Added example how to update account transactions

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/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