import 'package:flutter/material.dart';
import 'package:chat_api/chat_api.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Chat API Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const ChatDemo(),
    );
  }
}

class ChatDemo extends StatefulWidget {
  const ChatDemo({Key? key}) : super(key: key);

  @override
  State<ChatDemo> createState() => _ChatDemoState();
}

class _ChatDemoState extends State<ChatDemo> {
  final ChatApi _chatApi = ChatApi();
  final TextEditingController _controller = TextEditingController();
  final List<ChatMessage> _messages = [];
  String _response = '';
  bool _isLoading = false;
  bool _isStreaming = false;

  @override
  void initState() {
    super.initState();
    _initializeChatApi();
    _listenToStream();
  }

  Future<void> _initializeChatApi() async {
    try {
      // 注意：请替换为你自己的API密钥
      await _chatApi.initialize(
        apiKey: 'your-api-key-here',
        model: 'gpt-3.5-turbo',
      );
      print('Chat API 初始化成功');
    } catch (e) {
      print('初始化失败: $e');
    }
  }

  void _listenToStream() {
    _chatApi.eventStream.listen((event) {
      switch (event.type) {
        case ChatApiEventType.token:
          setState(() {
            _response += event.content;
          });
          break;
        case ChatApiEventType.complete:
          setState(() {
            _isStreaming = false;
            _messages.add(ChatMessage(
              role: MessageRole.assistant,
              content: _response,
            ));
          });
          break;
        case ChatApiEventType.error:
          setState(() {
            _isStreaming = false;
            _response = '错误: ${event.content}';
          });
          break;
        case ChatApiEventType.functionCall:
          print('函数调用: ${event.content}');
          break;
      }
    });
  }

  Future<void> _sendMessage() async {
    if (_controller.text.isEmpty) return;

    final userMessage = ChatMessage(
      role: MessageRole.user,
      content: _controller.text,
    );

    setState(() {
      _messages.add(userMessage);
      _response = '';
      _isStreaming = true;
    });

    _controller.clear();

    try {
      await _chatApi.sendMessageStream(
        messages: _messages,
        temperature: 0.7,
      );
    } catch (e) {
      setState(() {
        _isStreaming = false;
        _response = '发送失败: $e';
      });
    }
  }

  Future<void> _sendNonStreamMessage() async {
    if (_controller.text.isEmpty) return;

    final userMessage = ChatMessage(
      role: MessageRole.user,
      content: _controller.text,
    );

    setState(() {
      _messages.add(userMessage);
      _isLoading = true;
    });

    _controller.clear();

    try {
      final response = await _chatApi.sendMessage(
        messages: _messages,
        temperature: 0.7,
      );

      setState(() {
        _messages.add(ChatMessage(
          role: MessageRole.assistant,
          content: response,
        ));
        _isLoading = false;
      });
    } catch (e) {
      setState(() {
        _isLoading = false;
      });
      ScaffoldMessenger.of(context).showSnackBar(
        SnackBar(content: Text('发送失败: $e')),
      );
    }
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Chat API Demo'),
        actions: [
          IconButton(
            icon: const Icon(Icons.delete),
            onPressed: () {
              setState(() {
                _messages.clear();
                _response = '';
              });
            },
          ),
        ],
      ),
      body: Column(
        children: [
          Expanded(
            child: ListView.builder(
              padding: const EdgeInsets.all(16),
              itemCount: _messages.length + (_isStreaming ? 1 : 0),
              itemBuilder: (context, index) {
                if (index == _messages.length && _isStreaming) {
                  return _buildMessage(
                    MessageRole.assistant,
                    _response.isEmpty ? '...' : _response,
                  );
                }
                final message = _messages[index];
                return _buildMessage(message.role, message.content.toString());
              },
            ),
          ),
          if (_isLoading)
            const LinearProgressIndicator(),
          Container(
            padding: const EdgeInsets.all(16),
            decoration: BoxDecoration(
              color: Colors.grey[100],
              boxShadow: [
                BoxShadow(
                  color: Colors.black.withOpacity(0.1),
                  blurRadius: 4,
                  offset: const Offset(0, -2),
                ),
              ],
            ),
            child: Row(
              children: [
                Expanded(
                  child: TextField(
                    controller: _controller,
                    decoration: const InputDecoration(
                      hintText: '输入消息...',
                      border: OutlineInputBorder(),
                    ),
                    onSubmitted: (_) => _sendMessage(),
                  ),
                ),
                const SizedBox(width: 8),
                IconButton(
                  icon: const Icon(Icons.send),
                  onPressed: _isStreaming || _isLoading ? null : _sendMessage,
                  color: Colors.blue,
                ),
                IconButton(
                  icon: const Icon(Icons.send_and_archive),
                  onPressed: _isStreaming || _isLoading ? null : _sendNonStreamMessage,
                  color: Colors.green,
                  tooltip: '非流式发送',
                ),
              ],
            ),
          ),
        ],
      ),
    );
  }

  Widget _buildMessage(MessageRole role, String content) {
    final isUser = role == MessageRole.user;
    return Container(
      margin: const EdgeInsets.only(bottom: 8),
      alignment: isUser ? Alignment.centerRight : Alignment.centerLeft,
      child: Container(
        padding: const EdgeInsets.all(12),
        decoration: BoxDecoration(
          color: isUser ? Colors.blue : Colors.grey[300],
          borderRadius: BorderRadius.circular(16),
        ),
        constraints: BoxConstraints(
          maxWidth: MediaQuery.of(context).size.width * 0.7,
        ),
        child: Text(
          content,
          style: TextStyle(
            color: isUser ? Colors.white : Colors.black87,
          ),
        ),
      ),
    );
  }

  @override
  void dispose() {
    _controller.dispose();
    _chatApi.dispose();
    super.dispose();
  }
}