Dust notes

sdk-ext-lib/src/main/java/cash/z/ecc/sdk/extension/ZatoshiExt.kt

@@ -2,6 +2,7 @@ package cash.z.ecc.sdk.extension
 
 import cash.z.ecc.android.sdk.ext.convertZatoshiToZecString
 import cash.z.ecc.android.sdk.model.Zatoshi
+import kotlin.math.floor
 
 private const val DECIMALS_MAX_LONG = 8
 private const val DECIMALS_MIN_LONG = 3
@@ -34,6 +35,8 @@ fun Zatoshi.toZecStringAbbreviated(suffix: String): ZecAmountPair {
     }
 }
 
+fun Zatoshi.floor(): Zatoshi = Zatoshi(floorRoundBy(value.toDouble(), 2500.0).toLong())
+
 data class ZecAmountPair(
     val main: String,
     val suffix: String
@@ -43,3 +46,8 @@ val Zatoshi.Companion.typicalFee: Zatoshi
     get() = Zatoshi(TYPICAL_FEE)
 
 private const val TYPICAL_FEE = 100000L
+
+private fun floorRoundBy(number: Double, multiple: Double): Double {
+    require(multiple != 0.0) { "Multiple cannot be zero" }
+    return floor(number / multiple) * multiple
+}

ui-lib/src/main/java/co/electriccoin/zcash/ui/common/usecase/CreateProposalUseCase.kt

@@ -1,6 +1,7 @@
 package co.electriccoin.zcash.ui.common.usecase
 
 import cash.z.ecc.android.sdk.model.ZecSend
+import cash.z.ecc.sdk.extension.floor
 import co.electriccoin.zcash.ui.NavigationRouter
 import co.electriccoin.zcash.ui.common.datasource.AccountDataSource
 import co.electriccoin.zcash.ui.common.model.KeystoneAccount
@@ -16,15 +17,16 @@ class CreateProposalUseCase(
     private val navigationRouter: NavigationRouter
 ) {
     @Suppress("TooGenericExceptionCaught")
-    suspend operator fun invoke(zecSend: ZecSend) {
+    suspend operator fun invoke(zecSend: ZecSend, floor: Boolean) {
+        val normalized = if (floor) zecSend.copy(amount = zecSend.amount.floor()) else zecSend
         try {
             when (accountDataSource.getSelectedAccount()) {
                 is KeystoneAccount -> {
-                    keystoneProposalRepository.createProposal(zecSend)
+                    keystoneProposalRepository.createProposal(normalized)
                     keystoneProposalRepository.createPCZTFromProposal()
                 }
                 is ZashiAccount ->
-                    zashiProposalRepository.createProposal(zecSend)
+                    zashiProposalRepository.createProposal(normalized)
             }
             navigationRouter.forward(ReviewTransaction)
         } catch (e: Exception) {

ui-lib/src/main/java/co/electriccoin/zcash/ui/screen/request/model/Request.kt

@@ -2,6 +2,8 @@ package co.electriccoin.zcash.ui.screen.request.model
 
 import android.content.Context
 import cash.z.ecc.android.sdk.ext.convertUsdToZec
+import cash.z.ecc.android.sdk.ext.convertZecToZatoshi
+import cash.z.ecc.android.sdk.ext.toZec
 import cash.z.ecc.android.sdk.ext.toZecString
 import cash.z.ecc.android.sdk.model.FiatCurrencyConversion
 import cash.z.ecc.android.sdk.model.Locale
@@ -9,6 +11,8 @@ import cash.z.ecc.android.sdk.model.Memo
 import cash.z.ecc.android.sdk.model.Zatoshi
 import cash.z.ecc.android.sdk.model.fromZecString
 import cash.z.ecc.android.sdk.model.toFiatString
+import cash.z.ecc.sdk.extension.floor
+import cash.z.ecc.sdk.extension.toZecStringFull
 import co.electriccoin.zcash.ui.screen.request.ext.convertToDouble
 
 data class Request(
@@ -17,63 +21,41 @@ data class Request(
     val qrCodeState: QrCodeState,
 )
 
-sealed class AmountState(
+data class AmountState(
-    open val amount: String,
+    val amount: String,
-    open val currency: RequestCurrency
+    val currency: RequestCurrency,
+    val isValid: Boolean?
 ) {
-    fun isValid(): Boolean = this is Valid
+    fun toZecString(
-
+        conversion: FiatCurrencyConversion,
-    abstract fun copyState(
+    ): String {
-        newValue: String = amount,
+        return runCatching {
-        newCurrency: RequestCurrency = currency
-    ): AmountState
-
-    fun toZecString(conversion: FiatCurrencyConversion): String =
-        runCatching {
             amount.convertToDouble().convertUsdToZec(conversion.priceOfZec).toZecString()
         }.getOrElse { "" }
-
-    fun toFiatString(
-        context: Context,
-        conversion: FiatCurrencyConversion
-    ): String =
-        kotlin
-            .runCatching {
-                Zatoshi.fromZecString(context, amount, Locale.getDefault())?.toFiatString(
-                    currencyConversion = conversion,
-                    locale = Locale.getDefault()
-                ) ?: ""
-            }.getOrElse { "" }
-
-    data class Valid(
-        override val amount: String,
-        override val currency: RequestCurrency
-    ) : AmountState(amount, currency) {
-        override fun copyState(
-            newValue: String,
-            newCurrency: RequestCurrency
-        ) = copy(amount = newValue, currency = newCurrency)
     }
 
-    data class Default(
+    fun toZecStringFloored(
-        override val amount: String,
+        conversion: FiatCurrencyConversion,
-        override val currency: RequestCurrency
+    ): String {
-    ) : AmountState(amount, currency) {
+        return runCatching {
-        override fun copyState(
+            amount.convertToDouble().convertUsdToZec(conversion.priceOfZec)
-            newValue: String,
+                .convertZecToZatoshi()
-            newCurrency: RequestCurrency
+                .floor()
-        ) = copy(amount = newValue, currency = newCurrency)
+                .toZecStringFull()
+        }.getOrElse { "" }
     }
 
-    data class InValid(
+    fun toFiatString(context: Context, conversion: FiatCurrencyConversion) =
-        override val amount: String,
+        runCatching {
-        override val currency: RequestCurrency
+            Zatoshi.fromZecString(
-    ) : AmountState(amount, currency) {
+                context = context,
-        override fun copyState(
+                zecString = amount,
-            newValue: String,
+                locale = Locale.getDefault()
-            newCurrency: RequestCurrency
+            )?.toFiatString(
-        ) = copy(amount = newValue, currency = newCurrency)
+                currencyConversion = conversion,
-    }
+                locale = Locale.getDefault()
+            ) ?: ""
+        }.getOrElse { "" }
 }
 
 sealed class MemoState(
@@ -96,10 +78,7 @@ sealed class MemoState(
     ) : MemoState(text, byteSize, zecAmount)
 
     companion object {
-        fun new(
+        fun new(memo: String, amount: String): MemoState {
-            memo: String,
-            amount: String
-        ): MemoState {
             val bytesCount = Memo.countLength(memo)
             return if (bytesCount > Memo.MAX_MEMO_LENGTH_BYTES) {
                 InValid(memo, bytesCount, amount)

ui-lib/src/main/java/co/electriccoin/zcash/ui/screen/request/model/RequestCurrency.kt

@@ -1,7 +1,3 @@
 package co.electriccoin.zcash.ui.screen.request.model
 
-sealed class RequestCurrency {
+enum class RequestCurrency { ZEC, FIAT }
-    data object Zec : RequestCurrency()
-
-    data object Fiat : RequestCurrency()
-}

ui-lib/src/main/java/co/electriccoin/zcash/ui/screen/request/view/RequestAmountView.kt

@@ -63,16 +63,16 @@ internal fun RequestAmountView(
 
         when (state.exchangeRateState) {
             is ExchangeRateState.Data -> {
-                if (state.request.amountState.currency == RequestCurrency.Zec) {
+                if (state.request.amountState.currency == RequestCurrency.ZEC) {
                     RequestAmountWithMainZecView(
                         state = state,
-                        onFiatPreferenceSwitch = { state.onSwitch(RequestCurrency.Fiat) },
+                        onFiatPreferenceSwitch = { state.onSwitch(RequestCurrency.FIAT) },
                         modifier = Modifier.padding(horizontal = ZcashTheme.dimens.screenHorizontalSpacingRegular)
                     )
                 } else {
                     RequestAmountWithMainFiatView(
                         state = state,
-                        onFiatPreferenceSwitch = { state.onSwitch(RequestCurrency.Zec) },
+                        onFiatPreferenceSwitch = { state.onSwitch(RequestCurrency.ZEC) },
                         modifier = Modifier.padding(horizontal = ZcashTheme.dimens.screenHorizontalSpacingRegular)
                     )
                 }
@@ -417,7 +417,7 @@ private fun InvalidAmountView(
                 .fillMaxWidth()
                 .requiredHeight(48.dp)
     ) {
-        if (amountState is AmountState.InValid) {
+        if (amountState.isValid == false) {
             Image(
                 painter = painterResource(id = R.drawable.ic_alert_outline),
                 contentDescription = null

ui-lib/src/main/java/co/electriccoin/zcash/ui/screen/request/view/RequestView.kt

@@ -65,7 +65,7 @@ private fun RequestPreview() =
                 RequestState.Amount(
                     request =
                         Request(
-                            amountState = AmountState.Valid("2.25", RequestCurrency.Zec),
+                            amountState = AmountState("2.25", RequestCurrency.ZEC, true),
                             memoState = MemoState.Valid("", 0, "2.25"),
                             qrCodeState =
                                 QrCodeState(
@@ -143,7 +143,7 @@ private fun RequestBottomBar(
                 ZashiButton(
                     text = stringResource(id = R.string.request_amount_btn),
                     onClick = state.onDone,
-                    enabled = state.request.amountState.isValid(),
+                    enabled = state.request.amountState.isValid == true,
                     modifier =
                         Modifier
                             .fillMaxWidth()

ui-lib/src/main/java/co/electriccoin/zcash/ui/screen/request/viewmodel/RequestViewModel.kt

@@ -43,6 +43,7 @@ import kotlinx.coroutines.flow.callbackFlow
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.filterNotNull
 import kotlinx.coroutines.flow.stateIn
+import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
 
 @Suppress("TooManyFunctions")
@@ -68,7 +69,11 @@ class RequestViewModel(
     internal val request =
         MutableStateFlow(
             Request(
-                amountState = AmountState.Default(defaultAmount, RequestCurrency.Zec),
+                amountState = AmountState(
+                    amount = defaultAmount,
+                    currency = RequestCurrency.ZEC,
+                    isValid = null
+                ),
                 memoState = MemoState.Valid(DEFAULT_MEMO, 0, defaultAmount),
                 qrCodeState = QrCodeState(DEFAULT_URI, defaultAmount, DEFAULT_MEMO),
             )
@@ -94,26 +99,13 @@ class RequestViewModel(
                         monetarySeparators = getMonetarySeparators(),
                         onAmount = { onAmount(resolveExchangeRateValue(exchangeRateUsd), it) },
                         onBack = { onBack() },
-                        onDone = {
+                        onDone = { onNextClick(walletAddress, zip321BuildUriUseCase, exchangeRateUsd) },
-                            when (walletAddress) {
-                                is WalletAddress.Transparent -> {
-                                    onAmountAndMemoDone(
-                                        walletAddress.address,
-                                        zip321BuildUriUseCase,
-                                        resolveExchangeRateValue(exchangeRateUsd)
-                                    )
-                                }
-                                is WalletAddress.Unified, is WalletAddress.Sapling -> {
-                                    onAmountDone(resolveExchangeRateValue(exchangeRateUsd))
-                                }
-                                else -> error("Unexpected address type")
-                            }
-                        },
                         onSwitch = { onSwitch(resolveExchangeRateValue(exchangeRateUsd), it) },
                         request = request,
                         zcashCurrency = getZcashCurrency(),
                     )
                 }
+
                 RequestStage.MEMO -> {
                     RequestState.Memo(
                         icon =
@@ -129,6 +121,7 @@ class RequestViewModel(
                         zcashCurrency = getZcashCurrency(),
                     )
                 }
+
                 RequestStage.QR_CODE -> {
                     RequestState.QrCode(
                         icon =
@@ -136,6 +129,7 @@ class RequestViewModel(
                                 is KeystoneAccount ->
                                     co.electriccoin.zcash.ui.design.R.drawable
                                         .ic_item_keystone_qr
+
                                 is ZashiAccount -> R.drawable.logo_zec_fill_stroke
                             },
                         fullScreenIcon =
@@ -143,6 +137,7 @@ class RequestViewModel(
                                 is KeystoneAccount ->
                                     co.electriccoin.zcash.ui.design.R.drawable
                                         .ic_item_keystone_qr_white
+
                                 is ZashiAccount -> R.drawable.logo_zec_fill_stroke_white
                             },
                         walletAddress = walletAddress,
@@ -169,6 +164,25 @@ class RequestViewModel(
 
     val shareResultCommand = MutableSharedFlow<Boolean>()
 
+    private fun onNextClick(
+        walletAddress: WalletAddress,
+        zip321BuildUriUseCase: Zip321BuildUriUseCase,
+        exchangeRateUsd: ExchangeRateState
+    ) {
+        when (walletAddress) {
+            is WalletAddress.Transparent -> onAmountAndMemoDone(
+                walletAddress.address,
+                zip321BuildUriUseCase,
+                resolveExchangeRateValue(exchangeRateUsd)
+            )
+
+            is WalletAddress.Unified, is WalletAddress.Sapling ->
+                onAmountDone(resolveExchangeRateValue(exchangeRateUsd))
+
+            else -> error("Unexpected address type")
+        }
+    }
+
     private fun resolveExchangeRateValue(exchangeRateUsd: ExchangeRateState): FiatCurrencyConversion? =
         when (exchangeRateUsd) {
             is ExchangeRateState.Data -> {
@@ -179,6 +193,7 @@ class RequestViewModel(
                     exchangeRateUsd.currencyConversion
                 }
             }
+
             else -> {
                 // Should not happen as the conversion rate related use cases should not be available
                 Twig.error { "Unexpected screen state" }
@@ -186,53 +201,54 @@ class RequestViewModel(
             }
         }
 
-    private fun onAmount(
+    private fun onAmount(conversion: FiatCurrencyConversion?, onAmount: OnAmount) {
-        conversion: FiatCurrencyConversion?,
+        request.update {
-        onAmount: OnAmount
+            val newState =
-    ) = viewModelScope.launch {
+                when (onAmount) {
-        val newState =
+                    is OnAmount.Number -> {
-            when (onAmount) {
+                        if (it.amountState.amount == defaultAmount) {
-                is OnAmount.Number -> {
+                            // Special case with current value only zero
-                    if (request.value.amountState.amount == defaultAmount) {
+                            validateAmountState(conversion, onAmount.number.toString())
-                        // Special case with current value only zero
+                        } else {
-                        validateAmountState(conversion, onAmount.number.toString())
+                            // Adding new number to the result string
-                    } else {
+                            validateAmountState(
-                        // Adding new number to the result string
+                                conversion,
-                        validateAmountState(
+                                it.amountState.amount + onAmount.number
-                            conversion,
+                            )
-                            request.value.amountState.amount + onAmount.number
+                        }
-                        )
+                    }
+
+                    is OnAmount.Delete -> {
+                        if (it.amountState.amount.length == 1) {
+                            // Deleting up to the last character
+                            AmountState(
+                                amount = defaultAmount,
+                                currency = it.amountState.currency,
+                                isValid = null
+                            )
+                        } else {
+                            validateAmountState(
+                                conversion,
+                                it.amountState.amount.dropLast(1)
+                            )
+                        }
+                    }
+
+                    is OnAmount.Separator -> {
+                        if (it.amountState.amount.contains(onAmount.separator)) {
+                            // Separator already present
+                            validateAmountState(conversion, it.amountState.amount)
+                        } else {
+                            validateAmountState(
+                                conversion,
+                                it.amountState.amount + onAmount.separator
+                            )
+                        }
                     }
                 }
-                is OnAmount.Delete -> {
+
-                    if (request.value.amountState.amount.length == 1) {
+            it.copy(amountState = newState)
-                        // Deleting up to the last character
+        }
-                        AmountState.Default(defaultAmount, request.value.amountState.currency)
-                    } else {
-                        validateAmountState(
-                            conversion,
-                            request.value.amountState.amount
-                                .dropLast(1)
-                        )
-                    }
-                }
-                is OnAmount.Separator -> {
-                    if (request.value.amountState.amount
-                            .contains(onAmount.separator)
-                    ) {
-                        // Separator already present
-                        validateAmountState(conversion, request.value.amountState.amount)
-                    } else {
-                        validateAmountState(
-                            conversion,
-                            request.value.amountState.amount + onAmount.separator
-                        )
-                    }
-                }
-            }
-        request.emit(
-            request.value.copy(amountState = newState)
-        )
     }
 
     // Validates only zeros and decimal separator
@@ -252,31 +268,40 @@ class RequestViewModel(
     ): AmountState {
         val newAmount =
             if (resultAmount.contains(defaultAmountValidationRegex)) {
-                AmountState.Default(
+                AmountState(
                     // Check for the max decimals in the default (i.e. 0.000) number, too
-                    if (!resultAmount.contains(allowedNumberFormatValidationRegex)) {
+                    amount = if (!resultAmount.contains(allowedNumberFormatValidationRegex)) {
                         request.value.amountState.amount
                     } else {
                         resultAmount
                     },
-                    request.value.amountState.currency
+                    currency = request.value.amountState.currency,
+                    isValid = null
                 )
             } else if (!resultAmount.contains(allowedNumberFormatValidationRegex)) {
-                AmountState.Valid(request.value.amountState.amount, request.value.amountState.currency)
+                AmountState(
+                    amount = request.value.amountState.amount,
+                    currency = request.value.amountState.currency,
+                    isValid = true
+                )
             } else {
-                AmountState.Valid(resultAmount, request.value.amountState.currency)
+                AmountState(
+                    amount = resultAmount,
+                    currency = request.value.amountState.currency,
+                    isValid = true
+                )
             }
 
         // Check for max Zcash supply
         return newAmount.amount.convertToDouble()?.let { currentValue ->
             val zecValue =
-                if (newAmount.currency == RequestCurrency.Fiat && conversion != null) {
+                if (newAmount.currency == RequestCurrency.FIAT && conversion != null) {
                     currentValue / conversion.priceOfZec
                 } else {
                     currentValue
                 }
             if (zecValue > MAX_ZCASH_SUPPLY) {
-                newAmount.copyState(request.value.amountState.amount)
+                newAmount.copy(amount = request.value.amountState.amount)
             } else {
                 newAmount
             }
@@ -299,89 +324,81 @@ class RequestViewModel(
             }
     }
 
-    internal fun onBack() =
+    internal fun onBack() {
-        viewModelScope.launch {
+        when (stage.value) {
-            when (stage.value) {
+            RequestStage.AMOUNT -> navigationRouter.back()
-                RequestStage.AMOUNT -> {
+
-                    navigationRouter.back()
+            RequestStage.MEMO -> stage.update { RequestStage.AMOUNT }
-                }
+
-                RequestStage.MEMO -> {
+            RequestStage.QR_CODE -> when (ReceiveAddressType.fromOrdinal(addressTypeOrdinal)) {
-                    stage.emit(RequestStage.AMOUNT)
+                ReceiveAddressType.Transparent -> stage.update { RequestStage.AMOUNT }
-                }
+
-                RequestStage.QR_CODE -> {
+                ReceiveAddressType.Unified, ReceiveAddressType.Sapling -> stage.update { RequestStage.MEMO }
-                    when (ReceiveAddressType.fromOrdinal(addressTypeOrdinal)) {
-                        ReceiveAddressType.Transparent -> {
-                            stage.emit(RequestStage.AMOUNT)
-                        }
-                        ReceiveAddressType.Unified, ReceiveAddressType.Sapling -> {
-                            stage.emit(RequestStage.MEMO)
-                        }
-                    }
-                }
             }
         }
+    }
 
     private fun onClose() = navigationRouter.back()
 
-    private fun onAmountDone(conversion: FiatCurrencyConversion?) =
+    private fun onAmountDone(conversion: FiatCurrencyConversion?) {
-        viewModelScope.launch {
+        request.update {
             val memoAmount =
-                when (request.value.amountState.currency) {
+                when (it.amountState.currency) {
-                    RequestCurrency.Fiat ->
+                    RequestCurrency.FIAT ->
                         if (conversion != null) {
-                            request.value.amountState.toZecString(conversion)
+                            it.amountState.toZecStringFloored(conversion)
                         } else {
                             Twig.error { "Unexpected screen state" }
-                            request.value.amountState.amount
+                            it.amountState.amount
                         }
 
-                    RequestCurrency.Zec -> request.value.amountState.amount
+                    RequestCurrency.ZEC -> it.amountState.amount
                 }
-            request.emit(request.value.copy(memoState = MemoState.new(DEFAULT_MEMO, memoAmount)))
-            stage.emit(RequestStage.MEMO)
-        }
 
-    private fun onMemoDone(
+            it.copy(memoState = MemoState.new(DEFAULT_MEMO, memoAmount))
-        address: String,
+        }
-        zip321BuildUriUseCase: Zip321BuildUriUseCase
+        stage.update { RequestStage.MEMO }
-    ) = viewModelScope.launch {
+    }
-        request.emit(
+
-            request.value.copy(
+    private fun onMemoDone(address: String, zip321BuildUriUseCase: Zip321BuildUriUseCase) {
+        request.update {
+            it.copy(
                 qrCodeState =
                     QrCodeState(
                         requestUri =
                             createZip321Uri(
                                 address = address,
-                                amount = request.value.memoState.zecAmount,
+                                amount = it.memoState.zecAmount,
-                                memo = request.value.memoState.text,
+                                memo = it.memoState.text,
                                 zip321BuildUriUseCase = zip321BuildUriUseCase
                             ),
-                        zecAmount = request.value.memoState.zecAmount,
+                        zecAmount = it.memoState.zecAmount,
-                        memo = request.value.memoState.text,
+                        memo = it.memoState.text,
                     )
             )
-        )
+        }
-        stage.emit(RequestStage.QR_CODE)
+        stage.update { RequestStage.QR_CODE }
     }
 
     private fun onAmountAndMemoDone(
         address: String,
         zip321BuildUriUseCase: Zip321BuildUriUseCase,
         conversion: FiatCurrencyConversion?
-    ) = viewModelScope.launch {
+    ) {
-        val qrCodeAmount =
+        request.update {
-            when (request.value.amountState.currency) {
+            val qrCodeAmount =
-                RequestCurrency.Fiat ->
+                when (it.amountState.currency) {
-                    if (conversion != null) {
+                    RequestCurrency.FIAT ->
-                        request.value.amountState.toZecString(conversion)
+                        if (conversion != null) {
-                    } else {
+                            it.amountState.toZecStringFloored(conversion)
-                        Twig.error { "Unexpected screen state" }
+                        } else {
-                        request.value.amountState.amount
+                            Twig.error { "Unexpected screen state" }
-                    }
+                            it.amountState.amount
-                RequestCurrency.Zec -> request.value.amountState.amount
+                        }
-            }
+
-        val newRequest =
+                    RequestCurrency.ZEC -> it.amountState.amount
-            request.value.copy(
+                }
+            it.copy(
                 qrCodeState =
                     QrCodeState(
                         requestUri =
@@ -395,49 +412,39 @@ class RequestViewModel(
                         memo = DEFAULT_MEMO,
                     )
             )
-        request.emit(newRequest)
+        }
-        stage.emit(RequestStage.QR_CODE)
+
+        stage.update { RequestStage.QR_CODE }
     }
 
     private fun onSwitch(
         conversion: FiatCurrencyConversion?,
         onSwitchTo: RequestCurrency
     ) = viewModelScope.launch {
-        if (conversion == null) {
+        if (conversion == null) return@launch
-            return@launch
+
+        request.update {
+            val newAmount =
+                when (onSwitchTo) {
+                    RequestCurrency.FIAT -> it.amountState.toFiatString(
+                        context = application.applicationContext,
+                        conversion = conversion
+                    )
+
+                    RequestCurrency.ZEC -> it.amountState.toZecString(conversion)
+                }
+
+            it.copy(
+                amountState = if (newAmount.contains(defaultAmountValidationRegex)) {
+                    it.amountState.copy(amount = defaultAmount, currency = onSwitchTo)
+                } else {
+                    it.amountState.copy(amount = newAmount, currency = onSwitchTo)
+                }
+            )
         }
-        val newAmount =
-            when (onSwitchTo) {
-                is RequestCurrency.Fiat -> {
-                    request.value.amountState.toFiatString(
-                        application.applicationContext,
-                        conversion
-                    )
-                }
-                is RequestCurrency.Zec -> {
-                    request.value.amountState.toZecString(
-                        conversion
-                    )
-                }
-            }
-
-        // Check default value and shrink it to 0 if necessary
-        val newState =
-            if (newAmount.contains(defaultAmountValidationRegex)) {
-                request.value.amountState.copyState(defaultAmount, onSwitchTo)
-            } else {
-                request.value.amountState.copyState(newAmount, onSwitchTo)
-            }
-
-        request.emit(
-            request.value.copy(amountState = newState)
-        )
     }
 
-    private fun onMemo(memoState: MemoState) =
+    private fun onMemo(memoState: MemoState) = request.update { it.copy(memoState = memoState) }
-        viewModelScope.launch {
-            request.emit(request.value.copy(memoState = memoState))
-        }
 
     private fun createZip321Uri(
         address: String,

ui-lib/src/main/java/co/electriccoin/zcash/ui/screen/send/AndroidSend.kt

@@ -192,7 +192,8 @@ internal fun WrapSend(
                     monetarySeparators = monetarySeparators,
                     value = amountState.value,
                     fiatValue = amountState.fiatValue,
-                    exchangeRateState = exchangeRateState
+                    exchangeRateState = exchangeRateState,
+                    lastFieldChangedByUser = amountState.lastFieldChangedByUser
                 )
             } else {
                 AmountState.newFromFiat(
@@ -302,6 +303,7 @@ internal fun WrapSend(
             onCreateZecSend = { newZecSend ->
                 viewModel.onCreateZecSendClick(
                     newZecSend = newZecSend,
+                    amountState = amountState,
                     setSendStage = setSendStage
                 )
             },

ui-lib/src/main/java/co/electriccoin/zcash/ui/screen/send/SendViewModel.kt

@@ -12,6 +12,8 @@ import co.electriccoin.zcash.ui.common.usecase.ObserveContactByAddressUseCase
 import co.electriccoin.zcash.ui.common.usecase.ObserveContactPickedUseCase
 import co.electriccoin.zcash.ui.screen.addressbook.AddressBookArgs
 import co.electriccoin.zcash.ui.screen.contact.AddContactArgs
+import co.electriccoin.zcash.ui.screen.send.model.AmountField
+import co.electriccoin.zcash.ui.screen.send.model.AmountState
 import co.electriccoin.zcash.ui.screen.send.model.RecipientAddressState
 import co.electriccoin.zcash.ui.screen.send.model.SendAddressBookState
 import co.electriccoin.zcash.ui.screen.send.model.SendStage
@@ -133,10 +135,11 @@ class SendViewModel(
     @Suppress("TooGenericExceptionCaught")
     fun onCreateZecSendClick(
         newZecSend: ZecSend,
+        amountState: AmountState,
         setSendStage: (SendStage) -> Unit
     ) = viewModelScope.launch {
         try {
-            createProposal(newZecSend)
+            createProposal(zecSend = newZecSend, floor = amountState.lastFieldChangedByUser == AmountField.FIAT)
         } catch (e: Exception) {
             setSendStage(SendStage.SendFailure(e.cause?.message ?: e.message ?: ""))
             Twig.error(e) { "Error creating proposal" }

ui-lib/src/main/java/co/electriccoin/zcash/ui/screen/send/model/AmountState.kt

@@ -16,16 +16,19 @@ import co.electriccoin.zcash.ui.common.wallet.ExchangeRateState
 sealed interface AmountState {
     val value: String
     val fiatValue: String
+    val lastFieldChangedByUser: AmountField
 
     data class Valid(
         override val value: String,
         override val fiatValue: String,
-        val zatoshi: Zatoshi
+        override val lastFieldChangedByUser: AmountField,
+        val zatoshi: Zatoshi,
     ) : AmountState
 
     data class Invalid(
         override val value: String,
-        override val fiatValue: String
+        override val fiatValue: String,
+        override val lastFieldChangedByUser: AmountField
     ) : AmountState
 
     companion object {
@@ -37,11 +40,12 @@ sealed interface AmountState {
             fiatValue: String,
             isTransparentOrTextRecipient: Boolean,
             exchangeRateState: ExchangeRateState,
+            lastFieldChangedByUser: AmountField = AmountField.ZEC
         ): AmountState {
             val isValid = validate(context, monetarySeparators, value)
 
             if (!isValid) {
-                return Invalid(value, if (value.isBlank()) "" else fiatValue)
+                return Invalid(value, if (value.isBlank()) "" else fiatValue, lastFieldChangedByUser)
             }
 
             val zatoshi = Zatoshi.fromZecString(context, value, Locale.getDefault())
@@ -57,8 +61,9 @@ sealed interface AmountState {
 
             // Note that the zero funds sending is supported for sending a memo-only shielded transaction
             return when {
-                (zatoshi == null) -> Invalid(value, if (value.isBlank()) "" else fiatValue)
+                (zatoshi == null) -> Invalid(value, if (value.isBlank()) "" else fiatValue, lastFieldChangedByUser)
-                (zatoshi.value == 0L && isTransparentOrTextRecipient) -> Invalid(value, fiatValue)
+                (zatoshi.value == 0L && isTransparentOrTextRecipient) ->
+                    Invalid(value, fiatValue, lastFieldChangedByUser)
                 else -> {
                     Valid(
                         value = value,
@@ -71,7 +76,8 @@ sealed interface AmountState {
                                     currencyConversion = currencyConversion,
                                     locale = Locale.getDefault(),
                                 )
-                            }
+                            },
+                        lastFieldChangedByUser = lastFieldChangedByUser
                     )
                 }
             }
@@ -89,7 +95,11 @@ sealed interface AmountState {
             val isValid = validate(context, monetarySeparators, fiatValue)
 
             if (!isValid) {
-                return Invalid(value = if (fiatValue.isBlank()) "" else value, fiatValue = fiatValue)
+                return Invalid(
+                    value = if (fiatValue.isBlank()) "" else value,
+                    fiatValue = fiatValue,
+                    lastFieldChangedByUser = AmountField.FIAT
+                )
             }
 
             val zatoshi =
@@ -101,16 +111,25 @@ sealed interface AmountState {
 
             return when {
                 (zatoshi == null) -> {
-                    Invalid(value = if (fiatValue.isBlank()) "" else value, fiatValue = fiatValue)
+                    Invalid(
+                        value = if (fiatValue.isBlank()) "" else value,
+                        fiatValue = fiatValue,
+                        lastFieldChangedByUser = AmountField.FIAT
+                    )
                 }
                 (zatoshi.value == 0L && isTransparentOrTextRecipient) -> {
-                    Invalid(if (fiatValue.isBlank()) "" else value, fiatValue)
+                    Invalid(
+                        value = if (fiatValue.isBlank()) "" else value,
+                        fiatValue = fiatValue,
+                        lastFieldChangedByUser = AmountField.FIAT
+                    )
                 }
                 else -> {
                     Valid(
                         value = zatoshi.toZecString(),
                         zatoshi = zatoshi,
-                        fiatValue = fiatValue
+                        fiatValue = fiatValue,
+                        lastFieldChangedByUser = AmountField.FIAT
                     )
                 }
             }
@@ -122,6 +141,7 @@ sealed interface AmountState {
         private const val KEY_VALUE = "value" // $NON-NLS
         private const val KEY_FIAT_VALUE = "fiat_value" // $NON-NLS
         private const val KEY_ZATOSHI = "zatoshi" // $NON-NLS
+        private const val KEY_LAST_FIELD_CHANGED_BY_USER = "last_field_changed_by_user" // $NON-NLS
 
         private fun validate(
             context: Context,
@@ -145,18 +165,22 @@ sealed interface AmountState {
                                 val amountString = (it[KEY_VALUE] as String)
                                 val fiatAmountString = (it[KEY_FIAT_VALUE] as String)
                                 val type = (it[KEY_TYPE] as String)
+                                val lastFieldChangedByUser =
+                                    AmountField.valueOf(it[KEY_LAST_FIELD_CHANGED_BY_USER] as String)
                                 when (type) {
                                     TYPE_VALID ->
                                         Valid(
                                             value = amountString,
                                             fiatValue = fiatAmountString,
-                                            zatoshi = Zatoshi(it[KEY_ZATOSHI] as Long)
+                                            zatoshi = Zatoshi(it[KEY_ZATOSHI] as Long),
+                                            lastFieldChangedByUser = lastFieldChangedByUser
                                         )
 
                                     TYPE_INVALID ->
                                         Invalid(
                                             value = amountString,
-                                            fiatValue = fiatAmountString
+                                            fiatValue = fiatAmountString,
+                                            lastFieldChangedByUser = lastFieldChangedByUser
                                         )
 
                                     else -> null
@@ -178,8 +202,11 @@ sealed interface AmountState {
             }
             saverMap[KEY_VALUE] = this.value
             saverMap[KEY_FIAT_VALUE] = this.fiatValue
+            saverMap[KEY_LAST_FIELD_CHANGED_BY_USER] = this.lastFieldChangedByUser.name
 
             return saverMap
         }
     }
 }
+
+enum class AmountField { ZEC, FIAT }

ui-lib/src/main/java/co/electriccoin/zcash/ui/screen/send/view/SendView.kt

@@ -78,6 +78,7 @@ import co.electriccoin.zcash.ui.fixture.ZashiMainTopAppBarStateFixture
 import co.electriccoin.zcash.ui.screen.balances.BalanceWidget
 import co.electriccoin.zcash.ui.screen.balances.BalanceWidgetState
 import co.electriccoin.zcash.ui.screen.send.SendTag
+import co.electriccoin.zcash.ui.screen.send.model.AmountField
 import co.electriccoin.zcash.ui.screen.send.model.AmountState
 import co.electriccoin.zcash.ui.screen.send.model.MemoState
 import co.electriccoin.zcash.ui.screen.send.model.RecipientAddressState
@@ -104,7 +105,8 @@ private fun PreviewSendForm() {
                 AmountState.Valid(
                     value = ZatoshiFixture.ZATOSHI_LONG.toString(),
                     fiatValue = "",
-                    zatoshi = ZatoshiFixture.new()
+                    zatoshi = ZatoshiFixture.new(),
+                    lastFieldChangedByUser = AmountField.FIAT
                 ),
             setMemoState = {},
             memoState = MemoState.new("Test message "),
@@ -143,7 +145,8 @@ private fun SendFormTransparentAddressPreview() {
                 AmountState.Valid(
                     value = ZatoshiFixture.ZATOSHI_LONG.toString(),
                     fiatValue = "",
-                    zatoshi = ZatoshiFixture.new()
+                    zatoshi = ZatoshiFixture.new(),
+                    lastFieldChangedByUser = AmountField.FIAT
                 ),
             setMemoState = {},
             memoState = MemoState.new("Test message"),
@@ -692,7 +695,7 @@ fun SendFormAmountTextField(
                 }
             )
 
-            if (exchangeRateState is ExchangeRateState.Data) {
+            if (exchangeRateState is ExchangeRateState.Data && exchangeRateState.currencyConversion != null) {
                 Spacer(modifier = Modifier.width(12.dp))
                 Image(
                     modifier = Modifier.padding(top = 12.dp),