fix: the speak action uses the car's voice, so it works again

The head unit has no Android TTS engine. It still talks — through the SAIC voice service —
so Speaker tries that first and keeps the platform engine as the fallback for a bench
emulator. It is also the cheaper path: one binder call, no engine to spin up, no audio
focus, nothing to block on.

SpeechEngines.any() now counts the vehicle voice, which is what stops the editor hiding an
action the car can perform, and the Diagnostic TTS row names it among the engines found.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: malys

MG4Hardware

@@ -117,7 +117,7 @@ object DiagnosticProbe {
         val bridge = ProfileBridge(appContext)
         val bridgeReachable = try { bridge.connect() } finally { bridge.disconnect() }
 
-        val engines = SpeechEngines.list(appContext)
+        val engines = SpeechEngines.describe(appContext)
         val caps = Diagnostics.Capabilities(
             vehicleLayerReady = MG4Hardware.isCarPropertyManagerReady(),
             gateVerdict = gateVerdict(),

app/src/main/java/com/mg4/tasker/debug/DiagnosticProbe.kt

@@ -7,19 +7,28 @@ import android.media.AudioManager
 import android.speech.tts.TextToSpeech
 import android.speech.tts.UtteranceProgressListener
 import com.mg4.hardware.AppLogger
+import com.mg4.hardware.saic.SaicTts
 import java.util.Locale
 import java.util.concurrent.CountDownLatch
 import java.util.concurrent.TimeUnit
 
 /**
- * Speaks a rule message through the platform TTS engine.
+ * Speaks a rule message.
  *
- * The engine is created per utterance and released once it has spoken: rules fire a few
- * times per drive at most, and a resident engine would hold an audio focus client alive
- * for the whole ignition cycle for nothing.
+ * **The car's own voice first.** The head unit talks — it announces tyre faults and
+ * navigation — but through a SAIC vendor service, not through `android.speech.tts`. Probing
+ * for a platform engine and finding none was the right answer to the wrong question: the
+ * vehicle has no Android TTS engine installed and does not need one. [SaicTts] is therefore
+ * tried first, and it is also the cheaper path — a one-way binder call, no engine to spin
+ * up, no audio focus to take, nothing to block on.
  *
- * ⚠️ Blocks until the engine has spoken (or the timeout expires); call off the main
- * thread — which is where the rule engine already runs.
+ * The platform engine stays as the fallback, for a bench emulator or a head unit whose
+ * vendor service is absent. There it is created per utterance and released once it has
+ * spoken: rules fire a few times per drive at most, and a resident engine would hold an
+ * audio focus client alive for the whole ignition cycle for nothing.
+ *
+ * ⚠️ The fallback blocks until the engine has spoken (or the timeout expires); call off the
+ * main thread — which is where the rule engine already runs.
  */
 object Speaker {
 
@@ -59,6 +68,12 @@ object Speaker {
     fun speak(context: Context, message: String): Failure? {
         if (message.isBlank()) return Failure.EMPTY_MESSAGE
 
+        // Queued, not interrupting: a tyre warning outranks "profile applied".
+        if (SaicTts.isAvailable && SaicTts.speak(message)) {
+            AppLogger.d(TAG, "spoken by the vehicle voice service")
+            return null
+        }
+
         val appContext = context.applicationContext
         val ready = CountDownLatch(1)
         var status = TextToSpeech.ERROR

app/src/main/java/com/mg4/tasker/util/Speaker.kt

@@ -4,6 +4,7 @@ import android.content.Context
 import android.content.Intent
 import android.provider.Settings
 import android.speech.tts.TextToSpeech
+import com.mg4.hardware.saic.SaicTts
 
 /**
  * Which text-to-speech engines this app can see on the head unit.
@@ -39,5 +40,18 @@ object SpeechEngines {
         return listOfNotNull(default?.takeIf { it.isNotBlank() })
     }
 
-    fun any(context: Context): Boolean = list(context).isNotEmpty()
+    /**
+     * Whether anything can speak — the vehicle's own voice counts.
+     *
+     * [list] only knows about Android TTS engines, and the MG4 has none: it talks through a
+     * SAIC vendor service. Answering "no engine" there hid the speak action from the editor
+     * on a car that speaks perfectly well, which is the bug this distinction exists to fix.
+     */
+    fun any(context: Context): Boolean = SaicTts.isAvailable || list(context).isNotEmpty()
+
+    /** Engine names for the report, the vehicle voice service included when it is bound. */
+    fun describe(context: Context): List<String> =
+        (if (SaicTts.isAvailable) listOf(VEHICLE_VOICE) else emptyList()) + list(context)
+
+    const val VEHICLE_VOICE = "com.saicmotor.voicetts (vehicle)"
 }

app/src/main/java/com/mg4/tasker/util/SpeechEngines.kt

@@ -4,6 +4,7 @@ import android.content.Context
 import com.mg4.hardware.saic.SaicHub
 import com.mg4.hardware.saic.SaicPhone
 import com.mg4.hardware.saic.SaicRadio
+import com.mg4.hardware.saic.SaicTts
 
 /**
  * Binds the SAIC vendor services the catalogue depends on.
@@ -21,5 +22,8 @@ object VendorServices {
         SaicHub.connect(appContext)
         SaicRadio.connect(appContext)
         SaicPhone.connect(appContext)
+        // The vehicle's own voice — what the "speak" action uses in preference to an Android
+        // TTS engine, which this head unit does not have.
+        SaicTts.connect(appContext)
     }
 }