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

/// 微软 Text-to-Speech 服务异常
class AzureTtsException implements Exception {
  final String message;
  AzureTtsException(this.message);
  
  @override
  String toString() => message;
}

/// 微软 Text-to-Speech 服务
/// 
/// 该服务通过平台通道与 Android 上的 Microsoft Speech SDK 交互，
/// 提供文本转语音功能。
class AzureTtsService extends GetxService {
  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;
  
  // 语音合成队列
  final List<_SpeechItem> _textQueue = [];
  bool _isProcessingQueue = false;
  bool _isSpeaking = false;
  
  // 流式输出缓冲区
  String _streamBuffer = '';
  
  // 可观察状态
  final isEnabled = true.obs;
  final isSpeaking = false.obs;
  
  String get currentVoice => _currentVoice;
  
  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'] ?? '';
  }
  
  /// 初始化TTS服务
  Future<bool> initialize({String language = 'zh-CN'}) 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;
      }
      
      final result = await _channel.invokeMethod('initialize', {
        'subscriptionKey': _subscriptionKey,
        'serviceRegion': _serviceRegion,
        'language': language,
      });
      
      _isInitialized = result;
      return result;
    } catch (e) {
      Logger.error('初始化失败: $e');
      return false;
    }
  }
  
  /// 设置语音
  Future<bool> setVoice(String voiceName) async {
    if (!_isInitialized) await initialize();
    
    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;
    }
  }
  
  /// 播放文本
  Future<String> speakText(String text) async {
    if (!_isInitialized) await initialize();
    if (!isEnabled.value) return "TTS服务已禁用";
    
    try {
      _isSpeaking = true;
      isSpeaking.value = true;
      
      final result = await _channel.invokeMethod('speakText', {'text': text});
      
      _isSpeaking = false;
      isSpeaking.value = false;
      
      return result;
    } catch (e) {
      _isSpeaking = false;
      isSpeaking.value = false;
      Logger.error('语音合成失败: $e');
      return "语音合成失败: $e";
    }
  }
  
  /// 播放SSML
  Future<String> speakSsml(String ssml) async {
    if (!_isInitialized) await initialize();
    if (!isEnabled.value) return "TTS服务已禁用";
    
    try {
      _isSpeaking = true;
      isSpeaking.value = true;
      
      final result = await _channel.invokeMethod('speakSsml', {'ssml': ssml});
      
      _isSpeaking = false;
      isSpeaking.value = false;
      
      return result;
    } catch (e) {
      _isSpeaking = false;
      isSpeaking.value = false;
      Logger.error('SSML语音合成失败: $e');
      return "SSML语音合成失败: $e";
    }
  }
  
  /// 添加文本到队列并播放
  Future<bool> speak(String text, {int? rate, int? pitch, int? volume}) async {
    if (!isEnabled.value || text.isEmpty) return false;
    
    _textQueue.add(_SpeechItem(
      text: text,
      rate: rate ?? _currentRate,
      pitch: pitch ?? _currentPitch,
      volume: volume ?? _currentVolume,
    ));
    
    if (!_isProcessingQueue) _processQueue();
    return true;
  }
  
  /// 处理AI流式输出文本
  /// 
  /// 将流式输出的文本片段添加到缓冲区，并在检测到完整句子时将其送入播放队列
  Future<bool> processStreamText(String textChunk) async {
    if (!isEnabled.value || textChunk.isEmpty) return false;
    
    // 添加文本到缓冲区
    _streamBuffer += textChunk;
    
    // 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;
  }
  
  /// 强制处理缓冲区中的剩余文本
  /// 
  /// 在流式输出结束时调用，确保缓冲区中的所有文本都被处理
  Future<bool> flushStreamBuffer() async {
    if (!isEnabled.value || _streamBuffer.isEmpty) return false;
    
    // 先尝试使用processStreamText处理可能的完整句子
    await processStreamText('');
    
    // 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();
      }
    }
    
    return true;
  }
  
  /// 连续播放多段文本
  Future<bool> speakMultiple(List<String> texts, {int? rate, int? pitch, int? volume}) async {
    if (!isEnabled.value || texts.isEmpty) return false;
    
    for (final text in texts) {
      if (text.isNotEmpty) {
        _textQueue.add(_SpeechItem(
          text: text,
          rate: rate ?? _currentRate,
          pitch: pitch ?? _currentPitch,
          volume: volume ?? _currentVolume,
        ));
      }
    }
    
    if (!_isProcessingQueue) _processQueue();
    return true;
  }
  
  /// 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,
          );
        }
        
        await speakText(item.text);
      }
    } catch (e) {
      Logger.error('处理语音队列出错: $e');
    } finally {
      _isProcessingQueue = false;
    }
  }
  
  /// 停止当前语音合成并清空队列
  Future<bool> stop() async {
    _textQueue.clear();
    _streamBuffer = ''; // 清空流缓冲区
    
    if (_isSpeaking) {
      try {
        final result = await _channel.invokeMethod('stopSpeaking');
        _isSpeaking = false;
        isSpeaking.value = false;
        return result;
      } catch (e) {
        Logger.error('停止语音合成出错: $e');
        return false;
      }
    }
    
    return true;
  }
  
  /// 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();
  }
  
  /// 释放资源
  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');
    }
  }
}

/// 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,
  });
}