Updated on 2026-08-14

features/send/impl/src/main/java/com/tangem/features/send/impl/presentation/state/fee/FeeConverter.kt

@@ -72,10 +72,7 @@ internal class FeeConverter(
             normalFee
         } else {
             when (normalFee) {
-                is Fee.Ethereum.Legacy -> ethereumCustomFeeConverter.convertBack(
-                    normalFee = normalFee,
-                    value = customValues,
-                )
+                is Fee.Ethereum -> ethereumCustomFeeConverter.convertBack(normalFee = normalFee, value = customValues)
                 is Fee.Bitcoin -> bitcoinCustomFeeConverter.convertBack(normalFee = normalFee, value = customValues)
                 is Fee.Kaspa -> kaspaCustomFeeConverter.convertBack(normalFee = normalFee, value = customValues)
                 else -> {

features/send/impl/src/main/java/com/tangem/features/send/impl/presentation/state/fee/SendFeeCustomFieldConverter.kt

@@ -49,7 +49,7 @@ internal class SendFeeCustomFieldConverter(
 
     override fun convert(value: Fee): ImmutableList<SendTextField.CustomFee> {
         return when (value) {
-            is Fee.Ethereum.Legacy -> ethereumCustomFeeConverter.convert(value)
+            is Fee.Ethereum -> ethereumCustomFeeConverter.convert(value)
             is Fee.Bitcoin -> bitcoinCustomFeeConverter.convert(value)
             is Fee.Kaspa -> kaspaCustomFeeConverter.convert(value)
             else -> persistentListOf()
@@ -59,6 +59,7 @@ internal class SendFeeCustomFieldConverter(
     fun onValueChange(feeSelectorState: FeeSelectorState.Content, index: Int, value: String) = feeSelectorState.copy(
         customValues = when (val fee = feeSelectorState.fees.normal) {
             is Fee.Ethereum -> ethereumCustomFeeConverter.onValueChange(
+                feeValue = fee,
                 customValues = feeSelectorState.customValues,
                 index = index,
                 value = value,

features/send/impl/src/main/java/com/tangem/features/send/impl/presentation/state/fee/custom/BaseEthereumCustomFeeConverter.kt

@@ -0,0 +1,24 @@
+package com.tangem.features.send.impl.presentation.state.fee.custom
+
+import com.tangem.blockchain.common.transaction.Fee
+import com.tangem.features.send.impl.presentation.state.fields.SendTextField
+import kotlinx.collections.immutable.ImmutableList
+
+/**
+ * Base ethereum custom fee converter
+ *
+ * @param T subtype of [Fee.Ethereum]
+ *
+[REDACTED_AUTHOR]
+ */
+internal interface BaseEthereumCustomFeeConverter<T : Fee.Ethereum> : CustomFeeConverter<T> {
+
+    fun getGasLimitIndex(feeValue: T): Int
+
+    fun onValueChange(
+        feeValue: T,
+        customValues: ImmutableList<SendTextField.CustomFee>,
+        index: Int,
+        value: String,
+    ): ImmutableList<SendTextField.CustomFee>
+}

features/send/impl/src/main/java/com/tangem/features/send/impl/presentation/state/fee/custom/EthereumCustomFeeConverter.kt

@@ -8,7 +8,6 @@ import com.tangem.blockchain.common.transaction.Fee
 import com.tangem.common.ui.amountScreen.utils.getFiatReference
 import com.tangem.core.ui.extensions.resourceReference
 import com.tangem.core.ui.utils.parseBigDecimal
-import com.tangem.core.ui.utils.parseToBigDecimal
 import com.tangem.domain.appcurrency.model.AppCurrency
 import com.tangem.domain.tokens.model.CryptoCurrencyStatus
 import com.tangem.features.send.impl.R
@@ -18,203 +17,115 @@ import com.tangem.features.send.impl.presentation.state.fields.SendTextField
 import com.tangem.features.send.impl.presentation.viewmodel.SendClickIntents
 import com.tangem.utils.Provider
 import kotlinx.collections.immutable.ImmutableList
-import kotlinx.collections.immutable.persistentListOf
 import kotlinx.collections.immutable.toImmutableList
-import java.math.RoundingMode
 
 internal class EthereumCustomFeeConverter(
     private val clickIntents: SendClickIntents,
     private val stateRouterProvider: Provider<StateRouter>,
     private val appCurrencyProvider: Provider<AppCurrency>,
     private val feeCryptoCurrencyStatusProvider: Provider<CryptoCurrencyStatus?>,
-) : CustomFeeConverter<Fee.Ethereum.Legacy> {
+) : BaseEthereumCustomFeeConverter<Fee.Ethereum> {
 
-    override fun convert(value: Fee.Ethereum.Legacy): ImmutableList<SendTextField.CustomFee> {
-        val feeValue = value.amount.value
-        val feeCurrency = feeCryptoCurrencyStatusProvider()?.value
-        return persistentListOf(
-            SendTextField.CustomFee(
-                value = feeValue?.parseBigDecimal(value.amount.decimals).orEmpty(),
-                decimals = value.amount.decimals,
-                symbol = value.amount.currencySymbol,
-                onValueChange = { clickIntents.onCustomFeeValueChange(FEE_AMOUNT, it) },
-                keyboardOptions = KeyboardOptions(
-                    imeAction = ImeAction.Next,
-                    keyboardType = KeyboardType.Number,
-                ),
-                title = resourceReference(R.string.send_max_fee),
-                footer = resourceReference(R.string.send_custom_amount_fee_footer),
-                label = getFiatReference(
-                    rate = feeCurrency?.fiatRate,
-                    value = feeValue,
-                    appCurrency = appCurrencyProvider(),
-                ),
-                keyboardActions = KeyboardActions(),
-            ),
-            SendTextField.CustomFee(
-                value = value.gasPrice.toBigDecimal().movePointLeft(GIGA_DECIMALS).parseBigDecimal(GIGA_DECIMALS),
-                decimals = GIGA_DECIMALS,
-                symbol = ETHEREUM_GAS_UNIT,
-                title = resourceReference(R.string.send_gas_price),
-                footer = resourceReference(R.string.send_gas_price_footer),
-                onValueChange = { clickIntents.onCustomFeeValueChange(GAS_PRICE, it) },
-                keyboardOptions = KeyboardOptions(
-                    imeAction = ImeAction.Next,
-                    keyboardType = KeyboardType.Number,
-                ),
-                keyboardActions = KeyboardActions(),
-            ),
-            SendTextField.CustomFee(
-                value = value.gasLimit.toString(),
-                decimals = GAS_DECIMALS,
-                symbol = "",
-                title = resourceReference(R.string.send_gas_limit),
-                footer = resourceReference(R.string.send_gas_limit_footer),
-                onValueChange = { clickIntents.onCustomFeeValueChange(GAS_LIMIT, it) },
-                keyboardOptions = KeyboardOptions(
-                    imeAction = if (
-                        checkExceedBalance(
-                            feeBalance = feeCurrency?.amount,
-                            feeAmount = feeValue,
-                        )
-                    ) {
-                        ImeAction.None
-                    } else {
-                        ImeAction.Done
-                    },
-                    keyboardType = KeyboardType.Number,
-                ),
-                keyboardActions = KeyboardActions(
-                    onDone = { clickIntents.onNextClick(stateRouterProvider().isEditState) },
-                ),
-            ),
-        )
+    private val feeCurrency: CryptoCurrencyStatus.Value?
+        get() = feeCryptoCurrencyStatusProvider()?.value
+
+    private val legacyFeeConverter = EthereumLegacyCustomFeeConverter(
+        clickIntents = clickIntents,
+        appCurrencyProvider = appCurrencyProvider,
+        feeCryptoCurrencyStatusProvider = feeCryptoCurrencyStatusProvider,
+    )
+
+    private val eipFeeConverter = EthereumEIPCustomFeeConverter(
+        clickIntents = clickIntents,
+        appCurrencyProvider = appCurrencyProvider,
+        feeCryptoCurrencyStatusProvider = feeCryptoCurrencyStatusProvider,
+    )
+
+    override fun convert(value: Fee.Ethereum): ImmutableList<SendTextField.CustomFee> {
+        return buildList {
+            convertFeeValue(value).let(::add)
+
+            when (value) {
+                is Fee.Ethereum.EIP1559 -> eipFeeConverter.convert(value)
+                is Fee.Ethereum.Legacy -> legacyFeeConverter.convert(value)
+            }
+                .let(::addAll)
+
+            convertGasLimitValue(value).let(::add)
+        }
+            .toImmutableList()
     }
 
-    override fun convertBack(
-        normalFee: Fee.Ethereum.Legacy,
-        value: ImmutableList<SendTextField.CustomFee>,
-    ): Fee.Ethereum.Legacy {
-        val feeAmount = value[FEE_AMOUNT].value.parseToBigDecimal(value[FEE_AMOUNT].decimals)
-        val gasPrice = value[GAS_PRICE].value.parseToBigDecimal(GAS_DECIMALS).toBigInteger()
-        val gasLimit = value[GAS_LIMIT].value.parseToBigDecimal(GAS_DECIMALS).toBigInteger()
-        return normalFee.copy(
-            amount = normalFee.amount.copy(value = feeAmount),
-            gasPrice = gasPrice,
-            gasLimit = gasLimit,
-        )
+    override fun convertBack(normalFee: Fee.Ethereum, value: ImmutableList<SendTextField.CustomFee>): Fee.Ethereum {
+        return when (normalFee) {
+            is Fee.Ethereum.EIP1559 -> eipFeeConverter.convertBack(normalFee = normalFee, value = value)
+            is Fee.Ethereum.Legacy -> legacyFeeConverter.convertBack(normalFee = normalFee, value = value)
+        }
     }
 
-    fun onValueChange(
+    override fun getGasLimitIndex(feeValue: Fee.Ethereum): Int {
+        return when (feeValue) {
+            is Fee.Ethereum.EIP1559 -> eipFeeConverter.getGasLimitIndex(feeValue)
+            is Fee.Ethereum.Legacy -> legacyFeeConverter.getGasLimitIndex(feeValue)
+        }
+    }
+
+    override fun onValueChange(
+        feeValue: Fee.Ethereum,
         customValues: ImmutableList<SendTextField.CustomFee>,
         index: Int,
         value: String,
     ): ImmutableList<SendTextField.CustomFee> {
-        val mutableCustomValues = customValues.toMutableList()
-        return mutableCustomValues.apply {
-            when (index) {
-                FEE_AMOUNT -> setOnAmountChange(value, index)
-                GAS_PRICE -> setOnGasPriceChange(value, index)
-                else -> setOnGasLimitChange(value, index)
-            }
-        }.toImmutableList()
-    }
-
-    private fun MutableList<SendTextField.CustomFee>.setEmpty(index: Int) {
-        set(index, this[index].copy(value = ""))
-    }
-
-    private fun MutableList<SendTextField.CustomFee>.setOnAmountChange(value: String, index: Int) {
-        val gasLimit = this[GAS_LIMIT].value.parseToBigDecimal(this[GAS_LIMIT].decimals)
-        if (value.isBlank()) {
-            setEmpty(FEE_AMOUNT)
-            setEmpty(GAS_PRICE)
-        } else {
-            val newFeeAmountDecimal = value.parseToBigDecimal(this[FEE_AMOUNT].decimals)
-            val newFeeAmount = newFeeAmountDecimal.movePointRight(this[GAS_PRICE].decimals) // from ETH to GWEI
-            val newGasPrice = newFeeAmount.divide(gasLimit, this[GAS_PRICE].decimals, RoundingMode.HALF_UP)
-            set(GAS_PRICE, this[GAS_PRICE].copy(value = newGasPrice.parseBigDecimal(this[GAS_PRICE].decimals)))
-            set(
-                index,
-                this[index].copy(
-                    value = value,
-                    label = getFiatReference(
-                        rate = feeCryptoCurrencyStatusProvider()?.value?.fiatRate,
-                        value = newFeeAmountDecimal,
-                        appCurrency = appCurrencyProvider(),
-                    ),
-                ),
-            )
+        return when (feeValue) {
+            is Fee.Ethereum.EIP1559 -> eipFeeConverter.onValueChange(feeValue, customValues, index, value)
+            is Fee.Ethereum.Legacy -> legacyFeeConverter.onValueChange(feeValue, customValues, index, value)
         }
     }
 
-    private fun MutableList<SendTextField.CustomFee>.setOnGasPriceChange(value: String, index: Int) {
-        val gasLimit = this[GAS_LIMIT].value.parseToBigDecimal(this[GAS_LIMIT].decimals)
-        if (value.isBlank()) {
-            setEmpty(FEE_AMOUNT)
-            setEmpty(GAS_PRICE)
-        } else {
-            val newGasPrice = value.parseToBigDecimal(this[GAS_PRICE].decimals)
-                .movePointLeft(this[GAS_PRICE].decimals) // from GWEI to ETH
-            val newFeeAmount = gasLimit * newGasPrice
-            set(
-                FEE_AMOUNT,
-                this[FEE_AMOUNT].copy(
-                    value = newFeeAmount.parseBigDecimal(this[FEE_AMOUNT].decimals),
-                    label = getFiatReference(
-                        rate = feeCryptoCurrencyStatusProvider()?.value?.fiatRate,
-                        value = newFeeAmount,
-                        appCurrency = appCurrencyProvider(),
-                    ),
-                ),
-            )
-            set(index, this[index].copy(value = value))
-        }
+    private fun convertFeeValue(value: Fee.Ethereum): SendTextField.CustomFee {
+        val feeValue = value.amount.value
+
+        return SendTextField.CustomFee(
+            value = feeValue?.parseBigDecimal(value.amount.decimals).orEmpty(),
+            decimals = value.amount.decimals,
+            symbol = value.amount.currencySymbol,
+            onValueChange = { clickIntents.onCustomFeeValueChange(FEE_AMOUNT, it) },
+            keyboardOptions = KeyboardOptions(imeAction = ImeAction.Next, keyboardType = KeyboardType.Number),
+            title = resourceReference(R.string.send_max_fee),
+            footer = resourceReference(R.string.send_custom_amount_fee_footer),
+            label = getFiatReference(
+                rate = feeCurrency?.fiatRate,
+                value = feeValue,
+                appCurrency = appCurrencyProvider(),
+            ),
+            keyboardActions = KeyboardActions(),
+        )
     }
 
-    private fun MutableList<SendTextField.CustomFee>.setOnGasLimitChange(value: String, index: Int) {
-        if (value.isBlank()) {
-            setEmpty(FEE_AMOUNT)
-            setEmpty(GAS_LIMIT)
-        } else {
-            val newGasLimit = value.parseToBigDecimal(this[GAS_LIMIT].decimals)
-            val gasPrice = this[GAS_PRICE].value.parseToBigDecimal(this[GAS_PRICE].decimals)
-                .movePointLeft(this[GAS_PRICE].decimals) // from GWEI to ETH
-            val newFeeAmount = newGasLimit * gasPrice
-            set(
-                FEE_AMOUNT,
-                this[FEE_AMOUNT].copy(
-                    value = newFeeAmount.parseBigDecimal(this[FEE_AMOUNT].decimals),
-                    label = getFiatReference(
-                        rate = feeCryptoCurrencyStatusProvider()?.value?.fiatRate,
-                        value = newFeeAmount,
-                        appCurrency = appCurrencyProvider(),
-                    ),
-                ),
-            )
-            val isNotExceedBalance = checkExceedBalance(
-                feeBalance = feeCryptoCurrencyStatusProvider()?.value?.amount,
-                feeAmount = newFeeAmount,
-            )
-            set(
-                index,
-                this[index].copy(
-                    value = value,
-                    keyboardOptions = KeyboardOptions(
-                        imeAction = if (!isNotExceedBalance) ImeAction.None else ImeAction.Done,
-                        keyboardType = KeyboardType.Number,
-                    ),
-                ),
-            )
-        }
+    private fun convertGasLimitValue(value: Fee.Ethereum): SendTextField.CustomFee {
+        val isExceedBalance = checkExceedBalance(feeBalance = feeCurrency?.amount, feeAmount = value.amount.value)
+
+        return SendTextField.CustomFee(
+            value = value.gasLimit.toString(),
+            decimals = GAS_DECIMALS,
+            symbol = "",
+            title = resourceReference(R.string.send_gas_limit),
+            footer = resourceReference(R.string.send_gas_limit_footer),
+            onValueChange = { clickIntents.onCustomFeeValueChange(getGasLimitIndex(value), it) },
+            keyboardOptions = KeyboardOptions(
+                imeAction = if (isExceedBalance) ImeAction.None else ImeAction.Done,
+                keyboardType = KeyboardType.Number,
+            ),
+            keyboardActions = KeyboardActions(
+                onDone = { clickIntents.onNextClick(stateRouterProvider().isEditState) },
+            ),
+        )
     }
 
     companion object {
-        private const val ETHEREUM_GAS_UNIT = "GWEI"
-        private const val GIGA_DECIMALS = 9
-        private const val FEE_AMOUNT = 0
-        private const val GAS_PRICE = 1
-        private const val GAS_LIMIT = 2
-        private const val GAS_DECIMALS = 0
+        const val ETHEREUM_GAS_UNIT = "GWEI"
+        const val GIGA_DECIMALS = 9
+        const val GAS_DECIMALS = 0
+        const val FEE_AMOUNT = 0
     }
 }

features/send/impl/src/main/java/com/tangem/features/send/impl/presentation/state/fee/custom/EthereumEIPCustomFeeConverter.kt

@@ -0,0 +1,156 @@
+package com.tangem.features.send.impl.presentation.state.fee.custom
+
+import androidx.compose.foundation.text.KeyboardActions
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.ui.text.input.ImeAction
+import androidx.compose.ui.text.input.KeyboardType
+import com.tangem.blockchain.common.transaction.Fee
+import com.tangem.common.ui.amountScreen.utils.getFiatReference
+import com.tangem.core.ui.extensions.resourceReference
+import com.tangem.core.ui.utils.parseBigDecimal
+import com.tangem.core.ui.utils.parseToBigDecimal
+import com.tangem.domain.appcurrency.model.AppCurrency
+import com.tangem.domain.tokens.model.CryptoCurrencyStatus
+import com.tangem.features.send.impl.R
+import com.tangem.features.send.impl.presentation.state.fee.custom.EthereumCustomFeeConverter.Companion.ETHEREUM_GAS_UNIT
+import com.tangem.features.send.impl.presentation.state.fee.custom.EthereumCustomFeeConverter.Companion.FEE_AMOUNT
+import com.tangem.features.send.impl.presentation.state.fee.custom.EthereumCustomFeeConverter.Companion.GAS_DECIMALS
+import com.tangem.features.send.impl.presentation.state.fee.custom.EthereumCustomFeeConverter.Companion.GIGA_DECIMALS
+import com.tangem.features.send.impl.presentation.state.fields.SendTextField
+import com.tangem.features.send.impl.presentation.viewmodel.SendClickIntents
+import com.tangem.utils.Provider
+import kotlinx.collections.immutable.ImmutableList
+import kotlinx.collections.immutable.persistentListOf
+import kotlinx.collections.immutable.toImmutableList
+import java.math.RoundingMode
+
+internal class EthereumEIPCustomFeeConverter(
+    private val clickIntents: SendClickIntents,
+    private val appCurrencyProvider: Provider<AppCurrency>,
+    private val feeCryptoCurrencyStatusProvider: Provider<CryptoCurrencyStatus?>,
+) : BaseEthereumCustomFeeConverter<Fee.Ethereum.EIP1559> {
+
+    override fun convert(value: Fee.Ethereum.EIP1559): ImmutableList<SendTextField.CustomFee> {
+        return persistentListOf(
+            SendTextField.CustomFee(
+                value = value.maxFeePerGas.toBigDecimal().movePointLeft(GIGA_DECIMALS).parseBigDecimal(GIGA_DECIMALS),
+                decimals = GIGA_DECIMALS,
+                symbol = ETHEREUM_GAS_UNIT,
+                title = resourceReference(R.string.send_custom_evm_max_fee),
+                footer = resourceReference(R.string.send_custom_evm_max_fee_footer),
+                onValueChange = { clickIntents.onCustomFeeValueChange(MAX_FEE, it) },
+                keyboardOptions = KeyboardOptions(imeAction = ImeAction.Next, keyboardType = KeyboardType.Number),
+                keyboardActions = KeyboardActions(),
+            ),
+            SendTextField.CustomFee(
+                value = value.priorityFee.toBigDecimal().movePointLeft(GIGA_DECIMALS).parseBigDecimal(GIGA_DECIMALS),
+                decimals = GIGA_DECIMALS,
+                symbol = ETHEREUM_GAS_UNIT,
+                title = resourceReference(R.string.send_custom_evm_priority_fee),
+                footer = resourceReference(R.string.send_custom_evm_priority_fee_footer),
+                onValueChange = { clickIntents.onCustomFeeValueChange(PRIORITY_FEE, it) },
+                keyboardOptions = KeyboardOptions(imeAction = ImeAction.Next, keyboardType = KeyboardType.Number),
+                keyboardActions = KeyboardActions(),
+            ),
+        )
+    }
+
+    override fun convertBack(
+        normalFee: Fee.Ethereum.EIP1559,
+        value: ImmutableList<SendTextField.CustomFee>,
+    ): Fee.Ethereum.EIP1559 {
+        val feeAmount = value[FEE_AMOUNT].value.parseToBigDecimal(value[FEE_AMOUNT].decimals)
+        val maxFee = value[MAX_FEE].value.parseToBigDecimal(GAS_DECIMALS).toBigInteger()
+        val priorityFee = value[PRIORITY_FEE].value.parseToBigDecimal(GAS_DECIMALS).toBigInteger()
+        val gasLimit = value[GAS_LIMIT].value.parseToBigDecimal(GAS_DECIMALS).toBigInteger()
+
+        return normalFee.copy(
+            amount = normalFee.amount.copy(value = feeAmount),
+            maxFeePerGas = maxFee,
+            priorityFee = priorityFee,
+            gasLimit = gasLimit,
+        )
+    }
+
+    override fun getGasLimitIndex(feeValue: Fee.Ethereum.EIP1559): Int = GAS_LIMIT
+
+    override fun onValueChange(
+        feeValue: Fee.Ethereum.EIP1559,
+        customValues: ImmutableList<SendTextField.CustomFee>,
+        index: Int,
+        value: String,
+    ): ImmutableList<SendTextField.CustomFee> {
+        val mutableCustomValues = customValues.toMutableList()
+        return mutableCustomValues.apply {
+            when (index) {
+                FEE_AMOUNT -> setOnAmountChange(value, index)
+                MAX_FEE -> setOnMaxFeeChange(value, index)
+                else -> set(index, this[index].copy(value = value))
+            }
+        }.toImmutableList()
+    }
+
+    private fun MutableList<SendTextField.CustomFee>.setEmpty(index: Int) {
+        set(index, this[index].copy(value = ""))
+    }
+
+    private fun MutableList<SendTextField.CustomFee>.setOnAmountChange(value: String, index: Int) {
+        val gasLimit = this[GAS_LIMIT].value.parseToBigDecimal(this[GAS_LIMIT].decimals)
+        if (value.isBlank()) {
+            setEmpty(FEE_AMOUNT)
+            setEmpty(MAX_FEE)
+        } else {
+            val newFeeAmountDecimal = value.parseToBigDecimal(this[FEE_AMOUNT].decimals)
+            val newFeeAmount = newFeeAmountDecimal.movePointRight(GIGA_DECIMALS) // from ETH to GWEI
+
+            val newMaxFee = newFeeAmount.divide(gasLimit, this[MAX_FEE].decimals, RoundingMode.HALF_UP)
+
+            set(
+                index = MAX_FEE,
+                element = this[MAX_FEE].copy(value = newMaxFee.parseBigDecimal(this[MAX_FEE].decimals)),
+            )
+
+            set(
+                index = index,
+                element = this[index].copy(
+                    value = value,
+                    label = getFiatReference(
+                        rate = feeCryptoCurrencyStatusProvider()?.value?.fiatRate,
+                        value = newFeeAmountDecimal,
+                        appCurrency = appCurrencyProvider(),
+                    ),
+                ),
+            )
+        }
+    }
+
+    private fun MutableList<SendTextField.CustomFee>.setOnMaxFeeChange(value: String, index: Int) {
+        val gasLimit = this[GAS_LIMIT].value.parseToBigDecimal(this[GAS_LIMIT].decimals)
+
+        if (value.isBlank()) {
+            setEmpty(FEE_AMOUNT)
+            setEmpty(MAX_FEE)
+        } else {
+            val newMaxFee = value.parseToBigDecimal(this[MAX_FEE].decimals).movePointLeft(this[MAX_FEE].decimals)
+            val newFeeAmount = gasLimit * newMaxFee
+            set(
+                FEE_AMOUNT,
+                this[FEE_AMOUNT].copy(
+                    value = newFeeAmount.parseBigDecimal(this[FEE_AMOUNT].decimals),
+                    label = getFiatReference(
+                        rate = feeCryptoCurrencyStatusProvider()?.value?.fiatRate,
+                        value = newFeeAmount,
+                        appCurrency = appCurrencyProvider(),
+                    ),
+                ),
+            )
+            set(index, this[index].copy(value = value))
+        }
+    }
+
+    private companion object {
+        const val MAX_FEE = 1
+        const val PRIORITY_FEE = 2
+        const val GAS_LIMIT = 3
+    }
+}

features/send/impl/src/main/java/com/tangem/features/send/impl/presentation/state/fee/custom/EthereumLegacyCustomFeeConverter.kt

@@ -0,0 +1,140 @@
+package com.tangem.features.send.impl.presentation.state.fee.custom
+
+import androidx.compose.foundation.text.KeyboardActions
+import androidx.compose.foundation.text.KeyboardOptions
+import androidx.compose.ui.text.input.ImeAction
+import androidx.compose.ui.text.input.KeyboardType
+import com.tangem.blockchain.common.transaction.Fee
+import com.tangem.common.ui.amountScreen.utils.getFiatReference
+import com.tangem.core.ui.extensions.resourceReference
+import com.tangem.core.ui.utils.parseBigDecimal
+import com.tangem.core.ui.utils.parseToBigDecimal
+import com.tangem.domain.appcurrency.model.AppCurrency
+import com.tangem.domain.tokens.model.CryptoCurrencyStatus
+import com.tangem.features.send.impl.R
+import com.tangem.features.send.impl.presentation.state.fee.custom.EthereumCustomFeeConverter.Companion.ETHEREUM_GAS_UNIT
+import com.tangem.features.send.impl.presentation.state.fee.custom.EthereumCustomFeeConverter.Companion.FEE_AMOUNT
+import com.tangem.features.send.impl.presentation.state.fee.custom.EthereumCustomFeeConverter.Companion.GAS_DECIMALS
+import com.tangem.features.send.impl.presentation.state.fee.custom.EthereumCustomFeeConverter.Companion.GIGA_DECIMALS
+import com.tangem.features.send.impl.presentation.state.fields.SendTextField
+import com.tangem.features.send.impl.presentation.viewmodel.SendClickIntents
+import com.tangem.utils.Provider
+import kotlinx.collections.immutable.ImmutableList
+import kotlinx.collections.immutable.persistentListOf
+import kotlinx.collections.immutable.toImmutableList
+import java.math.RoundingMode
+
+internal class EthereumLegacyCustomFeeConverter(
+    private val clickIntents: SendClickIntents,
+    private val appCurrencyProvider: Provider<AppCurrency>,
+    private val feeCryptoCurrencyStatusProvider: Provider<CryptoCurrencyStatus?>,
+) : BaseEthereumCustomFeeConverter<Fee.Ethereum.Legacy> {
+
+    override fun convert(value: Fee.Ethereum.Legacy): ImmutableList<SendTextField.CustomFee> {
+        return persistentListOf(
+            SendTextField.CustomFee(
+                value = value.gasPrice.toBigDecimal().movePointLeft(GIGA_DECIMALS).parseBigDecimal(GIGA_DECIMALS),
+                decimals = GIGA_DECIMALS,
+                symbol = ETHEREUM_GAS_UNIT,
+                title = resourceReference(R.string.send_gas_price),
+                footer = resourceReference(R.string.send_gas_price_footer),
+                onValueChange = { clickIntents.onCustomFeeValueChange(GAS_PRICE, it) },
+                keyboardOptions = KeyboardOptions(
+                    imeAction = ImeAction.Next,
+                    keyboardType = KeyboardType.Number,
+                ),
+                keyboardActions = KeyboardActions(),
+            ),
+        )
+    }
+
+    override fun convertBack(
+        normalFee: Fee.Ethereum.Legacy,
+        value: ImmutableList<SendTextField.CustomFee>,
+    ): Fee.Ethereum.Legacy {
+        val feeAmount = value[FEE_AMOUNT].value.parseToBigDecimal(value[FEE_AMOUNT].decimals)
+        val gasPrice = value[GAS_PRICE].value.parseToBigDecimal(GAS_DECIMALS).toBigInteger()
+        val gasLimit = value[GAS_LIMIT].value.parseToBigDecimal(GAS_DECIMALS).toBigInteger()
+
+        return normalFee.copy(
+            amount = normalFee.amount.copy(value = feeAmount),
+            gasPrice = gasPrice,
+            gasLimit = gasLimit,
+        )
+    }
+
+    override fun getGasLimitIndex(feeValue: Fee.Ethereum.Legacy): Int = GAS_LIMIT
+
+    override fun onValueChange(
+        feeValue: Fee.Ethereum.Legacy,
+        customValues: ImmutableList<SendTextField.CustomFee>,
+        index: Int,
+        value: String,
+    ): ImmutableList<SendTextField.CustomFee> {
+        val mutableCustomValues = customValues.toMutableList()
+        return mutableCustomValues.apply {
+            when (index) {
+                FEE_AMOUNT -> setOnAmountChange(value, index)
+                GAS_PRICE -> setOnGasPriceChange(value, index)
+                else -> set(index, this[index].copy(value = value))
+            }
+        }.toImmutableList()
+    }
+
+    private fun MutableList<SendTextField.CustomFee>.setEmpty(index: Int) {
+        set(index, this[index].copy(value = ""))
+    }
+
+    private fun MutableList<SendTextField.CustomFee>.setOnAmountChange(value: String, index: Int) {
+        val gasLimit = this[GAS_LIMIT].value.parseToBigDecimal(this[GAS_LIMIT].decimals)
+        if (value.isBlank()) {
+            setEmpty(FEE_AMOUNT)
+            setEmpty(GAS_PRICE)
+        } else {
+            val newFeeAmountDecimal = value.parseToBigDecimal(this[FEE_AMOUNT].decimals)
+            val newFeeAmount = newFeeAmountDecimal.movePointRight(this[GAS_PRICE].decimals) // from ETH to GWEI
+            val newGasPrice = newFeeAmount.divide(gasLimit, this[GAS_PRICE].decimals, RoundingMode.HALF_UP)
+            set(GAS_PRICE, this[GAS_PRICE].copy(value = newGasPrice.parseBigDecimal(this[GAS_PRICE].decimals)))
+            set(
+                index,
+                this[index].copy(
+                    value = value,
+                    label = getFiatReference(
+                        rate = feeCryptoCurrencyStatusProvider()?.value?.fiatRate,
+                        value = newFeeAmountDecimal,
+                        appCurrency = appCurrencyProvider(),
+                    ),
+                ),
+            )
+        }
+    }
+
+    private fun MutableList<SendTextField.CustomFee>.setOnGasPriceChange(value: String, index: Int) {
+        val gasLimit = this[GAS_LIMIT].value.parseToBigDecimal(this[GAS_LIMIT].decimals)
+        if (value.isBlank()) {
+            setEmpty(FEE_AMOUNT)
+            setEmpty(GAS_PRICE)
+        } else {
+            val newGasPrice = value.parseToBigDecimal(this[GAS_PRICE].decimals)
+                .movePointLeft(this[GAS_PRICE].decimals) // from GWEI to ETH
+            val newFeeAmount = gasLimit * newGasPrice
+            set(
+                FEE_AMOUNT,
+                this[FEE_AMOUNT].copy(
+                    value = newFeeAmount.parseBigDecimal(this[FEE_AMOUNT].decimals),
+                    label = getFiatReference(
+                        rate = feeCryptoCurrencyStatusProvider()?.value?.fiatRate,
+                        value = newFeeAmount,
+                        appCurrency = appCurrencyProvider(),
+                    ),
+                ),
+            )
+            set(index, this[index].copy(value = value))
+        }
+    }
+
+    private companion object {
+        const val GAS_PRICE = 1
+        const val GAS_LIMIT = 2
+    }
+}