const mysql = require('mysql2/promise');
const { Client } = require('ssh2');

let pool;

async function setupSshTunnel() {
  const sshConfig = {
    host: process.env.PROD_SSH_HOST,
    port: process.env.PROD_SSH_PORT || 22,
    username: process.env.PROD_SSH_USER,
    privateKey: process.env.PROD_SSH_KEY_PATH
      ? require('fs').readFileSync(process.env.PROD_SSH_KEY_PATH)
      : undefined,
    compress: true
  };

  return new Promise((resolve, reject) => {
    const ssh = new Client();

    ssh.on('error', (err) => {
      console.error('SSH connection error:', err);
      reject(err);
    });

    ssh.on('ready', () => {
      ssh.forwardOut(
        '127.0.0.1',
        0,
        process.env.PROD_DB_HOST || 'localhost',
        process.env.PROD_DB_PORT || 3306,
        (err, stream) => {
          if (err) reject(err);
          resolve({ ssh, stream });
        }
      );
    }).connect(sshConfig);
  });
}

async function initPool(config) {
  try {
    const tunnel = await setupSshTunnel();
    
    pool = mysql.createPool({
      ...config,
      stream: tunnel.stream,
      host: process.env.PROD_DB_HOST || 'localhost',
      user: process.env.PROD_DB_USER,
      password: process.env.PROD_DB_PASSWORD,
      database: process.env.PROD_DB_NAME,
      port: process.env.PROD_DB_PORT || 3306
    });

    // Test the connection
    const connection = await pool.getConnection();
    console.log('[Database] Connected successfully through SSH tunnel');
    connection.release();

    return pool;
  } catch (error) {
    console.error('[Database] Error initializing pool:', error);
    throw error;
  }
}

async function getConnection() {
  if (!pool) {
    throw new Error('Database pool not initialized');
  }
  return pool.getConnection();
}

module.exports = {
  initPool,
  getConnection,
  getPool: () => pool
};