import 'package:get/get.dart';
import 'dart:async';
import 'volcano_ai_service.dart';
import 'volcano_tts_service.dart';
import '../../modules/chat/models/message_model.dart';

class BackgroundAgentService extends GetxService {
  static BackgroundAgentService get to => Get.find();
  
  final VolcanoAIService _aiService;
  final VolcanoTtsService _ttsService;
  final List<Message> _messageHistory = [];
  String _pendingTtsText = '';
  static const int _minTtsLength = 20;
  bool _isProcessing = false;

  BackgroundAgentService()
      : _aiService = VolcanoAIService(),
        _ttsService = Get.find<VolcanoTtsService>();

  Future<void> handleAgentInteraction(String systemPrompt) async {
    if (_isProcessing) return;
    _isProcessing = true;

    try {
      // 构建用于生成回应的消息列表
      final messages = [
        {'role': 'system', 'content': systemPrompt},
        {'role': 'user', 'content': '请用一句简短的话回应我，要体现你的特点，不要超过12个字。'},
      ];

      String fullResponse = '';
      await for (final chunk in _aiService.sendMessageStream(
        messages: messages,
        systemPrompt: systemPrompt,
      )) {
        fullResponse += chunk;
        
        // 累积文本并处理TTS
        _pendingTtsText += chunk;
        if (_ttsService.isEnabled.value) {
          if (_pendingTtsText.length >= _minTtsLength) {
            int lastSentenceEnd = _findLastSentenceEnd(_pendingTtsText);
            if (lastSentenceEnd > 0) {
              String textToSpeak = _pendingTtsText.substring(0, lastSentenceEnd + 1);
              await _ttsService.speak(textToSpeak);
              _pendingTtsText = _pendingTtsText.substring(lastSentenceEnd + 1);
            }
          }
        }
      }

      // 处理剩余的文本
      if (_ttsService.isEnabled.value && _pendingTtsText.isNotEmpty) {
        await _ttsService.speak(_pendingTtsText);
      }
      _pendingTtsText = '';

      // 保存对话历史
      _messageHistory.add(Message(
        role: 'assistant',
        content: fullResponse,
        timestamp: DateTime.now(),
      ));

      // 限制历史记录长度
      if (_messageHistory.length > 10) {
        _messageHistory.removeAt(0);
      }
    } catch (e) {
      print('Background agent interaction failed: $e');
    } finally {
      _isProcessing = false;
    }
  }

  int _findLastSentenceEnd(String text) {
    final sentenceEnds = [
      text.lastIndexOf('。'),
      text.lastIndexOf('！'),
      text.lastIndexOf('？'),
      text.lastIndexOf('.'),
      text.lastIndexOf('!'),
      text.lastIndexOf('?'),
    ];
    
    return sentenceEnds.reduce((max, pos) => pos > max ? pos : max);
  }

  List<Message> get messageHistory => List.unmodifiable(_messageHistory);

  void clearHistory() {
    _messageHistory.clear();
  }
}