Updated on 2026-08-14

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

@@ -0,0 +1,73 @@
+package com.tangem.data.transaction
+
+import com.tangem.blockchain.common.Blockchain
+import com.tangem.blockchainsdk.utils.fromNetworkId
+import com.tangem.data.transaction.converters.GaslessTokenDtoToCryptoCurrencyConverter
+import com.tangem.datasource.api.common.response.getOrThrow
+import com.tangem.datasource.api.gasless.GaslessTxServiceApi
+import com.tangem.domain.models.currency.CryptoCurrency
+import com.tangem.domain.models.network.Network
+import com.tangem.domain.transaction.GaslessTransactionRepository
+import com.tangem.utils.coroutines.CoroutineDispatcherProvider
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.update
+import kotlinx.coroutines.withContext
+import java.math.BigInteger
+
+class DefaultGaslessTransactionRepository(
+    private val gaslessTxServiceApi: GaslessTxServiceApi,
+    private val coroutineDispatcherProvider: CoroutineDispatcherProvider,
+) : GaslessTransactionRepository {
+
+    private val gaslessTokenDtoToCryptoCurrency = GaslessTokenDtoToCryptoCurrencyConverter()
+    private val supportedTokensState = MutableStateFlow<Set<CryptoCurrency>?>(null)
+
+    override fun isNetworkSupported(network: Network): Boolean {
+        val blockchain = Blockchain.fromNetworkId(network.backendId) ?: return false
+        return SUPPORTED_BLOCKCHAINS.contains(blockchain)
+    }
+
+    override suspend fun getSupportedTokens(): Set<CryptoCurrency> {
+        return withContext(coroutineDispatcherProvider.io) {
+            val storedTokens = supportedTokensState.value
+            if (storedTokens != null) {
+                return@withContext storedTokens
+            }
+            val supportedTokensData = gaslessTxServiceApi.getSupportedTokens().getOrThrow()
+            if (supportedTokensData.isSuccess) {
+                val supportedTokens = supportedTokensData.result.tokens.map {
+                    gaslessTokenDtoToCryptoCurrency.convert(it)
+                }.toSet()
+                // update local cache
+                supportedTokensState.update { supportedTokens }
+                return@withContext supportedTokens
+            } else {
+                error("Gasless service returned unsuccessful response")
+            }
+        }
+    }
+
+    override fun getTokenFeeReceiverAddress(): String {
+        return TOKEN_RECEIVER_ADDRESS
+    }
+
+    override fun getBaseGasForTransaction(): BigInteger {
+        return BASE_GAS_FOR_TRANSACTION
+    }
+
+    private companion object {
+
+        const val TOKEN_RECEIVER_ADDRESS = "0x"
+
+        val BASE_GAS_FOR_TRANSACTION: BigInteger = BigInteger("100000")
+        val SUPPORTED_BLOCKCHAINS = arrayOf(
+            Blockchain.Ethereum,
+            Blockchain.BSC,
+            Blockchain.Base,
+            Blockchain.Polygon,
+            Blockchain.Arbitrum,
+            Blockchain.XDC,
+            Blockchain.Optimism,
+        )
+    }
+}

data/transaction/src/main/java/com/tangem/data/transaction/converters/GaslessTokenDtoToCryptoCurrencyConverter.kt

@@ -0,0 +1,12 @@
+package com.tangem.data.transaction.converters
+
+import com.tangem.datasource.api.gasless.models.GaslessTokenDTO
+import com.tangem.domain.models.currency.CryptoCurrency
+import com.tangem.utils.converter.Converter
+
+internal class GaslessTokenDtoToCryptoCurrencyConverter : Converter<GaslessTokenDTO, CryptoCurrency> {
+
+    override fun convert(value: GaslessTokenDTO): CryptoCurrency {
+        TODO("implement conversion logic here")
+    }
+}