import 'dart:async';
import 'dart:io';
import 'package:flutter/services.dart';
import 'package:get/get.dart';
import 'package:flutter_dotenv/flutter_dotenv.dart';
import '../../../core/utils/logger.dart';
import '../tts_service.dart';

/// 微软 Text-to-Speech 服务
/// 
/// 该服务通过平台通道与原生 Microsoft Speech SDK 交互，
/// 提供文本转语音功能。
class AzureTtsService extends GetxService implements TtsService {
  static final AzureTtsService to = Get.put(AzureTtsService());
  static const MethodChannel _channel = MethodChannel('com.deep_voice.azure_tts');
  
  bool _isInitialized = false;
  late final String _subscriptionKey;
  late final String _serviceRegion;
  
  // 当前设置
  String _currentVoice = 'zh-CN-XiaoxiaoNeural';
  int _currentRate = 0;
  int _currentPitch = 0;
  int _currentVolume = 100;
  
  // 支持的语音列表
  final List<String> _supportedVoices = [
    'zh-CN-XiaoxiaoNeural',
    'zh-CN-YunxiNeural',
    'zh-CN-YunjianNeural',
    'en-US-JennyNeural',
    'en-US-GuyNeural'
  ];
  
  // 语音合成队列
  final List<_SpeechItem> _textQueue = [];
  bool _isProcessingQueue = false;
  
  // 可观察状态
  final isEnabled = true.obs;
  
  // 流式文本缓冲区
  String _streamBuffer = '';
  
  /// 缓存的播放状态
  bool _speakingCache = false;
  DateTime _lastSpeakingCheck = DateTime.now();
  
  @override
  String get currentVoice => _currentVoice;
  
  @override
  bool get isSpeaking {
    // 如果未初始化，直接返回false
    if (!_isInitialized) return false;
    
    // 如果距离上次检查不到50ms，则使用缓存值
    if (DateTime.now().difference(_lastSpeakingCheck).inMilliseconds < 50) {
      return _speakingCache;
    }
    
    // 否则异步更新缓存（但仍返回当前缓存值）
    _checkSpeakingStatus();
    return _speakingCache;
  }
  
  @override
  Stream<TtsEvent> get onEvent => const Stream.empty();
  
  @override
  List<String> get supportedVoices => _supportedVoices;
  
  
  AzureTtsService() {
    _loadConfig();
  }
  
  /// 从环境变量加载配置
  void _loadConfig() {
    _subscriptionKey = dotenv.env['AZURE_SPEECH_KEY'] ?? '';
    _serviceRegion = dotenv.env['AZURE_SPEECH_REGION'] ?? '';
  }

  @override
  Future<bool> initialize({
    List<String>? supportedLanguages,
  }) async {
    if (_isInitialized) return true;
    
    try {
      if (_subscriptionKey.isEmpty || _serviceRegion.isEmpty) {
        Logger.error('未找到Azure语音服务配置');
        return false;
      }
      
      // 始终优先使用中文作为默认语言
      final String defaultLanguage = 'zh-CN';
      
      // 更新支持的语音列表（如果提供）
      if (supportedLanguages != null && supportedLanguages.isNotEmpty) {
        // 如果支持中文，优先使用中文，否则使用提供的第一种语言
        String language = supportedLanguages.contains(defaultLanguage) 
            ? defaultLanguage 
            : supportedLanguages.first;
        
        final result = await _channel.invokeMethod('initialize', {
          'subscriptionKey': _subscriptionKey,
          'region': _serviceRegion,
          'language': language,
        });
        
        _isInitialized = result;
        return result;
      } else {
        // 使用默认语言初始化
        final result = await _channel.invokeMethod('initialize', {
          'subscriptionKey': _subscriptionKey,
          'region': _serviceRegion,
          'language': 'zh-CN',
        });
        
        _isInitialized = result;
        return result;
      }
    } catch (e) {
      Logger.error('初始化失败: $e');
      return false;
    }
  }
  
  @override
  Future<bool> setVoice(String voiceName) async {
    if (!_isInitialized) await initialize();
    if (voiceName == _currentVoice) return true;
    
    try {
      final result = await _channel.invokeMethod('setVoice', {
        'voiceName': voiceName,
      });
      
      if (result) _currentVoice = voiceName;
      return result;
    } catch (e) {
      Logger.error('设置语音失败: $e');
      return false;
    }
  }
  
  /// 设置语音参数
  Future<bool> setSpeechParams({int rate = 0, int pitch = 0, int volume = 100}) async {
    if (!_isInitialized) await initialize();
    
    try {
      final result = await _channel.invokeMethod('setSpeechParams', {
        'rate': rate,
        'pitch': pitch,
        'volume': volume,
      });
      
      if (result) {
        _currentRate = rate;
        _currentPitch = pitch;
        _currentVolume = volume;
      }
      
      return result;
    } catch (e) {
      Logger.error('设置语音参数失败: $e');
      return false;
    }
  }
  
  @override
  Future<bool> speakOnce(String text) async {
    if (!_isInitialized) await initialize();
    if (!isEnabled.value || text.isEmpty) return false;
    
    try {
      // 主动设置缓存状态为true
      _speakingCache = true;
      
      final result = await _channel.invokeMethod('speakText', {'text': text});
      
      // 调用完成后主动检查状态
      _checkSpeakingStatus();
      
      return result == "OK";
    } catch (e) {
      // 发生错误时重置状态
      _speakingCache = false;
      Logger.error('语音合成失败: $e');
      return false;
    }
  }
  
  /// 播放SSML
  Future<bool> speakSsmlOnce(String ssml) async {
    if (!_isInitialized) await initialize();
    if (!isEnabled.value || ssml.isEmpty) return false;
    
    try {
      // 主动设置缓存状态为true
      _speakingCache = true;
      
      final result = await _channel.invokeMethod('speakSsml', {'ssml': ssml});
      
      // 调用完成后主动检查状态
      _checkSpeakingStatus();
      
      return result == "OK";
    } catch (e) {
      // 发生错误时重置状态
      _speakingCache = false;
      Logger.error('SSML语音合成失败: $e');
      return false;
    }
  }
  
  /// 等待语音播放完成
  Future<void> waitForSpeechCompletion({Duration timeout = const Duration(seconds: 30)}) async {
    // 首先检查当前状态
    _checkSpeakingStatus();
    if (!_speakingCache) return;
    
    final stopwatch = Stopwatch()..start();
    
    while (_speakingCache && stopwatch.elapsed < timeout) {
      // 短暂等待后再次检查
      await Future.delayed(const Duration(milliseconds: 100));
      // 检查状态
      await _channel.invokeMethod<bool>('isSpeaking').then((result) {
        if (result != null) {
          _speakingCache = result;
          _lastSpeakingCheck = DateTime.now();
        }
      });
    }
  }
  
  @override
  Future<bool> speakStream(String text) async {
    if (!isEnabled.value || text.isEmpty) return false;
    
    try {
      // 添加文本到缓冲区
      _streamBuffer += text;
      
      // 如果缓冲区为空，直接返回
      if (_streamBuffer.isEmpty) return true;
      
      // 使用正则表达式匹配句子，包括结束符号
      // 匹配任意字符，直到遇到句子结束符号
      final sentenceRegex = RegExp(
        r'([^。.！!？?；;：\n\r]+[。.！!？?；;：:\n\r]|[^。.！!？?；;：\n\r]+(?:\.{3,}|…)|[^。.！!？?；;：\n\r]+["」』])'
      );
      
      bool hasProcessed = false;
      
      // 查找所有完整句子
      final matches = sentenceRegex.allMatches(_streamBuffer);
      final List<String> sentences = [];
      int lastMatchEnd = 0;
      
      for (final match in matches) {
        // 提取完整句子（包含结束符号）
        final sentence = match.group(1)?.trim();
        if (sentence != null && sentence.isNotEmpty) {
          sentences.add(sentence);
          lastMatchEnd = match.end;
        }
      }
      
      // 处理找到的句子
      for (final sentence in sentences) {
        _textQueue.add(_SpeechItem(
          text: sentence,
          rate: _currentRate,
          pitch: _currentPitch,
          volume: _currentVolume,
        ));
        hasProcessed = true;
      }
      
      // 更新缓冲区，只保留未完成的部分
      if (lastMatchEnd > 0) {
        _streamBuffer = _streamBuffer.substring(lastMatchEnd);
      }
      
      // 如果处理了文本并且队列未在处理中，开始处理队列
      if (hasProcessed && !_isProcessingQueue) {
        _processQueue();
      }
      
      return true;
    } catch (e) {
      Logger.error('处理流式文本失败: $e');
      return false;
    }
  }
  
  @override
  Future<bool> flushStream() async {
    if (_textQueue.isEmpty && _streamBuffer.isEmpty) return true;
    
    try {
      // 处理缓冲区中可能的完整句子
      await speakStream('');
      
      // 如果缓冲区仍有剩余文本，将其添加到播放队列
      if (_streamBuffer.isNotEmpty && _streamBuffer.trim().isNotEmpty) {
        _textQueue.add(_SpeechItem(
          text: _streamBuffer,
          rate: _currentRate,
          pitch: _currentPitch,
          volume: _currentVolume,
        ));
        
        // 清空缓冲区
        _streamBuffer = '';
        
        // 如果队列未在处理中，开始处理队列
        if (!_isProcessingQueue) {
          _processQueue();
        }
      }
      
      Logger.info('等待TTS队列播放完成，剩余${_textQueue.length}条');
      
      // 等待队列处理完成
      await _checkSpeakingStatus();
      while (_isProcessingQueue || _speakingCache) {
        await Future.delayed(const Duration(milliseconds: 100));
        await _checkSpeakingStatus();
      }
      
      Logger.info('TTS队列播放完成');
      return true;
    } catch (e) {
      Logger.error('刷新TTS流失败: $e');
      return false;
    }
  }
  
  /// 处理语音合成队列
  Future<void> _processQueue() async {
    if (_textQueue.isEmpty || _isProcessingQueue) return;
    
    _isProcessingQueue = true;
    
    try {
      while (_textQueue.isNotEmpty) {
        if (!isEnabled.value) {
          _textQueue.clear();
          break;
        }
        
        final item = _textQueue.removeAt(0);
        
        if (item.rate != _currentRate || item.pitch != _currentPitch || item.volume != _currentVolume) {
          await setSpeechParams(
            rate: item.rate,
            pitch: item.pitch,
            volume: item.volume,
          );
        }
        
        // 使用speakOnce播放当前项
        await speakOnce(item.text);
        
        // 等待播放完成
        await waitForSpeechCompletion();
      }
    } catch (e) {
      Logger.error('处理语音队列出错: $e');
    } finally {
      _isProcessingQueue = false;
    }
  }
  
  @override
  Future<bool> stop() async {
    try {
      _textQueue.clear();
      
      if (_speakingCache) {
        final result = await _channel.invokeMethod('stopSpeaking');
        // 重置缓存状态
        _speakingCache = false;
        return result;
      }
      
      return true;
    } catch (e) {
      Logger.error('停止语音合成出错: $e');
      return false;
    }
  }
  
  /// 生成SSML文本
  String generateSsml({
    required String text,
    String? voiceName,
    int? rate,
    int? pitch,
    int? volume,
  }) {
    final voice = voiceName ?? _currentVoice;
    final rateValue = (rate ?? _currentRate).clamp(-100, 100);
    final pitchValue = (pitch ?? _currentPitch).clamp(-100, 100);
    final volumeValue = (volume ?? _currentVolume).clamp(0, 100);
    
    final rateStr = rateValue == 0 ? '0%' : rateValue < 0 ? '${(rateValue * 0.9).round()}%' : '$rateValue%';
    final pitchStr = pitchValue == 0 ? '0%' : '${(pitchValue * 0.5).round()}%';
    final volumeStr = "$volumeValue%";
    
    return '''
    <speak version="1.0" xmlns="http://www.w3.org/2001/10/synthesis" xmlns:mstts="https://www.w3.org/2001/mstts" xml:lang="zh-CN">
      <voice name="$voice">
        <prosody rate="$rateStr" pitch="$pitchStr" volume="$volumeStr">
          $text
        </prosody>
      </voice>
    </speak>
    ''';
  }
  
  /// 切换启用状态
  void toggleEnabled() {
    isEnabled.toggle();
    if (!isEnabled.value) stop();
  }
  
  @override
  Future<void> dispose() async {
    if (!_isInitialized) return;
    
    try {
      await stop();
      await _channel.invokeMethod('dispose');
      _isInitialized = false;
    } catch (e) {
      Logger.error('释放资源失败: $e');
    }
  }

  /// 异步检查并更新播放状态缓存
  Future<bool> _checkSpeakingStatus() async {
    _lastSpeakingCheck = DateTime.now();
    try {
      final result = await _channel.invokeMethod<bool>('isSpeaking');
      if (result != null) {
        _speakingCache = result;
      }
      return _speakingCache;
    } catch (e) {
      Logger.error('获取播放状态失败: $e');
      return _speakingCache;
    }
  }
  
}

/// 语音合成项目
class _SpeechItem {
  final String text;
  final int rate;
  final int pitch;
  final int volume;
  
  _SpeechItem({
    required this.text,
    this.rate = 0,
    this.pitch = 0,
    this.volume = 100,
  });
}