const express = require('express');
const mysql = require('mysql2/promise');
const cors = require('cors');
const bcrypt = require('bcryptjs');
const jwt = require('jsonwebtoken');
require('dotenv').config();

const app = express();
const PORT = process.env.PORT || 5000;
const JWT_SECRET = 'weiMonkey2024_secret_key';

// 中间件
app.use(cors());
app.use(express.json());

// 数据库连接配置
const dbConfig = {
  host: 'localhost',
  port: 3306,
  user: 'root',
  password: '123456',
  database: 'myuser'
};

// 创建数据库连接池
const pool = mysql.createPool(dbConfig);

// 初始化数据库表
async function initDatabase() {
  try {
    const connection = await pool.getConnection();
    
    // 创建待办事项表
    await connection.execute(`
      CREATE TABLE IF NOT EXISTS todos (
        id INT AUTO_INCREMENT PRIMARY KEY,
        title VARCHAR(255) NOT NULL,
        priority ENUM('low', 'medium', 'high', 'urgent') DEFAULT 'medium',
        completed BOOLEAN DEFAULT FALSE,
        suspended BOOLEAN DEFAULT FALSE,
        date DATE NOT NULL,
        suspended_date DATE NULL,
        created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
        updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
      )
    `);
    
    // 添加suspended字段（如果表已存在但没有该字段）
    try {
      await connection.execute(`
        ALTER TABLE todos 
        ADD COLUMN suspended BOOLEAN DEFAULT FALSE,
        ADD COLUMN suspended_date DATE NULL
      `);
    } catch (error) {
      // 字段可能已存在，忽略错误
      console.log('Suspended columns may already exist');
    }
    
    connection.release();
    console.log('数据库表初始化成功');
  } catch (error) {
    console.error('数据库初始化失败:', error);
  }
}

// 验证密码的中间件
const authenticatePassword = (req, res, next) => {
  const { password } = req.body;
  const correctPassword = 'weiMonkey2024';
  
  if (password !== correctPassword) {
    return res.status(401).json({ error: '密码错误' });
  }
  
  next();
};

// 路由

// 验证密码
app.post('/api/auth', authenticatePassword, (req, res) => {
  const token = jwt.sign({ authenticated: true }, JWT_SECRET, { expiresIn: '24h' });
  res.json({ success: true, token });
});

// 验证token的中间件
const authenticateToken = (req, res, next) => {
  const authHeader = req.headers['authorization'];
  const token = authHeader && authHeader.split(' ')[1];

  if (!token) {
    return res.status(401).json({ error: '需要认证' });
  }

  jwt.verify(token, JWT_SECRET, (err, user) => {
    if (err) {
      return res.status(403).json({ error: '无效的token' });
    }
    req.user = user;
    next();
  });
};

// 获取历史待办事项（一周之前的）
app.get('/api/todos/history', authenticateToken, async (req, res) => {
  try {
    const connection = await pool.getConnection();
    
    // 获取一周之前的历史数据
    const today = new Date();
    const oneWeekAgo = new Date(today.getTime() - 7 * 24 * 60 * 60 * 1000);
    
    const [rows] = await connection.execute(
      'SELECT * FROM todos WHERE date < ? ORDER BY date DESC, priority DESC, created_at DESC',
      [oneWeekAgo.toISOString().split('T')[0]]
    );
    
    connection.release();
    res.json(rows);
  } catch (error) {
    console.error('获取历史待办事项失败:', error);
    res.status(500).json({ error: '服务器错误' });
  }
});

// 获取最近一周的待办事项（排除挂起的）
app.get('/api/todos', authenticateToken, async (req, res) => {
  try {
    const connection = await pool.getConnection();
    
    // 获取最近一周的日期范围
    const today = new Date();
    const oneWeekAgo = new Date(today.getTime() - 7 * 24 * 60 * 60 * 1000);
    
    const [rows] = await connection.execute(
      'SELECT * FROM todos WHERE date >= ? AND date <= ? AND suspended = FALSE ORDER BY date DESC, priority DESC, created_at DESC',
      [oneWeekAgo.toISOString().split('T')[0], today.toISOString().split('T')[0]]
    );
    
    connection.release();
    res.json(rows);
  } catch (error) {
    console.error('获取待办事项失败:', error);
    res.status(500).json({ error: '服务器错误' });
  }
});

// 创建新的待办事项
app.post('/api/todos', authenticateToken, async (req, res) => {
  try {
    const { title, priority, date } = req.body;
    
    if (!title || !date) {
      return res.status(400).json({ error: '标题和日期是必需的' });
    }
    
    const connection = await pool.getConnection();
    
    const [result] = await connection.execute(
      'INSERT INTO todos (title, priority, date) VALUES (?, ?, ?)',
      [title, priority || 'medium', date]
    );
    
    const [newTodo] = await connection.execute(
      'SELECT * FROM todos WHERE id = ?',
      [result.insertId]
    );
    
    connection.release();
    res.status(201).json(newTodo[0]);
  } catch (error) {
    console.error('创建待办事项失败:', error);
    res.status(500).json({ error: '服务器错误' });
  }
});

// 更新待办事项状态
app.put('/api/todos/:id', authenticateToken, async (req, res) => {
  try {
    const { id } = req.params;
    const { completed } = req.body;
    
    const connection = await pool.getConnection();
    
    await connection.execute(
      'UPDATE todos SET completed = ? WHERE id = ?',
      [completed, id]
    );
    
    const [updatedTodo] = await connection.execute(
      'SELECT * FROM todos WHERE id = ?',
      [id]
    );
    
    connection.release();
    res.json(updatedTodo[0]);
  } catch (error) {
    console.error('更新待办事项失败:', error);
    res.status(500).json({ error: '服务器错误' });
  }
});

// 删除待办事项
app.delete('/api/todos/:id', authenticateToken, async (req, res) => {
  try {
    const { id } = req.params;
    
    const connection = await pool.getConnection();
    
    await connection.execute('DELETE FROM todos WHERE id = ?', [id]);
    
    connection.release();
    res.json({ success: true });
  } catch (error) {
    console.error('删除待办事项失败:', error);
    res.status(500).json({ error: '服务器错误' });
  }
});

// 挂起今天的待办事项
app.put('/api/todos/:id/suspend', authenticateToken, async (req, res) => {
  try {
    const { id } = req.params;
    const today = new Date().toISOString().split('T')[0];
    
    const connection = await pool.getConnection();
    
    // 检查是否是今天的待办事项
    const [todoCheck] = await connection.execute(
      'SELECT * FROM todos WHERE id = ? AND date = ?',
      [id, today]
    );
    
    if (todoCheck.length === 0) {
      connection.release();
      return res.status(400).json({ error: '只能挂起今天的待办事项' });
    }
    
    // 更新挂起状态
    await connection.execute(
      'UPDATE todos SET suspended = TRUE, suspended_date = ? WHERE id = ?',
      [today, id]
    );
    
    const [updatedTodo] = await connection.execute(
      'SELECT * FROM todos WHERE id = ?',
      [id]
    );
    
    connection.release();
    res.json(updatedTodo[0]);
  } catch (error) {
    console.error('挂起待办事项失败:', error);
    res.status(500).json({ error: '服务器错误' });
  }
});

// 获取所有挂起的待办事项
app.get('/api/todos/suspended', authenticateToken, async (req, res) => {
  try {
    const connection = await pool.getConnection();
    
    const [rows] = await connection.execute(
      'SELECT * FROM todos WHERE suspended = TRUE ORDER BY suspended_date DESC, priority DESC, created_at DESC'
    );
    
    connection.release();
    res.json(rows);
  } catch (error) {
    console.error('获取挂起待办事项失败:', error);
    res.status(500).json({ error: '服务器错误' });
  }
});

// 恢复挂起的待办事项到今天
app.put('/api/todos/:id/resume', authenticateToken, async (req, res) => {
  try {
    const { id } = req.params;
    const today = new Date().toISOString().split('T')[0];
    
    const connection = await pool.getConnection();
    
    // 检查是否是挂起的待办事项
    const [todoCheck] = await connection.execute(
      'SELECT * FROM todos WHERE id = ? AND suspended = TRUE',
      [id]
    );
    
    if (todoCheck.length === 0) {
      connection.release();
      return res.status(400).json({ error: '待办事项未处于挂起状态' });
    }
    
    // 恢复待办事项到今天
    await connection.execute(
      'UPDATE todos SET suspended = FALSE, suspended_date = NULL, date = ?, completed = FALSE WHERE id = ?',
      [today, id]
    );
    
    const [updatedTodo] = await connection.execute(
      'SELECT * FROM todos WHERE id = ?',
      [id]
    );
    
    connection.release();
    res.json(updatedTodo[0]);
  } catch (error) {
    console.error('恢复待办事项失败:', error);
    res.status(500).json({ error: '服务器错误' });
  }
});

// 将历史未完成待办迁移到今天
app.post('/api/todos/migrate-pending', authenticateToken, async (req, res) => {
  try {
    const connection = await pool.getConnection();
    
    // 获取今天的日期
    const today = new Date().toISOString().split('T')[0];
    
    // 查找今天之前所有未完成且未挂起的待办事项
    const [pendingTodos] = await connection.execute(
      'SELECT * FROM todos WHERE date < ? AND completed = FALSE AND suspended = FALSE ORDER BY date DESC, priority DESC',
      [today]
    );
    
    let migratedCount = 0;
    
    // 将每个未完成的待办事项迁移到今天
    for (const todo of pendingTodos) {
      await connection.execute(
        'UPDATE todos SET date = ? WHERE id = ?',
        [today, todo.id]
      );
      migratedCount++;
    }
    
    connection.release();
    res.json({ 
      success: true, 
      migratedCount,
      message: `已迁移 ${migratedCount} 个未完成的待办事项到今天`
    });
  } catch (error) {
    console.error('迁移待办事项失败:', error);
    res.status(500).json({ error: '服务器错误' });
  }
});

// 启动服务器
app.listen(PORT, async () => {
  console.log(`服务器运行在端口 ${PORT}`);
  await initDatabase();
});