FrontendScreen filter out messages not coming from the frontend external bus

app/src/main/kotlin/io/homeassistant/companion/android/frontend/FrontendScreen.kt

@@ -48,6 +48,8 @@ import io.homeassistant.companion.android.frontend.error.FrontendConnectionError
 import io.homeassistant.companion.android.frontend.externalbus.WebViewScript
 import io.homeassistant.companion.android.frontend.externalbus.incoming.HapticType
 import io.homeassistant.companion.android.frontend.haptic.HapticFeedbackPerformer
+import io.homeassistant.companion.android.frontend.js.FrontendJsBridge
+import io.homeassistant.companion.android.frontend.js.FrontendJsCallback
 import io.homeassistant.companion.android.frontend.permissions.NotificationPermissionPrompt
 import io.homeassistant.companion.android.frontend.permissions.PendingWebViewPermissionRequest
 import io.homeassistant.companion.android.frontend.permissions.WebViewPermissionEffect
@@ -167,6 +169,7 @@ internal fun FrontendScreenContent(
     WebViewEffects(
         webView = webView,
         url = viewState.url,
+        frontendJsCallback = frontendJsCallback,
         scriptsToEvaluate = scriptsToEvaluate,
         hapticEvents = hapticEvents,
     )
@@ -183,7 +186,6 @@ internal fun FrontendScreenContent(
             onWebViewCreated = { webView = it },
             webViewClient = webViewClient,
             webChromeClient = webChromeClient,
-            frontendJsCallback = frontendJsCallback,
             contentState = viewState as? FrontendViewState.Content,
             onWebViewCreationFailed = onWebViewCreationFailed,
         )
@@ -371,7 +373,6 @@ private fun SafeHAWebView(
     onBackClick: () -> Unit,
     onWebViewCreated: (WebView) -> Unit,
     webViewClient: WebViewClient,
-    frontendJsCallback: FrontendJsCallback,
     contentState: FrontendViewState.Content?,
     onWebViewCreationFailed: (Throwable) -> Unit,
     webChromeClient: WebChromeClient? = null,
@@ -411,9 +412,6 @@ private fun SafeHAWebView(
                     .background(Color.Transparent),
                 configure = {
                     onWebViewCreated(this)
-                    // Injecting the javascript interface should happen as early as possible in the process
-                    // even before loading the server URL to not miss any events from the frontend.
-                    frontendJsCallback.attachToWebView(this)
                     this.webViewClient = webViewClient
                     webChromeClient?.let { this.webChromeClient = it }
                 },
@@ -455,11 +453,13 @@ private fun Color.Overlay(modifier: Modifier = Modifier) {
 private fun WebViewEffects(
     webView: WebView?,
     url: String,
+    frontendJsCallback: FrontendJsCallback,
     scriptsToEvaluate: Flow<WebViewScript>,
     hapticEvents: Flow<HapticType>,
 ) {
     if (webView != null) {
         LaunchedEffect(webView, url) {
+            frontendJsCallback.attachToWebView(webView)
             Timber.v("Load url ${sensitive(url)}")
             webView.loadUrl(url)
         }

app/src/main/kotlin/io/homeassistant/companion/android/frontend/FrontendViewModel.kt

@@ -13,8 +13,11 @@ import io.homeassistant.companion.android.frontend.error.FrontendConnectionError
 import io.homeassistant.companion.android.frontend.error.FrontendConnectionErrorStateProvider
 import io.homeassistant.companion.android.frontend.externalbus.WebViewScript
 import io.homeassistant.companion.android.frontend.externalbus.incoming.HapticType
+import io.homeassistant.companion.android.frontend.handler.FrontendBusObserver
 import io.homeassistant.companion.android.frontend.handler.FrontendHandlerEvent
-import io.homeassistant.companion.android.frontend.handler.FrontendMessageHandler
+import io.homeassistant.companion.android.frontend.js.BridgeState
+import io.homeassistant.companion.android.frontend.js.FrontendJsBridgeFactory
+import io.homeassistant.companion.android.frontend.js.FrontendJsCallback
 import io.homeassistant.companion.android.frontend.navigation.FrontendNavigationEvent
 import io.homeassistant.companion.android.frontend.navigation.FrontendRoute
 import io.homeassistant.companion.android.frontend.permissions.PermissionManager
@@ -61,29 +64,32 @@ internal class FrontendViewModel @VisibleForTesting constructor(
     initialServerId: Int,
     initialPath: String?,
     webViewClientFactory: HAWebViewClientFactory,
-    private val frontendMessageHandler: FrontendMessageHandler,
+    private val frontendBusObserver: FrontendBusObserver,
     private val urlManager: FrontendUrlManager,
     private val connectivityCheckRepository: ConnectivityCheckRepository,
     private val permissionManager: PermissionManager,
+    private val frontendJsBridgeFactory: FrontendJsBridgeFactory,
 ) : ViewModel(),
     FrontendConnectionErrorStateProvider {
 
     @Inject
     constructor(
         savedStateHandle: SavedStateHandle,
         webViewClientFactory: HAWebViewClientFactory,
-        frontendMessageHandler: FrontendMessageHandler,
+        frontendBusObserver: FrontendBusObserver,
         urlManager: FrontendUrlManager,
         connectivityCheckRepository: ConnectivityCheckRepository,
         permissionManager: PermissionManager,
+        frontendJsBridgeFactory: FrontendJsBridgeFactory,
     ) : this(
         initialServerId = savedStateHandle.toRoute<FrontendRoute>().serverId,
         initialPath = savedStateHandle.toRoute<FrontendRoute>().path,
         webViewClientFactory = webViewClientFactory,
-        frontendMessageHandler = frontendMessageHandler,
+        frontendBusObserver = frontendBusObserver,
         urlManager = urlManager,
         connectivityCheckRepository = connectivityCheckRepository,
         permissionManager = permissionManager,
+        frontendJsBridgeFactory = frontendJsBridgeFactory,
     )
 
     /**
@@ -147,23 +153,21 @@ internal class FrontendViewModel @VisibleForTesting constructor(
             .stateIn(viewModelScope, SharingStarted.Eagerly, (_viewState.value as? FrontendViewState.Error)?.error)
 
     /** Flow of scripts to be evaluated in the WebView. */
-    val scriptsToEvaluate: Flow<WebViewScript> = frontendMessageHandler.scriptsToEvaluate()
+    val scriptsToEvaluate: Flow<WebViewScript> = frontendBusObserver.scriptsToEvaluate()
 
     /**
      * JavaScript bridge for communication between the WebView and native code.
      *
-     * Must be attached to the WebView via [FrontendJsBridge.attachToWebView].
+     * Must be attached to the WebView via [io.homeassistant.companion.android.frontend.js.FrontendJsBridge.attachToWebView].
      */
-    val frontendJsCallback: FrontendJsCallback = FrontendJsBridge(
-        handler = frontendMessageHandler,
-        serverIdProvider = { viewState.value.serverId },
+    val frontendJsCallback: FrontendJsCallback = frontendJsBridgeFactory.create(
         scope = viewModelScope,
+        stateProvider = { BridgeState(serverId = viewState.value.serverId, url = viewState.value.url) },
     )
 
     val webViewClient: HAWebViewClient = webViewClientFactory.create(
         currentUrlFlow = urlFlow,
         onFrontendError = ::onError,
-        frontendJsCallback = frontendJsCallback,
         onCrash = ::onRetry,
     )
 
@@ -200,7 +204,7 @@ internal class FrontendViewModel @VisibleForTesting constructor(
         }
 
         viewModelScope.launch {
-            frontendMessageHandler.messageResults().collect { result ->
+            frontendBusObserver.messageResults().collect { result ->
                 handleMessageResult(result)
             }
         }

app/src/main/kotlin/io/homeassistant/companion/android/frontend/externalbus/FrontendExternalBusRepository.kt

@@ -4,6 +4,7 @@ import io.homeassistant.companion.android.frontend.externalbus.incoming.Incoming
 import io.homeassistant.companion.android.frontend.externalbus.outgoing.OutgoingExternalBusMessage
 import kotlinx.coroutines.CompletableDeferred
 import kotlinx.coroutines.flow.Flow
+import kotlinx.serialization.json.JsonElement
 
 /**
  * Represents a JavaScript script to be evaluated in the WebView.
@@ -59,7 +60,7 @@ interface FrontendExternalBusRepository {
      *
      * The message is deserialized and emitted to subscribers of [incomingMessages].
      *
-     * @param messageJson The raw JSON string from the frontend
+     * @param messageJson The JSON message from the frontend
      */
-    suspend fun onMessageReceived(messageJson: String)
+    suspend fun onMessageReceived(messageJson: JsonElement)
 }

app/src/main/kotlin/io/homeassistant/companion/android/frontend/externalbus/FrontendExternalBusRepositoryImpl.kt

@@ -11,6 +11,8 @@ import kotlinx.coroutines.flow.MutableSharedFlow
 import kotlinx.coroutines.flow.asSharedFlow
 import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.JsonElement
+import kotlinx.serialization.json.decodeFromJsonElement
 import kotlinx.serialization.modules.plus
 import timber.log.Timber
 
@@ -65,22 +67,20 @@ class FrontendExternalBusRepositoryImpl @Inject constructor() : FrontendExternal
 
     override fun incomingMessages(): Flow<IncomingExternalBusMessage> = incomingFlow.asSharedFlow()
 
-    override suspend fun onMessageReceived(messageJson: String) {
+    override suspend fun onMessageReceived(messageJson: JsonElement) {
         val message = deserializeMessage(messageJson)
         if (message != null) {
             incomingFlow.emit(message)
         }
     }
 
-    private fun deserializeMessage(json: String): IncomingExternalBusMessage? {
-        if (json.isBlank()) return null
-
+    private fun deserializeMessage(json: JsonElement): IncomingExternalBusMessage? {
         return runCatching {
-            frontendExternalBusJson.decodeFromString<IncomingExternalBusMessage>(json)
+            frontendExternalBusJson.decodeFromJsonElement<IncomingExternalBusMessage>(json)
         }.onFailure { error ->
             Timber.w(
                 error,
-                "Failed to deserialize external bus message: ${sensitive(json)}",
+                "Failed to deserialize external bus message: ${sensitive { json.toString() }}",
             )
         }.getOrNull()
     }