DCDirectTerminalDetector.swift

import Foundation
import BrightFutures
import Result
import CocoaAsyncSocket

// "CocoaAsyncSocket" is a socket library
// Ref: https://github.com/robbiehanson/CocoaAsyncSocket

class DCDirectTerminalDetector: NSObject, GCDAsyncUdpSocketDelegate {
    
    static let queue = DispatchQueue(
        label: "com.app.DCDirectTerminalDetector", attributes: []
    )
    
    var socket: GCDAsyncUdpSocket!
    
    let broadcastPort: UInt16 = 9001
    let broadcastHost: String = "255.255.255.255"
    let broadcastTimeout = 5.0

    override init() {
        super.init()
        socket = GCDAsyncUdpSocket(
            delegate: self,
            delegateQueue: DCDirectTerminalDetector.queue
        )
    }
    
    func broadcastMessage() {
        do {
            try socket.bind(toPort: broadcastPort)
            try socket.enableBroadcast(true)
            try socket.beginReceiving()
            
            // The one on the label-
            // IPSN: 3201141914844303
            // IPSN: 3011087720077752
            
            // The one on the device-
            // S/N: 183567303261086003685327
            // S/N: 210787313031070220075924
            
            let data = "Who has 3011087720077752".data(using: .utf8)!
            socket.send(data, toHost: broadcastHost, port: broadcastPort, withTimeout: broadcastTimeout, tag: 0)
        } catch {
            print("Failed to send message \(error)")
        }
    }
    
    // MARK:- GCDAsyncUdpSocketDelegate
    
    func udpSocket(_ sock: GCDAsyncUdpSocket, didReceive data: Data, fromAddress address: Data, withFilterContext filterContext: Any?) {
        let parsedData = String(data: data, encoding: .utf8)
        let parsedAddress = String(data: address, encoding: .utf8)

        Log.debug("parsedData \(String(describing: parsedData))") // Output- parsedData Optional("Who has 3011087720077752")
        Log.debug("parsedAddress \(String(describing: parsedAddress))") // Output- parsedAddress nil
        
    }
    
}