Updated on 2026-08-14

app/build.gradle.kts

@@ -76,6 +76,7 @@ dependencies {
     implementation(projects.data.txhistory)
     implementation(projects.data.wallets)
     implementation(projects.data.analytics)
+    implementation(projects.data.transaction)
 
     /** Features */
     implementation(projects.features.onboarding)

app/src/main/java/com/tangem/tap/di/domain/TransactionDomainModule.kt

@@ -2,6 +2,8 @@ package com.tangem.tap.di.domain
 
 import com.tangem.domain.card.repository.CardSdkConfigRepository
 import com.tangem.domain.demo.IsDemoCardUseCase
+import com.tangem.domain.transaction.TransactionRepository
+import com.tangem.domain.transaction.usecase.CreateTransactionUseCase
 import com.tangem.domain.transaction.usecase.GetFeeUseCase
 import com.tangem.domain.transaction.usecase.SendTransactionUseCase
 import com.tangem.domain.walletmanager.WalletManagersFacade
@@ -38,4 +40,10 @@ internal object TransactionDomainModule {
             walletManagersFacade = walletManagersFacade,
         )
     }
+
+    @Provides
+    @ViewModelScoped
+    fun provideCreateTransactionUseCase(transactionRepository: TransactionRepository): CreateTransactionUseCase {
+        return CreateTransactionUseCase(transactionRepository)
+    }
 }

data/transaction/.gitignore

@@ -0,0 +1 @@
+/build

data/transaction/build.gradle.kts

@@ -0,0 +1,30 @@
+plugins {
+    alias(deps.plugins.android.library)
+    alias(deps.plugins.kotlin.android)
+    alias(deps.plugins.kotlin.kapt)
+    alias(deps.plugins.hilt.android)
+    id("configuration")
+}
+
+android {
+    namespace = "com.tangem.data.transaction"
+}
+
+dependencies {
+
+    /** Tangem SDKs */
+    implementation(deps.tangem.blockchain)
+
+    /** Core */
+    implementation(projects.core.utils)
+
+    /** Domain */
+    implementation(projects.domain.transaction)
+    implementation(projects.domain.legacy)
+    implementation(projects.domain.wallets.models)
+    implementation(projects.domain.tokens.models)
+
+    /** DI */
+    implementation(deps.hilt.android)
+    kapt(deps.hilt.kapt)
+}

data/transaction/src/main/java/com/tangem/data/transaction/DefaultTransactionRepository.kt

@@ -0,0 +1,65 @@
+package com.tangem.data.transaction
+
+import androidx.core.text.isDigitsOnly
+import com.tangem.blockchain.blockchains.binance.BinanceTransactionExtras
+import com.tangem.blockchain.blockchains.cosmos.CosmosTransactionExtras
+import com.tangem.blockchain.blockchains.stellar.StellarMemo
+import com.tangem.blockchain.blockchains.stellar.StellarTransactionExtras
+import com.tangem.blockchain.blockchains.ton.TonTransactionExtras
+import com.tangem.blockchain.blockchains.xrp.XrpTransactionBuilder
+import com.tangem.blockchain.common.Amount
+import com.tangem.blockchain.common.Blockchain
+import com.tangem.blockchain.common.TransactionData
+import com.tangem.blockchain.common.TransactionExtras
+import com.tangem.blockchain.common.transaction.Fee
+import com.tangem.domain.tokens.model.Network
+import com.tangem.domain.transaction.TransactionRepository
+import com.tangem.domain.walletmanager.WalletManagersFacade
+import com.tangem.domain.wallets.models.UserWalletId
+import com.tangem.utils.coroutines.CoroutineDispatcherProvider
+import kotlinx.coroutines.withContext
+
+internal class DefaultTransactionRepository(
+    private val walletManagersFacade: WalletManagersFacade,
+    private val coroutineDispatcherProvider: CoroutineDispatcherProvider,
+) : TransactionRepository {
+
+    override suspend fun createTransaction(
+        amount: Amount,
+        fee: Fee,
+        memo: String?,
+        destination: String,
+        userWalletId: UserWalletId,
+        network: Network,
+    ): TransactionData? = withContext(coroutineDispatcherProvider.io) {
+        val blockchain = Blockchain.fromId(network.id.value)
+        val walletManager = walletManagersFacade.getOrCreateWalletManager(
+            userWalletId = userWalletId,
+            blockchain = blockchain,
+            derivationPath = network.derivationPath.value,
+        )
+
+        return@withContext walletManager?.createTransaction(amount, fee, destination)?.copy(
+            extras = getMemoExtras(network.id.value, memo),
+        )
+    }
+
+    private fun getMemoExtras(networkId: String, memo: String?): TransactionExtras? {
+        val blockchain = Blockchain.fromId(networkId)
+        if (memo == null) return null
+        return when (blockchain) {
+            Blockchain.Stellar -> {
+                val xmlMemo = when {
+                    memo.isNotEmpty() && memo.isDigitsOnly() -> StellarMemo.Id(memo.toBigInteger())
+                    else -> StellarMemo.Text(memo)
+                }
+                StellarTransactionExtras(xmlMemo)
+            }
+            Blockchain.Binance -> BinanceTransactionExtras(memo)
+            Blockchain.XRP -> memo.toLongOrNull()?.let { XrpTransactionBuilder.XrpTransactionExtras(it) }
+            Blockchain.Cosmos -> CosmosTransactionExtras(memo)
+            Blockchain.TON -> TonTransactionExtras(memo)
+            else -> null
+        }
+    }
+}

data/transaction/src/main/java/com/tangem/data/transaction/di/TransactionDataModule.kt

@@ -0,0 +1,28 @@
+package com.tangem.data.transaction.di
+
+import com.tangem.data.transaction.DefaultTransactionRepository
+import com.tangem.domain.transaction.TransactionRepository
+import com.tangem.domain.walletmanager.WalletManagersFacade
+import com.tangem.utils.coroutines.CoroutineDispatcherProvider
+import dagger.Module
+import dagger.Provides
+import dagger.hilt.InstallIn
+import dagger.hilt.components.SingletonComponent
+import javax.inject.Singleton
+
+@Module
+@InstallIn(SingletonComponent::class)
+internal object TransactionDataModule {
+
+    @Provides
+    @Singleton
+    fun providesTransactionRepository(
+        walletManagersFacade: WalletManagersFacade,
+        coroutineDispatcherProvider: CoroutineDispatcherProvider,
+    ): TransactionRepository {
+        return DefaultTransactionRepository(
+            walletManagersFacade = walletManagersFacade,
+            coroutineDispatcherProvider = coroutineDispatcherProvider,
+        )
+    }
+}

domain/transaction/src/main/java/com/tangem/domain/transaction/TransactionRepository.kt

@@ -0,0 +1,20 @@
+package com.tangem.domain.transaction
+
+import com.tangem.blockchain.common.Amount
+import com.tangem.blockchain.common.TransactionData
+import com.tangem.blockchain.common.transaction.Fee
+import com.tangem.domain.tokens.model.Network
+import com.tangem.domain.wallets.models.UserWalletId
+
+interface TransactionRepository {
+
+    @Suppress("LongParameterList")
+    suspend fun createTransaction(
+        amount: Amount,
+        fee: Fee,
+        memo: String?,
+        destination: String,
+        userWalletId: UserWalletId,
+        network: Network,
+    ): TransactionData?
+}

domain/transaction/src/main/java/com/tangem/domain/transaction/usecase/CreateTransactionUseCase.kt

@@ -0,0 +1,37 @@
+package com.tangem.domain.transaction.usecase
+
+import arrow.core.Either
+import com.tangem.blockchain.common.Amount
+import com.tangem.blockchain.common.transaction.Fee
+import com.tangem.domain.tokens.model.Network
+import com.tangem.domain.transaction.TransactionRepository
+import com.tangem.domain.wallets.models.UserWalletId
+
+class CreateTransactionUseCase(
+    private val transactionRepository: TransactionRepository,
+) {
+
+    /**
+     * [REDACTED_TODO_COMMENT]
+     */
+    @Suppress("LongParameterList")
+    suspend operator fun invoke(
+        amount: Amount,
+        fee: Fee,
+        memo: String?,
+        destination: String,
+        userWalletId: UserWalletId,
+        network: Network,
+    ) = Either.catch {
+        requireNotNull(
+            transactionRepository.createTransaction(
+                amount = amount,
+                fee = fee,
+                memo = memo,
+                destination = destination,
+                userWalletId = userWalletId,
+                network = network,
+            ),
+        ) { "Failed to create transaction" }
+    }
+}

features/send/impl/src/main/java/com/tangem/features/send/impl/presentation/ui/SendNavigationButtons.kt

@@ -14,7 +14,6 @@ import androidx.compose.material3.Icon
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.State
 import androidx.compose.runtime.collectAsState
-import androidx.compose.runtime.remember
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.draw.clip
 import androidx.compose.ui.hapticfeedback.HapticFeedbackType
@@ -77,13 +76,11 @@ private fun SendPrimaryNavigationButton(uiState: SendUiState, modifier: Modifier
     val isSending = uiState.sendState?.isSending?.collectAsStateWithLifecycle()?.value ?: false
     val txUrl = uiState.sendState?.txUrl?.collectAsStateWithLifecycle()?.value.orEmpty()
 
-    val (buttonTextId, buttonClick) = remember {
+    val (buttonTextId, buttonClick) = getButtonData(
-        getButtonData(
         currentState = currentState,
         isSuccess = isSuccess,
         uiState = uiState,
     )
-    }
 
     val isButtonEnabled = isButtonEnabled(
         currentState = currentState,

features/send/impl/src/main/java/com/tangem/features/send/impl/presentation/viewmodel/MemoVerification.kt

@@ -1,52 +0,0 @@
-package com.tangem.features.send.impl.presentation.viewmodel
-
-import androidx.core.text.isDigitsOnly
-import com.tangem.blockchain.common.Blockchain
-import com.tangem.domain.tokens.model.CryptoCurrency
-import java.math.BigInteger
-
-internal fun validateMemo(memo: String, cryptoCurrency: CryptoCurrency?): Boolean {
-    if (cryptoCurrency == null) return false
-    if (memo.isEmpty()) return true
-    return when (cryptoCurrency.network.id.value) {
-        Blockchain.XRP.id -> {
-            val tag = memo.toLongOrNull()
-            tag != null && tag <= XRP_TAG_MAX_NUMBER
-        }
-        Blockchain.Stellar.id -> {
-            isAssignableValue(memo)
-        }
-        else -> true
-    }
-}
-
-private fun isAssignableValue(value: String): Boolean {
-    val memoType = when {
-        value.isNotEmpty() && value.isDigitsOnly() -> XlmMemoType.ID
-        else -> XlmMemoType.TEXT
-    }
-    return when (memoType) {
-        XlmMemoType.TEXT -> {
-            // from org.stellar.sdk.MemoText
-            value.toByteArray().size <= XLM_MEMO_MAX_LENGTH
-        }
-        XlmMemoType.ID -> {
-            try {
-                // from com.tangem.blockchain.blockchains.stellar.StellarMemo.toStellarSdkMemo
-                value.toBigInteger() in BigInteger.ZERO..Long.MAX_VALUE.toBigInteger() * 2.toBigInteger()
-            } catch (ex: NumberFormatException) {
-                false
-            }
-        }
-    }
-}
-
-fun determineXlmMemoType(value: String): XlmMemoType = when {
-    value.isNotEmpty() && value.isDigitsOnly() -> XlmMemoType.ID
-    else -> XlmMemoType.TEXT
-}
-
-enum class XlmMemoType { TEXT, ID }
-
-private const val XRP_TAG_MAX_NUMBER = 4294967295
-private const val XLM_MEMO_MAX_LENGTH = 28

features/send/impl/src/main/java/com/tangem/features/send/impl/presentation/viewmodel/SendViewModel.kt

@@ -6,15 +6,8 @@ import androidx.compose.runtime.setValue
 import androidx.lifecycle.*
 import androidx.paging.PagingData
 import arrow.core.getOrElse
-import com.tangem.blockchain.blockchains.binance.BinanceTransactionExtras
-import com.tangem.blockchain.blockchains.cosmos.CosmosTransactionExtras
-import com.tangem.blockchain.blockchains.stellar.StellarMemo
-import com.tangem.blockchain.blockchains.stellar.StellarTransactionExtras
-import com.tangem.blockchain.blockchains.ton.TonTransactionExtras
 import com.tangem.blockchain.blockchains.xrp.XrpAddressService
-import com.tangem.blockchain.blockchains.xrp.XrpTransactionBuilder
 import com.tangem.blockchain.common.Blockchain
-import com.tangem.blockchain.common.TransactionExtras
 import com.tangem.blockchain.common.transaction.Fee
 import com.tangem.blockchain.common.transaction.TransactionFee
 import com.tangem.domain.appcurrency.GetSelectedAppCurrencyUseCase
@@ -25,6 +18,7 @@ import com.tangem.domain.tokens.GetNetworkCoinStatusUseCase
 import com.tangem.domain.tokens.model.CryptoCurrency
 import com.tangem.domain.tokens.model.CryptoCurrencyStatus
 import com.tangem.domain.tokens.utils.convertToAmount
+import com.tangem.domain.transaction.usecase.CreateTransactionUseCase
 import com.tangem.domain.transaction.usecase.GetFeeUseCase
 import com.tangem.domain.transaction.usecase.SendTransactionUseCase
 import com.tangem.domain.txhistory.models.TxHistoryItem
@@ -57,6 +51,7 @@ import kotlinx.coroutines.awaitAll
 import kotlinx.coroutines.coroutineScope
 import kotlinx.coroutines.flow.*
 import kotlinx.coroutines.launch
+import timber.log.Timber
 import java.math.BigDecimal
 import javax.inject.Inject
 import kotlin.properties.Delegates
@@ -75,6 +70,7 @@ internal class SendViewModel @Inject constructor(
     private val txHistoryItemsCountUseCase: GetTxHistoryItemsCountUseCase,
     private val getFeeUseCase: GetFeeUseCase,
     private val sendTransactionUseCase: SendTransactionUseCase,
+    private val createTransactionUseCase: CreateTransactionUseCase,
     private val getExplorerTransactionUrlUseCase: GetExplorerTransactionUrlUseCase,
     private val validateWalletAddressUseCase: ValidateWalletAddressUseCase,
     private val walletManagersFacade: WalletManagersFacade,
@@ -135,7 +131,7 @@ internal class SendViewModel @Inject constructor(
                     getCurrenciesStatusUpdates(owner, wallet)
                 },
                 ifLeft = {
-                    // TODO add error handling
+                    // todo add error handling [[REDACTED_JIRA]]
                     return@launch
                 },
             )
@@ -299,7 +295,7 @@ internal class SendViewModel @Inject constructor(
                                     uiState = stateFactory.onFeeOnLoadedState(it, true)
                                 },
                                 ifLeft = {
-                                    // TODO add error handling
+                                    // todo add error handling [[REDACTED_JIRA]]
                                 },
                             )
                         }
@@ -421,7 +417,7 @@ internal class SendViewModel @Inject constructor(
 
         val amountToSend = amount.toBigDecimal().convertToAmount(cryptoCurrency)
 
-        // todo add notifications [[REDACTED_JIRA]]
+        // todo add error handling [[REDACTED_JIRA]]
         // val transactionErrors = walletManagersFacade.validateTransaction(
         //     amount = amountToSend,
         //     fee = fee.amount,
@@ -429,15 +425,19 @@ internal class SendViewModel @Inject constructor(
         //     network = cryptoCurrency.network,
         // )
 
-        val txData = walletManagersFacade.createTransaction(
+        createTransactionUseCase(
             amount = amountToSend,
             fee = fee,
             memo = memo,
             destination = recipient,
             userWalletId = userWalletId,
             network = cryptoCurrency.network,
-        )?.copy(extras = getMemoExtras(cryptoCurrency.network.id.value, memo)) ?: return
+        ).fold(
-
+            ifLeft = {
+                Timber.e(it)
+                // todo add error handling [[REDACTED_JIRA]]
+            },
+            ifRight = { txData ->
                 sendTransactionUseCase(
                     txData = txData,
                     userWallet = userWallet,
@@ -445,7 +445,7 @@ internal class SendViewModel @Inject constructor(
                 ).fold(
                     ifLeft = {
                         sendState.isSending.update { false }
-                // todo add notifications [[REDACTED_JIRA]]
+                        // todo add error handling [[REDACTED_JIRA]]
                     },
                     ifRight = {
                         sendState.transactionDate.update {
@@ -457,6 +457,8 @@ internal class SendViewModel @Inject constructor(
                         }
                     },
                 )
+            },
+        )
     }
 
     private fun getFee(feeState: FeeSelectorState.Content): Fee? {
@@ -499,25 +501,6 @@ internal class SendViewModel @Inject constructor(
     }
     // endregion
 
-    private fun getMemoExtras(networkId: String, memo: String?): TransactionExtras? {
-        val blockchain = Blockchain.fromId(networkId)
-        if (memo == null) return null
-        return when (blockchain) {
-            Blockchain.Stellar -> {
-                val xmlMemo = when (determineXlmMemoType(memo)) {
-                    XlmMemoType.TEXT -> StellarMemo.Text(memo)
-                    XlmMemoType.ID -> StellarMemo.Id(memo.toBigInteger())
-                }
-                StellarTransactionExtras(xmlMemo)
-            }
-            Blockchain.Binance -> BinanceTransactionExtras(memo)
-            Blockchain.XRP -> memo.toLongOrNull()?.let { XrpTransactionBuilder.XrpTransactionExtras(it) }
-            Blockchain.Cosmos -> CosmosTransactionExtras(memo)
-            Blockchain.TON -> TonTransactionExtras(memo)
-            else -> null
-        }
-    }
-
     companion object {
         private const val XRP_X_ADDRESS = 'X'
         private const val DEFAULT_VALUE = "0.00"

settings.gradle.kts

@@ -143,4 +143,5 @@ include(":data:settings")
 include(":data:txhistory")
 include(":data:wallets")
 include(":data:analytics")
+include(":data:transaction")
 // endregion Data modules