package jp.ac.u_ryukyu.treevnc;

import com.glavsoft.rfb.protocol.ProtocolContext.TreeCommand;
import com.glavsoft.rfb.protocol.ReceiverTask;
import com.glavsoft.transport.Reader;
import com.glavsoft.viewer.ViewerInterface;
import com.glavsoft.viewer.swing.ConnectionParams;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.net.*;

import static com.glavsoft.rfb.protocol.ReceiverTask.FRAMEBUFFER_UPDATE;

public class TreeRootFinderListener implements Runnable {
    public static final String Ipv4McastAddr = "224.0.0.1";
    public static final String Ipv6McastAddr = "ff02::1";
    public static String McastAddr = Ipv4McastAddr;

	static final int BufSize = 1024;
	private boolean stopFlag = false;
	private ViewerInterface vps;
	private MulticastSocket soc;
	private SecurityManager securityManager;

	public TreeRootFinderListener(ViewerInterface vncProxyService) {
		vps = vncProxyService;
		try {
			soc = createMulticastSocket();
			System.out.println("FindRoot listening on "+ InetAddress.getByName(McastAddr));
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

    public static MulticastSocket createMulticastSocket() throws IOException {
        MulticastSocket soc = new MulticastSocket(ConnectionParams.DEFAULT_VNC_ROOT_FINDER);
		try {
			soc.joinGroup(InetAddress.getByName(McastAddr));
		} catch (SocketException e) {
			System.out.println("join to " +  Ipv4McastAddr + " failed.");
		}
		try {
			soc.joinGroup(InetAddress.getByName(Ipv6McastAddr));
		} catch (SocketException e) {
			System.out.println("join to " +  Ipv6McastAddr + " failed.");
		}
        return soc;
    }

    /**
	 * To find TreeVNC root, a client sends me a multicast, reply our address to him.
	 *  It contains a port to receive, so multiple TREEVNC clients can run on a PC. 
	 */
	private void replyToRootSearchMulticast() {
		byte[] buf = new byte[BufSize];
		try {

            DatagramPacket recvPacket = new DatagramPacket(buf, BufSize);
            while (!stopFlag) {
				soc.receive(recvPacket);
				String hostname = recvPacket.getAddress().getHostAddress();
		        byte[] reply = recvPacket.getData();
				int len = recvPacket.getLength();
				boolean isTreeRoot = vps.getRfb().isTreeManager();
				if (isTreeRoot && len == 12 && (reply[0] & 0xff) == TreeCommand.FIND_ROOT.cmd) {
					int port = reply[8];
					port = port * 256 + reply[9];
					port = port * 256 + reply[10];
					port = port * 256 + reply[11];

					TreeVncProtocol t = new TreeVncProtocol(hostname, port);
					t.findRootReply(vps.getRfb().getAcceptPort());
				}
			}
		} catch (Exception e) {
            System.out.println("tree-root-find-listener :" + e.getMessage());
		}
	}

    public void run() {
		replyToRootSearchMulticast();
	}

    // it looks like that we never stop
	public void setStopFlag(boolean stopFlag) {
		this.stopFlag = stopFlag;
	}

	public boolean isStopFlag() {
		return stopFlag;
	}

	public MulticastSocket getSocket() {
		return soc;
	}
}