/**
 * connect mysql using ssh port forwarding
 *
 **/
'use strict';

const mysql = require('mysql');
let dbConfig = {
	host: 'dbhost',
	user: 'user_name',
	password: 'password',
	database: 'db_name',
	port: 3306
};

function _forwardingConnect(dbParam, callback)
{
	const freeport = require('freeport');
	const tunnel   = require('tunnel-ssh');
	const fs       = require('fs');
	let portForwardingConfig = {
		username: 'ssh_user_name',
		port: 22,
		host: "0.0.0.0", // SSH IP
		privateKey: fs.readFileSync('./id_rsa'),
		dstHost: dbParam.host,
		dstPort: 3306,
		srcHost: 'localhost',
		srcPort: null,
		localHost: 'localhost',
		localPort: null,
		keepAlive: true
	};
	dbParam.host = "localhost";
	freeport((err, freePort) => {
		// change port
		portForwardingConfig.srcPort = freePort;
		portForwardingConfig.localPort = freePort;
		dbParam.port = freePort;
		// tunneling
		tunnel(portForwardingConfig, (sshTunnel) => {
			var _dbConn = mysql.createConnection(dbParam);
			_dbConn.connect();
			callback(_dbConn);
		});
	});
};

const getConn = ((callback) => {
	_forwardingConnect(dbConfig, callback);
});

exports.getConn = getConn;