fix(Android): add alert dialog for errors in auth flow (#4835)

fixes #4723

kotlin/android/app/src/main/java/dev/firezone/android/features/customuri/notifications/CustomUriNotification.kt

@@ -0,0 +1,71 @@
+/* Licensed under Apache 2.0 (C) 2024 Firezone, Inc. */
+package dev.firezone.android.features.customuri.notifications
+
+import android.app.NotificationChannel
+import android.app.NotificationManager
+import android.app.PendingIntent
+import android.content.Context
+import android.content.Context.NOTIFICATION_SERVICE
+import android.content.Intent
+import android.util.Log
+import androidx.core.app.NotificationCompat
+import dev.firezone.android.R
+import dev.firezone.android.core.presentation.MainActivity
+
+object CustomUriNotification {
+    private const val CHANNEL_ID = "firezone-authentication-status"
+    private const val CHANNEL_NAME = "firezone-authentication-status"
+    private const val CHANNEL_DESCRIPTION = "Firezone authentication status"
+    const val ID = 1338
+    private const val TAG: String = "CustomUriNotification"
+
+    fun update(
+        context: Context,
+        status: StatusType,
+    ): NotificationCompat.Builder {
+        Log.d(TAG, "update")
+        val manager = context.getSystemService(NOTIFICATION_SERVICE) as NotificationManager
+
+        val chan =
+            NotificationChannel(
+                CHANNEL_ID,
+                CHANNEL_NAME,
+                NotificationManager.IMPORTANCE_DEFAULT,
+            )
+        chan.description = CHANNEL_DESCRIPTION
+        manager.createNotificationChannel(chan)
+
+        val notificationBuilder =
+            NotificationCompat.Builder(context, CHANNEL_ID)
+                .setContentIntent(configIntent(context))
+        return status.applySettings(notificationBuilder)
+    }
+
+    private fun configIntent(context: Context): PendingIntent {
+        Log.d(TAG, "configIntent")
+        val intent = Intent(context, MainActivity::class.java)
+        intent.flags = Intent.FLAG_ACTIVITY_NEW_TASK or Intent.FLAG_ACTIVITY_CLEAR_TASK
+        return PendingIntent.getActivity(
+            context,
+            0,
+            intent,
+            PendingIntent.FLAG_UPDATE_CURRENT or PendingIntent.FLAG_IMMUTABLE,
+        )
+    }
+
+    data class Error(val message: String) : StatusType() {
+        override fun applySettings(builder: NotificationCompat.Builder) =
+            builder.apply {
+                setSmallIcon(R.drawable.ic_firezone_logo)
+                setContentTitle("Authentication Error")
+                setContentText(message)
+                setStyle(NotificationCompat.BigTextStyle().bigText(message))
+                setPriority(NotificationCompat.PRIORITY_HIGH)
+                setAutoCancel(true)
+            }
+    }
+
+    sealed class StatusType {
+        abstract fun applySettings(builder: NotificationCompat.Builder): NotificationCompat.Builder
+    }
+}

kotlin/android/app/src/main/java/dev/firezone/android/features/customuri/ui/CustomUriHandlerActivity.kt

@@ -1,6 +1,8 @@
 /* Licensed under Apache 2.0 (C) 2024 Firezone, Inc. */
 package dev.firezone.android.features.customuri.ui
 
+import android.app.NotificationManager
+import android.content.Context
 import android.content.Intent
 import android.os.Bundle
 import androidx.activity.viewModels
@@ -9,6 +11,7 @@ import dagger.hilt.android.AndroidEntryPoint
 import dev.firezone.android.R
 import dev.firezone.android.core.presentation.MainActivity
 import dev.firezone.android.databinding.ActivityCustomUriHandlerBinding
+import dev.firezone.android.features.customuri.notifications.CustomUriNotification
 import dev.firezone.android.tunnel.TunnelService
 
 @AndroidEntryPoint
@@ -33,6 +36,10 @@ class CustomUriHandlerActivity : AppCompatActivity(R.layout.activity_custom_uri_
                         Intent(this, MainActivity::class.java),
                     )
                 }
+                is CustomUriViewModel.ViewAction.AuthFlowError -> {
+                    notifyError("Errors occurred during authentication:\n${action.errors.joinToString(separator = "\n")}")
+                    startActivity(Intent(this, MainActivity::class.java))
+                }
                 else -> {
                     throw IllegalStateException("Unknown action: $action")
                 }
@@ -41,4 +48,10 @@ class CustomUriHandlerActivity : AppCompatActivity(R.layout.activity_custom_uri_
             finish()
         }
     }
+
+    private fun notifyError(message: String) {
+        val notification = CustomUriNotification.update(this, CustomUriNotification.Error(message)).build()
+        val manager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
+        manager.notify(CustomUriNotification.ID, notification)
+    }
 }

kotlin/android/app/src/main/java/dev/firezone/android/features/customuri/ui/CustomUriViewModel.kt

@@ -14,7 +14,6 @@ import dev.firezone.android.core.data.Repository
 import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.flow.firstOrNull
 import kotlinx.coroutines.launch
-import java.lang.IllegalStateException
 import javax.inject.Inject
 
 @HiltViewModel
@@ -28,39 +27,47 @@ internal class CustomUriViewModel
 
         fun parseCustomUri(intent: Intent) {
             viewModelScope.launch {
+                val accumulatedErrors = mutableListOf<String>()
+                val error = { msg: String ->
+                    accumulatedErrors += msg
+                    Firebase.crashlytics.log(msg)
+                    Log.e(TAG, msg)
+                }
+
                 when (intent.data?.host) {
                     PATH_CALLBACK -> {
                         intent.data?.getQueryParameter(QUERY_ACTOR_NAME)?.let { actorName ->
-                            Log.d("CustomUriViewModel", "Found actor name: $actorName")
+                            Log.d(TAG, "Found actor name: $actorName")
                             repo.saveActorName(actorName).collect()
                         }
                         intent.data?.getQueryParameter(QUERY_CLIENT_STATE)?.let { state ->
                             if (repo.validateState(state).firstOrNull() == true) {
-                                Log.d("CustomUriViewModel", "Valid state parameter. Continuing to save state...")
+                                Log.d(TAG, "Valid state parameter. Continuing to save state...")
                             } else {
-                                throw IllegalStateException("Invalid state parameter $state! Authentication will not succeed...")
+                                error("Invalid state parameter $state")
                             }
-                            intent.data?.getQueryParameter(QUERY_CLIENT_AUTH_FRAGMENT)?.let { fragment ->
-                                if (fragment.isNotBlank()) {
-                                    Log.d("CustomUriViewModel", "Found valid auth fragment in response")
+                        }
+                        intent.data?.getQueryParameter(QUERY_CLIENT_AUTH_FRAGMENT)?.let { fragment ->
+                            if (fragment.isNotBlank()) {
+                                Log.d(TAG, "Found valid auth fragment in response")
 
-                                    // Save token, then clear nonce and state since we don't
-                                    // need to keep them around anymore
-                                    repo.saveToken(fragment).collect()
-                                    repo.clearNonce()
-                                    repo.clearState()
-
-                                    actionMutableLiveData.postValue(ViewAction.AuthFlowComplete)
-                                } else {
-                                    throw IllegalStateException("Invalid auth fragment $fragment! Authentication will not succeed...")
-                                }
+                                // Save token, then clear nonce and state since we don't
+                                // need to keep them around anymore
+                                repo.saveToken(fragment).collect()
+                                repo.clearNonce()
+                                repo.clearState()
+                            } else {
+                                error("Auth fragment was empty")
                             }
                         }
                     }
-                    else -> {
-                        Firebase.crashlytics.log("Unknown path segment: ${intent.data?.lastPathSegment}")
-                        Log.e("CustomUriViewModel", "Unknown path segment: ${intent.data?.lastPathSegment}")
-                    }
+                    else -> error("Unknown path segment: ${intent.data?.lastPathSegment}")
+                }
+                if (accumulatedErrors.isNotEmpty()) {
+                    actionMutableLiveData.postValue(ViewAction.AuthFlowError(accumulatedErrors))
+                } else {
+                    Log.d(TAG, "Auth flow complete")
+                    actionMutableLiveData.postValue(ViewAction.AuthFlowComplete)
                 }
             }
         }
@@ -70,9 +77,15 @@ internal class CustomUriViewModel
             private const val QUERY_CLIENT_STATE = "state"
             private const val QUERY_CLIENT_AUTH_FRAGMENT = "fragment"
             private const val QUERY_ACTOR_NAME = "actor_name"
+
+            private const val TAG = "CustomUriViewModel"
         }
 
         internal sealed class ViewAction {
-            object AuthFlowComplete : ViewAction()
+            data object AuthFlowComplete : ViewAction()
+
+            data class AuthFlowError(val errors: Iterable<String>) : ViewAction() {
+                constructor(vararg errors: String) : this(errors.toList())
+            }
         }
     }