sdis1819-t7g05

import java.io.File;

import java.io.IOException;

import java.net.DatagramPacket;

import java.net.InetAddress;

import java.net.MulticastSocket;

import java.util.Arrays;

/**

 * MDBListener

 */

public class MDBListener implements Runnable {

    private static final int PACKET_SIZE = 65000; //65KBytes, just enough space for the chunk itself

    private MulticastSocket socket;

    private InetAddress address;

    private int port;

    private int serverId;

    private InetAddress MCaddress;

    private int MCport;

    private Peer peer;

    MDBListener(InetAddress address, int port, int serverId, InetAddress MCaddress, int MCport, Peer peer) throws IOException {

        this.address = address;

        this.port = port;

        this.serverId = serverId;

        this.MCaddress = MCaddress;

        this.MCport = MCport;

        this.peer = peer;

        socket = new MulticastSocket(port);

        socket.joinGroup(this.address);

    }

    @Override

    public void run() {

        print("MDB-Listener started: Address-"+this.address.getHostName()+" Port-"+this.port);

        while (true) {

            byte[] buf = new byte[PACKET_SIZE];

            DatagramPacket packet = new DatagramPacket(buf, buf.length);

            try {

                socket.receive(packet);

                parseMessage(Arrays.copyOfRange(buf, 0, packet.getLength()));

            } catch (IOException e) {

                e.printStackTrace();

            }

        }

    }

    private void parseMessage(byte[] data) {

        String message = new String(data);

        String[] args = message.split(" ");

        switch (args[0]) {

            case "PUTCHUNK":

                                print("received PUTCHUNK message: <SenderId> "+args[2]+" <FileId> "+args[3]+" <ChunkNo> "+args[4]+" <replicationDeg> "+args[5]);

                                int headerLength = 0;

                                for(int i = 0; i < 6; i++)

                                        headerLength += args[i].length()+1;

                                headerLength += 4;

                byte[] body = Arrays.copyOfRange(data, headerLength, data.length);

                String fileId = args[3];

                int chunkNo = Integer.parseInt(args[4]);

                File chunk = new File("Peer-"+this.serverId+File.separator+"Chunks"+File.separator+fileId+File.separator+chunkNo);

                if (Integer.parseInt(args[2]) == this.serverId) {

                    print("The initiator-peer can't store the chunks himself!");

                    return;

                }

                if(chunk.exists()){

                    print("Chunk already exists");

                    return;

                }

                new Thread(new PutChunkTask(args, this.MCaddress, this.MCport, this, this.peer, body)).start();

                print("starting PUTCHUNK protocol");

                break;

            default:

                break;

        }

    }

    public void print(String message) {

        System.out.println("[PEER-"+this.serverId+"-MDB] "+message);

    }

}