Provide interface for external bus outside WebViewActivity

app/src/main/java/io/homeassistant/companion/android/webview/WebView.kt

@@ -1,6 +1,7 @@
 package io.homeassistant.companion.android.webview
 
 import android.net.http.SslError
+import io.homeassistant.companion.android.webview.externalbus.ExternalBusMessage
 
 interface WebView {
     enum class ErrorType {
@@ -16,6 +17,8 @@ interface WebView {
 
     fun setExternalAuth(script: String)
 
+    fun sendExternalBusMessage(message: ExternalBusMessage)
+
     fun relaunchApp()
 
     fun unlockAppIfNeeded()

app/src/main/java/io/homeassistant/companion/android/webview/WebViewActivity.kt

@@ -101,6 +101,7 @@ import io.homeassistant.companion.android.util.TLSWebViewClient
 import io.homeassistant.companion.android.util.isStarted
 import io.homeassistant.companion.android.websocket.WebsocketManager
 import io.homeassistant.companion.android.webview.WebView.ErrorType
+import io.homeassistant.companion.android.webview.externalbus.ExternalBusMessage
 import java.util.concurrent.Executors
 import javax.inject.Inject
 import javax.inject.Named
@@ -155,14 +156,17 @@ class WebViewActivity : BaseActivity(), io.homeassistant.companion.android.webvi
             }
         }
     private val writeNfcTag = registerForActivityResult(WriteNfcTag()) { messageId ->
-        webView.externalBus(
-            id = messageId,
-            type = "result",
-            success = true,
-            result = emptyMap<String, String>()
-        ) {
-            Log.d(TAG, "NFC Write Complete $it")
-        }
+        sendExternalBusMessage(
+            ExternalBusMessage(
+                id = messageId,
+                type = "result",
+                success = true,
+                result = emptyMap<String, String>(),
+                callback = {
+                    Log.d(TAG, "NFC Write Complete $it")
+                }
+            )
+        )
     }
     private val showWebFileChooser = registerForActivityResult(ShowWebFileChooser()) { result ->
         mFilePathCallback?.onReceiveValue(result)
@@ -726,23 +730,26 @@ class WebViewActivity : BaseActivity(), io.homeassistant.companion.android.webvi
                                     val hasNfc = pm.hasSystemFeature(PackageManager.FEATURE_NFC)
                                     val canCommissionMatter = presenter.appCanCommissionMatterDevice()
                                     val canExportThread = presenter.appCanExportThreadCredentials()
-                                    webView.externalBus(
-                                        id = JSONObject(message).get("id"),
-                                        type = "result",
-                                        success = true,
-                                        result = JSONObject(
-                                            mapOf(
-                                                "hasSettingsScreen" to true,
-                                                "canWriteTag" to hasNfc,
-                                                "hasExoPlayer" to true,
-                                                "canCommissionMatter" to canCommissionMatter,
-                                                "canImportThreadCredentials" to canExportThread,
-                                                "hasAssist" to true
-                                            )
+                                    sendExternalBusMessage(
+                                        ExternalBusMessage(
+                                            id = JSONObject(message).get("id"),
+                                            type = "result",
+                                            success = true,
+                                            result = JSONObject(
+                                                mapOf(
+                                                    "hasSettingsScreen" to true,
+                                                    "canWriteTag" to hasNfc,
+                                                    "hasExoPlayer" to true,
+                                                    "canCommissionMatter" to canCommissionMatter,
+                                                    "canImportThreadCredentials" to canExportThread,
+                                                    "hasAssist" to true
+                                                )
+                                            ),
+                                            callback = {
+                                                Log.d(TAG, "Callback $it")
+                                            }
                                         )
-                                    ) {
-                                        Log.d(TAG, "Callback $it")
-                                    }
+                                    )
 
                                     // TODO This feature is deprecated and should be removed after 2022.6
                                     getAndSetStatusBarNavigationBarColors()
@@ -793,6 +800,7 @@ class WebViewActivity : BaseActivity(), io.homeassistant.companion.android.webvi
                                 "exoplayer/resize" -> exoResizeHls(json)
                                 "haptic" -> processHaptic(json.getJSONObject("payload").getString("hapticType"))
                                 "theme-update" -> getAndSetStatusBarNavigationBarColors()
+                                else -> presenter.onExternalBusMessage(json)
                             }
                         }
                     }
@@ -958,14 +966,16 @@ class WebViewActivity : BaseActivity(), io.homeassistant.companion.android.webvi
             exoPlayerView.visibility = View.VISIBLE
             findViewById<ImageButton>(R.id.exo_ha_mute)?.setOnClickListener { exoToggleMute() }
         }
-        webView.externalBus(
-            id = json.get("id"),
-            type = "result",
-            success = true,
-            result = null
-        ) {
-            Log.d(TAG, "Callback $it")
-        }
+        sendExternalBusMessage(
+            ExternalBusMessage(
+                id = json.get("id"),
+                type = "result",
+                success = true,
+                callback = {
+                    Log.d(TAG, "Callback $it")
+                }
+            )
+        )
     }
 
     fun exoStopHls() {
@@ -1490,28 +1500,21 @@ class WebViewActivity : BaseActivity(), io.homeassistant.companion.android.webvi
         )
     }
 
-    private fun WebView.externalBus(
-        id: Any,
-        type: String,
-        success: Boolean,
-        result: Any? = null,
-        error: Any? = null,
-        callback: ValueCallback<String>?
-    ) {
+    override fun sendExternalBusMessage(message: ExternalBusMessage) {
         val map = mutableMapOf(
-            "id" to id,
-            "type" to type,
-            "success" to success
+            "id" to message.id,
+            "type" to message.type,
+            "success" to message.success
         )
-        if (result != null) map["result"] = result
-        if (error != null) map["error"] = error
+        message.result?.let { map["result"] = it }
+        message.error?.let { map["error"] = it }
 
         val json = JSONObject(map.toMap())
         val script = "externalBus($json);"
 
         Log.d(TAG, script)
 
-        this.evaluateJavascript(script, callback)
+        webView.evaluateJavascript(script, message.callback)
     }
 
     private fun downloadFile(url: String, contentDisposition: String, mimetype: String) {

app/src/main/java/io/homeassistant/companion/android/webview/WebViewPresenter.kt

@@ -4,6 +4,7 @@ import android.content.Context
 import android.content.IntentSender
 import androidx.activity.result.ActivityResult
 import kotlinx.coroutines.flow.Flow
+import org.json.JSONObject
 
 interface WebViewPresenter {
 
@@ -41,6 +42,8 @@ interface WebViewPresenter {
 
     fun sessionTimeOut(): Int
 
+    fun onExternalBusMessage(message: JSONObject)
+
     fun onStart(context: Context)
 
     fun onFinish()

app/src/main/java/io/homeassistant/companion/android/webview/WebViewPresenterImpl.kt

@@ -17,6 +17,7 @@ import io.homeassistant.companion.android.matter.MatterManager
 import io.homeassistant.companion.android.thread.ThreadManager
 import io.homeassistant.companion.android.util.UrlUtil
 import io.homeassistant.companion.android.util.UrlUtil.baseIsEqual
+import io.homeassistant.companion.android.webview.externalbus.ExternalBusRepository
 import java.net.SocketTimeoutException
 import java.net.URL
 import java.util.regex.Matcher
@@ -35,10 +36,12 @@ import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.runBlocking
 import kotlinx.coroutines.withContext
+import org.json.JSONObject
 
 class WebViewPresenterImpl @Inject constructor(
     @ActivityContext context: Context,
     private val serverManager: ServerManager,
+    private val externalBusRepository: ExternalBusRepository,
     private val prefsRepository: PrefsRepository,
     private val matterUseCase: MatterManager,
     private val threadUseCase: ThreadManager
@@ -63,6 +66,16 @@ class WebViewPresenterImpl @Inject constructor(
 
     init {
         updateActiveServer()
+
+        mainScope.launch {
+            externalBusRepository.getSentFlow().collect {
+                try {
+                    view.sendExternalBusMessage(it)
+                } catch (e: Exception) {
+                    Log.w(TAG, "Unable to send message to external bus $it", e)
+                }
+            }
+        }
     }
 
     override fun onViewReady(path: String?) {
@@ -285,6 +298,12 @@ class WebViewPresenterImpl @Inject constructor(
         prefsRepository.isAlwaysShowFirstViewOnAppStartEnabled()
     }
 
+    override fun onExternalBusMessage(message: JSONObject) {
+        mainScope.launch {
+            externalBusRepository.received(message)
+        }
+    }
+
     override fun sessionTimeOut(): Int = runBlocking {
         serverManager.getServer(serverId)?.let {
             serverManager.integrationRepository(serverId).getSessionTimeOut()

app/src/main/java/io/homeassistant/companion/android/webview/externalbus/ExternalBusMessage.kt

@@ -0,0 +1,12 @@
+package io.homeassistant.companion.android.webview.externalbus
+
+import android.webkit.ValueCallback
+
+data class ExternalBusMessage(
+    val id: Any,
+    val type: String,
+    val success: Boolean,
+    val result: Any? = null,
+    val error: Any? = null,
+    val callback: ValueCallback<String>? = null
+)

app/src/main/java/io/homeassistant/companion/android/webview/externalbus/ExternalBusModule.kt

@@ -0,0 +1,16 @@
+package io.homeassistant.companion.android.webview.externalbus
+
+import dagger.Binds
+import dagger.Module
+import dagger.hilt.InstallIn
+import dagger.hilt.components.SingletonComponent
+import javax.inject.Singleton
+
+@Module
+@InstallIn(SingletonComponent::class)
+abstract class ExternalBusModule {
+
+    @Binds
+    @Singleton
+    abstract fun externalBusRepository(externalBusRepositoryImpl: ExternalBusRepositoryImpl): ExternalBusRepository
+}

app/src/main/java/io/homeassistant/companion/android/webview/externalbus/ExternalBusRepository.kt

@@ -0,0 +1,34 @@
+package io.homeassistant.companion.android.webview.externalbus
+
+import kotlinx.coroutines.flow.Flow
+import org.json.JSONObject
+
+/**
+ * A repository to communicate with the external bus which is provided by the frontend,
+ * in contexts where there is no 'line of sight' to the webview (usually: other activity).
+ *
+ * The [WebViewActivity] or listener should be alive for this to work, and the repository
+ * does not guarantee that the the receiver will immediately receive the message as the
+ * system can limit background activity.
+ */
+interface ExternalBusRepository {
+
+    /** Send a message to the external bus (for native) */
+    suspend fun send(message: ExternalBusMessage)
+
+    /**
+     * Register to receive certain messages from the external bus (for native)
+     * @param types List of which message `type`s should be received
+     * @return Flow with received messages for the specified types
+     */
+    fun receive(types: List<String>): Flow<JSONObject>
+
+    /** Send a message from the external bus to registered receivers (for webview) */
+    suspend fun received(message: JSONObject)
+
+    /**
+     * @return Flow with [ExternalBusMessage]s that should be sent on the external
+     * bus (for webview)
+     */
+    fun getSentFlow(): Flow<ExternalBusMessage>
+}

app/src/main/java/io/homeassistant/companion/android/webview/externalbus/ExternalBusRepositoryImpl.kt

@@ -0,0 +1,43 @@
+package io.homeassistant.companion.android.webview.externalbus
+
+import android.util.Log
+import javax.inject.Inject
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.MutableSharedFlow
+import kotlinx.coroutines.flow.asSharedFlow
+import org.json.JSONObject
+
+class ExternalBusRepositoryImpl @Inject constructor() : ExternalBusRepository {
+
+    companion object {
+        private const val TAG = "ExternalBusRepo"
+    }
+
+    private val externalBusFlow = MutableSharedFlow<ExternalBusMessage>(
+        // Don't suspend if the WebView is temporarily unavailable
+        extraBufferCapacity = 100
+    )
+    private val receiverFlows = mutableMapOf<List<String>, MutableSharedFlow<JSONObject>>()
+
+    override suspend fun send(message: ExternalBusMessage) {
+        externalBusFlow.emit(message)
+    }
+
+    override fun receive(types: List<String>): Flow<JSONObject> {
+        val flow = receiverFlows[types] ?: MutableSharedFlow()
+        receiverFlows[types] = flow
+        return flow.asSharedFlow()
+    }
+
+    override suspend fun received(message: JSONObject) {
+        if (!message.has("type")) return
+        val type = message.getString("type")
+        val receivers = receiverFlows.filter { it.key.contains(type) }
+        Log.d(TAG, "Sending message of type $type to ${receivers.size} receiver(s)")
+        receivers.forEach { (_, flow) ->
+            flow.emit(message)
+        }
+    }
+
+    override fun getSentFlow(): Flow<ExternalBusMessage> = externalBusFlow.asSharedFlow()
+}