import { createPool } from 'mariadb';

async function handler(req, res) {
  if (req.method !== 'GET') {
    return res.status(405).json({ message: '只支持GET请求' });
  }

  const { startDate, endDate, limit } = req.query;

  let pool;
  try {
    pool = createPool({
      host: process.env.DB_HOST || '192.168.111.111',
      port: parseInt(process.env.DB_PORT || '3306'),
      user: process.env.DB_USER || 'root',
      password: process.env.DB_PASSWORD || 'fullstack',
      database: process.env.DB_NAME || 'iboard',
      connectionLimit: 5
    });

    let query = 'SELECT date, close FROM econ_SH300Index';
    const params = [];
    const conditions = [];

    if (startDate && endDate) {
      conditions.push('date BETWEEN ? AND ?');
      params.push(startDate, endDate);
    }

    if (conditions.length > 0) {
      query += ' WHERE ' + conditions.join(' AND ');
    }

    query += ' ORDER BY date DESC';

    const result = await pool.query(query, params);

    // 限制返回数量，默认为30
    const limitValue = limit ? parseInt(limit) : 30;
    const limitedResult = result.slice(0, limitValue);
    
    // 反转顺序，使日期从早到晚
    const sortedResult = limitedResult.reverse();

    const data = sortedResult.map(row => {
      let dateStr;
      if (row.date instanceof Date) {
        dateStr = row.date.toISOString().split('T')[0];
      } else if (typeof row.date === 'string') {
        dateStr = row.date;
      } else {
        dateStr = String(row.date);
      }
      return {
        date: dateStr,
        close: parseFloat(row.close)
      };
    });

    return res.status(200).json({
      success: true,
      data: data
    });

  } catch (error) {
    console.error('获取沪深300数据失败:', error);
    return res.status(500).json({
      success: false,
      message: '获取沪深300数据失败: ' + error.message
    });
  } finally {
    if (pool) {
      await pool.end();
    }
  }
}

export default handler;