Added example how to update account transactions

BankingClient/src/commonMain/kotlin/net/codinux/banking/client/BankingClient.kt

@@ -1,8 +1,10 @@
 package net.codinux.banking.client
 
+import net.codinux.banking.client.model.*
 import net.codinux.banking.client.model.options.RetrieveTransactions
 import net.codinux.banking.client.model.request.GetAccountDataRequest
 import net.codinux.banking.client.model.response.GetAccountDataResponse
+import net.codinux.banking.client.model.response.GetTransactionsResponse
 import net.codinux.banking.client.model.response.Response
 
 interface BankingClient {
@@ -30,4 +32,11 @@ interface BankingClient {
      */
     suspend fun getAccountDataAsync(request: GetAccountDataRequest): Response<GetAccountDataResponse>
 
+    /**
+     * Convenience wrapper around [getAccountDataAsync].
+     * Updates account's transactions beginning from [BankAccount.lastTransactionsRetrievalTime].
+     * This may requires TAN if [BankAccount.lastTransactionsRetrievalTime] is older than 90 days.
+     */
+    suspend fun updateAccountTransactionsAsync(user: UserAccount, accounts: List<BankAccount>? = null): Response<List<GetTransactionsResponse>>
+
 }

BankingClient/src/commonMain/kotlin/net/codinux/banking/client/BankingClientForUser.kt

@@ -1,8 +1,10 @@
 package net.codinux.banking.client
 
+import net.codinux.banking.client.model.BankAccount
 import net.codinux.banking.client.model.options.GetAccountDataOptions
 import net.codinux.banking.client.model.options.RetrieveTransactions
 import net.codinux.banking.client.model.response.GetAccountDataResponse
+import net.codinux.banking.client.model.response.GetTransactionsResponse
 import net.codinux.banking.client.model.response.Response
 
 interface BankingClientForUser {
@@ -30,4 +32,11 @@ interface BankingClientForUser {
      */
     suspend fun getAccountDataAsync(options: GetAccountDataOptions): Response<GetAccountDataResponse>
 
+    /**
+     * Convenience wrapper around [getAccountDataAsync].
+     * Updates account's transactions beginning from [BankAccount.lastTransactionsRetrievalTime].
+     * This may requires TAN if [BankAccount.lastTransactionsRetrievalTime] is older than 90 days.
+     */
+    suspend fun updateAccountTransactionsAsync(): Response<List<GetTransactionsResponse>>
+
 }

BankingClient/src/commonMain/kotlin/net/codinux/banking/client/BankingClientForUserBase.kt

@@ -1,15 +1,27 @@
 package net.codinux.banking.client
 
 import net.codinux.banking.client.model.AccountCredentials
+import net.codinux.banking.client.model.UserAccount
 import net.codinux.banking.client.model.options.GetAccountDataOptions
 import net.codinux.banking.client.model.request.GetAccountDataRequest
+import net.codinux.banking.client.model.response.GetTransactionsResponse
+import net.codinux.banking.client.model.response.Response
 
 abstract class BankingClientForUserBase(
     protected val credentials: AccountCredentials,
     protected val client: BankingClient
 ) : BankingClientForUser {
 
+    private lateinit var user: UserAccount
+
     override suspend fun getAccountDataAsync(options: GetAccountDataOptions) =
-        client.getAccountDataAsync(GetAccountDataRequest(credentials, options))
+        client.getAccountDataAsync(GetAccountDataRequest(credentials, options)).also {
+            it.data?.user?.let { retrievedUser ->
+                this.user = retrievedUser
+            }
+        }
+
+    override suspend fun updateAccountTransactionsAsync(): Response<List<GetTransactionsResponse>> =
+        client.updateAccountTransactionsAsync(user)
 
 }

BankingClient/src/commonMain/kotlin/net/codinux/banking/client/service/BankingModelService.kt

@@ -0,0 +1,24 @@
+package net.codinux.banking.client.service
+
+import net.codinux.banking.client.model.AccountTransaction
+
+open class BankingModelService {
+
+    /**
+     * It's not possible to retrieve only new transactions from bank server (almost no bank implements HKKAN job). So
+     * for updating account transactions we start at the date of latest account transactions retrieval time (e.g.
+     * transactions have at last been fetched at 01. September 12:00, then there may have been some other transactions
+     * been booked on September 1st after 12:00 o'clock).
+     *
+     * Therefore retrieved account transactions may contain transactions that we already have locally. This method filters
+     * from [retrievedTransactions] those already in [existingTransactions] and returns only that ones, that are not in
+     * [existingTransactions].
+     */
+    open fun findNewTransactions(retrievedTransactions: List<AccountTransaction>, existingTransactions: List<AccountTransaction>): List<AccountTransaction> {
+        val existingTransactionsByIdentifier = existingTransactions.associateBy { it.identifier }
+        val existingTransactionsIdentifiers = existingTransactionsByIdentifier.keys
+
+        return retrievedTransactions.filter { transaction -> existingTransactionsIdentifiers.contains(transaction.identifier) == false }
+    }
+
+}

BankingClient/src/jvmMain/kotlin/net/codinux/banking/client/BankingClientExtensions.kt

@@ -1,6 +1,8 @@
 package net.codinux.banking.client
 
 import kotlinx.coroutines.runBlocking
+import net.codinux.banking.client.model.BankAccount
+import net.codinux.banking.client.model.UserAccount
 import net.codinux.banking.client.model.options.GetAccountDataOptions
 import net.codinux.banking.client.model.request.GetAccountDataRequest
 
@@ -12,10 +14,19 @@ fun BankingClient.getAccountData(request: GetAccountDataRequest) = runBlocking {
     this@getAccountData.getAccountDataAsync(request)
 }
 
+fun BankingClient.updateAccountTransactions(user: UserAccount, accounts: List<BankAccount>? = null) = runBlocking {
+    this@updateAccountTransactions.updateAccountTransactionsAsync(user, accounts)
+}
+
+
 fun BankingClientForUser.getAccountData() = runBlocking {
     this@getAccountData.getAccountDataAsync()
 }
 
 fun BankingClientForUser.getAccountData(options: GetAccountDataOptions) = runBlocking {
     this@getAccountData.getAccountDataAsync(options)
+}
+
+fun BankingClientForUser.updateAccountTransactions() = runBlocking {
+    this@updateAccountTransactions.updateAccountTransactionsAsync()
 }

BankingClientModel/src/commonMain/kotlin/net/codinux/banking/client/model/AccountTransaction.kt

@@ -7,7 +7,7 @@ import net.codinux.banking.client.model.config.NoArgConstructor
 open class AccountTransaction(
     val amount: Amount = Amount.Zero,
     val currency: String,
-    val reference: String, // Alternative: purpose (or Remittance information)
+    val unparsedReference: String, // Alternative: purpose (or Remittance information)
 
     /**
      * Transaction date (Buchungstag) - der Tag, an dem ein Zahlungsvorgang in das System einer Bank eingegangen ist.
@@ -62,5 +62,13 @@ open class AccountTransaction(
     var category: String? = null,
     var notes: String? = null,
 ) {
+
+    val reference: String
+        get() = sepaReference ?: unparsedReference
+
+    open val identifier by lazy {
+        "$amount $currency $bookingDate $valueDate $unparsedReference $sepaReference $otherPartyName $otherPartyBankCode $otherPartyAccountId"
+    }
+
     override fun toString() = "${valueDate.dayOfMonth}.${valueDate.monthNumber}.${valueDate.year} ${amount.toString().padStart(4, ' ')} ${if (currency == "EUR") "€" else currency} ${otherPartyName ?: ""} - $reference"
 }

BankingClientModel/src/commonMain/kotlin/net/codinux/banking/client/model/BankAccount.kt

@@ -1,6 +1,8 @@
 package net.codinux.banking.client.model
 
+import kotlinx.datetime.Instant
 import kotlinx.datetime.LocalDate
+import net.codinux.banking.client.model.config.JsonIgnore
 import net.codinux.banking.client.model.config.NoArgConstructor
 
 @NoArgConstructor
@@ -14,13 +16,14 @@ open class BankAccount(
     val currency: String = "EUR",
     var accountLimit: String? = null,
 
-    val isAccountTypeSupportedByApplication: Boolean = true,
-    val features: Set<BankAccountFeatures> = emptySet(),
-
 //    var balance: BigDecimal = BigDecimal.ZERO,
     var balance: Amount = Amount.Zero, // TODO: add a BigDecimal library
+
+    val isAccountTypeSupportedByApplication: Boolean = false,
+    val features: Set<BankAccountFeatures> = emptySet(),
+
+    open var lastTransactionsRetrievalTime: Instant? = null,
     var retrievedTransactionsFrom: LocalDate? = null,
-    var retrievedTransactionsTo: LocalDate? = null,
 
     var haveAllTransactionsBeenRetrieved: Boolean = false,
     val countDaysForWhichTransactionsAreKept: Int? = null,
@@ -34,5 +37,12 @@ open class BankAccount(
     var hideAccount: Boolean = false,
     var includeInAutomaticAccountsUpdate: Boolean = true
 ) {
+    @get:JsonIgnore
+    open val displayName: String
+        get() = userSetDisplayName ?: productName ?: identifier
+
+    fun supportsAnyFeature(vararg features: BankAccountFeatures): Boolean =
+        features.any { this.features.contains(it) }
+
     override fun toString() = "$type $identifier $productName (IBAN: $iban)"
 }

BankingClientModel/src/commonMain/kotlin/net/codinux/banking/client/model/UserAccount.kt

@@ -51,6 +51,11 @@ open class UserAccount(
     var displayIndex: Int = 0
 
 
+    @get:JsonIgnore
+    open val displayName: String
+        get() = userSetDisplayName ?: bankName
+
+
     @get:JsonIgnore
     val selectedTanMethod: TanMethod
         get() = tanMethods.first { it.identifier == selectedTanMethodId }

BankingClientModel/src/commonMain/kotlin/net/codinux/banking/client/model/response/GetTransactionsResponse.kt

@@ -0,0 +1,22 @@
+package net.codinux.banking.client.model.response
+
+import kotlinx.datetime.Instant
+import kotlinx.datetime.LocalDate
+import net.codinux.banking.client.model.AccountTransaction
+import net.codinux.banking.client.model.Amount
+import net.codinux.banking.client.model.BankAccount
+import net.codinux.banking.client.model.UnbookedAccountTransaction
+import net.codinux.banking.client.model.config.NoArgConstructor
+
+@NoArgConstructor
+open class GetTransactionsResponse(
+    val account: BankAccount,
+    val balance: Amount? = null,
+    val bookedTransactions: List<AccountTransaction>,
+    val unbookedTransactions: List<UnbookedAccountTransaction>,
+    val transactionsRetrievalTime: Instant,
+    val retrievedTransactionsFrom: LocalDate? = null,
+    val retrievedTransactionsTo: LocalDate? = null
+) {
+    override fun toString() = "${account.productName} $balance, ${bookedTransactions.size} booked transactions from $retrievedTransactionsFrom"
+}

BankingClientModel/src/commonMain/kotlin/net/codinux/banking/client/model/tan/TanChallenge.kt

@@ -9,9 +9,9 @@ import net.codinux.banking.client.model.config.NoArgConstructor
 @Suppress("RUNTIME_ANNOTATION_NOT_SUPPORTED")
 @NoArgConstructor
 open class TanChallenge(
-    val type: TanChallengeType,
+    open val type: TanChallengeType,
-    val forAction: ActionRequiringTan,
+    open val forAction: ActionRequiringTan,
-    val messageToShowToUser: String,
+    open val messageToShowToUser: String,
 
     /**
      * Identifier of selected TanMethod.
@@ -19,7 +19,7 @@ open class TanChallenge(
      * As [availableTanMethods] also contains selected TanMethod, we didn't want to duplicate this object. Use
      * [selectedTanMethod] to get selected TanMethod or iterate over [availableTanMethods] and filter selected one by this id.
      */
-    val selectedTanMethodId: String,
+    open val selectedTanMethodId: String,
     /**
      * When adding an account, frontend has no UserAccount object in BankingClientCallback to know which TanMethods are
      * available for User.
@@ -28,7 +28,7 @@ open class TanChallenge(
      *
      * Therefore i added list with up to date TanMethods here to ensure EnterTanDialog can display user's up to date TanMethods.
      */
-    val availableTanMethods: List<TanMethod>,
+    open val availableTanMethods: List<TanMethod>,
 
     /**
      * Identifier of selected TanMedium.
@@ -36,24 +36,35 @@ open class TanChallenge(
      * As [availableTanMedia] also contains selected TanMedium, we didn't want to duplicate this object. Use
      * [selectedTanMedium] to get selected TanMedium or iterate over [availableTanMedia] and filter selected one by this medium name.
      */
-    val selectedTanMediumName: String? = null,
+    open val selectedTanMediumName: String? = null,
-    val availableTanMedia: List<TanMedium> = emptyList(),
+    open val availableTanMedia: List<TanMedium> = emptyList(),
 
-    val tanImage: TanImage? = null,
+    open val tanImage: TanImage? = null,
-    val flickerCode: FlickerCode? = null,
+    open val flickerCode: FlickerCode? = null,
-    val user: UserAccountViewInfo,
+    open val user: UserAccountViewInfo,
-    val account: BankAccountViewInfo? = null
+    open val account: BankAccountViewInfo? = null
 ) {
 
     @get:JsonIgnore
-    val selectedTanMethod: TanMethod
+    open val selectedTanMethod: TanMethod
         get() = availableTanMethods.first { it.identifier == selectedTanMethodId }
 
     @get:JsonIgnore
-    val selectedTanMedium: TanMedium?
+    open val selectedTanMedium: TanMedium?
         get() = availableTanMedia.firstOrNull { it.mediumName == selectedTanMediumName }
 
 
+    /**
+     * Principally a no-op method, not implemented for all client, only implementing client for not: FinTs4jBankingClient.
+     *
+     * If a TAN is requested for a decoupled TAN method like [TanMethodType.DecoupledTan] or [TanMethodType.DecoupledPushTan],
+     * you can add a callback to get notified when user approved TAN in her app e.g. to close a EnterTanDialog.
+     */
+    open fun addUserApprovedDecoupledTanCallback(callback: () -> Unit) {
+
+    }
+
+
     override fun toString(): String {
         return "$selectedTanMethod $forAction: $messageToShowToUser" + when (type) {
             TanChallengeType.EnterTan -> ""

BankingClientModel/src/commonMain/kotlin/net/codinux/banking/client/model/tan/TanGeneratorTanMedium.kt

@@ -4,6 +4,10 @@ import kotlinx.datetime.LocalDate
 import net.codinux.banking.client.model.config.NoArgConstructor
 
 @NoArgConstructor
+/**
+ * 'TanGenerator' is in most cases a debit card, but can also be something like "BestSign" app (Postbank).
+ * In latter case [cardNumber] can also be, contrary to specification, be an empty string.
+ */
 open class TanGeneratorTanMedium(
     val cardNumber: String,
     val cardSequenceNumber: String? = null,

BankingClientModel/src/commonMain/kotlin/net/codinux/banking/client/model/tan/TanMedium.kt

@@ -16,5 +16,49 @@ open class TanMedium(
      */
     val mobilePhone: MobilePhoneTanMedium? = null
 ) {
+
+    /**
+     * Using only [mediumName] as identifier does not work as e.g. Sparkasse names all their TanGenerator TAN media
+     * "SparkassenCard (Debitkarte)" - so it's not possible to differentiate between them solely by medium name.
+     */
+    val identifier: String by lazy {
+        // TODO: translate
+        var id = mediumName ?: when (type) {
+            TanMediumType.MobilePhone -> "Mobiltelefon"
+            TanMediumType.TanGenerator -> "Tan Generator"
+            TanMediumType.Generic -> "Unbenanntes TAN Medium"
+        }
+
+        if (mobilePhone != null) {
+            id += " " + (mobilePhone.concealedPhoneNumber ?: mobilePhone.phoneNumber)
+        }
+        if (tanGenerator != null) {
+            if (tanGenerator.cardNumber.isNotBlank()) {
+                id += " " + tanGenerator.cardNumber
+            }
+            if (tanGenerator.cardSequenceNumber.isNullOrBlank() == false) {
+                id += " " + tanGenerator.cardSequenceNumber
+            }
+
+            if (tanGenerator.validFrom != null && tanGenerator.validTo != null) {
+                id += ", gültig von " + tanGenerator.validFrom.let { "${it.dayOfMonth}.${it.monthNumber}${it.year}" } +
+                        " - " + tanGenerator.validTo.let { "${it.dayOfMonth}.${it.monthNumber}${it.year}" }
+            } else if (tanGenerator.validTo != null) {
+                id += ", gültig bis " + tanGenerator.validTo.let { "${it.dayOfMonth}.${it.monthNumber}${it.year}" }
+            }
+        }
+
+        id
+    }
+
+    val displayName: String by lazy {
+        identifier + " " + when (status) {
+            TanMediumStatus.Used -> "Aktive"
+            TanMediumStatus.Available -> "Verfügbar"
+            TanMediumStatus.ActiveFollowUpCard -> " Folgekarte, aktiv bei erster Nutzung"
+            TanMediumStatus.AvailableFollowUpCard -> " Folgekarte, die erst aktiviert werden muss"
+        }
+    }
+
     override fun toString() = "$mediumName $status"
 }

BankingClientModel/src/commonMain/kotlin/net/codinux/banking/client/model/tan/TanMethod.kt

@@ -4,11 +4,11 @@ import net.codinux.banking.client.model.config.NoArgConstructor
 
 @NoArgConstructor
 open class TanMethod(
-    val displayName: String,
+    open val displayName: String,
-    val type: TanMethodType,
+    open val type: TanMethodType,
-    val identifier: String,
+    open val identifier: String,
-    val maxTanInputLength: Int? = null,
+    open val maxTanInputLength: Int? = null,
-    val allowedTanFormat: AllowedTanFormat = AllowedTanFormat.Alphanumeric
+    open val allowedTanFormat: AllowedTanFormat = AllowedTanFormat.Alphanumeric
 ) {
     override fun toString() = "$displayName ($type, ${identifier})"
 }

BankingClientModel/src/commonMain/kotlin/net/codinux/banking/client/model/tan/TanMethodType.kt

@@ -17,22 +17,30 @@ enum class TanMethodType {
 
     AppTan,
 
+    DecoupledTan,
+
+    DecoupledPushTan,
+
     photoTan,
 
     QrCode
     ;
 
 
+    val isDecoupledMethod: Boolean
+        get() = this == DecoupledTan || this == DecoupledPushTan
+
+
     companion object {
 
-        val NonVisual = listOf(TanMethodType.AppTan, TanMethodType.SmsTan, TanMethodType.ChipTanManuell, TanMethodType.EnterTan)
+        val NonVisual = listOf(TanMethodType.DecoupledTan, TanMethodType.DecoupledPushTan, TanMethodType.AppTan, TanMethodType.SmsTan, TanMethodType.ChipTanManuell, TanMethodType.EnterTan)
 
         val ImageBased = listOf(TanMethodType.QrCode, TanMethodType.ChipTanQrCode, TanMethodType.photoTan, TanMethodType.ChipTanPhotoTanMatrixCode)
 
         val NonVisualOrImageBased = buildList {
-            addAll(listOf(TanMethodType.AppTan, TanMethodType.SmsTan, TanMethodType.EnterTan))
+            addAll(listOf(TanMethodType.DecoupledTan, TanMethodType.DecoupledPushTan, TanMethodType.AppTan, TanMethodType.SmsTan, TanMethodType.EnterTan))
             addAll(ImageBased)
-            addAll(listOf(TanMethodType.ChipTanManuell)) // this is quite inconvenient for user, so i added it at last
+            addAll(listOf(TanMethodType.ChipTanManuell)) // this is quite inconvenient for user, so i added it as last
         }
 
     }

FinTs4jBankingClient/build.gradle.kts

@@ -77,7 +77,7 @@ kotlin {
             dependencies {
                 api(project(":BankingClient"))
 
-                api("net.codinux.banking:fints4k:1.0.0-Alpha-12")
+                api("net.codinux.banking:fints4k:1.0.0-Alpha-13-SNAPSHOT")
 
                 api("org.jetbrains.kotlinx:kotlinx-datetime:$kotlinxDateTimeVersion")
             }

FinTs4jBankingClient/src/commonMain/kotlin/net/codinux/banking/client/fints4k/FinTs4kBankingClient.kt

@@ -2,12 +2,15 @@ package net.codinux.banking.client.fints4k
 
 import net.codinux.banking.client.BankingClient
 import net.codinux.banking.client.BankingClientCallback
+import net.codinux.banking.client.model.BankAccount
+import net.codinux.banking.client.model.BankAccountFeatures
+import net.codinux.banking.client.model.UserAccount
 import net.codinux.banking.client.model.options.GetAccountDataOptions
 import net.codinux.banking.client.model.request.GetAccountDataRequest
-import net.codinux.banking.client.model.response.GetAccountDataResponse
+import net.codinux.banking.client.model.response.*
-import net.codinux.banking.client.model.response.Response
 import net.codinux.banking.fints.FinTsClient
 import net.codinux.banking.fints.config.FinTsClientConfiguration
+import net.codinux.banking.fints.model.BankData
 
 open class FinTs4kBankingClient(
     config: FinTsClientConfiguration = FinTsClientConfiguration(),
@@ -28,4 +31,28 @@ open class FinTs4kBankingClient(
         return mapper.map(response)
     }
 
+    override suspend fun updateAccountTransactionsAsync(user: UserAccount, accounts: List<BankAccount>?): Response<List<GetTransactionsResponse>> {
+        val accountsToRequest = (accounts ?: user.accounts).filter { it.supportsAnyFeature(BankAccountFeatures.RetrieveBalance, BankAccountFeatures.RetrieveBalance) }
+
+        if (accountsToRequest.isNotEmpty()) {
+            var finTsModel: BankData? = null
+
+            val responses = accountsToRequest.map { account ->
+                val parameter = mapper.mapToUpdateAccountTransactionsParameter(user, account, finTsModel)
+
+                val response = client.getAccountDataAsync(parameter)
+
+                if (response.finTsModel != null) {
+                    finTsModel = response.finTsModel // so that basic account data doesn't have to be retrieved another time if user has multiple accounts
+                }
+
+                Triple(account, parameter, response)
+            }
+
+            return mapper.map(responses)
+        }
+
+        return Response.error(ErrorType.NoneOfTheAccountsSupportsRetrievingData, "Keiner der Konten unterstützt das Abholen der Umsätze oder des Kontostands") // TODO: translate
+    }
+
 }

FinTs4jBankingClient/src/commonMain/kotlin/net/codinux/banking/client/fints4k/FinTs4kBankingClientForUser.kt

@@ -5,7 +5,7 @@ import net.codinux.banking.client.BankingClientForUserBase
 import net.codinux.banking.client.model.AccountCredentials
 import net.codinux.banking.fints.config.FinTsClientConfiguration
 
-open class FinTs4KBankingClientForUser(credentials: AccountCredentials, config: FinTsClientConfiguration = FinTsClientConfiguration(), callback: BankingClientCallback)
+open class FinTs4kBankingClientForUser(credentials: AccountCredentials, config: FinTsClientConfiguration = FinTsClientConfiguration(), callback: BankingClientCallback)
     : BankingClientForUserBase(credentials, FinTs4kBankingClient(config, callback)) {
 
     constructor(bankCode: String, loginName: String, password: String, callback: BankingClientCallback)

FinTs4jBankingClient/src/commonMain/kotlin/net/codinux/banking/client/fints4k/FinTs4kMapper.kt

@@ -1,5 +1,8 @@
 package net.codinux.banking.client.fints4k
 
+import kotlinx.datetime.Clock
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toLocalDateTime
 import net.codinux.banking.client.model.*
 import net.codinux.banking.client.model.AccountTransaction
 import net.codinux.banking.client.model.Amount
@@ -11,6 +14,7 @@ import net.codinux.banking.client.model.tan.TanChallenge
 import net.codinux.banking.client.model.tan.TanImage
 import net.codinux.banking.client.model.tan.TanMethod
 import net.codinux.banking.client.model.tan.TanMethodType
+import net.codinux.banking.fints.extensions.EuropeBerlin
 import net.dankito.banking.client.model.BankAccountIdentifierImpl
 import net.dankito.banking.client.model.parameter.GetAccountDataParameter
 import net.dankito.banking.client.model.parameter.RetrieveTransactions
@@ -41,6 +45,21 @@ open class FinTs4kMapper {
         abortIfTanIsRequired = options.abortIfTanIsRequired
     )
 
+    open fun mapToUpdateAccountTransactionsParameter(user: UserAccount, account: BankAccount, finTsModel: BankData?): GetAccountDataParameter {
+        val accountIdentifier = BankAccountIdentifierImpl(account.identifier, account.subAccountNumber, account.iban)
+        val from = account.lastTransactionsRetrievalTime?.toLocalDateTime(TimeZone.EuropeBerlin)?.date // TODO: in case lastTransactionsUpdateTime is not set, this would retrieve all transactions (and require a TAN im most cases)
+        val retrieveTransactions = if (from != null) RetrieveTransactions.AccordingToRetrieveFromAndTo else RetrieveTransactions.OfLast90Days
+//        val preferredTanMethods = listOf(mapTanMethodType(user.selectedTanMethod.type)) // TODO: currently we aren't saving TanMethods in database, re-enable as soon as TanMethods get saved
+        val preferredTanMethods = emptyList<net.codinux.banking.fints.model.TanMethodType>()
+
+        return GetAccountDataParameter(user.bankCode, user.loginName, user.password!!, listOf(accountIdentifier), true,
+            retrieveTransactions, from,
+            preferredTanMethods = preferredTanMethods,
+            preferredTanMedium = user.selectedTanMediumName,
+            finTsModel = finTsModel
+        )
+    }
+
     protected open fun mapTanMethodType(type: TanMethodType): net.codinux.banking.fints.model.TanMethodType =
         net.codinux.banking.fints.model.TanMethodType.valueOf(type.name)
 
@@ -53,6 +72,35 @@ open class FinTs4kMapper {
         }
     }
 
+    open fun map(responses: List<Triple<BankAccount, GetAccountDataParameter, net.dankito.banking.client.model.response.GetAccountDataResponse>>): Response<List<GetTransactionsResponse>> {
+        val type = if (responses.all { it.third.successful }) ResponseType.Success else ResponseType.Error
+
+        // TODO: update UserAccount and BankAccount objects according to retrieved data
+        val mappedResponses = responses.map { (account, param, getAccountDataResponse) ->
+            val user = getAccountDataResponse.customerAccount
+            val finTsBankAccount = user?.accounts?.firstOrNull { it.identifier == account.identifier && it.subAccountNumber == account.subAccountNumber }
+
+            if (getAccountDataResponse.successful && user != null && finTsBankAccount != null) {
+                if (finTsBankAccount.lastTransactionsRetrievalTime != null) {
+                    account.lastTransactionsRetrievalTime = finTsBankAccount.lastTransactionsRetrievalTime
+                }
+                if (account.retrievedTransactionsFrom == null || (finTsBankAccount.retrievedTransactionsFrom != null
+                            && account.retrievedTransactionsFrom!! < finTsBankAccount.retrievedTransactionsFrom!!)) {
+                    account.retrievedTransactionsFrom = finTsBankAccount.retrievedTransactionsFrom
+                }
+
+                Response.success(GetTransactionsResponse(account, mapAmount(finTsBankAccount.balance), mapBookedTransactions(finTsBankAccount), emptyList(),
+                    finTsBankAccount.lastTransactionsRetrievalTime ?: Clock.System.now(), param.retrieveTransactionsFrom, param.retrieveTransactionsTo))
+            } else {
+                mapError(getAccountDataResponse)
+            }
+        }
+
+        val data = mappedResponses.filter { it.type == ResponseType.Success }.mapNotNull { it.data }
+
+        return (object : Response<List<GetTransactionsResponse>>(type, data, mappedResponses.firstNotNullOfOrNull { it.error }) { })
+    }
+
 
     open fun mapToUserAccountViewInfo(bank: BankData): UserAccountViewInfo = UserAccountViewInfo(
         bank.bankCode, bank.customerId, bank.bankName, getBankingGroup(bank.bankName, bank.bic)
@@ -82,12 +130,12 @@ open class FinTs4kMapper {
 
     protected open fun mapAccount(account: net.dankito.banking.client.model.BankAccount) = BankAccount(
         account.identifier, account.accountHolderName, mapAccountType(account.type), account.iban, account.subAccountNumber,
-        account.productName, account.currency, account.accountLimit, account.isAccountTypeSupportedByApplication,
+        account.productName, account.currency, account.accountLimit, mapAmount(account.balance),
-        mapFeatures(account),
+        account.isAccountTypeSupportedByApplication, mapFeatures(account),
-        mapAmount(account.balance), account.retrievedTransactionsFrom, account.retrievedTransactionsTo,
+        account.lastTransactionsRetrievalTime, account.retrievedTransactionsFrom,
         // TODO: map haveAllTransactionsBeenRetrieved
         countDaysForWhichTransactionsAreKept = account.countDaysForWhichTransactionsAreKept,
-        bookedTransactions = account.bookedTransactions.map { mapTransaction(it) }.toMutableList()
+        bookedTransactions = mapBookedTransactions(account).toMutableList()
     )
 
     protected open fun mapAccountType(type: net.dankito.banking.client.model.BankAccountType): BankAccountType =
@@ -109,6 +157,9 @@ open class FinTs4kMapper {
     }
 
 
+    protected open fun mapBookedTransactions(account: net.dankito.banking.client.model.BankAccount): List<AccountTransaction> =
+        account.bookedTransactions.map { mapTransaction(it) }
+
     protected open fun mapTransaction(transaction: net.dankito.banking.client.model.AccountTransaction): AccountTransaction = AccountTransaction(
         mapAmount(transaction.amount), transaction.amount.currency.code, transaction.unparsedReference,
         transaction.bookingDate, transaction.valueDate,
@@ -144,7 +195,8 @@ open class FinTs4kMapper {
         val selectedTanMethodId = challenge.tanMethod.securityFunction.code
 
         val tanMedia = challenge.bank.tanMedia.map { mapTanMedium(it) }
-        val selectedTanMediumName = challenge.bank.selectedTanMedium?.mediumName
+        // TanMedium has not natural id in FinTS model so we have to create our own one
+        val selectedTanMediumName = challenge.bank.selectedTanMedium?.let { selected -> tanMedia.firstOrNull { it == selected } }?.identifier
 
         val user = mapToUserAccountViewInfo(challenge.bank)
         val account = challenge.account?.let { mapToBankAccountViewInfo(it) }
@@ -152,7 +204,11 @@ open class FinTs4kMapper {
         val tanImage = if (challenge is ImageTanChallenge) mapTanImage(challenge.image) else null
         val flickerCode = if (challenge is FlickerCodeTanChallenge) mapFlickerCode(challenge.flickerCode) else null
 
-        return TanChallenge(type, action, challenge.messageToShowToUser, selectedTanMethodId, tanMethods, selectedTanMediumName, tanMedia, tanImage, flickerCode, user, account)
+        return object : TanChallenge(type, action, challenge.messageToShowToUser, selectedTanMethodId, tanMethods, selectedTanMediumName, tanMedia, tanImage, flickerCode, user, account) {
+            override fun addUserApprovedDecoupledTanCallback(callback: () -> Unit) {
+                challenge.addUserApprovedDecoupledTanCallback(callback)
+            }
+        }
     }
 
     protected open fun mapTanChallengeType(challenge: net.codinux.banking.fints.model.TanChallenge): TanChallengeType = when {

FinTs4jBankingClient/src/commonTest/kotlin/net/codinux/banking/client/fints4k/FinTs4kBankingClientTest.kt

@@ -19,7 +19,7 @@ class FinTs4kBankingClientTest {
     }
 
 
-    private val underTest = FinTs4KBankingClientForUser(bankCode, loginName, password, SimpleBankingClientCallback { tanChallenge, callback ->
+    private val underTest = FinTs4kBankingClientForUser(bankCode, loginName, password, SimpleBankingClientCallback { tanChallenge, callback ->
 
     })
 

README.md

@@ -51,11 +51,11 @@ class ShowUsage {
 
 
     fun getAccountData() {
-        val client = FinTs4kBankingClientForUser(bankCode, loginName, password, SimpleBankingClientCallback())
+        val client = FinTs4kBankingClient(SimpleBankingClientCallback())
 
-        val response = client.getAccountData()
+        val response = client.getAccountData(bankCode, loginName, password) // that's all
 
-        printReceivedData(response)
+        printReceivedData(response) // now print retrieved data (save it to database, display it in UI, ...)
     }
 
 
@@ -82,15 +82,6 @@ class ShowUsage {
 
 This fetches the booked account transactions of the last 90 days. In most cases no TAN is required for this.
 
-In case there is, add TAN handling in Client Callback:
-
-```kotlin
-val client = FinTs4kBankingClientForUser(bankCode, loginName, password, SimpleBankingClientCallback { tanChallenge, callback ->
-    val tan: String? = null // if a TAN is required, add a UI or ...
-    callback.invoke(EnterTanResult(tan)) // ...  set a break point here, get TAN e.g. from your TAN app, set tan variable in debugger view and resume debugger
-})
-```
-
 You can also specify options e.g. which transactions should be retrieved:
 
 ```kotlin
@@ -104,10 +95,53 @@ val options = GetAccountDataOptions(
 val response = client.getAccountData(options)
 ```
 
+Retrieving transactions older than 90 days requires a TAN, so add TAN handling in Client Callback:
+
+```kotlin
+val client = FinTs4kBankingClientForUser(bankCode, loginName, password, SimpleBankingClientCallback { tanChallenge, callback ->
+    val tan: String? = null // if a TAN is required, add a UI or ...
+    callback.invoke(EnterTanResult(tan)) // ...  set a break point here, get TAN e.g. from your TAN app, set tan variable in debugger view and resume debugger
+})
+```
+
 Add some error handling by checking `response.error`:
 
 ```kotlin
 response.error?.let{ error ->
     println("Could not fetch account data: ${error.internalError ?: error.errorMessagesFromBank.joinToString()}")
 }
+```
+
+
+### Update Account Transactions
+
+The data model saves when it retrieved account transactions the last time (in `BankAccount.lastTransactionsRetrievalTime`).
+So you only need to call `FinTs4kBankingClient.updateAccountTransactions()` to retrieve all transactions starting from
+`BankAccount.lastTransactionsRetrievalTime`.
+
+But as we can only specify from which day on account transactions should be retrieved, response may contain some transactions
+from the day of `lastTransactionsRetrievalTime` that we already have locally. To filter out these you can use
+`BankingModelService().findNewTransactions(retrieveTransactions, existingTransactions)`:
+
+```kotlin
+fun updateAccountTransactions() {
+    val client = FinTs4kBankingClientForUser(bankCode, loginName, password, SimpleBankingClientCallback())
+
+    // simulate account transactions we retrieved last time
+    val today = Clock.System.now().toLocalDateTime(TimeZone.currentSystemDefault()).date
+    val lastCallToBankServer = client.getAccountData(GetAccountDataOptions(RetrieveTransactions.AccordingToRetrieveFromAndTo, retrieveTransactionsFrom = today.minusDays(90), retrieveTransactionsTo = today.minusDays(30)))
+    
+    if (lastCallToBankServer.data != null) { // now update account transactions
+        val existingTransactions = lastCallToBankServer.data!!.bookedTransactions
+        
+        val updateTransactionsResponse = client.updateAccountTransactions()
+        
+        if (updateTransactionsResponse.data != null) {
+            val retrievedTransactions = updateTransactionsResponse.data!!.flatMap { it.bookedTransactions }
+            val newTransactions = BankingModelService().findNewTransactions(retrievedTransactions, existingTransactions)
+            // `retrievedTransactions` may contain transactions we already have locally, `newTransactions` only 
+            // transactions that are not in `existingTransactions`
+        }
+    }
+}
 ```

SampleApp/build.gradle.kts

@@ -12,5 +12,5 @@ repositories {
 
 
 dependencies {
-    implementation("net.codinux.banking.client:fints4k-banking-client:0.5.0")
+    implementation(project(":fints4k-banking-client"))
 }

SampleApp/src/main/kotlin/net/codinux/banking/client/fints4k/example/ShowUsage.kt

@@ -1,7 +1,11 @@
 package net.codinux.banking.client.fints4k.example
 
+import kotlinx.datetime.Clock
 import kotlinx.datetime.LocalDate
+import kotlinx.datetime.TimeZone
+import kotlinx.datetime.toLocalDateTime
 import net.codinux.banking.client.SimpleBankingClientCallback
+import net.codinux.banking.client.fints4k.FinTs4kBankingClient
 import net.codinux.banking.client.fints4k.FinTs4kBankingClientForUser
 import net.codinux.banking.client.getAccountData
 import net.codinux.banking.client.model.options.GetAccountDataOptions
@@ -9,6 +13,9 @@ import net.codinux.banking.client.model.options.RetrieveTransactions
 import net.codinux.banking.client.model.response.GetAccountDataResponse
 import net.codinux.banking.client.model.response.Response
 import net.codinux.banking.client.model.tan.EnterTanResult
+import net.codinux.banking.client.service.BankingModelService
+import net.codinux.banking.client.updateAccountTransactions
+import net.codinux.banking.fints.extensions.minusDays
 
 fun main() {
     val showUsage = ShowUsage()
@@ -27,11 +34,11 @@ class ShowUsage {
 
 
     fun getAccountDataSimpleExample() {
-        val client = FinTs4kBankingClientForUser(bankCode, loginName, password, SimpleBankingClientCallback())
+        val client = FinTs4kBankingClient(SimpleBankingClientCallback())
 
-        val response = client.getAccountData()
+        val response = client.getAccountData(bankCode, loginName, password) // that's all
 
-        printReceivedData(response)
+        printReceivedData(response) // now print retrieved data (save it to database, display it in UI, ...)
     }
 
     fun getAccountDataFullExample() {
@@ -57,6 +64,28 @@ class ShowUsage {
     }
 
 
+    fun updateAccountTransactions() {
+        val client = FinTs4kBankingClientForUser(bankCode, loginName, password, SimpleBankingClientCallback())
+
+        // simulate account transactions we retrieved last time
+        val today = Clock.System.now().toLocalDateTime(TimeZone.currentSystemDefault()).date
+        val lastCallToBankServer = client.getAccountData(GetAccountDataOptions(RetrieveTransactions.AccordingToRetrieveFromAndTo, retrieveTransactionsFrom = today.minusDays(90), retrieveTransactionsTo = today.minusDays(30)))
+
+        if (lastCallToBankServer.data != null) { // now update account transactions
+            val existingTransactions = lastCallToBankServer.data!!.bookedTransactions
+
+            val updateTransactionsResponse = client.updateAccountTransactions()
+
+            if (updateTransactionsResponse.data != null) {
+                val retrievedTransactions = updateTransactionsResponse.data!!.flatMap { it.bookedTransactions }
+                val newTransactions = BankingModelService().findNewTransactions(retrievedTransactions, existingTransactions)
+                // `retrievedTransactions` may contain transactions we already have locally, `newTransactions` only
+                // transactions that are not in `existingTransactions`
+            }
+        }
+    }
+
+
     private fun printReceivedData(response: Response<GetAccountDataResponse>) {
         response.data?.let { data ->
             val user = data.user