import * as portastic from 'portastic';

const pollInterval = 500;

export function waitUntilPortState(port: number, iface: string, isListening: boolean, timeoutMs: number, callback: (err: any) => void) {

if (!(timeoutMs > 0)) {

throw new Error(`Timed out waiting for port ${ port } to become ${ isListening ? 'in use' : 'free' }`);

}

portastic.test(port, iface).then(

actuallyIsAvailable => {

const actuallyIsListening = !actuallyIsAvailable;

if (actuallyIsListening === isListening) {

// Desired state is reached

callback(null);

} else {

// Wait longer

setTimeout(() => {

waitUntilPortState(port, iface, isListening, timeoutMs - pollInterval, callback);

}, pollInterval);

}

},

callback

)

}