fix: handle missing mnemonic during VSS backup setup

Author: piotr-iohk

app/src/main/java/to/bitkit/data/backup/VssBackupClient.kt

@@ -16,7 +16,6 @@ import to.bitkit.data.keychain.Keychain
 import to.bitkit.di.IoDispatcher
 import to.bitkit.env.Env
 import to.bitkit.utils.Logger
-import to.bitkit.utils.ServiceError
 import javax.inject.Inject
 import javax.inject.Singleton
 import kotlin.time.Duration.Companion.seconds
@@ -29,7 +28,23 @@ class VssBackupClient @Inject constructor(
 ) {
     private var isSetup = CompletableDeferred<Unit>()
 
-    suspend fun setup(walletIndex: Int = 0) = withContext(ioDispatcher) {
+    /**
+     * Sets up the VSS client. Returns true if setup succeeded, false if mnemonic not available.
+     * Throws on other errors.
+     */
+    suspend fun setup(walletIndex: Int = 0): Boolean = withContext(ioDispatcher) {
+        // If already set up successfully, return immediately
+        if (isSetup.isCompleted && !isSetup.isCancelled) {
+            runCatching { isSetup.await() }.onSuccess { return@withContext true }
+        }
+
+        // Check if mnemonic is available before proceeding
+        val mnemonic = keychain.loadString(Keychain.Key.BIP39_MNEMONIC.name)
+        if (mnemonic == null) {
+            Logger.warn("VSS client setup deferred: mnemonic not available yet", context = TAG)
+            return@withContext false
+        }
+
         runCatching {
             withTimeout(30.seconds) {
                 Logger.debug("VSS client setting up…", context = TAG)
@@ -39,8 +54,6 @@ class VssBackupClient @Inject constructor(
                 Logger.verbose("Building VSS client with vssUrl: '$vssUrl'", context = TAG)
                 Logger.verbose("Building VSS client with lnurlAuthServerUrl: '$lnurlAuthServerUrl'", context = TAG)
                 if (lnurlAuthServerUrl.isNotEmpty()) {
-                    val mnemonic = keychain.loadString(Keychain.Key.BIP39_MNEMONIC.name)
-                        ?: throw ServiceError.MnemonicNotFound()
                     val passphrase = keychain.loadString(Keychain.Key.BIP39_PASSPHRASE.name)
 
                     vssNewClientWithLnurlAuth(
@@ -63,6 +76,7 @@ class VssBackupClient @Inject constructor(
             isSetup.completeExceptionally(it)
             Logger.error("VSS client setup error", e = it, context = TAG)
         }
+        true
     }
 
     fun reset() {

app/src/main/java/to/bitkit/repositories/BackupRepo.kt

@@ -120,7 +120,7 @@ class BackupRepo @Inject constructor(
         isObserving = true
         Logger.debug("Start observing backup statuses and data store changes", context = TAG)
 
-        scope.launch { vssBackupClient.setup() }
+        scope.launch { setupVssClientWithRetry() }
 
         scope.launch {
             BackupCategory.entries.forEach { category ->
@@ -166,6 +166,33 @@ class BackupRepo @Inject constructor(
         Logger.debug("Stopped observing backup statuses and data store changes", context = TAG)
     }
 
+    private suspend fun setupVssClientWithRetry() {
+        var attempt = 0
+        val maxAttempts = 10
+        val baseDelayMs = 1000L
+
+        while (attempt < maxAttempts && isObserving) {
+            val success = runCatching { vssBackupClient.setup() }.getOrDefault(false)
+            if (success) {
+                Logger.debug("VSS client setup succeeded on attempt ${attempt + 1}", context = TAG)
+                return
+            }
+            attempt++
+            if (attempt < maxAttempts) {
+                val delayMs = baseDelayMs * attempt // Linear backoff: 1s, 2s, 3s, ...
+                Logger.debug(
+                    "VSS client setup deferred, retrying in ${delayMs}ms (attempt $attempt/$maxAttempts)",
+                    context = TAG,
+                )
+                delay(delayMs)
+            }
+        }
+
+        if (isObserving) {
+            Logger.warn("VSS client setup failed after $maxAttempts attempts", context = TAG)
+        }
+    }
+
     private fun startBackupStatusObservers() {
         // Observe backup status changes for each category
         BackupCategory.entries.forEach { category ->