fix(withdrawal): resolve fee currency mismatch in TransactionReceipt

Convert the server fee (always USD) to the user's entry currency in the
ViewModel before passing it to the receipt composable. This prevents
Cannot subtract different currencies crashes for non-USD users.

- Add entryRate to WithdrawalViewModel.State, dispatched from observeEntryRate()
- Add feeInEntryCurrency and netTransferAmount computed properties
- Use convertingToUsdIfNeeded in TransactionReceipt for token estimation
- Fix OnWithdraw handler to use pre-computed netTransferAmount
- Fix preview fees to match their balance currencies

Signed-off-by: Brandon McAnsh <git@bmcreations.dev>

Author: bmc08gt

apps/flipcash/features/withdrawal/src/main/kotlin/com/flipcash/app/withdrawal/WithdrawalViewModel.kt

@@ -26,6 +26,7 @@ import com.getcode.opencode.model.financial.LocalFiat
 import com.getcode.opencode.model.financial.Rate
 import com.getcode.opencode.model.financial.TokenWithBalance
 import com.getcode.opencode.model.financial.minus
+import com.getcode.opencode.model.financial.toFiat
 import com.getcode.opencode.model.transactions.WithdrawalAvailability
 import com.getcode.solana.keys.Mint
 import com.getcode.ui.components.text.AmountAnimatedInputUiModel
@@ -77,7 +78,7 @@ internal class WithdrawalViewModel @Inject constructor(
     clipboardManager: ClipboardManager,
     activityFeedCoordinator: ActivityFeedCoordinator,
     analytics: FlipcashAnalyticsService,
-    tokenCoordinator: TokenCoordinator,
+    private val tokenCoordinator: TokenCoordinator,
     dispatchers: DispatcherProvider,
 ) : BaseViewModel2<WithdrawalViewModel.State, WithdrawalViewModel.Event>(
     initialState = State(),
@@ -90,6 +91,7 @@ internal class WithdrawalViewModel @Inject constructor(
     internal data class State(
         val selectedTokenAddress: Mint? = null,
         val token: TokenWithBalance? = null,
+        val entryRate: Rate? = null,
         val amountEntryState: AmountEntryState = AmountEntryState(),
         val destinationState: DestinationState = DestinationState(),
         val withdrawalState: LoadingSuccessState = LoadingSuccessState(),
@@ -100,6 +102,20 @@ internal class WithdrawalViewModel @Inject constructor(
         val tokenBalance: Fiat
             get() = token?.balance ?: Fiat.Zero
 
+        val feeInEntryCurrency: Fiat?
+            get() {
+                val fee = destinationState.availability?.feeAmount ?: return null
+                val rate = entryRate ?: return fee
+                return fee.convertingTo(rate)
+            }
+
+        val netTransferAmount: Fiat
+            get() {
+                val amount = amountEntryState.selectedAmount.localFiat.nativeAmount
+                val fee = feeInEntryCurrency ?: 0.toFiat(amount.currencyCode)
+                return amount - fee
+            }
+
         val isError: Boolean
             get() {
                 if (amountEntryState.amountAnimatedModel.amountData.isEmpty()) return false
@@ -125,6 +141,7 @@ internal class WithdrawalViewModel @Inject constructor(
         data class OnAmountChanged(val amountAnimatedModel: AmountAnimatedInputUiModel) : Event
         data class OnCurrencyChanged(val currency: Currency) : Event
         data object OnAmountConfirmed : Event
+        data class OnEntryRateUpdated(val rate: Rate) : Event
         data class OnAmountAccepted(val amount: VerifiedFiat) : Event
         data object OnDestinationConfirmed : Event
         data class UpdateConfirmingAmountState(
@@ -218,6 +235,7 @@ internal class WithdrawalViewModel @Inject constructor(
                 // reset when entry rate changes
                 numberInputHelper.reset()
                 dispatchEvent(Event.OnAmountChanged(AmountAnimatedInputUiModel()))
+                dispatchEvent(Event.OnEntryRateUpdated(it))
             }.launchIn(viewModelScope)
 
         eventFlow
@@ -269,14 +287,14 @@ internal class WithdrawalViewModel @Inject constructor(
             .filterNot { checkBalanceLimit() }
             .onEach { data ->
                 dispatchEvent(Event.UpdateConfirmingAmountState(loading = true))
-                val rate = exchange.rateForUsd()
+                val rate = exchange.entryRate
                 val token = stateFlow.value.token!!.token
                 val amountVerified = verifiedFiatCalculator.compute(
                     amount = Fiat(data.amountData.amount, rate.currency),
                     token = token,
                     balance = stateFlow.value.token!!.balance,
                     rate = rate,
-                ).getOrElse { cause ->
+                ).getOrElse {
                     dispatchEvent(Event.UpdateConfirmingAmountState(loading = false))
                     BottomBarManager.showAlert(
                         title = resources.getString(R.string.error_title_staleRates),
@@ -350,10 +368,7 @@ internal class WithdrawalViewModel @Inject constructor(
         eventFlow
             .filterIsInstance<Event.OnWithdraw>()
             .onEach {
-                val amount = stateFlow.value.amountEntryState.selectedAmount.localFiat
-                val withdrawalChecks = stateFlow.value.destinationState.availability
-                val fee = withdrawalChecks?.feeAmount
-                if (amount.nativeAmount - (fee ?: Fiat.Zero) < Fiat.Zero) {
+                if (stateFlow.value.netTransferAmount < Fiat.Zero) {
                     dispatchEvent(Event.UpdateWithdrawalState(loading = false))
                     dispatchEvent(Event.OnWithdrawalTooSmall)
                     return@onEach
@@ -402,6 +417,23 @@ internal class WithdrawalViewModel @Inject constructor(
                     return@mapNotNull null
                 }
 
+                // Refresh balance from network before submitting to ensure
+                // the on-chain balance matches what we're about to withdraw.
+                tokenCoordinator.updateTokenAccount(token.address)
+
+                // underlyingTokenAmount.quarks are token quarks, not USD —
+                // convert back through the bonding curve for an apples-to-apples comparison.
+                val amountInUsd = Fiat.tokenBalance(amount.localFiat.underlyingTokenAmount.quarks, token)
+                val refreshedBalance = tokenCoordinator.balanceForToken(token)
+                if (amountInUsd > refreshedBalance) {
+                    dispatchEvent(Event.UpdateWithdrawalState(loading = false))
+                    BottomBarManager.showAlert(
+                        title = resources.getString(R.string.error_title_insufficientFunds),
+                        message = resources.getString(R.string.error_description_insufficientFunds)
+                    )
+                    return@mapNotNull null
+                }
+
                 val sendingVault = owner.withTimelockForToken(token)
 
                 val feeInMint = feeInUsd?.let { fee ->
@@ -503,6 +535,10 @@ internal class WithdrawalViewModel @Inject constructor(
                     )
                 }
 
+                is Event.OnEntryRateUpdated -> { state ->
+                    state.copy(entryRate = event.rate)
+                }
+
                 is Event.OnAmountAccepted -> { state ->
                     val entryState = state.amountEntryState
                     state.copy(

apps/flipcash/features/withdrawal/src/main/kotlin/com/flipcash/app/withdrawal/internal/components/TransactionReceipt.kt

@@ -48,6 +48,7 @@ import com.getcode.opencode.model.financial.Rate
 import com.getcode.opencode.model.financial.Token
 import com.getcode.opencode.model.financial.TokenWithBalance
 import com.getcode.opencode.model.financial.minus
+import com.getcode.opencode.model.financial.toFiat
 import com.getcode.opencode.model.financial.usdf
 import com.getcode.theme.CodeTheme
 import com.getcode.theme.White05
@@ -62,6 +63,7 @@ internal fun TransactionReceipt(
     modifier: Modifier = Modifier,
     onLearnMoreClicked: () -> Unit
 ) {
+    val exchange = LocalExchange.current
     Column(
         modifier = Modifier
             .fillMaxWidth()
@@ -81,7 +83,7 @@ internal fun TransactionReceipt(
     ) {
         val netTransferAmount by remember(tokenWithBalance, fee) {
             derivedStateOf {
-                tokenWithBalance.balance - (fee ?: Fiat.Zero)
+                tokenWithBalance.balance - (fee ?: 0.toFiat(tokenWithBalance.balance.currencyCode))
             }
         }
 
@@ -107,7 +109,8 @@ internal fun TransactionReceipt(
                 showName = false,
                 horizontalArrangement = Arrangement.spacedBy(CodeTheme.dimens.grid.x2),
                 formattedBalance = { amount ->
-                    amount.estimatedTokenAmountIn(tokenWithBalance.token, fractionDigits = 2)
+                    amount.convertingToUsdIfNeeded(exchange.entryRate)
+                        .estimatedTokenAmountIn(tokenWithBalance.token, fractionDigits = 2)
                 },
                 sizing = rememberTokenBalanceRowSizing(
                     balanceTextStyle = CodeTheme.typography.displayMedium.bolded(),
@@ -181,10 +184,12 @@ private fun LineItems(
             )
         }
 
+        val exchange = LocalExchange.current
         ReceiptLineItem(
             modifier = Modifier.fillMaxWidth(),
             label = AnnotatedString("Amount in ${tokenWithBalance.token.name}"),
-            amount = transferAmount.estimatedTokenAmountIn(tokenWithBalance.token, fractionDigits = 2),
+            amount = transferAmount.convertingToUsdIfNeeded(exchange.entryRate)
+                .estimatedTokenAmountIn(tokenWithBalance.token, fractionDigits = 2),
         )
     }
 }
@@ -199,7 +204,8 @@ private val rates = mapOf(
     CurrencyCode.USD to cadToUsdRate,
 )
 
-private val fee = Fiat(0.50, CurrencyCode.USD)
+private val feeUsd = Fiat(0.50, CurrencyCode.USD)
+private val feeCad = feeUsd.convertingTo(usdToCadRate)
 
 @Preview
 @Composable
@@ -217,7 +223,7 @@ private fun Preview_CadWithdrawalWithFeeReceipt() {
                     token = Token.usdf,
                     balance = fiveCad
                 ),
-                fee = fee,
+                fee = feeCad,
             ) {
 
             }
@@ -265,7 +271,7 @@ private fun Preview_UsdWithdrawalWithFeeReceipt() {
                     token = Token.usdf,
                     balance = fiveUsd
                 ),
-                fee = fee,
+                fee = feeUsd,
             ) {
 
             }
@@ -313,7 +319,7 @@ private fun Preview_CadWithdrawalWithFeeButTooSmallReceipt() {
                     token = Token.usdf,
                     balance = halfDollarCad
                 ),
-                fee = fee,
+                fee = feeCad,
             ) {
 
             }

apps/flipcash/features/withdrawal/src/main/kotlin/com/flipcash/app/withdrawal/internal/confirmation/WithdrawalConfirmationScreen.kt

@@ -76,7 +76,7 @@ private fun WithdrawalConfirmationScreenContent(
                     balance = state.amountEntryState.selectedAmount.localFiat.nativeAmount,
                 ),
                 destination = state.destinationState.textFieldState.text.toString(),
-                fee = state.destinationState.availability?.feeAmount,
+                fee = state.feeInEntryCurrency,
                 onLearnMoreClicked = {
                     dispatchEvent(WithdrawalViewModel.Event.OnLearnAboutFee)
                 }