Fix multiple loading activities launched

app/src/main/java/org/thoughtcrime/securesms/onboarding/LinkDeviceActivity.kt

@@ -66,6 +66,7 @@ import com.google.mlkit.vision.barcode.BarcodeScanning
 import com.google.mlkit.vision.barcode.common.Barcode
 import com.google.mlkit.vision.common.InputImage
 import dagger.hilt.android.AndroidEntryPoint
+import kotlinx.coroutines.flow.first
 import kotlinx.coroutines.launch
 import network.loki.messenger.R
 import org.session.libsession.utilities.TextSecurePreferences
@@ -78,6 +79,7 @@ import org.thoughtcrime.securesms.ui.colorDestructive
 import org.thoughtcrime.securesms.ui.components.SessionTabRow
 import java.util.concurrent.Executors
 import javax.inject.Inject
+import kotlin.coroutines.CoroutineContext
 
 private const val TAG = "LinkDeviceActivity"
 
@@ -108,6 +110,7 @@ class LinkDeviceActivity : BaseActionBarActivity() {
         lifecycleScope.launch {
             viewModel.eventFlow.collect {
                 startLoadingActivity(it.mnemonic)
+                finish()
             }
         }
 
@@ -115,7 +118,7 @@ class LinkDeviceActivity : BaseActionBarActivity() {
             setContent {
                 val state by viewModel.stateFlow.collectAsState()
                 AppTheme {
-                    LoadAccountScreen(state, viewModel::onChange, viewModel::tryPhrase)
+                    LoadAccountScreen(state, viewModel::onChange, viewModel::onContinue)
                 }
             }
         }.let(::setContentView)

app/src/main/java/org/thoughtcrime/securesms/onboarding/LinkDeviceViewModel.kt

@@ -1,28 +1,26 @@
 package org.thoughtcrime.securesms.onboarding
 
 import android.app.Application
-import androidx.compose.runtime.snapshots.SnapshotApplyResult
 import androidx.lifecycle.AndroidViewModel
 import androidx.lifecycle.viewModelScope
 import dagger.hilt.android.lifecycle.HiltViewModel
-import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.channels.Channel
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.flow.consumeAsFlow
-import kotlinx.coroutines.flow.distinctUntilChanged
-import kotlinx.coroutines.flow.first
+import kotlinx.coroutines.flow.debounce
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.receiveAsFlow
+import kotlinx.coroutines.flow.take
 import kotlinx.coroutines.flow.takeWhile
-import kotlinx.coroutines.flow.transformWhile
 import kotlinx.coroutines.flow.update
 import kotlinx.coroutines.launch
 import org.session.libsignal.crypto.MnemonicCodec
 import org.session.libsignal.utilities.Hex
 import org.thoughtcrime.securesms.crypto.MnemonicUtilities
 import javax.inject.Inject
+import kotlin.time.Duration.Companion.seconds
 
 class LinkDeviceEvent(val mnemonic: ByteArray)
 
@@ -30,38 +28,51 @@ class LinkDeviceEvent(val mnemonic: ByteArray)
 class LinkDeviceViewModel @Inject constructor(
     application: Application
 ): AndroidViewModel(application) {
+    private val QR_ERROR_TIME = 3.seconds
     private val state = MutableStateFlow(LinkDeviceState())
     val stateFlow = state.asStateFlow()
 
-    private val qrErrors = Channel<Throwable>()
     private val event = Channel<LinkDeviceEvent>()
-    val eventFlow = event.receiveAsFlow()
+    val eventFlow = event.receiveAsFlow().take(1)
+    private val qrErrors = Channel<Throwable>()
+    private val qrErrorsFlow = qrErrors.receiveAsFlow().debounce(QR_ERROR_TIME).takeWhile { event.isEmpty }
 
-    private val phrases = Channel<String>()
+    private val codec by lazy { MnemonicCodec { MnemonicUtilities.loadFileContents(getApplication(), it) } }
 
-    init {
+    fun onContinue() {
         viewModelScope.launch {
-            phrases.receiveAsFlow().map {
-                runCatching {
-                    MnemonicCodec { MnemonicUtilities.loadFileContents(getApplication(), it) }
-                        .decode(it)
-                        .let(Hex::fromStringCondensed)
-                }
-            }.takeWhile {
-                it.getOrNull()?.let(::LinkDeviceEvent)?.let { event.send(it) }
-                it.exceptionOrNull()?.let { qrErrors.send(it) }
-                it.isFailure
-            }.collect()
+            runDecodeCatching(state.value.recoveryPhrase)
+                .onSuccess(::onSuccess)
+                .onFailure(::onFailure)
         }
     }
 
-    fun tryPhrase(string: String = state.value.recoveryPhrase) {
+    fun scan(string: String) {
         viewModelScope.launch {
-            phrases.send(string)
+            runDecodeCatching(string)
+                .onSuccess(::onSuccess)
+                .onFailure(::onScanFailure)
         }
     }
 
+
     fun onChange(recoveryPhrase: String) {
         state.value = LinkDeviceState(recoveryPhrase)
     }
+    private fun onSuccess(seed: ByteArray) {
+        viewModelScope.launch { event.send(LinkDeviceEvent(seed)) }
+    }
+
+    private fun onFailure(error: Throwable) {
+        state.update { it.copy(error = error.message) }
+    }
+
+    private fun onScanFailure(error: Throwable) {
+        state.update { it.copy(error = error.message) }
+    }
+
+    private fun runDecodeCatching(mnemonic: String) = runCatching {
+        decode(mnemonic)
+    }
+    private fun decode(mnemonic: String) = codec.decode(mnemonic).let(Hex::fromStringCondensed)!!
 }