var exec = require('shelljs').exec;

var isWin = /^win/.test(process.platform);

var isPortOpen = function (port) {
    var cmd;
    if (isWin)
        cmd = 'netstat -an | find /i ":' + port + '" | find /i "listening"';
    else
        cmd = 'lsof -i:' + port + " | tail -n 1 | awk '{print $2}'";
    var portResponse = exec(cmd, {
        silent: true
    }).output;
    return portResponse ? false : true;
}

module.exports = function (startPort) {
    while (!isPortOpen(startPort)) {
        startPort += 1;
    }

    return startPort;
}