+                VStack {
+                    NavigationLink(destination: EnterTanDialog(tanChallenge), isActive: $isShowingEnterTanDialog) { EmptyView() }
+                    
+                    ContentView()
+                        .onAppear {
+                            self.initApp()
+                        }
+                        .environmentObject(presenter)
+                }
+                .navigationBarHidden(true)
+            }
         }
     }
+    
+    func initApp() {
+        self.presenter.setEnterTanCallback { tanChallenge in
+            self.tanChallenge = tanChallenge
+            
+            self.isShowingEnterTanDialog = true
+        }
+    }
+    
 }
diff --git a/SampleApplications/iOSApp/fints4k iOS/fints4k iOS/service/UrlSessionWebClient.swift b/SampleApplications/iOSApp/fints4k iOS/fints4k iOS/service/UrlSessionWebClient.swift
index 21a4132b..9582bc0d 100644
--- a/SampleApplications/iOSApp/fints4k iOS/fints4k iOS/service/UrlSessionWebClient.swift	
+++ b/SampleApplications/iOSApp/fints4k iOS/fints4k iOS/service/UrlSessionWebClient.swift	
@@ -3,10 +3,10 @@ import fints4k
 
 class UrlSessionWebClient : IWebClient {
     
-    func post(url: String, body: String, contentType: String, userAgent: String, callback: @escaping (WebClientResponse) -> Void) {
+    func post(url: String, body: String, contentType: String, userAgent: String, completionHandler: @escaping (WebClientResponse?, Error?) -> Void) {
         let request = requestFor(url, "POST", body)
         
-        executeRequestAsync(request, callback)
+        executeRequestAsync(request) { response in completionHandler(response, nil) }
     }
     
     func getAsync(_ url: String, callback: @escaping (WebClientResponse) -> Void) {
diff --git a/SampleApplications/iOSApp/fints4k iOS/fints4k iOS/ui/EnterTanDialog.swift b/SampleApplications/iOSApp/fints4k iOS/fints4k iOS/ui/EnterTanDialog.swift
new file mode 100644
index 00000000..ae14961b
--- /dev/null
+++ b/SampleApplications/iOSApp/fints4k iOS/fints4k iOS/ui/EnterTanDialog.swift	
@@ -0,0 +1,118 @@
+import SwiftUI
+import fints4k
+
+
+struct EnterTanDialog: View {
+    
+    @Environment(\.presentationMode) var presentation
+    
+    
+    private var tanChallenge: TanChallenge
+    
+    private let imageTanChallenge: ImageTanChallenge?
+    
+    private let messageToShowToUser: String
+    
+    @State private var enteredTan = ""
+
+    private var senteredTanBinding: Binding<String> {
+        Binding<String>(
+            get: { self.enteredTan },
+            set: {
+                self.enteredTan = $0
+        })
+    }
+    
+    
+    @EnvironmentObject private var presenter: Presenter
+    
+    
+    init(_ tanChallenge: TanChallenge) {
+        self.tanChallenge = tanChallenge
+        
+        self.imageTanChallenge = tanChallenge as? ImageTanChallenge
+        
+        self.messageToShowToUser = tanChallenge.messageToShowToUser//.htmlToString // parse in init() calling this method in body { } crashes application
+    }
+    
+    
+    var body: some View {
+        Form {
+            imageTanChallenge.map { imageTanChallenge in
+                Image(uiImage: UIImage(data: imageTanChallenge.image.imageBytesAsNSData())!)
+            }
+            
+            VStack {
+                HStack {
+                    Text("TAN hint from your bank:")
+                    Spacer()
+                }
+                
+                HStack {
+                    Text(messageToShowToUser)
+                        .multilineTextAlignment(.leading)
+                        .lineLimit(5) // hm, we doesn't it show more then three lines?
+                    
+                    Spacer()
+                }
+                .padding(.top, 6)
+            }
+            .padding(.vertical, 2)
+            
+            Section {
+                HStack(alignment: .center) {
+                    Text("Enter TAN:")
+
+                    Spacer()
+
+                    TextField("Enter the TAN here", text: self.$enteredTan)
+                        .keyboardType(tanChallenge.tanMethod.isNumericTan ? .numberPad : .default)
+                        .autocapitalization(.none)
+                }
+            }
+            
+            Section {
+                HStack {
+                    Spacer()
+                    Button(action: { self.enteringTanDone() },
+                           label: { Text("OK") })
+                        .disabled( !self.isRequiredDataEntered())
+                    Spacer()
+                }
+            }
+        }
+        .navigationTitle("Enter TAN")
+        .navigationBarTitleDisplayMode(.inline)
+    }
+    
+    
+    private func isRequiredDataEntered() -> Bool {
+        return self.enteredTan.isEmpty == false
+    }
+    
+    
+    private func enteringTanDone() {
+        if self.isRequiredDataEntered() {
+            self.tanChallenge.userEnteredTan(enteredTan: self.enteredTan)
+        } else {
+            self.tanChallenge.userDidNotEnterTan()
+        }
+        
+        // TODO: if a TAN has been entered, check result if user has made a mistake and has to re-enter TAN
+        dismissDialog()
+    }
+    
+    private func dismissDialog() {
+        presentation.wrappedValue.dismiss()
+    }
+
+}
+
+
+//struct EnterTanDialog_Previews: PreviewProvider {
+//
+//    static var previews: some View {
+//        EnterTanDialog()
+//    }
+//
+//}
diff --git a/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/FinTsJobExecutor.kt b/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/FinTsJobExecutor.kt
index 63ac8e5f..5f9b5742 100644
--- a/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/FinTsJobExecutor.kt
+++ b/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/FinTsJobExecutor.kt
@@ -1,5 +1,6 @@
 package net.dankito.banking.fints
 
+import kotlinx.coroutines.delay
 import kotlinx.datetime.LocalDate
 import net.dankito.banking.fints.messages.MessageBuilder
 import net.dankito.banking.fints.messages.MessageBuilderResult
@@ -17,7 +18,6 @@ import net.dankito.banking.fints.tan.FlickerCodeDecoder
 import net.dankito.banking.fints.tan.TanImageDecoder
 import net.dankito.banking.fints.util.TanMethodSelector
 import net.dankito.utils.multiplatform.log.LoggerFactory
-import net.dankito.utils.multiplatform.ObjectReference
 import net.dankito.utils.multiplatform.extensions.millisSinceEpochAtEuropeBerlin
 import net.dankito.utils.multiplatform.extensions.minusDays
 import net.dankito.utils.multiplatform.extensions.todayAtEuropeBerlin
@@ -376,17 +376,25 @@ open class FinTsJobExecutor(
 
     protected open suspend fun handleEnteringTanRequired(context: JobContext, tanResponse: TanResponse, response: BankResponse): BankResponse {
         val bank = context.bank // TODO: copy required data to TanChallenge
-        val tanChallenge = createTanChallenge(tanResponse, bank)
 
-        val userDidCancelEnteringTan = ObjectReference(false)
+        // on all platforms run on Dispatchers.Main, but on iOS skip this (or wrap in withContext(Dispatchers.IO) )
+//        val enteredTanResult = GlobalScope.async {
+            val tanChallenge = createTanChallenge(tanResponse, bank)
 
-        val enteredTanResult =  context.callback.enterTan(bank, tanChallenge)
-        userDidCancelEnteringTan.value = true
+            context.callback.enterTan(tanChallenge)
+
+            while (tanChallenge.enterTanResult == null) {
+                delay(250)
+
+                mayRetrieveAutomaticallyIfUserEnteredDecoupledTan(context, tanChallenge, tanResponse)
+
+                // TODO: add a timeout of e.g. 30 min
+            }
+
+        val enteredTanResult = tanChallenge.enterTanResult!!
+//        }
 
         return handleEnterTanResult(context, enteredTanResult, tanResponse, response)
-
-        // TODO:
-//        mayRetrieveAutomaticallyIfUserEnteredDecoupledTan(context, tanChallenge, tanResponse, userDidCancelEnteringTan)
     }
 
     protected open fun createTanChallenge(tanResponse: TanResponse, bank: BankData): TanChallenge {
@@ -409,17 +417,15 @@ open class FinTsJobExecutor(
         }
     }
 
-    protected open fun mayRetrieveAutomaticallyIfUserEnteredDecoupledTan(context: JobContext, tanChallenge: TanChallenge, tanResponse: TanResponse,
-                                                                         userDidCancelEnteringTan: ObjectReference<Boolean>
-    ) {
+    protected open fun mayRetrieveAutomaticallyIfUserEnteredDecoupledTan(context: JobContext, tanChallenge: TanChallenge, tanResponse: TanResponse) {
         context.bank.selectedTanMethod.decoupledParameters?.let { decoupledTanMethodParameters ->
             if (tanResponse.tanProcess == TanProcess.AppTan && decoupledTanMethodParameters.periodicStateRequestsAllowed) {
-                automaticallyRetrieveIfUserEnteredDecoupledTan(context, tanChallenge, userDidCancelEnteringTan)
+                automaticallyRetrieveIfUserEnteredDecoupledTan(context, tanChallenge)
             }
         }
     }
 
-    protected open fun automaticallyRetrieveIfUserEnteredDecoupledTan(context: JobContext, tanChallenge: TanChallenge, userDidCancelEnteringTan: ObjectReference<Boolean>) {
+    protected open fun automaticallyRetrieveIfUserEnteredDecoupledTan(context: JobContext, tanChallenge: TanChallenge) {
         log.info("automaticallyRetrieveIfUserEnteredDecoupledTan() called for $tanChallenge")
     }
 
diff --git a/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/callback/FinTsClientCallback.kt b/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/callback/FinTsClientCallback.kt
index d4e611e9..195fb8f0 100644
--- a/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/callback/FinTsClientCallback.kt
+++ b/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/callback/FinTsClientCallback.kt
@@ -18,7 +18,7 @@ interface FinTsClientCallback {
      */
     suspend fun askUserForTanMethod(supportedTanMethods: List<TanMethod>, suggestedTanMethod: TanMethod?): TanMethod?
 
-    suspend fun enterTan(bank: BankData, tanChallenge: TanChallenge): EnterTanResult
+    suspend fun enterTan(tanChallenge: TanChallenge)
 
     /**
      * This method gets called for chipTan TAN generators when the bank asks the customer to synchronize her/his TAN generator.
diff --git a/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/callback/NoOpFinTsClientCallback.kt b/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/callback/NoOpFinTsClientCallback.kt
index 7b0d8203..a1bb118a 100644
--- a/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/callback/NoOpFinTsClientCallback.kt
+++ b/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/callback/NoOpFinTsClientCallback.kt
@@ -10,8 +10,8 @@ open class NoOpFinTsClientCallback : FinTsClientCallback {
         return suggestedTanMethod
     }
 
-    override suspend fun enterTan(bank: BankData, tanChallenge: TanChallenge): EnterTanResult {
-        return EnterTanResult.userDidNotEnterTan()
+    override suspend fun enterTan(tanChallenge: TanChallenge) {
+        return tanChallenge.userDidNotEnterTan()
     }
 
     override suspend fun enterTanGeneratorAtc(bank: BankData, tanMedium: TanGeneratorTanMedium): EnterTanGeneratorAtcResult {
diff --git a/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/callback/SimpleFinTsClientCallback.kt b/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/callback/SimpleFinTsClientCallback.kt
index 62441cb5..9b90695d 100644
--- a/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/callback/SimpleFinTsClientCallback.kt
+++ b/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/callback/SimpleFinTsClientCallback.kt
@@ -5,14 +5,14 @@ import net.dankito.banking.fints.model.*
 
 
 open class SimpleFinTsClientCallback(
-    protected open val enterTan: ((bank: BankData, tanChallenge: TanChallenge) -> EnterTanResult)? = null,
+    protected open val enterTan: ((tanChallenge: TanChallenge) -> Unit)? = null,
     protected open val enterTanGeneratorAtc: ((bank: BankData, tanMedium: TanGeneratorTanMedium) -> EnterTanGeneratorAtcResult)? = null,
     protected open val askUserForTanMethod: ((supportedTanMethods: List<TanMethod>, suggestedTanMethod: TanMethod?) -> TanMethod?)? = null
 ) : FinTsClientCallback {
 
     constructor() : this(null) // Swift does not support default parameter values -> create constructor overloads
 
-    constructor(enterTan: ((bank: BankData, tanChallenge: TanChallenge) -> EnterTanResult)?) : this(enterTan, null)
+    constructor(enterTan: ((tanChallenge: TanChallenge) -> Unit)?) : this(enterTan, null)
 
 
     override suspend fun askUserForTanMethod(supportedTanMethods: List<TanMethod>, suggestedTanMethod: TanMethod?): TanMethod? {
@@ -20,8 +20,8 @@ open class SimpleFinTsClientCallback(
         return askUserForTanMethod?.invoke(supportedTanMethods, suggestedTanMethod) ?: suggestedTanMethod
     }
 
-    override suspend fun enterTan(bank: BankData, tanChallenge: TanChallenge): EnterTanResult {
-        return enterTan?.invoke(bank, tanChallenge) ?: EnterTanResult.userDidNotEnterTan()
+    override suspend fun enterTan(tanChallenge: TanChallenge) {
+        enterTan?.invoke(tanChallenge) ?: run { tanChallenge.userDidNotEnterTan() }
     }
 
     override suspend fun enterTanGeneratorAtc(bank: BankData, tanMedium: TanGeneratorTanMedium): EnterTanGeneratorAtcResult {
diff --git a/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/model/EnterTanResult.kt b/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/model/EnterTanResult.kt
index dafdebe3..e33c1a89 100644
--- a/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/model/EnterTanResult.kt
+++ b/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/model/EnterTanResult.kt
@@ -4,33 +4,13 @@ import net.dankito.banking.fints.messages.datenelemente.implementierte.tan.TanMe
 import net.dankito.banking.fints.response.client.FinTsClientResponse
 
 
-open class EnterTanResult protected constructor(
+open class EnterTanResult(
     val enteredTan: String?,
     val changeTanMethodTo: TanMethod? = null,
     val changeTanMediumTo: TanMedium? = null,
     val changeTanMediumResultCallback: ((FinTsClientResponse) -> Unit)? = null
 ) {
 
-    companion object {
-
-        fun userEnteredTan(enteredTan: String): EnterTanResult {
-            return EnterTanResult(enteredTan.replace(" ", ""))
-        }
-
-        fun userDidNotEnterTan(): EnterTanResult {
-            return EnterTanResult(null)
-        }
-
-        fun userAsksToChangeTanMethod(changeTanMethodTo: TanMethod): EnterTanResult {
-            return EnterTanResult(null, changeTanMethodTo)
-        }
-
-        fun userAsksToChangeTanMedium(changeTanMediumTo: TanMedium, changeTanMediumResultCallback: ((FinTsClientResponse) -> Unit)?): EnterTanResult {
-            return EnterTanResult(null, null, changeTanMediumTo, changeTanMediumResultCallback)
-        }
-
-    }
-
     override fun toString(): String {
         if (changeTanMethodTo != null) {
             return "User asks to change TAN method to $changeTanMethodTo"
diff --git a/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/model/TanChallenge.kt b/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/model/TanChallenge.kt
index 9464a035..032be286 100644
--- a/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/model/TanChallenge.kt
+++ b/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/model/TanChallenge.kt
@@ -1,5 +1,8 @@
 package net.dankito.banking.fints.model
 
+import net.dankito.banking.fints.messages.datenelemente.implementierte.tan.TanMedium
+import net.dankito.banking.fints.response.client.FinTsClientResponse
+
 
 open class TanChallenge(
     val messageToShowToUser: String,
@@ -8,6 +11,30 @@ open class TanChallenge(
     val tanMediaIdentifier: String?
 ) {
 
+    var enterTanResult: EnterTanResult? = null
+        private set
+
+    open val isEnteringTanDone: Boolean
+        get() = enterTanResult != null
+
+
+    fun userEnteredTan(enteredTan: String) {
+        this.enterTanResult = EnterTanResult(enteredTan.replace(" ", ""))
+    }
+
+    fun userDidNotEnterTan() {
+        this.enterTanResult = EnterTanResult(null)
+    }
+
+    fun userAsksToChangeTanMethod(changeTanMethodTo: TanMethod) {
+        this.enterTanResult = EnterTanResult(null, changeTanMethodTo)
+    }
+
+    fun userAsksToChangeTanMedium(changeTanMediumTo: TanMedium, changeTanMediumResultCallback: ((FinTsClientResponse) -> Unit)?) {
+        this.enterTanResult = EnterTanResult(null, null, changeTanMediumTo, changeTanMediumResultCallback)
+    }
+
+
     override fun toString(): String {
         return "$tanMethod (medium: $tanMediaIdentifier): $messageToShowToUser"
     }
diff --git a/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/model/TanMethod.kt b/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/model/TanMethod.kt
index 1924d547..d4f15af6 100644
--- a/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/model/TanMethod.kt
+++ b/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/model/TanMethod.kt
@@ -20,6 +20,10 @@ open class TanMethod(
 
 
 
+    open val isNumericTan: Boolean
+        get() = allowedTanFormat == AllowedTanFormat.Numeric
+
+
     override fun equals(other: Any?): Boolean {
         if (this === other) return true
         if (other !is TanMethod) return false
diff --git a/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/webclient/IWebClient.kt b/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/webclient/IWebClient.kt
index da312bf9..6a887a95 100644
--- a/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/webclient/IWebClient.kt
+++ b/fints4k/src/commonMain/kotlin/net/dankito/banking/fints/webclient/IWebClient.kt
@@ -20,10 +20,6 @@ interface IWebClient {
     }
 
 
-    suspend fun post(url: String, body: String): WebClientResponse { // some platforms don't support default parameters
-        return post(url, body)
-    }
-
     suspend fun post(url: String, body: String, contentType: String = "application/octet-stream", userAgent: String = DefaultUserAgent): WebClientResponse
 
 }
\ No newline at end of file
diff --git a/fints4k/src/iosMain/kotlin/net/dankito/banking/fints/extensions/TanImageExtensions.kt b/fints4k/src/iosMain/kotlin/net/dankito/banking/fints/extensions/TanImageExtensions.kt
new file mode 100644
index 00000000..614f05df
--- /dev/null
+++ b/fints4k/src/iosMain/kotlin/net/dankito/banking/fints/extensions/TanImageExtensions.kt
@@ -0,0 +1,11 @@
+package net.dankito.banking.fints.extensions
+
+import net.dankito.banking.fints.tan.TanImage
+import net.dankito.utils.multiplatform.extensions.toNSData
+import kotlinx.cinterop.*
+import platform.Foundation.*
+
+
+fun TanImage.imageBytesAsNSData(): NSData {
+    return imageBytes.toNSData()
+}
\ No newline at end of file
diff --git a/fints4k/src/iosMain/kotlin/net/dankito/banking/fints/iOSFinTsClient.kt b/fints4k/src/iosMain/kotlin/net/dankito/banking/fints/iOSFinTsClient.kt
new file mode 100644
index 00000000..89f44213
--- /dev/null
+++ b/fints4k/src/iosMain/kotlin/net/dankito/banking/fints/iOSFinTsClient.kt
@@ -0,0 +1,30 @@
+package net.dankito.banking.fints
+
+
+import kotlinx.coroutines.*
+import net.dankito.banking.fints.callback.FinTsClientCallback
+import net.dankito.banking.fints.model.AddAccountParameter
+import net.dankito.banking.fints.response.client.AddAccountResponse
+import net.dankito.banking.fints.webclient.IWebClient
+
+open class iOSFinTsClient(
+    callback: FinTsClientCallback,
+    webClient: IWebClient
+) {
+
+    protected open val fintsClient = FinTsClientDeprecated(callback, FinTsJobExecutor(RequestExecutor(webClient = webClient)))
+
+    open var callback: FinTsClientCallback
+        get() = fintsClient.callback
+        set(value) {
+            fintsClient.callback = value
+        }
+
+
+    open fun addAccountAsync(parameter: AddAccountParameter, callback: (AddAccountResponse) -> Unit) {
+        GlobalScope.launch(Dispatchers.Main) { // do not block UI thread as with runBlocking { } but stay on UI thread as passing mutable state between threads currently doesn't work in Kotlin/Native
+            callback(fintsClient.addAccountAsync(parameter))
+        }
+    }
+
+}
\ No newline at end of file
diff --git a/fints4k/src/nativeMain/kotlin/Application.kt b/fints4k/src/nativeMain/kotlin/Application.kt
index 14ac98f7..0ae8058d 100644
--- a/fints4k/src/nativeMain/kotlin/Application.kt
+++ b/fints4k/src/nativeMain/kotlin/Application.kt
@@ -4,6 +4,7 @@ import net.dankito.banking.fints.FinTsClientDeprecated
 import net.dankito.banking.fints.callback.SimpleFinTsClientCallback
 import net.dankito.banking.fints.model.AddAccountParameter
 import net.dankito.banking.fints.model.RetrievedAccountData
+import net.dankito.banking.fints.model.TanChallenge
 import net.dankito.banking.fints.response.client.AddAccountResponse
 import net.dankito.utils.multiplatform.extensions.*
 import platform.posix.exit
@@ -22,7 +23,7 @@ class Application {
 
   fun retrieveAccountData(bankCode: String, customerId: String, pin: String, finTs3ServerAddress: String) {
     runBlocking {
-      val client = FinTsClientDeprecated(SimpleFinTsClientCallback())
+      val client = FinTsClientDeprecated(SimpleFinTsClientCallback { tanChallenge -> enterTan(tanChallenge) })
 
       val response = client.addAccountAsync(AddAccountParameter(bankCode, customerId, pin, finTs3ServerAddress))
 
@@ -32,6 +33,23 @@ class Application {
     }
   }
 
+
+  private fun enterTan(tanChallenge: TanChallenge) {
+    println("A TAN is required:")
+    println(tanChallenge.messageToShowToUser)
+    println()
+
+    print("TAN: ")
+    val enteredTan = readLine()
+
+    if (enteredTan.isNullOrBlank()) {
+      tanChallenge.userDidNotEnterTan()
+    } else {
+      tanChallenge.userEnteredTan(enteredTan)
+    }
+  }
+
+
   private fun displayRetrievedAccountData(response: AddAccountResponse) {
     if (response.retrievedData.isEmpty()) {
       println()
diff --git a/multiplatform-utils/src/iosMain/kotlin/net/dankito/utils/multiplatform/extensions/ByteArrayExtensions.kt b/multiplatform-utils/src/iosMain/kotlin/net/dankito/utils/multiplatform/extensions/ByteArrayExtensions.kt
new file mode 100644
index 00000000..7caa8829
--- /dev/null
+++ b/multiplatform-utils/src/iosMain/kotlin/net/dankito/utils/multiplatform/extensions/ByteArrayExtensions.kt
@@ -0,0 +1,12 @@
+package net.dankito.utils.multiplatform.extensions
+
+import kotlinx.cinterop.*
+import platform.Foundation.*
+
+
+fun ByteArray.toNSData(): NSData = NSMutableData().apply {
+    if (isEmpty()) return@apply
+    this@toNSData.usePinned {
+        appendBytes(it.addressOf(0), size.convert())
+    }
+}
\ No newline at end of file