/*
 * PEnetration TEsting Proxy (PETEP)
 *
 * Copyright (C) 2021 Michal Válka
 *
 * This program is free software: you can redistribute it and/or modify it under the terms of the
 * GNU General Public License as published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without
 * even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along with this program. If
 * not, see <https://www.gnu.org/licenses/>.
 */
package com.warxim.petep.extension.internal.udp.echo;

import lombok.RequiredArgsConstructor;
import lombok.extern.java.Log;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
import java.util.logging.Level;

import static com.warxim.petep.test.proxy.common.Constant.BUFFER_SIZE;

@Log
@RequiredArgsConstructor
public class TestUdpServer extends Thread {
    private final String ip;
    private final int port;
    private final int parallelConnections;

    public void run() {
        var executor = Executors.newFixedThreadPool(parallelConnections);

        try (var socket = new DatagramSocket(port, InetAddress.getByName(ip))) {
            while (true) {
                var buffer = new byte[BUFFER_SIZE];
                var packet = new DatagramPacket(buffer, buffer.length);
                socket.receive(packet);

                executor.submit(() -> handlePacket(socket, packet));
            }
        } catch (IOException e) {
            log.log(Level.SEVERE, "Exception in server!", e);
        }

        // Shutdown
        executor.shutdown();
        try {
            if (executor.awaitTermination(1, TimeUnit.MINUTES)) {
                return;
            }
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
        }
        executor.shutdownNow();
    }

    private void handlePacket(DatagramSocket socket, DatagramPacket packet) {
        try {
            var address = packet.getAddress();
            var port = packet.getPort();

            packet = new DatagramPacket(packet.getData(), packet.getLength(), address, port);

            socket.send(packet);
        } catch (IOException e) {
            log.log(Level.SEVERE, "Exception in server!", e);
        }
    }
}