import mysql from 'mysql2/promise';

// 資料庫配置
const dbConfig = {
  host: process.env.DB_HOST || 'mysql.theaken.com',
  port: parseInt(process.env.DB_PORT || '33306'),
  user: process.env.DB_USER || 'root',
  password: process.env.DB_PASSWORD || 'zh6161168',
  database: process.env.DB_NAME || 'db_AI_scoring',
  charset: 'utf8mb4',
  timezone: '+08:00',
  acquireTimeout: 60000,
  timeout: 60000,
  reconnect: true,
  multipleStatements: true,
};

// 建立連接池
const pool = mysql.createPool({
  ...dbConfig,
  waitForConnections: true,
  connectionLimit: 10,
  queueLimit: 0,
});

// 資料庫連接函數
export async function getConnection() {
  try {
    const connection = await pool.getConnection();
    return connection;
  } catch (error) {
    console.error('資料庫連接失敗:', error);
    throw error;
  }
}

// 執行查詢函數
export async function query(sql: string, params?: any[]) {
  try {
    const [rows] = await pool.execute(sql, params);
    return rows;
  } catch (error) {
    console.error('查詢執行失敗:', error);
    throw error;
  }
}

// 執行事務函數
export async function transaction(callback: (connection: mysql.PoolConnection) => Promise<any>) {
  const connection = await pool.getConnection();
  try {
    await connection.beginTransaction();
    const result = await callback(connection);
    await connection.commit();
    return result;
  } catch (error) {
    await connection.rollback();
    throw error;
  } finally {
    connection.release();
  }
}

// 測試資料庫連接
export async function testConnection() {
  try {
    const connection = await getConnection();
    await connection.ping();
    connection.release();
    console.log('✅ 資料庫連接成功');
    return true;
  } catch (error) {
    console.error('❌ 資料庫連接失敗:', error);
    return false;
  }
}

export default pool;