tts: add native tts plugin for Android (#1376)

apps/readest-app/src-tauri/plugins/tauri-plugin-native-tts/android/.gitignore

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+/build
+/.tauri

apps/readest-app/src-tauri/plugins/tauri-plugin-native-tts/android/build.gradle.kts

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+plugins {
+    id("com.android.library")
+    id("org.jetbrains.kotlin.android")
+}
+
+android {
+    namespace = "com.readest.native_tts"
+    compileSdk = 34
+
+    defaultConfig {
+        minSdk = 21
+
+        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+        consumerProguardFiles("consumer-rules.pro")
+    }
+
+    buildTypes {
+        release {
+            isMinifyEnabled = false
+            proguardFiles(
+                getDefaultProguardFile("proguard-android-optimize.txt"),
+                "proguard-rules.pro"
+            )
+        }
+    }
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_1_8
+        targetCompatibility = JavaVersion.VERSION_1_8
+    }
+    kotlinOptions {
+        jvmTarget = "1.8"
+    }
+}
+
+dependencies {
+
+    implementation("androidx.core:core-ktx:1.9.0")
+    implementation("androidx.appcompat:appcompat:1.6.0")
+    implementation("com.google.android.material:material:1.7.0")
+    testImplementation("junit:junit:4.13.2")
+    androidTestImplementation("androidx.test.ext:junit:1.1.5")
+    androidTestImplementation("androidx.test.espresso:espresso-core:3.5.1")
+    implementation(project(":tauri-android"))
+}

apps/readest-app/src-tauri/plugins/tauri-plugin-native-tts/android/proguard-rules.pro

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+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile

apps/readest-app/src-tauri/plugins/tauri-plugin-native-tts/android/settings.gradle

@@ -0,0 +1,31 @@
+pluginManagement {
+    repositories {
+        mavenCentral()
+        gradlePluginPortal()
+        google()
+    }
+    resolutionStrategy {
+        eachPlugin {
+            switch (requested.id.id) {
+                case "com.android.library":
+                    useVersion("8.0.2")
+                    break
+                case "org.jetbrains.kotlin.android":
+                    useVersion("1.8.20")
+                    break
+            }
+        }
+    }
+}
+
+dependencyResolutionManagement {
+    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
+    repositories {
+        mavenCentral()
+        google()
+
+    }
+}
+
+include ':tauri-android'
+project(':tauri-android').projectDir = new File('./.tauri/tauri-api')

apps/readest-app/src-tauri/plugins/tauri-plugin-native-tts/android/src/androidTest/java/ExampleInstrumentedTest.kt

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+package com.readest.native-tts
+
+import androidx.test.platform.app.InstrumentationRegistry
+import androidx.test.ext.junit.runners.AndroidJUnit4
+
+import org.junit.Test
+import org.junit.runner.RunWith
+
+import org.junit.Assert.*
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+@RunWith(AndroidJUnit4::class)
+class ExampleInstrumentedTest {
+    @Test
+    fun useAppContext() {
+        // Context of the app under test.
+        val appContext = InstrumentationRegistry.getInstrumentation().targetContext
+        assertEquals("com.readest.native-tts", appContext.packageName)
+    }
+}

apps/readest-app/src-tauri/plugins/tauri-plugin-native-tts/android/src/main/AndroidManifest.xml

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+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+</manifest>

apps/readest-app/src-tauri/plugins/tauri-plugin-native-tts/android/src/main/java/NativeTTSPlugin.kt

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+package com.readest.native_tts
+
+import android.os.Bundle
+import android.app.Activity
+import android.content.Context
+import android.speech.tts.TextToSpeech
+import android.speech.tts.UtteranceProgressListener
+import android.speech.tts.Voice
+import android.util.Log
+import app.tauri.annotation.Command
+import app.tauri.annotation.InvokeArg
+import app.tauri.annotation.TauriPlugin
+import app.tauri.plugin.Invoke
+import app.tauri.plugin.JSObject
+import app.tauri.plugin.Plugin
+import app.tauri.plugin.PluginResult
+import kotlinx.coroutines.*
+import kotlinx.coroutines.channels.Channel
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.flow
+import org.json.JSONArray
+import org.json.JSONObject
+import java.util.*
+import java.util.concurrent.ConcurrentHashMap
+import java.util.concurrent.atomic.AtomicBoolean
+import java.util.concurrent.atomic.AtomicReference
+
+data class TTSVoiceData(
+    val id: String,
+    val name: String,
+    val lang: String,
+    val disabled: Boolean = false
+)
+
+data class TTSMessageEvent(
+    val code: String, // 'boundary' | 'error' | 'end'
+    val message: String? = null,
+    val mark: String? = null
+)
+
+enum class TTSGranularity(val value: String) {
+    WORD("word"),
+    SENTENCE("sentence"),
+    PARAGRAPH("paragraph")
+}
+
+@TauriPlugin
+class NativeTTSPlugin(private val activity: Activity) : Plugin(activity) {
+    
+    companion object {
+        private const val TAG = "NativeTTSPlugin"
+        private const val CHANNEL_NAME = "tts_events"
+    }
+    
+    private var textToSpeech: TextToSpeech? = null
+    private var isInitialized = AtomicBoolean(false)
+    private var isPaused = AtomicBoolean(false)
+    private var isSpeaking = AtomicBoolean(false)
+    private var currentVoiceId = AtomicReference<String>("")
+    private var currentLang = AtomicReference<String>("en-US")
+    private var currentRate = AtomicReference<Float>(1.0f)
+    private var currentPitch = AtomicReference<Float>(1.0f)
+    
+    // Event channels for each speaking session
+    private val eventChannels = ConcurrentHashMap<String, Channel<TTSMessageEvent>>()
+    private val speakingJobs = ConcurrentHashMap<String, Job>()
+    
+    private val coroutineScope = CoroutineScope(Dispatchers.Main + SupervisorJob())
+    
+    @Command
+    fun init(invoke: Invoke) {
+        coroutineScope.launch {
+            try {
+                val success = initializeTTS()
+                val result = JSObject().apply {
+                    put("success", success)
+                }
+                invoke.resolve(result)
+            } catch (e: Exception) {
+                Log.e(TAG, "Failed to initialize TTS", e)
+                invoke.reject("Failed to initialize TTS: ${e.message}")
+            }
+        }
+    }
+    
+    private suspend fun initializeTTS(): Boolean = suspendCancellableCoroutine { continuation ->
+        try {
+            textToSpeech = TextToSpeech(activity) { status ->
+                when (status) {
+                    TextToSpeech.SUCCESS -> {
+                        setupTTSListener()
+                        isInitialized.set(true)
+                        continuation.resume(true) {}
+                    }
+                    else -> {
+                        Log.e(TAG, "TTS initialization failed with status: $status")
+                        continuation.resume(false) {}
+                    }
+                }
+            }
+        } catch (e: Exception) {
+            Log.e(TAG, "Exception during TTS initialization", e)
+            continuation.resume(false) {}
+        }
+    }
+    
+    private fun setupTTSListener() {
+        textToSpeech?.setOnUtteranceProgressListener(object : UtteranceProgressListener() {
+            override fun onStart(utteranceId: String?) {
+                utteranceId?.let { id ->
+                    isSpeaking.set(true)
+                    sendEvent(id, TTSMessageEvent("boundary", "start"))
+                }
+            }
+            
+            override fun onDone(utteranceId: String?) {
+                utteranceId?.let { id ->
+                    isSpeaking.set(false)
+                    sendEvent(id, TTSMessageEvent("end"))
+                    closeEventChannel(id)
+                }
+            }
+            
+            override fun onError(utteranceId: String?) {
+                utteranceId?.let { id ->
+                    isSpeaking.set(false)
+                    sendEvent(id, TTSMessageEvent("error", "TTS playback error"))
+                    closeEventChannel(id)
+                }
+            }
+            
+            override fun onRangeStart(utteranceId: String?, start: Int, end: Int, frame: Int) {
+                utteranceId?.let { id ->
+                    sendEvent(id, TTSMessageEvent("boundary", "range", "pos:$start-$end"))
+                }
+            }
+        })
+    }
+    
+    @Command
+    fun speak(invoke: Invoke) {
+        val args = invoke.parseArgs(SpeakArgs::class.java)
+        
+        if (!isInitialized.get()) {
+            invoke.reject("TTS not initialized")
+            return
+        }
+        
+        val utteranceId = UUID.randomUUID().toString()
+        
+        coroutineScope.launch {
+            try {
+                val eventChannel = Channel<TTSMessageEvent>(Channel.UNLIMITED)
+                eventChannels[utteranceId] = eventChannel
+                
+                val speakJob = launch {
+                    speakText(args.ssml, utteranceId, args.preload ?: false)
+                }
+                speakingJobs[utteranceId] = speakJob
+                
+                // Return the utterance ID so frontend can listen to events
+                val result = JSObject().apply {
+                    put("utteranceId", utteranceId)
+                }
+                invoke.resolve(result)
+                
+                // Start sending events to the frontend
+                startEventStream(utteranceId)
+                
+            } catch (e: Exception) {
+                Log.e(TAG, "Failed to start speaking", e)
+                invoke.reject("Failed to start speaking: ${e.message}")
+            }
+        }
+    }
+    
+    private suspend fun speakText(ssml: String, utteranceId: String, preload: Boolean) {
+        withContext(Dispatchers.Main) {
+            try {
+                // Parse SSML and extract text
+                val text = parseSSML(ssml)
+
+                textToSpeech?.apply {
+                    setSpeechRate(currentRate.get())
+                    setPitch(currentPitch.get())
+                }
+                
+                val params = Bundle().apply {
+                    putString(TextToSpeech.Engine.KEY_PARAM_UTTERANCE_ID, utteranceId)
+                }
+                
+                val result = textToSpeech?.speak(
+                    text,
+                    if (preload) TextToSpeech.QUEUE_ADD else TextToSpeech.QUEUE_FLUSH,
+                    params,
+                    utteranceId
+                )
+                
+                if (result != TextToSpeech.SUCCESS) {
+                    sendEvent(utteranceId, TTSMessageEvent("error", "Failed to start speech"))
+                }
+            } catch (e: Exception) {
+                sendEvent(utteranceId, TTSMessageEvent("error", "Exception during speech: ${e.message}"))
+            }
+        }
+    }
+    
+    private fun parseSSML(ssml: String): String {
+        // Simple SSML parsing - extract text content
+        return ssml
+            .replace(Regex("<[^>]*>"), " ")
+            .replace(Regex("\\s+"), " ")
+            .trim()
+    }
+    
+    private fun startEventStream(utteranceId: String) {
+        coroutineScope.launch {
+            val channel = eventChannels[utteranceId] ?: return@launch
+            
+            try {
+                for (event in channel) {
+                    val eventData = JSObject().apply {
+                        put("utteranceId", utteranceId)
+                        put("code", event.code)
+                        event.message?.let { put("message", it) }
+                        event.mark?.let { put("mark", it) }
+                    }
+                    
+                    // Send event to frontend via Tauri event system
+                    trigger(CHANNEL_NAME, eventData)
+                }
+            } catch (e: Exception) {
+                Log.e(TAG, "Error in event stream for $utteranceId", e)
+            }
+        }
+    }
+    
+    private fun sendEvent(utteranceId: String, event: TTSMessageEvent) {
+        coroutineScope.launch {
+            eventChannels[utteranceId]?.trySend(event)
+        }
+    }
+    
+    private fun closeEventChannel(utteranceId: String) {
+        coroutineScope.launch {
+            eventChannels[utteranceId]?.close()
+            eventChannels.remove(utteranceId)
+            speakingJobs[utteranceId]?.cancel()
+            speakingJobs.remove(utteranceId)
+        }
+    }
+    
+    @Command
+    fun pause(invoke: Invoke) {
+        try {
+            if (textToSpeech?.stop() == TextToSpeech.SUCCESS) {
+                isPaused.set(true)
+                invoke.resolve()
+            } else {
+                invoke.reject("Failed to pause TTS")
+            }
+        } catch (e: Exception) {
+            invoke.reject("Exception while pausing: ${e.message}")
+        }
+    }
+    
+    @Command
+    fun resume(invoke: Invoke) {
+        // Android TTS doesn't have native resume, so we'll need to track state
+        try {
+            isPaused.set(false)
+            invoke.resolve()
+        } catch (e: Exception) {
+            invoke.reject("Exception while resuming: ${e.message}")
+        }
+    }
+    
+    @Command
+    fun stop(invoke: Invoke) {
+        try {
+            if (textToSpeech?.stop() == TextToSpeech.SUCCESS) {
+                isSpeaking.set(false)
+                isPaused.set(false)
+                
+                // Cancel all active speaking jobs and close channels
+                speakingJobs.values.forEach { it.cancel() }
+                eventChannels.values.forEach { it.close() }
+                speakingJobs.clear()
+                eventChannels.clear()
+                
+                invoke.resolve()
+            } else {
+                invoke.reject("Failed to stop TTS")
+            }
+        } catch (e: Exception) {
+            invoke.reject("Exception while stopping: ${e.message}")
+        }
+    }
+    
+    @Command
+    fun set_primary_lang(invoke: Invoke) {
+        val args = invoke.parseArgs(SetLangArgs::class.java)
+        try {
+            val locale = Locale.forLanguageTag(args.lang)
+            val result = textToSpeech?.setLanguage(locale)
+            
+            when (result) {
+                TextToSpeech.LANG_AVAILABLE,
+                TextToSpeech.LANG_COUNTRY_AVAILABLE,
+                TextToSpeech.LANG_COUNTRY_VAR_AVAILABLE -> {
+                    currentLang.set(args.lang)
+                    invoke.resolve()
+                }
+                else -> {
+                    invoke.reject("Language not supported: ${args.lang}")
+                }
+            }
+        } catch (e: Exception) {
+            invoke.reject("Exception setting language: ${e.message}")
+        }
+    }
+    
+    @Command
+    fun set_rate(invoke: Invoke) {
+        val args = invoke.parseArgs(SetRateArgs::class.java)
+        try {
+            currentRate.set(args.rate)
+            invoke.resolve()
+        } catch (e: Exception) {
+            invoke.reject("Exception setting rate: ${e.message}")
+        }
+    }
+    
+    @Command
+    fun set_pitch(invoke: Invoke) {
+        val args = invoke.parseArgs(SetPitchArgs::class.java)
+        try {
+            currentPitch.set(args.pitch)
+            invoke.resolve()
+        } catch (e: Exception) {
+            invoke.reject("Exception setting pitch: ${e.message}")
+        }
+    }
+    
+    @Command
+    fun set_voice(invoke: Invoke) {
+        val args = invoke.parseArgs(SetVoiceArgs::class.java)
+        try {
+            val voices = textToSpeech?.voices
+            val targetVoice = voices?.find { it.name == args.voice }
+            
+            if (targetVoice != null) {
+                val result = textToSpeech?.setVoice(targetVoice)
+                if (result == TextToSpeech.SUCCESS) {
+                    currentVoiceId.set(args.voice)
+                    invoke.resolve()
+                } else {
+                    invoke.reject("Failed to set voice: ${args.voice}")
+                }
+            } else {
+                invoke.reject("Voice not found: ${args.voice}")
+            }
+        } catch (e: Exception) {
+            invoke.reject("Exception setting voice: ${e.message}")
+        }
+    }
+    
+    @Command
+    fun get_all_voices(invoke: Invoke) {
+        try {
+            val voices = textToSpeech?.voices?.map { voice ->
+                JSObject().apply {
+                    put("id", voice.name)
+                    put("name", voice.name)
+                    put("lang", voice.locale.toLanguageTag())
+                    put("disabled", false)
+                }
+            } ?: emptyList()
+            
+            val result = JSObject().apply {
+                put("voices", JSONArray(voices))
+            }
+            invoke.resolve(result)
+        } catch (e: Exception) {
+            invoke.reject("Exception getting voices: ${e.message}")
+        }
+    }
+    
+    @Command
+    fun get_voices(invoke: Invoke) {
+        val args = invoke.parseArgs(GetVoicesArgs::class.java)
+        try {
+            val locale = Locale.forLanguageTag(args.lang)
+            val voices = textToSpeech?.voices?.filter { voice ->
+                voice.locale.language == locale.language
+            }?.map { voice ->
+                JSObject().apply {
+                    put("id", voice.name)
+                    put("name", voice.name)
+                    put("lang", voice.locale.toLanguageTag())
+                    put("disabled", false)
+                }
+            } ?: emptyList()
+            
+            val result = JSObject().apply {
+                put("voices", JSONArray(voices))
+            }
+            invoke.resolve(result)
+        } catch (e: Exception) {
+            invoke.reject("Exception getting voices for language: ${e.message}")
+        }
+    }
+    
+    @Command
+    fun get_granularities(invoke: Invoke) {
+        try {
+            val granularities = TTSGranularity.values().map { it.value }
+            val result = JSObject().apply {
+                put("granularities", JSONArray(granularities))
+            }
+            invoke.resolve(result)
+        } catch (e: Exception) {
+            invoke.reject("Exception getting granularities: ${e.message}")
+        }
+    }
+    
+    @Command
+    fun get_voice_id(invoke: Invoke) {
+        try {
+            val result = JSObject().apply {
+                put("voiceId", currentVoiceId.get())
+            }
+            invoke.resolve(result)
+        } catch (e: Exception) {
+            invoke.reject("Exception getting voice ID: ${e.message}")
+        }
+    }
+    
+    @Command
+    fun get_speaking_lang(invoke: Invoke) {
+        try {
+            val result = JSObject().apply {
+                put("lang", currentLang.get())
+            }
+            invoke.resolve(result)
+        } catch (e: Exception) {
+            invoke.reject("Exception getting speaking language: ${e.message}")
+        }
+    }
+    
+    fun destroy() {
+        coroutineScope.cancel()
+        textToSpeech?.shutdown()
+        eventChannels.values.forEach { it.close() }
+        eventChannels.clear()
+        speakingJobs.values.forEach { it.cancel() }
+        speakingJobs.clear()
+    }
+}
+
+// Data classes for command arguments
+data class SpeakArgs(
+    val ssml: String,
+    val preload: Boolean? = false
+)
+
+data class SetLangArgs(
+    val lang: String
+)
+
+data class SetRateArgs(
+    val rate: Float
+)
+
+data class SetPitchArgs(
+    val pitch: Float
+)
+
+data class SetVoiceArgs(
+    val voice: String
+)
+
+data class GetVoicesArgs(
+    val lang: String
+)

apps/readest-app/src-tauri/plugins/tauri-plugin-native-tts/android/src/test/java/ExampleUnitTest.kt

@@ -0,0 +1,17 @@
+package com.readest.native-tts
+
+import org.junit.Test
+
+import org.junit.Assert.*
+
+/**
+ * Example local unit test, which will execute on the development machine (host).
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+class ExampleUnitTest {
+    @Test
+    fun addition_isCorrect() {
+        assertEquals(4, 2 + 2)
+    }
+}