package com.company;

import java.io.*;
import java.io.IOException;
import java.net.*;
import java.net.InetAddress;
import java.net.MulticastSocket;
import java.net.SocketTimeoutException;
import java.util.*;
import java.util.Map;

public class Main {

    public static void main(String[] args) throws IOException {
        String message = "";
        byte[] sendPacket = message.getBytes();
        byte[] rcvPacket = new byte[0];

        //сохраняем инет-адрес + время получения сообщения
        Map<String, Long> messageMap = new HashMap<>();


        MulticastSocket multicastSocket = new MulticastSocket(8000);
        InetAddress inetGroupAddress = InetAddress.getByName("224.1.1.1");
        multicastSocket.joinGroup(inetGroupAddress);

        DatagramPacket datagramSendPacket = new DatagramPacket(sendPacket, sendPacket.length, inetGroupAddress, 8000 );
        DatagramPacket datagramRcvPacket = new DatagramPacket(rcvPacket, rcvPacket.length);

        InetAddress currentAddress = InetAddress.getByName("192.168.145.1");
        messageMap.put(currentAddress.getHostAddress(), System.currentTimeMillis());
        //System.out.println(multicastSocket.getLocalAddress());
        //пускаем в цикл
        long timeout = 2000;
        multicastSocket.setSoTimeout((int)timeout);
        // multicastSocket.setTimeToLive(20);
        while (true) {
            multicastSocket.send(datagramSendPacket);
            //получаем время последнего отправления пакета
            long sendTime = System.currentTimeMillis();

            while (timeout - (System.currentTimeMillis() - sendTime) > 0) {
                //multicastSocket.setSoTimeout((int) (timeout - (System.currentTimeMillis() - sendTime)));
                multicastSocket.setSoTimeout((Long.valueOf(timeout - (System.currentTimeMillis() - sendTime))).intValue() + 1);

                try {
                    multicastSocket.receive(datagramRcvPacket);
                } catch (SocketTimeoutException exception) {
                    continue;
                    //exception.printStackTrace();
                    //throw new IllegalStateException("Can't set socket timeout", exception);
                }

                String inetRcvAddress = datagramRcvPacket.getAddress().getHostAddress();
                Long appearedEarlier = messageMap.put(inetRcvAddress, System.currentTimeMillis());
                System.out.println(inetRcvAddress);
                System.out.println(datagramSendPacket.getAddress().getHostAddress());
                if (appearedEarlier == null) {
                    System.out.println("Another clone appeared!!");
                } else System.out.println("No clone appeared!");

            }
        }
        // multicastSocket.leaveGroup(inetAddress);

    }
}