import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetAddress;
import java.net.SocketException;

public class Server {

	private final DatagramSocket socket;

	public Server(int port) throws SocketException {
		this.socket = new DatagramSocket(port);
		new Thread(this::readMessages).start();
	}

	public int getPort() {
		return this.socket.getLocalPort();
	}

	private void sendMessage(String message, InetAddress address, int port) throws IOException {
		byte[] buffer = message.getBytes();
		DatagramPacket packet = new DatagramPacket(buffer, buffer.length, address, port);
		this.socket.send(packet);
	}

	private void processHandshake(DatagramPacket packet) throws IOException {
		String message = new String(packet.getData(), 0, packet.getLength());
		String machineName = message.split(" ")[2];
		System.out.println("\t[Server] Nouveau client : @" + packet.getAddress().getHostAddress() + ": " + packet.getPort());
		sendMessage("Serveur " + machineName + " ready", packet.getAddress(), packet.getPort());
	}

	private void processMessage(DatagramPacket packet) throws IOException {
		String message = new String(packet.getData(), 0, packet.getLength());
		System.out.println("[Server] Message recieved : " + message);
		if (message.startsWith("hello serveur")) {
			processHandshake(packet);
			return;
		}
		sendMessage(message, packet.getAddress(), packet.getPort());
	}

	private void readMessages() {
		while (true) {
			byte[] buffer = new byte[1024];
			DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
			try {
				this.socket.receive(packet);
				processMessage(packet);
			} catch (IOException e) {
				e.printStackTrace();
				break;
			}
		}
	}

}