Updated on 2026-08-14

blockchain/src/main/java/com/tangem/blockchain/blockchains/binance/BinanceTransactionBuilder.kt

@@ -1,6 +1,5 @@
 package com.tangem.blockchain.blockchains.binance
 
-import com.tangem.blockchain.blockchains.binance.client.BinanceDexApiRestClient
 import com.tangem.blockchain.blockchains.binance.client.domain.broadcast.TransactionOption
 import com.tangem.blockchain.blockchains.binance.client.domain.broadcast.Transfer
 import com.tangem.blockchain.blockchains.binance.client.encoding.message.MessageType
@@ -8,6 +7,8 @@ import com.tangem.blockchain.blockchains.binance.client.encoding.message.Transac
 import com.tangem.blockchain.blockchains.binance.client.encoding.message.TransferMessage
 import com.tangem.blockchain.common.Blockchain
 import com.tangem.blockchain.common.TransactionData
+import com.tangem.blockchain.extensions.Result
+import com.tangem.blockchain.extensions.isAboveZero
 import com.tangem.common.extensions.calculateSha256
 import com.tangem.common.extensions.toCompressedPublicKey
 import org.bitcoinj.core.ECKey
@@ -15,7 +16,7 @@ import org.bitcoinj.core.Utils
 import java.math.BigInteger
 
 class BinanceTransactionBuilder(
-        publicKey: ByteArray, private val client: BinanceDexApiRestClient, isTestNet: Boolean = false
+        publicKey: ByteArray, isTestNet: Boolean = false
 ) {
     var accountNumber: Long? = null
     var sequence: Long? = null
@@ -26,7 +27,12 @@ class BinanceTransactionBuilder(
     private var transactionAssembler: TransactionRequestAssemblerExtSign? = null
     private var transferMessage: TransferMessage? = null
 
-    fun buildToSign(transactionData: TransactionData): ByteArray {
+    fun buildToSign(transactionData: TransactionData): Result<ByteArray> {
+
+        if (!transactionData.amount.isAboveZero()) return Result.Failure(Exception("Transaction amount is not defined"))
+        val accountNumber = accountNumber ?: return Result.Failure(Exception("No account number"))
+        val sequence = sequence ?: return Result.Failure(Exception("No sequence"))
+
         val transfer = Transfer()
         transfer.coin = transactionData.amount.currencySymbol
         transfer.fromAddress = transactionData.sourceAddress
@@ -36,12 +42,12 @@ class BinanceTransactionBuilder(
 
         val options = TransactionOption.DEFAULT_INSTANCE
 
-        val accountData = BinanceAccountData(chainId, accountNumber!!, sequence!!)
+        val accountData = BinanceAccountData(chainId, accountNumber, sequence)
 
-        transactionAssembler = client.prepareTransfer(transfer, accountData, prefixedPubKey, options, true)
+        transactionAssembler = TransactionRequestAssemblerExtSign(accountData, prefixedPubKey, options)
         transferMessage = transactionAssembler!!.createTransferMessage(transfer)
 
-        return transactionAssembler!!.prepareForSign(transferMessage).calculateSha256()
+        return Result.Success(transactionAssembler!!.prepareForSign(transferMessage).calculateSha256())
     }
 
     fun buildToSend(signature: ByteArray): ByteArray {

blockchain/src/main/java/com/tangem/blockchain/blockchains/binance/BinanceWalletManager.kt

@@ -39,14 +39,18 @@ class BinanceWalletManager(
     }
 
     override suspend fun send(transactionData: TransactionData, signer: TransactionSigner): SimpleResult {
-        val transactionHash = transactionBuilder.buildToSign(transactionData)
-
-        when (val signerResponse = signer.sign(arrayOf(transactionHash), cardId)) {
-            is CompletionResult.Success -> {
-                val transactionToSend = transactionBuilder.buildToSend(signerResponse.data.signature)
-                return networkManager.sendTransaction(transactionToSend)
+        val buildTransactionResult = transactionBuilder.buildToSign(transactionData)
+        when (buildTransactionResult) {
+            is Result.Failure -> return SimpleResult.Failure(buildTransactionResult.error)
+            is Result.Success -> {
+                when (val signerResponse = signer.sign(arrayOf(buildTransactionResult.data), cardId)) {
+                    is CompletionResult.Success -> {
+                        val transactionToSend = transactionBuilder.buildToSend(signerResponse.data.signature)
+                        return networkManager.sendTransaction(transactionToSend)
+                    }
+                    is CompletionResult.Failure -> return SimpleResult.Failure(signerResponse.error)
+                }
             }
-            is CompletionResult.Failure -> return SimpleResult.Failure(signerResponse.error)
         }
     }
 

blockchain/src/main/java/com/tangem/blockchain/blockchains/binance/network/BinanceNetworkManager.kt

@@ -1,6 +1,7 @@
 package com.tangem.blockchain.blockchains.binance.network
 
 import com.tangem.blockchain.blockchains.binance.client.BinanceDexApiClientFactory
+import com.tangem.blockchain.blockchains.binance.client.BinanceDexApiRestClient
 import com.tangem.blockchain.blockchains.binance.client.BinanceDexEnvironment
 import com.tangem.blockchain.blockchains.binance.client.encoding.message.TransactionRequestAssemblerExtSign
 import com.tangem.blockchain.common.Blockchain
@@ -14,11 +15,15 @@ import okhttp3.RequestBody
 import java.math.BigDecimal
 
 class BinanceNetworkManager(isTestNet: Boolean = false) {
-    val api = createRetrofitInstance(if (!isTestNet) API_BINANCE else API_BINANCE_TESTNET)
-            .create(BinanceApi::class.java)
-    val client = BinanceDexApiClientFactory.newInstance().newRestClient(
-            if (!isTestNet) BinanceDexEnvironment.PROD.baseUrl else BinanceDexEnvironment.TEST_NET.baseUrl
-    )
+    val api: BinanceApi by lazy {
+        createRetrofitInstance(if (!isTestNet) API_BINANCE else API_BINANCE_TESTNET)
+                .create(BinanceApi::class.java)
+    }
+    val client: BinanceDexApiRestClient by lazy {
+        BinanceDexApiClientFactory.newInstance().newRestClient(
+                if (!isTestNet) BinanceDexEnvironment.PROD.baseUrl else BinanceDexEnvironment.TEST_NET.baseUrl
+        )
+    }
 
     suspend fun getInfo(address: String): Result<BinanceInfoResponse> {
         return try {

blockchain/src/main/java/com/tangem/blockchain/blockchains/bitcoin/BitcoinWalletManager.kt

@@ -89,6 +89,6 @@ class BitcoinWalletManager(
     private fun BigDecimal.calculateFee(transactionSize: BigDecimal): BigDecimal {
         val bytesInKb = BigDecimal(1024)
         return this.divide(bytesInKb).multiply(transactionSize)
-                .setScale(8, blockchain.roundingMode())
+                .setScale(8, BigDecimal.ROUND_DOWN)
     }
 }

blockchain/src/main/java/com/tangem/blockchain/blockchains/ethereum/network/EthereumNetworkManager.kt

@@ -1,6 +1,5 @@
 package com.tangem.blockchain.blockchains.ethereum.network
 
-import com.tangem.blockchain.common.Blockchain
 import com.tangem.blockchain.extensions.Result
 import com.tangem.blockchain.extensions.SimpleResult
 import com.tangem.blockchain.extensions.retryIO
@@ -87,7 +86,7 @@ class EthereumNetworkManager {
 
     private fun BigDecimal.convertFeeToEth(): BigDecimal {
         return this.divide(ETH_IN_WEI.toBigDecimal())
-                .setScale(12, Blockchain.Ethereum.roundingMode()).stripTrailingZeros()
+                .setScale(12, BigDecimal.ROUND_DOWN).stripTrailingZeros()
     }
 
 }

blockchain/src/main/java/com/tangem/blockchain/common/Amount.kt

@@ -21,4 +21,6 @@ data class Amount(
 
     constructor(amount: Amount, value: BigDecimal) :
             this(amount.currencySymbol, value, amount.address, amount.decimals, amount.type)
-}
+}
+
+enum class AmountType { Coin, Token, Reserve }

blockchain/src/main/java/com/tangem/blockchain/common/Token.kt

@@ -0,0 +1,7 @@
+package com.tangem.blockchain.common
+
+data class Token(
+        val symbol: String,
+        val contractAddress: String,
+        val decimals: Int
+)

blockchain/src/main/java/com/tangem/blockchain/common/Wallet.kt

@@ -58,13 +58,4 @@ class Wallet(
         return amounts[amountType]?.value ?: BigDecimal.ZERO
     }
 
-//    fun validateTransaction(amount: Amount, fee: Amount?): EnumSet<ValidationError> {
-//        TODO("not implemented")
-//    }
-}
-
-enum class AmountType { Coin, Token, Reserve }
-
-interface TransactionValidator {
-    fun validateTransaction(amount: Amount, fee: Amount?): EnumSet<TransactionError>
 }

blockchain/src/main/java/com/tangem/blockchain/common/WalletManagerFactory.kt

@@ -82,19 +82,17 @@ object WalletManagerFactory {
                 )
             }
             Blockchain.Binance -> {
-                val networkManager = BinanceNetworkManager()
                 return BinanceWalletManager(
                         cardId, wallet,
-                        BinanceTransactionBuilder(walletPublicKey, networkManager.client),
-                        networkManager
+                        BinanceTransactionBuilder(walletPublicKey),
+                        BinanceNetworkManager()
                 )
             }
             Blockchain.BinanceTestnet -> {
-                val networkManager = BinanceNetworkManager(true)
                 return BinanceWalletManager(
                         cardId, wallet,
-                        BinanceTransactionBuilder(walletPublicKey, networkManager.client, true),
-                        networkManager
+                        BinanceTransactionBuilder(walletPublicKey, true),
+                        BinanceNetworkManager(true)
                 )
             }
             else -> return null
@@ -107,10 +105,4 @@ object WalletManagerFactory {
         val decimals = card.cardData?.tokenDecimal ?: return null
         return Token(symbol, contractAddress, decimals)
     }
-}
-
-data class Token(
-        val symbol: String,
-        val contractAddress: String,
-        val decimals: Int
-)
+}