feat: Enhance TTS player functionality and UI

- Added resume functionality to TTS player when paused.
- Display voice name or language in TTS player UI.
- Improved error handling in reader provider with debug messages.
- Updated TTS service to configure Vietnamese voice and handle platform-specific audio settings.
- Removed wakelock dependency and related code.
- Fixed search screen error handling.
- Updated settings screen to navigate to home after sign out.
- Improved splash screen with timer management.
- Enhanced main app error handling with logging.
- Removed unused package_info_plus and wakelock_plus dependencies.
- Added environment variable support for mobile runtime.
- Integrated Google Sign-In configuration for Android.
- Created logging observer for Riverpod providers.
- Added scripts for environment setup and Google Sign-In validation.

lib/features/reader/tts/tts_service.dart

@@ -1,6 +1,7 @@
+import 'dart:io';
+
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:flutter_tts/flutter_tts.dart';
-import 'package:wakelock_plus/wakelock_plus.dart';
 
 enum TtsStatus { idle, playing, paused }
 
@@ -9,12 +10,16 @@ class TtsState {
   final int paragraphIndex;
   final int totalParagraphs;
   final double speed;
+  final String language;
+  final String? voiceName;
 
   const TtsState({
     this.status = TtsStatus.idle,
     this.paragraphIndex = 0,
     this.totalParagraphs = 0,
     this.speed = 1.0,
+    this.language = 'vi-VN',
+    this.voiceName,
   });
 
   TtsState copyWith({
@@ -22,12 +27,17 @@ class TtsState {
     int? paragraphIndex,
     int? totalParagraphs,
     double? speed,
+    String? language,
+    String? voiceName,
+    bool clearVoiceName = false,
   }) =>
       TtsState(
         status: status ?? this.status,
         paragraphIndex: paragraphIndex ?? this.paragraphIndex,
         totalParagraphs: totalParagraphs ?? this.totalParagraphs,
         speed: speed ?? this.speed,
+        language: language ?? this.language,
+        voiceName: clearVoiceName ? null : (voiceName ?? this.voiceName),
       );
 
   bool get isPlaying => status == TtsStatus.playing;
@@ -36,17 +46,42 @@ class TtsState {
 class TtsNotifier extends StateNotifier<TtsState> {
   final FlutterTts _tts = FlutterTts();
   List<String> _paragraphs = [];
+  bool _initialized = false;
+  Future<void>? _initFuture;
 
   TtsNotifier() : super(const TtsState()) {
-    _init();
+    _initFuture = _init();
   }
 
   Future<void> _init() async {
-    await _tts.setLanguage('vi-VN');
+    await _tts.awaitSpeakCompletion(true);
+    await _tts.setSharedInstance(true);
+
+    if (Platform.isIOS) {
+      await _tts.setIosAudioCategory(
+        IosTextToSpeechAudioCategory.playback,
+        [
+          IosTextToSpeechAudioCategoryOptions.allowBluetooth,
+          IosTextToSpeechAudioCategoryOptions.allowBluetoothA2DP,
+          IosTextToSpeechAudioCategoryOptions.mixWithOthers,
+        ],
+        IosTextToSpeechAudioMode.defaultMode,
+      );
+    }
+
+    if (Platform.isAndroid) {
+      await _tts.setAudioAttributesForNavigation();
+    }
+
+    await _configureVietnameseVoice();
     await _tts.setSpeechRate(1.0);
     await _tts.setVolume(1.0);
     await _tts.setPitch(1.0);
 
+    _tts.setStartHandler(() {
+      state = state.copyWith(status: TtsStatus.playing);
+    });
+
     _tts.setCompletionHandler(() {
       if (state.status == TtsStatus.playing) {
         _next();
@@ -55,12 +90,49 @@ class TtsNotifier extends StateNotifier<TtsState> {
 
     _tts.setErrorHandler((msg) {
       state = state.copyWith(status: TtsStatus.idle);
-      WakelockPlus.disable();
     });
+
+    _initialized = true;
+  }
+
+  Future<void> _configureVietnameseVoice() async {
+    final dynamic voicesRaw = await _tts.getVoices;
+
+    String? selectedName;
+    String selectedLanguage = 'vi-VN';
+
+    if (voicesRaw is List) {
+      final vietnamese = voicesRaw.whereType<Map>().where((voice) {
+        final locale = (voice['locale'] ?? voice['language'] ?? '').toString().toLowerCase();
+        return locale.startsWith('vi');
+      }).toList();
+
+      if (vietnamese.isNotEmpty) {
+        final preferred = vietnamese.firstWhere(
+          (voice) =>
+              (voice['name']?.toString().toLowerCase().contains('female') ?? false) ||
+              (voice['name']?.toString().toLowerCase().contains('natural') ?? false),
+          orElse: () => vietnamese.first,
+        );
+        selectedName = preferred['name']?.toString();
+        selectedLanguage =
+            (preferred['locale'] ?? preferred['language'] ?? 'vi-VN').toString();
+      }
+    }
+
+    await _tts.setLanguage(selectedLanguage);
+    if (selectedName != null) {
+      await _tts.setVoice({'name': selectedName, 'locale': selectedLanguage});
+    }
+    state = state.copyWith(language: selectedLanguage, voiceName: selectedName);
   }
 
   /// Start reading from [content] starting at optional [paragraphIndex].
   Future<void> startReading(String content, {int paragraphIndex = 0}) async {
+    if (!_initialized) {
+      await (_initFuture ?? _init());
+    }
+
     _paragraphs = content
         .split(RegExp(r'\n+'))
         .map((p) => p.trim())
@@ -75,14 +147,12 @@ class TtsNotifier extends StateNotifier<TtsState> {
       paragraphIndex: validIndex,
       totalParagraphs: _paragraphs.length,
     );
-    await WakelockPlus.enable();
     await _speak(validIndex);
   }
 
   Future<void> _speak(int index) async {
     if (index >= _paragraphs.length) {
       state = state.copyWith(status: TtsStatus.idle);
-      await WakelockPlus.disable();
       return;
     }
     await _tts.setSpeechRate(state.speed);
@@ -93,7 +163,6 @@ class TtsNotifier extends StateNotifier<TtsState> {
     final next = state.paragraphIndex + 1;
     if (next >= state.totalParagraphs) {
       state = state.copyWith(status: TtsStatus.idle, paragraphIndex: 0);
-      await WakelockPlus.disable();
       return;
     }
     state = state.copyWith(paragraphIndex: next);
@@ -103,20 +172,18 @@ class TtsNotifier extends StateNotifier<TtsState> {
   Future<void> pause() async {
     await _tts.pause();
     state = state.copyWith(status: TtsStatus.paused);
-    await WakelockPlus.disable();
   }
 
   Future<void> resume() async {
     if (state.status != TtsStatus.paused) return;
     state = state.copyWith(status: TtsStatus.playing);
-    await WakelockPlus.enable();
+    // Use paragraph-level resume for consistent behavior across engines.
     await _speak(state.paragraphIndex);
   }
 
   Future<void> stop() async {
     await _tts.stop();
     state = state.copyWith(status: TtsStatus.idle, paragraphIndex: 0);
-    await WakelockPlus.disable();
   }
 
   Future<void> skipForward() async {
@@ -126,6 +193,7 @@ class TtsNotifier extends StateNotifier<TtsState> {
 
   Future<void> skipBack() async {
     await _tts.stop();
+    if (state.totalParagraphs <= 0) return;
     final prev = (state.paragraphIndex - 1).clamp(0, state.totalParagraphs - 1);
     state = state.copyWith(paragraphIndex: prev);
     if (state.status == TtsStatus.playing) await _speak(prev);
@@ -139,7 +207,6 @@ class TtsNotifier extends StateNotifier<TtsState> {
   @override
   void dispose() {
     _tts.stop();
-    WakelockPlus.disable();
     super.dispose();
   }
 }