feat(exchange): utilize Balance Rate as app-wide rate; make changes in entry flows empheremal

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

Author: bmc08gt

apps/flipcash/features/cash/src/main/kotlin/com/flipcash/app/cash/internal/CashScreenViewModel.kt

@@ -335,6 +335,10 @@ internal class CashScreenViewModel @Inject constructor(
             }.launchIn(viewModelScope)
     }
 
+    override fun onCleared() {
+        exchange.resetEntryToBalance()
+    }
+
     internal companion object {
         val updateStateForEvent: (Event) -> ((State) -> State) = { event ->
             when (event) {

apps/flipcash/features/onramp/src/main/kotlin/com/flipcash/app/onramp/internal/OnRampViewModel.kt

@@ -84,7 +84,7 @@ internal data class AmountEntryState(
 @HiltViewModel
 internal class OnRampViewModel @Inject constructor(
     userManager: UserManager,
-    exchange: Exchange,
+    private val exchange: Exchange,
     transactionController: TransactionOperations,
     private val resources: ResourceHelper,
     onRampController: OnRampController,
@@ -513,6 +513,10 @@ internal class OnRampViewModel @Inject constructor(
         }
     }
 
+    override fun onCleared() {
+        exchange.resetEntryToBalance()
+    }
+
     internal companion object {
         val updateStateForEvent: (Event) -> ((State) -> State) = { event ->
             when (event) {

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

@@ -443,6 +443,10 @@ internal class WithdrawalViewModel @Inject constructor(
             .launchIn(viewModelScope)
     }
 
+    override fun onCleared() {
+        exchange.resetEntryToBalance()
+    }
+
     internal companion object {
         val updateStateForEvent: (Event) -> ((State) -> State) = { event ->
             when (event) {

apps/flipcash/shared/currency-selection/core/src/main/kotlin/com/flipcash/app/currency/PreferredCurrencyController.kt

@@ -80,21 +80,15 @@ class PreferredCurrencyController @Inject constructor(
                         prefs[initKey] = true
                     }
 
-                    val entryCurrency = prefs[kindKeyForUser(
-                        kind = RegionSelectionKind.Entry,
-                        userId
-                    )]?.let { CurrencyCode.tryValueOf(it) }
-                        ?: CurrencyCode.tryValueOf(locale.getDefaultCurrencyName())
-                        ?: CurrencyCode.USD
-
                     val balanceCurrency = prefs[kindKeyForUser(
                         kind = RegionSelectionKind.Balance,
                         userId
                     )]?.let { CurrencyCode.tryValueOf(it) }
                         ?: CurrencyCode.tryValueOf(locale.getDefaultCurrencyName())
                         ?: CurrencyCode.USD
 
-                    exchange.setPreferredEntryCurrency(entryCurrency)
+                    // entry defaults to balance — no longer read from DataStore
+                    exchange.setPreferredEntryCurrency(balanceCurrency)
                     exchange.setPreferredBalanceCurrency(balanceCurrency)
                 }
             }.launchIn(dataScope)
@@ -104,12 +98,17 @@ class PreferredCurrencyController @Inject constructor(
     fun observePreferredForKind(
         kind: RegionSelectionKind
     ): Flow<String> {
-        val identifier = userManager.accountId?.base58 ?: return emptyFlow()
-
-        return storage.data
-            .map { prefs ->
-                prefs[kindKeyForUser(kind, identifier)] ?: locale.getDefaultCurrencyName()
+        return when (kind) {
+            RegionSelectionKind.Entry -> {
+                exchange.observeEntryRate().map { it.currency.name }
+            }
+            RegionSelectionKind.Balance -> {
+                val identifier = userManager.accountId?.base58 ?: return emptyFlow()
+                storage.data.map { prefs ->
+                    prefs[kindKeyForUser(kind, identifier)] ?: locale.getDefaultCurrencyName()
+                }
             }
+        }
     }
 
     fun observeRecentCurrencies(): Flow<Set<String>> {
@@ -122,28 +121,24 @@ class PreferredCurrencyController @Inject constructor(
         kind: RegionSelectionKind,
         currency: Currency
     ) {
-        val identifier = userManager.accountId?.base58 ?: return
-        storage.edit { prefs ->
-            prefs[kindKeyForUser(kind, identifier)] = currency.code
-
-            val recentKey = recentsKeyForUser(identifier)
-            val recents = prefs[recentKey].orEmpty()
-
-            prefs[recentKey] = updateRecents(recents, currency.code)
-        }
+        val code = CurrencyCode.tryValueOf(currency.code) ?: return
         when (kind) {
             RegionSelectionKind.Entry -> {
-                val code = CurrencyCode.tryValueOf(currency.code)
-                if (code != null) {
-                    exchange.setPreferredEntryCurrency(code)
-                }
+                // temporary — only update Exchange, don't persist
+                exchange.setPreferredEntryCurrency(code)
             }
             RegionSelectionKind.Balance -> {
-                val code = CurrencyCode.tryValueOf(currency.code)
-                if (code != null) {
-                    exchange.setPreferredBalanceCurrency(code)
-                    settingsController.update()
+                val identifier = userManager.accountId?.base58 ?: return
+                storage.edit { prefs ->
+                    prefs[kindKeyForUser(kind, identifier)] = currency.code
+
+                    val recentKey = recentsKeyForUser(identifier)
+                    val recents = prefs[recentKey].orEmpty()
+
+                    prefs[recentKey] = updateRecents(recents, currency.code)
                 }
+                exchange.setPreferredBalanceCurrency(code)
+                settingsController.update()
             }
         }
     }

apps/flipcash/shared/tokens/src/main/kotlin/com/flipcash/app/tokens/ui/SwapViewModel.kt

@@ -66,7 +66,7 @@ data class AmountEntryState(
 @HiltViewModel
 class SwapViewModel @Inject constructor(
     userManager: UserManager,
-    exchange: Exchange,
+    private val exchange: Exchange,
     transactionController: TransactionOperations,
     resources: ResourceHelper,
     tokenCoordinator: TokenCoordinator,
@@ -667,6 +667,10 @@ class SwapViewModel @Inject constructor(
         }
     }
 
+    override fun onCleared() {
+        exchange.resetEntryToBalance()
+    }
+
     internal companion object {
         val updateStateForEvent: (Event) -> ((State) -> State) = { event ->
             when (event) {

services/opencode-compose/src/main/kotlin/com/getcode/opencode/compose/Exchange.kt

@@ -28,6 +28,8 @@ private class ExchangeNull : Exchange {
 
     }
 
+    override fun resetEntryToBalance() = Unit
+
     override fun observeBalanceRate(): Flow<Rate> {
         return emptyFlow()
     }

services/opencode-compose/src/main/kotlin/com/getcode/opencode/compose/ExchangeStub.kt

@@ -24,6 +24,7 @@ class ExchangeStub(
     override fun observeEntryRate(): Flow<Rate> = emptyFlow()
 
     override suspend fun setPreferredEntryCurrency(currencyCode: CurrencyCode) = Unit
+    override fun resetEntryToBalance() = Unit
 
     override val balanceRate: Rate = Rate.oneToOne
 

services/opencode/src/main/kotlin/com/getcode/opencode/exchange/Exchange.kt

@@ -11,6 +11,7 @@ interface Exchange {
     val entryRate: Rate
     fun observeEntryRate(): Flow<Rate>
     suspend fun setPreferredEntryCurrency(currencyCode: CurrencyCode)
+    fun resetEntryToBalance()
     val balanceRate: Rate
     fun observeBalanceRate(): Flow<Rate>
     suspend fun setPreferredBalanceCurrency(currencyCode: CurrencyCode)

services/opencode/src/main/kotlin/com/getcode/opencode/internal/exchange/OpenCodeExchange.kt

@@ -96,6 +96,10 @@ internal class OpenCodeExchange @Inject constructor(
         }
     }
 
+    override fun resetEntryToBalance() {
+        scope.launch { setPreferredEntryCurrency(balanceRate.currency) }
+    }
+
     private var balanceCurrency: CurrencyCode? = null
     private var entryCurrency: CurrencyCode? = null