const mysql = require('mysql2/promise');

const dbConfig = {
  host: 'rm-t4na9qj85v7790tf84o.mysql.singapore.rds.aliyuncs.com',
  port: 3306,
  user: 'crawler_admin',
  password: 'cyber#crawler_2023',
  database: 'tools_auto_access',
  charset: 'utf8mb4',
  timezone: '+08:00',
  acquireTimeout: 60000,
  timeout: 60000,
  reconnect: true
};

let pool;

const createPool = () => {
  pool = mysql.createPool({
    ...dbConfig,
    waitForConnections: true,
    connectionLimit: 10,
    queueLimit: 0
  });

  console.log('Database pool created');
  return pool;
};

const getConnection = async () => {
  if (!pool) {
    createPool();
  }
  return await pool.getConnection();
};

const executeQuery = async (sql, params = []) => {
  const connection = await getConnection();
  try {
    const [rows] = await connection.execute(sql, params);
    return rows;
  } catch (error) {
    console.error('Database query error:', error);
    throw error;
  } finally {
    connection.release();
  }
};

module.exports = {
  createPool,
  getConnection,
  executeQuery
};