[#1458] Detect unavailable service and show a dialog

* [#1458] Detect unavailable service and show a dialog

- Closes #1458
- Changelog update

* Provide unsorted trx list when disconnected

- These changes also improve the app’s ability to use the SDK’s APIs to provide a transaction history list, even in a disconnected state. In such a case, the list is sorted by its original order.
- Changelog update

CHANGELOG.md

@@ -11,6 +11,9 @@ directly impact users rather than highlighting other key architectural updates.*
 
 ### Added
 - Grid pattern background has been added to several screens
+- A new disconnected dialog reminder has been added to inform users about possible server issues
+- The transaction history list will be displayed when the app has server connection issues. Such a list might have a 
+  slightly different order.
 
 ### Changed
 - The color palette used across the app has been reworked to align with the updated design document

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

@@ -5,13 +5,17 @@ import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.lifecycle.LifecycleCoroutineScope
 import androidx.lifecycle.SavedStateHandle
+import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import androidx.lifecycle.lifecycleScope
+import androidx.navigation.NavBackStackEntry
 import androidx.navigation.NavHostController
 import androidx.navigation.NavOptionsBuilder
 import androidx.navigation.compose.NavHost
 import androidx.navigation.compose.composable
 import androidx.navigation.compose.rememberNavController
+import cash.z.ecc.android.sdk.Synchronizer
 import cash.z.ecc.android.sdk.model.ZecSend
+import co.electriccoin.zcash.spackle.Twig
 import co.electriccoin.zcash.ui.NavigationArguments.MULTIPLE_SUBMISSION_CLEAR_FORM
 import co.electriccoin.zcash.ui.NavigationArguments.SEND_CONFIRM_AMOUNT
 import co.electriccoin.zcash.ui.NavigationArguments.SEND_CONFIRM_INITIAL_STAGE
@@ -43,6 +47,7 @@ import co.electriccoin.zcash.ui.screen.authentication.AuthenticationUseCase
 import co.electriccoin.zcash.ui.screen.authentication.WrapAuthentication
 import co.electriccoin.zcash.ui.screen.chooseserver.WrapChooseServer
 import co.electriccoin.zcash.ui.screen.deletewallet.WrapDeleteWallet
+import co.electriccoin.zcash.ui.screen.disconnected.WrapDisconnected
 import co.electriccoin.zcash.ui.screen.exportdata.WrapExportPrivateData
 import co.electriccoin.zcash.ui.screen.home.WrapHome
 import co.electriccoin.zcash.ui.screen.scan.WrapScanValidator
@@ -88,42 +93,7 @@ internal fun MainActivity.Navigation() {
         popExitTransition = { popExitTransition() }
     ) {
         composable(HOME) { backStack ->
-            WrapHome(
+            NavigationHome(navController, backStack)
-                goBack = { finish() },
-                goScan = { navController.navigateJustOnce(SCAN) },
-                goSendConfirmation = { zecSend ->
-                    navController.currentBackStackEntry?.savedStateHandle?.let { handle ->
-                        fillInHandleForConfirmation(handle, zecSend, SendConfirmationStage.Confirmation)
-                    }
-                    navController.navigateJustOnce(SEND_CONFIRMATION)
-                },
-                goSettings = { navController.navigateJustOnce(SETTINGS) },
-                goMultiTrxSubmissionFailure = {
-                    // Ultimately we could approach reworking the MultipleTrxFailure screen into a separate
-                    // navigation endpoint
-                    navController.currentBackStackEntry?.savedStateHandle?.let { handle ->
-                        fillInHandleForConfirmation(handle, null, SendConfirmationStage.MultipleTrxFailure)
-                    }
-                    navController.navigateJustOnce(SEND_CONFIRMATION)
-                },
-                sendArguments =
-                    SendArguments(
-                        recipientAddress =
-                            backStack.savedStateHandle.get<String>(SEND_SCAN_RECIPIENT_ADDRESS)?.let {
-                                Json.decodeFromString<SerializableAddress>(it).toRecipient()
-                            },
-                        clearForm = backStack.savedStateHandle.get<Boolean>(MULTIPLE_SUBMISSION_CLEAR_FORM) ?: false
-                    ).also {
-                        // Remove Send screen arguments passed from the Scan or MultipleSubmissionFailure screens if
-                        // some exist after we use them
-                        backStack.savedStateHandle.remove<String>(SEND_SCAN_RECIPIENT_ADDRESS)
-                        backStack.savedStateHandle.remove<Boolean>(MULTIPLE_SUBMISSION_CLEAR_FORM)
-                    },
-            )
-
-            if (ConfigurationEntries.IS_APP_UPDATE_CHECK_ENABLED.getValue(RemoteConfig.current)) {
-                WrapCheckForUpdate()
-            }
         }
         composable(SETTINGS) {
             WrapSettings(
@@ -280,6 +250,65 @@ internal fun MainActivity.Navigation() {
     }
 }
 
+/**
+ * This is the Home screens sub-navigation. We could consider creating a separate sub-navigation graph.
+ */
+@Composable
+private fun MainActivity.NavigationHome(
+    navController: NavHostController,
+    backStack: NavBackStackEntry
+) {
+    WrapHome(
+        goBack = { finish() },
+        goScan = { navController.navigateJustOnce(SCAN) },
+        goSendConfirmation = { zecSend ->
+            navController.currentBackStackEntry?.savedStateHandle?.let { handle ->
+                fillInHandleForConfirmation(handle, zecSend, SendConfirmationStage.Confirmation)
+            }
+            navController.navigateJustOnce(SEND_CONFIRMATION)
+        },
+        goSettings = { navController.navigateJustOnce(SETTINGS) },
+        goMultiTrxSubmissionFailure = {
+            // Ultimately we could approach reworking the MultipleTrxFailure screen into a separate
+            // navigation endpoint
+            navController.currentBackStackEntry?.savedStateHandle?.let { handle ->
+                fillInHandleForConfirmation(handle, null, SendConfirmationStage.MultipleTrxFailure)
+            }
+            navController.navigateJustOnce(SEND_CONFIRMATION)
+        },
+        sendArguments =
+            SendArguments(
+                recipientAddress =
+                    backStack.savedStateHandle.get<String>(SEND_SCAN_RECIPIENT_ADDRESS)?.let {
+                        Json.decodeFromString<SerializableAddress>(it).toRecipient()
+                    },
+                clearForm = backStack.savedStateHandle.get<Boolean>(MULTIPLE_SUBMISSION_CLEAR_FORM) ?: false
+            ).also {
+                // Remove Send screen arguments passed from the Scan or MultipleSubmissionFailure screens if
+                // some exist after we use them
+                backStack.savedStateHandle.remove<String>(SEND_SCAN_RECIPIENT_ADDRESS)
+                backStack.savedStateHandle.remove<Boolean>(MULTIPLE_SUBMISSION_CLEAR_FORM)
+            },
+    )
+
+    val sdkStatus = walletViewModel.walletSnapshot.collectAsStateWithLifecycle().value?.status
+
+    if (Synchronizer.Status.DISCONNECTED == sdkStatus) {
+        Twig.info { "Disconnected state received from Synchronizer" }
+
+        WrapDisconnected(
+            goChooseServer = {
+                navController.navigateJustOnce(CHOOSE_SERVER)
+            },
+            onIgnore = {
+                // Keep the current navigation location
+            }
+        )
+    } else if (ConfigurationEntries.IS_APP_UPDATE_CHECK_ENABLED.getValue(RemoteConfig.current)) {
+        WrapCheckForUpdate()
+    }
+}
+
 @Composable
 private fun MainActivity.ShowSystemAuthentication(
     navHostController: NavHostController,

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

@@ -220,11 +220,11 @@ class WalletViewModel(application: Application) : AndroidViewModel(application)
                 combine(
                     synchronizer.transactions,
                     synchronizer.status,
-                    synchronizer.networkHeight.filterNotNull()
+                    synchronizer.networkHeight
                 ) {
                         transactions: List<TransactionOverview>,
                         status: Synchronizer.Status,
-                        networkHeight: BlockHeight ->
+                        networkHeight: BlockHeight? ->
                     val enhancedTransactions =
                         transactions
                             .sortedByDescending {

ui-lib/src/main/java/co/electriccoin/zcash/ui/screen/account/ext/TransactionOverviewExt.kt

@@ -11,7 +11,13 @@ data class TransactionOverviewExt(
     val recipientAddressType: AddressType?
 )
 
-fun TransactionOverview.getSortHeight(networkHeight: BlockHeight): BlockHeight {
+/**
+ * This extension provides the best height that can currently be offered.
+ *
+ * @return It returns a height for the transaction list sorting in this order:
+ * [minedHeight] -> [expiryHeight] -> [networkHeight] -> null
+ */
+fun TransactionOverview.getSortHeight(networkHeight: BlockHeight?): BlockHeight? {
     // Non-null assertion operator is necessary here as the smart cast to is impossible because `minedHeight` and
     // `expiryHeight` are declared in a different module
     return when {

ui-lib/src/main/java/co/electriccoin/zcash/ui/screen/disconnected/AndroidDisconnected.kt

@@ -0,0 +1,43 @@
+@file:Suppress("ktlint:standard:filename")
+
+package co.electriccoin.zcash.ui.screen.disconnected
+
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.mutableStateOf
+import androidx.compose.runtime.saveable.rememberSaveable
+import co.electriccoin.zcash.ui.MainActivity
+import co.electriccoin.zcash.ui.screen.disconnected.model.DisconnectedUiState
+import co.electriccoin.zcash.ui.screen.disconnected.view.ServerDisconnected
+
+@Composable
+internal fun MainActivity.WrapDisconnected(
+    goChooseServer: () -> Unit,
+    onIgnore: () -> Unit,
+) {
+    co.electriccoin.zcash.ui.screen.disconnected.WrapDisconnected(
+        goChooseServer = goChooseServer,
+        onIgnore = onIgnore,
+    )
+}
+
+@Composable
+private fun WrapDisconnected(
+    goChooseServer: () -> Unit,
+    onIgnore: () -> Unit,
+) {
+    val (disconnectedUi, setDisconnectedUi) =
+        rememberSaveable(stateSaver = DisconnectedUiState.Saver) { mutableStateOf(DisconnectedUiState.Displayed) }
+
+    if (disconnectedUi == DisconnectedUiState.Displayed) {
+        ServerDisconnected(
+            onChooseServer = {
+                setDisconnectedUi(DisconnectedUiState.Dismissed)
+                goChooseServer()
+            },
+            onIgnore = {
+                setDisconnectedUi(DisconnectedUiState.Dismissed)
+                onIgnore()
+            },
+        )
+    }
+}

ui-lib/src/main/java/co/electriccoin/zcash/ui/screen/disconnected/model/DisconnectedUiState.kt

@@ -0,0 +1,44 @@
+package co.electriccoin.zcash.ui.screen.disconnected.model
+
+import androidx.compose.runtime.saveable.mapSaver
+
+internal sealed class DisconnectedUiState {
+    data object Displayed : DisconnectedUiState()
+
+    data object Dismissed : DisconnectedUiState()
+
+    companion object {
+        private const val TYPE_DISPLAYED = "displayed" // $NON-NLS
+        private const val TYPE_DISMISSED = "dismissed" // $NON-NLS
+        private const val KEY_TYPE = "type" // $NON-NLS
+
+        internal val Saver
+            get() =
+                run {
+                    mapSaver(
+                        save = { it.toSaverMap() },
+                        restore = {
+                            if (it.isEmpty()) {
+                                null
+                            } else {
+                                val sendStageString = (it[KEY_TYPE] as String)
+                                when (sendStageString) {
+                                    TYPE_DISPLAYED -> Displayed
+                                    TYPE_DISMISSED -> Dismissed
+                                    else -> null
+                                }
+                            }
+                        }
+                    )
+                }
+
+        private fun DisconnectedUiState.toSaverMap(): HashMap<String, String> {
+            val saverMap = HashMap<String, String>()
+            when (this) {
+                Displayed -> saverMap[KEY_TYPE] = TYPE_DISPLAYED
+                Dismissed -> saverMap[KEY_TYPE] = TYPE_DISMISSED
+            }
+            return saverMap
+        }
+    }
+}

ui-lib/src/main/java/co/electriccoin/zcash/ui/screen/disconnected/view/DisconnectedView.kt

@@ -0,0 +1,59 @@
+package co.electriccoin.zcash.ui.screen.disconnected.view
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.rememberScrollState
+import androidx.compose.foundation.verticalScroll
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.tooling.preview.Preview
+import co.electriccoin.zcash.ui.R
+import co.electriccoin.zcash.ui.design.component.AppAlertDialog
+import co.electriccoin.zcash.ui.design.component.BlankSurface
+import co.electriccoin.zcash.ui.design.theme.ZcashTheme
+
+@Preview("Server Disconnected")
+@Composable
+private fun PreviewServerDisconnected() {
+    ZcashTheme(forceDarkMode = false) {
+        BlankSurface {
+            ServerDisconnected(
+                onChooseServer = {},
+                onIgnore = {}
+            )
+        }
+    }
+}
+
+@Composable
+fun ServerDisconnected(
+    onChooseServer: () -> Unit,
+    onIgnore: () -> Unit,
+) {
+    ServerDisconnectedDialog(
+        onChooseServer = onChooseServer,
+        onIgnore = onIgnore,
+    )
+}
+
+@Composable
+fun ServerDisconnectedDialog(
+    onChooseServer: () -> Unit,
+    onIgnore: () -> Unit,
+) {
+    AppAlertDialog(
+        title = stringResource(id = R.string.server_disconnected_dialog_title),
+        text = {
+            Column(
+                Modifier.verticalScroll(rememberScrollState())
+            ) {
+                Text(text = stringResource(id = R.string.server_disconnected_dialog_message))
+            }
+        },
+        confirmButtonText = stringResource(id = R.string.server_disconnected_dialog_switch_btn),
+        onConfirmButtonClick = onChooseServer,
+        dismissButtonText = stringResource(id = R.string.server_disconnected_dialog_ignore_btn),
+        onDismissButtonClick = onIgnore,
+    )
+}

ui-lib/src/main/res/ui/common/values/strings.xml

@@ -8,4 +8,11 @@
     <string name="support_email_address" />
     <string name="restoring_wallet_label">[Restoring Your Wallet…]</string>
     <string name="unable_to_open_play_store">Unable to launch Google Play store app…</string>
+
+    <string name="server_disconnected_dialog_title">Caution</string>
+    <string name="server_disconnected_dialog_message">The server you\'re presently connected to is experiencing
+        difficulties. For better performance, navigate to Advanced Settings and choose a different server. Please
+        also check your device connection.</string>
+    <string name="server_disconnected_dialog_switch_btn">Switch Server</string>
+    <string name="server_disconnected_dialog_ignore_btn">Ignore</string>
 </resources>