Updated on 2026-08-14

features/swap/presentation/src/main/java/com/tangem/feature/swap/ui/StateBuilder.kt

@@ -693,6 +693,32 @@ internal class StateBuilder(
         )
     }
 
+    fun updateSendCurrencyBalance(
+        uiState: SwapStateHolder,
+        cryptoCurrencyStatus: CryptoCurrencyStatus,
+    ): SwapStateHolder {
+        if (uiState.sendCardData !is SwapCardState.SwapCardData) return uiState
+
+        return uiState.copy(
+            sendCardData = uiState.sendCardData.copy(
+                balance = cryptoCurrencyStatus.getFormattedAmount(isNeedSymbol = false),
+            ),
+        )
+    }
+
+    fun updateReceiveCurrencyBalance(
+        uiState: SwapStateHolder,
+        cryptoCurrencyStatus: CryptoCurrencyStatus,
+    ): SwapStateHolder {
+        if (uiState.receiveCardData !is SwapCardState.SwapCardData) return uiState
+
+        return uiState.copy(
+            receiveCardData = uiState.receiveCardData.copy(
+                balance = cryptoCurrencyStatus.getFormattedAmount(isNeedSymbol = false),
+            ),
+        )
+    }
+
     fun updateBalanceHiddenState(uiState: SwapStateHolder, isBalanceHidden: Boolean): SwapStateHolder {
         if (uiState.sendCardData !is SwapCardState.SwapCardData) return uiState
         if (uiState.receiveCardData !is SwapCardState.SwapCardData) return uiState

features/swap/presentation/src/main/java/com/tangem/feature/swap/viewmodels/SwapViewModel.kt

@@ -4,6 +4,7 @@ import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.setValue
 import androidx.lifecycle.*
+import arrow.core.Either
 import arrow.core.getOrElse
 import com.tangem.core.analytics.api.AnalyticsEventHandler
 import com.tangem.core.analytics.models.AnalyticsParam
@@ -13,11 +14,13 @@ import com.tangem.domain.appcurrency.GetSelectedAppCurrencyUseCase
 import com.tangem.domain.appcurrency.model.AppCurrency
 import com.tangem.domain.balancehiding.GetBalanceHidingSettingsUseCase
 import com.tangem.domain.tokens.GetCryptoCurrencyStatusSyncUseCase
+import com.tangem.domain.tokens.GetCurrencyStatusUpdatesUseCase
 import com.tangem.domain.tokens.UpdateDelayedNetworkStatusUseCase
 import com.tangem.domain.tokens.model.CryptoCurrency
 import com.tangem.domain.tokens.model.CryptoCurrencyStatus
 import com.tangem.domain.tokens.model.Network
 import com.tangem.domain.wallets.models.UserWallet
+import com.tangem.domain.wallets.models.UserWalletId
 import com.tangem.feature.swap.analytics.SwapEvents
 import com.tangem.feature.swap.domain.BlockchainInteractor
 import com.tangem.feature.swap.domain.SwapInteractor
@@ -62,6 +65,7 @@ internal class SwapViewModel @Inject constructor(
     private val getSelectedAppCurrencyUseCase: GetSelectedAppCurrencyUseCase,
     private val getCryptoCurrencyStatusUseCase: GetCryptoCurrencyStatusSyncUseCase,
     private val updateDelayedCurrencyStatusUseCase: UpdateDelayedNetworkStatusUseCase,
+    private val getCurrencyStatusUpdatesUseCase: GetCurrencyStatusUpdatesUseCase,
     savedStateHandle: SavedStateHandle,
 ) : ViewModel(), DefaultLifecycleObserver {
 
@@ -104,6 +108,9 @@ internal class SwapViewModel @Inject constructor(
             (it.error is DataError.ExchangeTooSmallAmountError || it.error is DataError.ExchangeTooBigAmountError)
     }
 
+    private val fromTokenBalanceJobHolder = JobHolder()
+    private val toTokenBalanceJobHolder = JobHolder()
+
     val currentScreen: SwapNavScreen
         get() = swapRouter.currentScreen
 
@@ -173,6 +180,23 @@ internal class SwapViewModel @Inject constructor(
                         state,
                     ),
                 )
+
+                val userWalletId = swapInteractor.getSelectedWallet()?.walletId ?: return@launch
+                (dataState.fromCryptoCurrency?.currency as? CryptoCurrency.Coin)?.let {
+                    subscribeToCoinBalanceUpdates(
+                        userWalletId = userWalletId,
+                        coin = it,
+                        isFromCurrency = true,
+                    )
+                }
+
+                (dataState.toCryptoCurrency?.currency as? CryptoCurrency.Coin)?.let {
+                    subscribeToCoinBalanceUpdates(
+                        userWalletId = userWalletId,
+                        coin = it,
+                        isFromCurrency = false,
+                    )
+                }
             }.onFailure {
                 Timber.tag(loggingTag).e(it)
 
@@ -617,7 +641,6 @@ internal class SwapViewModel @Inject constructor(
                         unavailable = unavailable,
                         afterSearch = true,
                     ),
-
                 )
             } else {
                 tokenDataState.copy(
@@ -647,15 +670,35 @@ internal class SwapViewModel @Inject constructor(
             analyticsEventHandler.send(SwapEvents.ChooseTokenScreenResult(tokenChosen = true, token = it))
         }
 
+        val userWalletId = swapInteractor.getSelectedWallet()?.walletId
+
         if (foundToken != null) {
             val fromToken: CryptoCurrencyStatus
             val toToken: CryptoCurrencyStatus
             if (isOrderReversed) {
                 fromToken = foundToken.currencyStatus
                 toToken = initialCryptoCurrencyStatus
+
+                val newToken = fromToken.currency as? CryptoCurrency.Coin
+                if (userWalletId != null && newToken != null) {
+                    subscribeToCoinBalanceUpdates(
+                        userWalletId = userWalletId,
+                        coin = newToken,
+                        isFromCurrency = true,
+                    )
+                }
             } else {
                 fromToken = initialCryptoCurrencyStatus
                 toToken = foundToken.currencyStatus
+
+                val newToken = toToken.currency as? CryptoCurrency.Coin
+                if (userWalletId != null && newToken != null) {
+                    subscribeToCoinBalanceUpdates(
+                        userWalletId = userWalletId,
+                        coin = newToken,
+                        isFromCurrency = false,
+                    )
+                }
             }
             dataState = dataState.copy(
                 fromCryptoCurrency = fromToken,
@@ -673,6 +716,36 @@ internal class SwapViewModel @Inject constructor(
         }
     }
 
+    private fun subscribeToCoinBalanceUpdates(
+        userWalletId: UserWalletId,
+        coin: CryptoCurrency.Coin,
+        isFromCurrency: Boolean,
+    ) {
+        Timber.d("Subscribe to ${coin.id} balance updates")
+
+        getCurrencyStatusUpdatesUseCase(
+            userWalletId = userWalletId,
+            currencyId = coin.id,
+            isSingleWalletWithTokens = false,
+        )
+            .mapNotNull { (it as? Either.Right)?.value }
+            .distinctUntilChanged { old, new -> old.value.amount == new.value.amount } // Check only balance changes
+            .onEach {
+                Timber.d("${coin.id} balance is ${it.value.amount}")
+
+                uiState = if (isFromCurrency) {
+                    dataState = dataState.copy(fromCryptoCurrency = it)
+                    stateBuilder.updateSendCurrencyBalance(uiState, it)
+                } else {
+                    dataState = dataState.copy(toCryptoCurrency = it)
+                    stateBuilder.updateReceiveCurrencyBalance(uiState, it)
+                }
+            }
+            .flowOn(dispatchers.main)
+            .launchIn(viewModelScope)
+            .saveIn(if (isFromCurrency) fromTokenBalanceJobHolder else toTokenBalanceJobHolder)
+    }
+
     private fun onChangeCardsClicked() {
         val newFromToken = dataState.toCryptoCurrency
         val newToToken = dataState.fromCryptoCurrency