const mysql = require('mysql2/promise');
require('dotenv').config();

const pool = mysql.createPool({
  host: process.env.DB_HOST || 'localhost',
  user: process.env.DB_USER || 'root',
  password: process.env.DB_PASSWORD || '123456',
  database: process.env.DB_NAME || 'score_management',
  waitForConnections: true,
  connectionLimit: 10,
  queueLimit: 0
});

// 测试数据库连接
async function testConnection() {
  try {
    const connection = await pool.getConnection();
    console.log('数据库连接成功');
    connection.release();
    return true;
  } catch (error) {
    console.error('数据库连接失败:', error.message);
    return false;
  }
}

// 执行查询
async function query(sql, params) {
  try {
    const [rows] = await pool.execute(sql, params);
    return rows;
  } catch (error) {
    console.error('数据库查询错误:', error.message);
    throw error;
  }
}

// 执行事务
async function executeTransaction(operations) {
  const connection = await pool.getConnection();
  try {
    await connection.beginTransaction();
    
    for (const operation of operations) {
      await connection.execute(operation.sql, operation.params);
    }
    
    await connection.commit();
    console.log('事务执行成功');
  } catch (error) {
    await connection.rollback();
    console.error('事务执行失败:', error.message);
    throw error;
  } finally {
    connection.release();
  }
}

module.exports = {
  pool,
  query,
  executeTransaction,
  testConnection
};