var argv = require('minimist')(process.argv.slice(2));
var exec = require('child_process').execSync;

// 1: Get usb/serial ports
try {
    var ports = exec('ls /dev/*usb*', {'stdio':'pipe'});
} catch (e) {
    console.error('No USB ports/devices detected');
    // console.log(e.stderr.toString());
    return 1
}

ports = ports.toString().trim().split("\n");

// 2: Check for port-by-list-index
if ('i' in argv) {
    let i = parseInt(argv['i'], 10);

    if (isNaN(i) || i >= ports.length){
        console.error(`invalid index: ${argv['i']}`);
        return 1;
    }
    console.log(ports[i]);
}

// 3. default: list ports
console.log('...................................................')
for (i=0; i<= ports.length-1; i++) {
    console.log(i + ': ' + ports[i]);
}
console.log('...................................................')