Navigation refactor - NavigationRouter added (#1698)

ui-lib/src/main/java/co/electriccoin/zcash/di/CoreModule.kt

@@ -7,6 +7,8 @@ import co.electriccoin.zcash.global.newInstance
 import co.electriccoin.zcash.preference.EncryptedPreferenceProvider
 import co.electriccoin.zcash.preference.StandardPreferenceProvider
 import co.electriccoin.zcash.preference.model.entry.PreferenceKey
+import co.electriccoin.zcash.ui.NavigationRouter
+import co.electriccoin.zcash.ui.NavigationRouterImpl
 import co.electriccoin.zcash.ui.preference.PersistableWalletPreferenceDefault
 import co.electriccoin.zcash.ui.screen.update.AppUpdateChecker
 import co.electriccoin.zcash.ui.screen.update.AppUpdateCheckerImpl
@@ -37,4 +39,6 @@ val coreModule =
         factoryOf(::AppUpdateCheckerImpl) bind AppUpdateChecker::class
 
         factory { AndroidConfigurationFactory.new() }
+
+        singleOf(::NavigationRouterImpl) bind NavigationRouter::class
     }

ui-lib/src/main/java/co/electriccoin/zcash/di/ViewModelModule.kt

@@ -67,6 +67,7 @@ val viewModelModule =
                 args = args,
                 observeAddressBookContacts = get(),
                 observeContactPicked = get(),
+                navigationRouter = get()
             )
         }
         viewModel { (address: String?) ->
@@ -75,6 +76,7 @@ val viewModelModule =
                 validateContactAddress = get(),
                 validateContactName = get(),
                 saveContact = get(),
+                navigationRouter = get()
             )
         }
         viewModelOf(::UpdateContactViewModel)

ui-lib/src/main/java/co/electriccoin/zcash/ui/Navigation.kt

@@ -10,6 +10,7 @@ import androidx.lifecycle.SavedStateHandle
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.lifecycleScope
 import androidx.navigation.NavBackStackEntry
+import androidx.navigation.NavGraph.Companion.findStartDestination
 import androidx.navigation.NavHostController
 import androidx.navigation.NavOptionsBuilder
 import androidx.navigation.NavType
@@ -101,6 +102,7 @@ import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.filterNotNull
 import kotlinx.coroutines.launch
 import kotlinx.serialization.json.Json
+import org.koin.compose.koinInject
 
 // TODO [#1297]: Consider: Navigation passing complex data arguments different way
 // TODO [#1297]: https://github.com/Electric-Coin-Company/zashi-android/issues/1297
@@ -117,16 +119,21 @@ internal fun MainActivity.Navigation() {
         rememberSaveable { mutableStateOf(false) }
     val (deleteWalletAuthentication, setDeleteWalletAuthentication) =
         rememberSaveable { mutableStateOf(false) }
+    val navigationRouter = koinInject<NavigationRouter>()
 
     LaunchedEffect(Unit) {
-        walletViewModel.navigationCommand.collect {
-            navController.navigateJustOnce(it)
-        }
-    }
-
-    LaunchedEffect(Unit) {
-        walletViewModel.backNavigationCommand.collect {
-            navController.popBackStack()
+        navigationRouter.observe().collect {
+            when (it) {
+                is NavigationCommand.Forward -> navController.navigate(it.route)
+                is NavigationCommand.Replace ->
+                    navController.navigate(it.route) {
+                        popUpTo(navController.graph.findStartDestination().id) {
+                            saveState = true
+                        }
+                        restoreState = true
+                    }
+                NavigationCommand.Back -> navController.popBackStack()
+            }
         }
     }
 

ui-lib/src/main/java/co/electriccoin/zcash/ui/NavigationRouter.kt

@@ -0,0 +1,53 @@
+package co.electriccoin.zcash.ui
+
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.SupervisorJob
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.consumeAsFlow
+import kotlinx.coroutines.launch
+
+interface NavigationRouter {
+    fun forward(route: String)
+
+    fun replace(route: String)
+
+    fun back()
+
+    fun observe(): Flow<NavigationCommand>
+}
+
+class NavigationRouterImpl : NavigationRouter {
+    private val scope = CoroutineScope(Dispatchers.Main.immediate + SupervisorJob())
+
+    private val channel = Channel<NavigationCommand>()
+
+    override fun forward(route: String) {
+        scope.launch {
+            channel.send(NavigationCommand.Forward(route))
+        }
+    }
+
+    override fun replace(route: String) {
+        scope.launch {
+            channel.send(NavigationCommand.Replace(route))
+        }
+    }
+
+    override fun back() {
+        scope.launch {
+            channel.send(NavigationCommand.Back)
+        }
+    }
+
+    override fun observe() = channel.consumeAsFlow()
+}
+
+sealed interface NavigationCommand {
+    data class Forward(val route: String) : NavigationCommand
+
+    data class Replace(val route: String) : NavigationCommand
+
+    data object Back : NavigationCommand
+}

ui-lib/src/main/java/co/electriccoin/zcash/ui/common/repository/ExchangeRateRepository.kt

@@ -5,6 +5,7 @@ import cash.z.ecc.sdk.ANDROID_STATE_FLOW_TIMEOUT
 import co.electriccoin.zcash.preference.StandardPreferenceProvider
 import co.electriccoin.zcash.preference.model.entry.NullableBooleanPreferenceDefault
 import co.electriccoin.zcash.spackle.Twig
+import co.electriccoin.zcash.ui.NavigationRouter
 import co.electriccoin.zcash.ui.NavigationTargets.EXCHANGE_RATE_OPT_IN
 import co.electriccoin.zcash.ui.common.wallet.ExchangeRateState
 import co.electriccoin.zcash.ui.common.wallet.RefreshLock
@@ -15,7 +16,6 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.ExperimentalCoroutinesApi
 import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.channels.awaitClose
-import kotlinx.coroutines.flow.MutableSharedFlow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.WhileSubscribed
@@ -36,10 +36,6 @@ import kotlinx.coroutines.launch
 import kotlin.time.Duration.Companion.minutes
 
 interface ExchangeRateRepository {
-    val navigationCommand: MutableSharedFlow<String>
-
-    val backNavigationCommand: MutableSharedFlow<Unit>
-
     val isExchangeRateUsdOptedIn: StateFlow<Boolean?>
 
     val state: StateFlow<ExchangeRateState>
@@ -54,6 +50,7 @@ interface ExchangeRateRepository {
 class ExchangeRateRepositoryImpl(
     private val walletRepository: WalletRepository,
     private val standardPreferenceProvider: StandardPreferenceProvider,
+    private val navigationRouter: NavigationRouter,
 ) : ExchangeRateRepository {
     private val scope = CoroutineScope(Dispatchers.IO + SupervisorJob())
 
@@ -164,10 +161,6 @@ class ExchangeRateRepositoryImpl(
             initialValue = ExchangeRateState.OptedOut
         )
 
-    override val navigationCommand = MutableSharedFlow<String>()
-
-    override val backNavigationCommand = MutableSharedFlow<Unit>()
-
     override fun refreshExchangeRateUsd() {
         refreshExchangeRateUsdInternal()
     }
@@ -182,27 +175,20 @@ class ExchangeRateRepositoryImpl(
         }
 
     override fun optInExchangeRateUsd(optIn: Boolean) {
-        scope.launch {
-            setNullableBooleanPreference(StandardPreferenceKeys.EXCHANGE_RATE_OPTED_IN, optIn)
-            backNavigationCommand.emit(Unit)
-        }
+        setNullableBooleanPreference(StandardPreferenceKeys.EXCHANGE_RATE_OPTED_IN, optIn)
+        navigationRouter.back()
     }
 
     override fun dismissOptInExchangeRateUsd() {
-        scope.launch {
-            setNullableBooleanPreference(StandardPreferenceKeys.EXCHANGE_RATE_OPTED_IN, false)
-            backNavigationCommand.emit(Unit)
-        }
+        setNullableBooleanPreference(StandardPreferenceKeys.EXCHANGE_RATE_OPTED_IN, false)
+        navigationRouter.back()
     }
 
     private fun dismissWidgetOptInExchangeRateUsd() {
         setNullableBooleanPreference(StandardPreferenceKeys.EXCHANGE_RATE_OPTED_IN, false)
     }
 
-    private fun showOptInExchangeRateUsd() =
-        scope.launch {
-            navigationCommand.emit(EXCHANGE_RATE_OPT_IN)
-        }
+    private fun showOptInExchangeRateUsd() = navigationRouter.forward(EXCHANGE_RATE_OPT_IN)
 
     private fun nullableBooleanStateFlow(default: NullableBooleanPreferenceDefault): StateFlow<Boolean?> =
         flow {

ui-lib/src/main/java/co/electriccoin/zcash/ui/common/viewmodel/WalletViewModel.kt

@@ -68,10 +68,6 @@ class WalletViewModel(
     private val isFlexaAvailable: IsFlexaAvailableUseCase,
     private val getSynchronizer: GetSynchronizerUseCase
 ) : AndroidViewModel(application) {
-    val navigationCommand = exchangeRateRepository.navigationCommand
-
-    val backNavigationCommand = exchangeRateRepository.backNavigationCommand
-
     val synchronizer = walletRepository.synchronizer
 
     val walletRestoringState = walletRepository.walletRestoringState

ui-lib/src/main/java/co/electriccoin/zcash/ui/screen/addressbook/AndroidAddressBook.kt

@@ -4,11 +4,9 @@ package co.electriccoin.zcash.ui.screen.addressbook
 
 import androidx.activity.compose.BackHandler
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.LaunchedEffect
 import androidx.compose.runtime.getValue
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import co.electriccoin.zcash.di.koinActivityViewModel
-import co.electriccoin.zcash.ui.common.compose.LocalNavController
 import co.electriccoin.zcash.ui.common.viewmodel.WalletViewModel
 import co.electriccoin.zcash.ui.screen.addressbook.view.AddressBookView
 import co.electriccoin.zcash.ui.screen.addressbook.viewmodel.AddressBookViewModel
@@ -17,24 +15,11 @@ import org.koin.core.parameter.parametersOf
 
 @Composable
 internal fun WrapAddressBook(args: AddressBookArgs) {
-    val navController = LocalNavController.current
     val walletViewModel = koinActivityViewModel<WalletViewModel>()
     val viewModel = koinViewModel<AddressBookViewModel> { parametersOf(args) }
     val walletState by walletViewModel.walletStateInformation.collectAsStateWithLifecycle()
     val state by viewModel.state.collectAsStateWithLifecycle()
 
-    LaunchedEffect(Unit) {
-        viewModel.navigationCommand.collect {
-            navController.navigate(it)
-        }
-    }
-
-    LaunchedEffect(Unit) {
-        viewModel.backNavigationCommand.collect {
-            navController.popBackStack()
-        }
-    }
-
     BackHandler {
         state.onBack()
     }

ui-lib/src/main/java/co/electriccoin/zcash/ui/screen/addressbook/viewmodel/AddressBookViewModel.kt

@@ -3,6 +3,7 @@ package co.electriccoin.zcash.ui.screen.addressbook.viewmodel
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.viewModelScope
 import cash.z.ecc.sdk.ANDROID_STATE_FLOW_TIMEOUT
+import co.electriccoin.zcash.ui.NavigationRouter
 import co.electriccoin.zcash.ui.R
 import co.electriccoin.zcash.ui.common.model.AddressBookContact
 import co.electriccoin.zcash.ui.common.usecase.ObserveAddressBookContactsUseCase
@@ -16,7 +17,6 @@ import co.electriccoin.zcash.ui.screen.contact.AddContactArgs
 import co.electriccoin.zcash.ui.screen.contact.UpdateContactArgs
 import co.electriccoin.zcash.ui.screen.scan.ScanNavigationArgs
 import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.flow.MutableSharedFlow
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.WhileSubscribed
 import kotlinx.coroutines.flow.flowOn
@@ -27,7 +27,8 @@ import kotlinx.coroutines.launch
 class AddressBookViewModel(
     observeAddressBookContacts: ObserveAddressBookContactsUseCase,
     private val args: AddressBookArgs,
-    private val observeContactPicked: ObserveContactPickedUseCase
+    private val observeContactPicked: ObserveContactPickedUseCase,
+    private val navigationRouter: NavigationRouter,
 ) : ViewModel() {
     val state =
         observeAddressBookContacts()
@@ -39,10 +40,6 @@ class AddressBookViewModel(
                 initialValue = createState(contacts = null)
             )
 
-    val navigationCommand = MutableSharedFlow<String>()
-
-    val backNavigationCommand = MutableSharedFlow<Unit>()
-
     private fun createState(contacts: List<AddressBookContact>?) =
         AddressBookState(
             isLoading = contacts == null,
@@ -80,34 +77,25 @@ class AddressBookViewModel(
                 .joinToString(separator = "")
         )
 
-    private fun onBack() =
-        viewModelScope.launch {
-            backNavigationCommand.emit(Unit)
-        }
+    private fun onBack() = navigationRouter.back()
 
     private fun onContactClick(contact: AddressBookContact) =
         viewModelScope.launch {
             when (args) {
                 AddressBookArgs.DEFAULT -> {
-                    navigationCommand.emit(UpdateContactArgs(contact.address))
+                    navigationRouter.forward(UpdateContactArgs(contact.address))
                 }
 
                 AddressBookArgs.PICK_CONTACT -> {
                     observeContactPicked.onContactPicked(contact)
-                    backNavigationCommand.emit(Unit)
+                    navigationRouter.back()
                 }
             }
         }
 
-    private fun onAddContactManuallyClick() =
-        viewModelScope.launch {
-            navigationCommand.emit(AddContactArgs(null))
-        }
+    private fun onAddContactManuallyClick() = navigationRouter.forward(AddContactArgs(null))
 
-    private fun onScanContactClick() =
-        viewModelScope.launch {
-            navigationCommand.emit(ScanNavigationArgs(ScanNavigationArgs.ADDRESS_BOOK))
-        }
+    private fun onScanContactClick() = navigationRouter.forward(ScanNavigationArgs(ScanNavigationArgs.ADDRESS_BOOK))
 }
 
 private const val ADDRESS_MAX_LENGTH = 20

ui-lib/src/main/java/co/electriccoin/zcash/ui/screen/advancedsettings/AndroidAdvancedSettings.kt

@@ -4,10 +4,8 @@ package co.electriccoin.zcash.ui.screen.advancedsettings
 
 import androidx.activity.compose.BackHandler
 import androidx.compose.runtime.Composable
-import androidx.compose.runtime.LaunchedEffect
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import co.electriccoin.zcash.di.koinActivityViewModel
-import co.electriccoin.zcash.ui.common.compose.LocalNavController
 import co.electriccoin.zcash.ui.common.viewmodel.WalletViewModel
 import co.electriccoin.zcash.ui.screen.advancedsettings.view.AdvancedSettings
 import co.electriccoin.zcash.ui.screen.advancedsettings.viewmodel.AdvancedSettingsViewModel
@@ -20,7 +18,6 @@ internal fun WrapAdvancedSettings(
     goExportPrivateData: () -> Unit,
     goSeedRecovery: () -> Unit,
 ) {
-    val navController = LocalNavController.current
     val walletViewModel = koinActivityViewModel<WalletViewModel>()
     val viewModel = koinViewModel<AdvancedSettingsViewModel>()
     val walletState = walletViewModel.walletStateInformation.collectAsStateWithLifecycle().value
@@ -42,18 +39,6 @@ internal fun WrapAdvancedSettings(
         viewModel.onBack()
     }
 
-    LaunchedEffect(Unit) {
-        viewModel.navigationCommand.collect {
-            navController.navigate(it)
-        }
-    }
-
-    LaunchedEffect(Unit) {
-        viewModel.backNavigationCommand.collect {
-            navController.popBackStack()
-        }
-    }
-
     AdvancedSettings(
         state = state,
         topAppBarSubTitleState = walletState,