const express = require('express');
const http = require('http');
const { Server } = require('socket.io');
const axios = require('axios');
const cors = require('cors'); 

const app = express();
const server = http.createServer(app);

app.use(cors({
  origin: "http://127.0.0.1:5500",
  methods: ["GET", "POST"],
  credentials: true
}));

const io = new Server(server, {
  cors: {
    origin: "http://127.0.0.1:5500",
    methods: ["GET", "POST"],
    credentials: true
  }
});

const AI_API_URL = 'https://api.siliconflow.cn/v1/chat/completions';
const AI_API_KEY = 'sk-xnnehzodtycretktyjuxyvfqfulfomvhytroftenszqnwxyt';
const AI_MODEL = 'Qwen/QwQ-32B';

const onlineUsers = new Map();

// 定义最大重试次数
const MAX_RETRIES = 3;

app.use(express.json()); 
app.post('/generate-strategy', async (req, res) => {
  try {
    const { destination, travelDate, travelDays, budget, preferences, specialNeed } = req.body;
    
    const prompt = `
      请严格按照以下格式生成${travelDays}天的${destination}旅游攻略（出行日期：${travelDate}，人均预算${budget}元）：
      1. 攻略标题：包含目的地、天数、出发日期；
      2. 每日行程：每天1个标题+3-4个时间段的行程（格式：时间-地点：描述，地点需含景点/餐厅，描述需含亮点）；
      3. 预算总结：分“门票”“餐饮”“住宿”3类，最后算总计（单位：元）；
      4. 兴趣偏好：优先满足${preferences.join('、')}；
      5. 特殊需求：${specialNeed || '无'}。
      示例格式：
      标题：北京2日游攻略（2025-01-01出发）
      第1天：历史文化之旅
        09:00-12:00 故宫：明清皇家宫殿，必看太和殿、乾清宫，建议租讲解器
        12:30-14:00 四季民福（故宫店）：北京烤鸭招牌店，可远眺故宫
        14:30-17:30 景山公园：登顶万春亭，俯瞰故宫全景
      第2天：自然休闲之旅
        09:00-12:00 颐和园：皇家园林，乘船游昆明湖，逛长廊
        12:30-14:00 苏州街：颐和园周边小吃街，尝豌豆黄、艾窝窝
        14:30-17:30 圆明园：遗址公园，感受历史，建议看西洋楼遗址
      预算总结：
        门票：故宫60 + 景山2 + 颐和园30 + 圆明园25 = 117元
        餐饮：午餐80*2 + 小吃30 = 190元
        住宿：经济型酒店300元/晚*1晚 = 300元
        总计：117+190+300=607元
    `;

    let aiResponse;
    let retryCount = 0;
    let finalError = null;
    // 增加重试逻辑，且动态调整超时时间
    while (retryCount <= MAX_RETRIES) {
      try {
        // 动态超时：基础60秒，每次重试加20秒
        const dynamicTimeout = 60000 + retryCount * 20000;
        aiResponse = await axios.post(
          AI_API_URL,
          {
            model: AI_MODEL,
            messages: [{ role: "user", content: prompt }],
            temperature: 0.7
          },
          {
            headers: {
              'Authorization': `Bearer ${AI_API_KEY}`,
              'Content-Type': 'application/json'
            },
            timeout: dynamicTimeout
          }
        );
        break; // 成功获取响应，跳出重试循环
      } catch (aiError) {
        retryCount++;
        finalError = aiError;
        // 每次重试前等待1-3秒（随机）
        await new Promise(resolve => setTimeout(resolve, Math.random() * 2000 + 1000));
        console.warn(`等待 ${(Math.random() * 2000 + 1000)/1000} 秒后，进行第 ${retryCount} 次重试，错误：`, aiError.response?.data || aiError.message);
      }
    }

    if (!aiResponse) {
      // 根据错误类型返回不同提示
      if (finalError.code === 'ECONNABORTED') {
        return res.status(504).json({
          code: 504,
          error: 'AI接口响应超时，可能是服务繁忙，请稍后再试'
        });
      } else {
        console.error('调用硅基流动AI接口多次失败，详细错误：', finalError.response?.data || finalError.message);
        return res.status(500).json({
          code: 500,
          error: '调用AI服务多次失败，可能是接口配置或网络问题，请检查后重试'
        });
      }
    }

    const rawContent = aiResponse.data.choices[0].message.content;
    const strategy = parseAiStrategy(rawContent, destination, travelDate, travelDays, budget);

    res.json({
      code: 200,
      data: strategy
    });

  } catch (error) {
    console.error('攻略生成失败：', error.response?.data || error.message);
    res.status(500).json({
      code: 500,
      error: '攻略生成失败，请检查AI服务或参数后重试'
    });
  }
});

function parseAiStrategy(rawContent, destination, travelDate, travelDays, budget) {
  const titleMatch = rawContent.match(/标题：(.+)/);
  const title = titleMatch ? titleMatch[1] : `${destination}${travelDays}日游攻略（${travelDate}出发）`;

  const days = [];
  for (let i = 1; i <= travelDays; i++) {
    const dayMatch = rawContent.match(new RegExp(`第${i}天：(.+?)(?=第${i+1}天|预算总结)`, 's'));
    if (dayMatch) {
      const dayContent = dayMatch[1];
      const scheduleMatches = dayContent.match(/(\d{2}:\d{2}-\d{2}:\d{2})\s+(.+?)\：(.+?)(?=\d{2}:\d{2}|$)/g) || [];
      const schedule = scheduleMatches.map(item => {
        const [time, location, description] = item.split(/\s+|\：/).filter(Boolean);
        return { time, location, description: description.trim() };
      });
      days.push({ title: `第${i}天：${dayMatch[1].split('\n')[0].trim()}`, schedule });
    }
  }

  const budgetSummary = { 门票: 0, 餐饮: 0, 住宿: 0 };
  const ticketMatch = rawContent.match(/门票：.*?= (\d+)元/);
  const foodMatch = rawContent.match(/餐饮：.*?= (\d+)元/);
  const hotelMatch = rawContent.match(/住宿：.*?= (\d+)元/);
  const totalMatch = rawContent.match(/总计：(\d+)元/);

  budgetSummary.门票 = ticketMatch ? parseInt(ticketMatch[1]) : Math.floor(budget * 0.2);
  budgetSummary.餐饮 = foodMatch ? parseInt(foodMatch[1]) : Math.floor(budget * 0.3);
  budgetSummary.住宿 = hotelMatch ? parseInt(hotelMatch[1]) : Math.floor(budget * 0.4);
  const totalBudget = totalMatch ? parseInt(totalMatch[1]) : budget;

  return {
    id: Date.now().toString(),
    title,
    days: days.length ? days : [{ title: `第1天：${destination}核心游`, schedule: [{ time: '09:00-17:00', location: destination, description: `建议游览${destination}核心景点，结合${preferences[0] || '自然风光'}体验` }] }],
    budgetSummary,
    totalBudget
  };
}

io.on('connection', (socket) => {
  console.log('新客户端连接:', socket.id);

  socket.on('login', (username) => {
    onlineUsers.set(socket.id, username);
    console.log(`${username} 已登录`);
    socket.emit('messageReceived', {
      sender: '系统',
      content: `欢迎来到AI聊天！我是硅基流动AI助手，有什么可以帮助你的吗？`
    });
  });

  socket.on('chatMessage', async (data) => {
    const sender = onlineUsers.get(socket.id);
    if (!sender) {
      socket.emit('messageReceived', { sender: '系统', content: '请先登录' });
      return;
    }

    console.log(`收到消息: ${sender} -> ${data.recipient}: ${data.message}`);
    socket.emit('messageReceived', { sender: sender, content: data.message });

    if (data.recipient === '硅基流动AI助手') {
      try {
        const aiRes = await axios.post(
          AI_API_URL,
          { model: AI_MODEL, messages: [{ role: "user", content: data.message }] },
          { headers: { 'Authorization': `Bearer ${AI_API_KEY}`, 'Content-Type': 'application/json' } }
        );
        socket.emit('messageReceived', {
          sender: '硅基流动AI助手',
          content: aiRes.data.choices[0].message.content
        });
      } catch (err) {
        console.error('AI聊天调用错误:', err);
        socket.emit('messageReceived', { sender: '系统', content: '抱歉，AI聊天服务暂时无法使用' });
      }
    }
  });

  socket.on('disconnect', () => {
    const username = onlineUsers.get(socket.id);
    if (username) {
      console.log(`${username} 已断开连接`);
      onlineUsers.delete(socket.id);
    }
    console.log('客户端断开连接:', socket.id);
  });
});

const PORT = 3005;
server.listen(PORT, () => {
  console.log(`服务器运行在 http://localhost:${PORT}`);
  console.log('攻略生成接口：POST http://localhost:3005/generate-strategy');
});