import 'package:get/get.dart';
import 'package:flutter/material.dart';
import 'package:get_storage/get_storage.dart';
import 'dart:convert';
import '../../../data/services/volcano_ai_service.dart';
import '../../../data/services/volcano_tts_service.dart';
import '../models/message_model.dart';

class ChatController extends GetxController {
  final String agentId;
  final String agentName;
  final String agentAvatar;
  final String? agentSubtitle;
  final String systemPrompt;
  final String welcomeMessage;
  final VolcanoAIService _aiService;
  late final VolcanoTtsService _ttsService;
  static const String _storagePrefix = 'chat_history_';
  
  final messages = <Message>[].obs;
  final isLoading = false.obs;
  final textController = TextEditingController();
  final scrollController = ScrollController();
  final _storage = GetStorage();
  
  // 用于存储当前正在流式生成的消息
  final RxString currentStreamMessage = ''.obs;
  Message? _currentAssistantMessage;
  String _pendingTtsText = '';  // 用于累积TTS文本
  static const int _minTtsLength = 20;  // TTS最小文本长度
  bool _isDisposed = false;  // 添加销毁标记

  ChatController({
    required this.agentId,
    required this.agentName,
    required this.agentAvatar,
    this.agentSubtitle,
    required this.systemPrompt,
    required this.welcomeMessage,
  }) : _aiService = VolcanoAIService() {
    _initTtsService();
  }

  void _initTtsService() {
    try {
      _ttsService = Get.find<VolcanoTtsService>();
    } catch (_) {
      // 如果找不到实例，创建一个新的
      _ttsService = Get.put(VolcanoTtsService(), permanent: true);
    }
    // 默认开启TTS
    _ttsService.isEnabled.value = true;
  }

  @override
  void onInit() async {
    super.onInit();
    await _initializeController();
  }

  Future<void> _initializeController() async {
    try {
      await _loadChatHistory();
      
      // 如果没有聊天记录，显示欢迎消息并生成个性化问候语
      if (messages.isEmpty) {
        // 添加欢迎消息
        final initialMessage = Message(
          role: 'assistant',
          content: welcomeMessage,
          timestamp: DateTime.now(),
        );
        messages.add(initialMessage);

        // 生成并添加个性化问候语
        try {
          currentStreamMessage.value = '';
          _currentAssistantMessage = Message(
            role: 'assistant',
            content: '',
            timestamp: DateTime.now(),
          );
          messages.add(_currentAssistantMessage!);

          await for (final chunk in _aiService.generateGreeting(
            agentName: agentName,
            systemPrompt: systemPrompt,
          )) {
            if (_isDisposed) break;

            currentStreamMessage.value += chunk;
            _updateAssistantMessage(currentStreamMessage.value);
            
            // 累积文本用于TTS
            if (!_isDisposed && _ttsService.isEnabled.value) {
              _ttsService.speak(chunk);
            }
          }

          // 保存聊天记录
          if (!_isDisposed) {
            await _saveChatHistory();
            // 延迟滚动以确保布局完成
            Future.delayed(const Duration(milliseconds: 100), _scrollToBottom);
          }
        } catch (e) {
          print('生成问候语失败: $e');
          // 如果生成问候语失败，移除空消息并只播放欢迎消息
          if (_currentAssistantMessage != null) {
            messages.remove(_currentAssistantMessage);
          }
          if (_ttsService.isEnabled.value) {
            _ttsService.speak(welcomeMessage);
          }
        } finally {
          if (!_isDisposed) {
            _currentAssistantMessage = null;
            currentStreamMessage.value = '';
          }
        }
      }
    } catch (e) {
      Get.snackbar(
        'Error',
        'Failed to initialize chat: $e',
        snackPosition: SnackPosition.BOTTOM,
      );
    }
  }

  @override
  void onClose() {
    _isDisposed = true;  // 标记为已销毁
    textController.dispose();
    scrollController.dispose();
    _ttsService.stop();  // 停止当前播放
    super.onClose();
  }

  Future<void> _loadChatHistory() async {
    try {
      final historyJson = _storage.read('${_storagePrefix}${agentId}');
      if (historyJson != null) {
        final List<dynamic> historyList = json.decode(historyJson);
        messages.value = historyList.map((item) => Message.fromJson(item)).toList();
      }
    } catch (e) {
      Get.snackbar(
        'Error',
        'Failed to load chat history: $e',
        snackPosition: SnackPosition.BOTTOM,
      );
    }
  }

  Future<void> _saveChatHistory() async {
    try {
      final historyJson = json.encode(messages.map((msg) => msg.toJson()).toList());
      await _storage.write('${_storagePrefix}${agentId}', historyJson);
    } catch (e) {
      Get.snackbar(
        'Error',
        'Failed to save chat history: $e',
        snackPosition: SnackPosition.BOTTOM,
      );
    }
  }

  void _scrollToBottom() {
    if (scrollController.hasClients) {
      scrollController.animateTo(
        scrollController.position.maxScrollExtent,
        duration: const Duration(milliseconds: 300),
        curve: Curves.easeOut,
      );
    }
  }

  void _updateAssistantMessage(String content) {
    if (_currentAssistantMessage != null) {
      final index = messages.indexWhere((msg) => 
        msg.timestamp == _currentAssistantMessage!.timestamp && 
        msg.role == 'assistant'
      );
      
      if (index != -1) {
        messages[index] = Message(
          role: 'assistant',
          content: content,
          timestamp: _currentAssistantMessage!.timestamp,
        );
        _scrollToBottom();
      }
    }
  }

  void sendMessage(String text) async {
    if (text.trim().isEmpty) return;

    final userMessage = Message(
      role: 'user',
      content: text,
      timestamp: DateTime.now(),
    );
    messages.add(userMessage);
    textController.clear();
    await _saveChatHistory();
    _scrollToBottom();

    isLoading.value = true;
    try {
      currentStreamMessage.value = '';
      _currentAssistantMessage = Message(
        role: 'assistant',
        content: '',
        timestamp: DateTime.now(),
      );
      messages.add(_currentAssistantMessage!);
      _pendingTtsText = '';

      await for (final chunk in _aiService.sendMessageStream(
        messages: messages.map((m) => {'role': m.role, 'content': m.content}).toList(),
        systemPrompt: systemPrompt,
      )) {
        if (_isDisposed) break;

        currentStreamMessage.value += chunk;
        _updateAssistantMessage(currentStreamMessage.value);
        
        // 累积文本并合成
        _pendingTtsText += chunk;
        if (!_isDisposed && _ttsService.isEnabled.value) {
          // 检查是否达到最小长度
          if (_pendingTtsText.length >= _minTtsLength ) {
            // 找到最后一个句子结束的位置
            int lastSentenceEnd = _findLastSentenceEnd(_pendingTtsText);
            if (lastSentenceEnd > 0) {
              // 播放到最后一个句子结束的位置
              String textToSpeak = _pendingTtsText.substring(0, lastSentenceEnd + 1);
              _ttsService.speak(textToSpeak);
              // 保留剩余的文本
              _pendingTtsText = _pendingTtsText.substring(lastSentenceEnd + 1);
            }
          }
        }
      }

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

      // 流式传输完成后保存聊天记录
      if (!_isDisposed) {
        await _saveChatHistory();
      }
    } catch (e) {
      if (!_isDisposed) {
        if (_currentAssistantMessage != null) {
          messages.remove(_currentAssistantMessage);
        }
        Get.snackbar(
          'Error',
          'Failed to get response from AI: $e',
          snackPosition: SnackPosition.BOTTOM,
        );
      }
    } finally {
      if (!_isDisposed) {
        _currentAssistantMessage = null;
        currentStreamMessage.value = '';
        isLoading.value = 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);
  }

  Future<void> clearChat() async {
    try {
      messages.clear();
      await _storage.remove('${_storagePrefix}${agentId}');
      
      // 重新添加欢迎消息
      final initialMessage = Message(
        role: 'assistant',
        content: welcomeMessage,
        timestamp: DateTime.now(),
      );
      messages.add(initialMessage);
      await _saveChatHistory();
      
      // 播放欢迎消息
      if (_ttsService.isEnabled.value) {
        _ttsService.speak(welcomeMessage);
      }
    } catch (e) {
      Get.snackbar(
        'Error',
        'Failed to clear chat: $e',
        snackPosition: SnackPosition.BOTTOM,
      );
    }
  }

  void toggleTTS() {
    _ttsService.toggleEnabled();
  }
}