feat: unify Exchange rate API around preferredRate (#752)

Replace entryRate with preferredRate across the Exchange interface and
all callers. Simplify OpenCodeExchange by removing redundant rate
properties and consolidating currency selection logic in
PreferredCurrencyController.

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

Author: bmc08gt

apps/flipcash/app/src/main/kotlin/com/flipcash/app/internal/ui/navigation/AppScreenContent.kt

@@ -90,7 +90,7 @@ fun appEntryProvider(
     }
     annotatedEntry<AppRoute.Main.AppRestricted> { key -> AppRestrictedScreen(key.restrictionType) }
     annotatedEntry<AppRoute.Main.Scanner> { ScannerScreen() }
-    annotatedEntry<AppRoute.Main.RegionSelection> { key -> RegionSelectionScreen(key.kind) }
+    annotatedEntry<AppRoute.Main.RegionSelection> { RegionSelectionScreen() }
 
     // Sheets (inner content — wrapped in Main.Sheet by navigateTo())
     annotatedEntry<AppRoute.Sheets.Give> { key -> CashScreen(key.mint, key.fromTokenInfo) }

apps/flipcash/core/src/main/kotlin/com/flipcash/app/core/AppRoute.kt

@@ -4,7 +4,6 @@ import android.os.Parcelable
 import androidx.navigation3.runtime.NavKey
 import com.flipcash.app.core.deposit.DepositResult
 import com.flipcash.app.core.deposit.DepositStep
-import com.flipcash.app.core.money.RegionSelectionKind
 import com.flipcash.app.core.tokens.CurrencyCreatorResult
 import com.flipcash.app.core.tokens.CurrencyCreatorStep
 import com.flipcash.app.core.tokens.SwapPurpose
@@ -71,7 +70,7 @@ sealed interface AppRoute : NavKey, Parcelable {
 
         // TODO: is there a better place for this to live?
         @Serializable
-        data class RegionSelection(val kind: RegionSelectionKind) : Main
+        data object RegionSelection : Main
 
         @Serializable
         @Parcelize

apps/flipcash/core/src/main/kotlin/com/flipcash/app/core/money/RegionSelectionKind.kt

@@ -11,7 +11,6 @@ import androidx.hilt.lifecycle.viewmodel.compose.hiltViewModel
 import com.flipcash.app.balance.internal.BalanceScreen
 import com.flipcash.app.balance.internal.BalanceViewModel
 import com.flipcash.app.core.AppRoute
-import com.flipcash.app.core.money.RegionSelectionKind
 import com.flipcash.app.core.tokens.TokenPurpose
 import com.flipcash.app.tokens.ui.SelectTokenViewModel
 import com.flipcash.core.R
@@ -55,11 +54,7 @@ fun BalanceScreen() {
             viewModel.eventFlow
                 .filterIsInstance<BalanceViewModel.Event.OpenCurrencySelection>()
                 .onEach {
-                    navigator.push(
-                        AppRoute.Main.RegionSelection(
-                            RegionSelectionKind.Balance
-                        )
-                    )
+                    navigator.push(AppRoute.Main.RegionSelection)
                 }.launchIn(this)
         }
 

apps/flipcash/features/balance/src/main/kotlin/com/flipcash/app/balance/BalanceScreen.kt

@@ -12,7 +12,6 @@ import androidx.compose.runtime.getValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.res.stringResource
 import com.flipcash.app.core.AppRoute
-import com.flipcash.app.core.money.RegionSelectionKind
 import com.flipcash.app.core.ui.AmountWithKeypad
 import com.flipcash.features.cash.R
 import com.getcode.navigation.core.LocalCodeNavigator
@@ -46,11 +45,7 @@ internal fun GiveScreenContent(viewModel: CashScreenViewModel) {
             },
             isClickable = true,
             onAmountClicked = {
-                navigator.push(
-                    AppRoute.Main.RegionSelection(
-                        kind = RegionSelectionKind.Entry
-                    )
-                )
+                navigator.push(AppRoute.Main.RegionSelection)
             },
             isError = state.isError,
             onNumberPressed = { viewModel.dispatchEvent(CashScreenViewModel.Event.OnNumberPressed(it)) },

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

@@ -142,7 +142,7 @@ internal class CashScreenViewModel @Inject constructor(
                         style = BottomBarManager.BottomBarButtonStyle.Filled,
                     ) {
                         viewModelScope.launch {
-                            val rate = exchange.entryRate
+                            val rate = exchange.preferredRate
                             val (token, balance) = stateFlow.value.token!!
                             val amountFiat = verifiedFiatCalculator.compute(
                                 amount =  Fiat(amount, rate.currency),
@@ -212,7 +212,7 @@ internal class CashScreenViewModel @Inject constructor(
                 combine(
                     tokenCoordinator.tokens,
                     tokenCoordinator.balanceForToken(tokenAddress),
-                    exchange.observeEntryRate(),
+                    exchange.observePreferredRate(),
                 ) { tokens, balance, rate ->
                     val token = tokens.find { it.address == tokenAddress } ?: return@combine null
                     TokenWithLocalizedBalance(
@@ -232,7 +232,7 @@ internal class CashScreenViewModel @Inject constructor(
                 dispatchEvent(Event.OnCurrencyChanged(it))
             }.launchIn(viewModelScope)
 
-        exchange.observeEntryRate()
+        exchange.observePreferredRate()
             .onEach {
                 // reset when entry rate changes
                 numberInputHelper.reset()
@@ -309,7 +309,7 @@ internal class CashScreenViewModel @Inject constructor(
             .onEach { data ->
                 dispatchEvent(Event.UpdateLoadingState(loading = true))
                 val (token, balance) = stateFlow.value.token!!
-                val rate = exchange.entryRate
+                val rate = exchange.preferredRate
 
                 val result = verifiedFiatCalculator.compute(
                     amount = Fiat(data.amountData.amount, rate.currency),
@@ -352,9 +352,6 @@ internal class CashScreenViewModel @Inject constructor(
             }.launchIn(viewModelScope)
     }
 
-    override fun onCleared() {
-        exchange.resetEntryToBalance()
-    }
 
     internal companion object {
         val updateStateForEvent: (Event) -> ((State) -> State) = { event ->

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

@@ -76,8 +76,8 @@ class CashScreenViewModelTest {
         every { resources.getString(R.string.error_description_sendLimitReached) } returns "error_description_sendLimitReached"
 
         // Default stubs for flows consumed in init
-        every { exchange.observeEntryRate() } returns emptyFlow()
-        every { exchange.entryRate } returns Rate.oneToOne
+        every { exchange.observePreferredRate() } returns emptyFlow()
+        every { exchange.preferredRate } returns Rate.oneToOne
         every { tokenCoordinator.observeSelectedTokenMint() } returns emptyFlow()
         every { tokenCoordinator.tokens } returns emptyFlow()
         every { transactionController.limits } returns MutableStateFlow(null)

apps/flipcash/features/cash/src/test/kotlin/com/flipcash/app/cash/internal/CashScreenViewModelTest.kt

@@ -118,7 +118,6 @@ private fun DepositSelectTokenScreen() {
             modifier = Modifier.fillMaxSize(),
             tokens = state.tokens,
             selectedToken = state.selectedToken,
-            showFlags = true,
             onTokenSelected = { viewModel.dispatchEvent(SelectTokenViewModel.Event.OnTokenSelected(it.address)) },
         )
     }

apps/flipcash/features/deposit/src/main/kotlin/com/flipcash/app/deposit/DepositFlowScreen.kt

@@ -15,7 +15,6 @@ import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.text.AnnotatedString
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import com.flipcash.app.core.AppRoute
-import com.flipcash.app.core.money.RegionSelectionKind
 import com.flipcash.app.core.onramp.ui.buildPhantomButtonLabel
 import com.flipcash.app.core.tokens.FundingSource
 import com.flipcash.app.core.tokens.SwapPurpose
@@ -87,11 +86,7 @@ internal fun SwapEntryScreenContent(
             decimalPlaces = entryState.currencyModel.fractionUnits,
             isClickable = (state.purpose as? SwapPurpose.Buy)?.fundingSource != FundingSource.Phantom,
             onAmountClicked = {
-                navigator.push(
-                    AppRoute.Main.RegionSelection(
-                        kind = RegionSelectionKind.Entry
-                    )
-                )
+                navigator.push(AppRoute.Main.RegionSelection)
             },
             isError = state.isError,
             onNumberPressed = {

apps/flipcash/features/tokens/src/main/kotlin/com/flipcash/app/tokens/internal/SwapEntryScreenContent.kt

@@ -35,7 +35,6 @@ import com.flipcash.app.analytics.FlipcashAnalyticsService
 import com.flipcash.app.analytics.rememberAnalytics
 import com.flipcash.app.core.AppRoute
 import com.flipcash.app.core.data.Loadable
-import com.flipcash.app.core.money.RegionSelectionKind
 import com.flipcash.app.core.tokens.SwapPurpose
 import com.flipcash.app.tokens.internal.components.info.MarketCapSection
 import com.flipcash.app.tokens.internal.components.info.TokenBalance
@@ -145,7 +144,7 @@ private fun TokenInfoScreen(
                                 onClick = {
                                     dispatch(
                                         TokenInfoViewModel.Event.OpenScreen(
-                                            AppRoute.Main.RegionSelection(kind = RegionSelectionKind.Balance)
+                                            AppRoute.Main.RegionSelection
                                         )
                                     )
                                 }