SDIS1819-T2G01

import java.net.DatagramPacket;

import java.net.InetAddress;

public class Message {

    private static final String CRLF = "\r\n";

    public String header;

    public byte[] body;

    public enum MessageType {

        PUTCHUNK, STORED, GETCHUNK, CHUNK, DELETE, REMOVED

    };

    public MessageType type;

    public Message() {

    }

    // Build a message

    public Message(MessageType type, String senderId, String fileId, int chunkN, int replicationDeg, byte[] bytes) {

        // Reset body

        body = new byte[0];

        // Add chunk

        body = bytes;

        // Assign type

        this.type = type;

        // Prepare type

        switch (type) {

        case PUTCHUNK:

            header = "PUTCHUNK";

            break;

        case STORED:

            header = "STORED";

            break;

        case GETCHUNK:

            header = "GETCHUNK";

            break;

        case CHUNK:

            header = "CHUNK";

            break;

        case DELETE:

            header = "DELETE";

            break;

        case REMOVED:

            header = "REMOVED";

            break;

        default:

            break;

        }

        // Version, SenderId and FileId are shared

        // TODO hardcoded version 1.0

        header += " 1.0";

        header += " " + senderId;

        header += " " + fileId;

        // Remaining message header

        // Technically it would be more efficient to add chunkN to all types and remove

        // in DELETE but eh

        switch (type) {

        case PUTCHUNK:

            header += " " + Integer.toString(chunkN);

            header += " " + Integer.toString(replicationDeg);

            break;

        case STORED:

            header += " " + Integer.toString(chunkN);

            break;

        case GETCHUNK:

            header += " " + Integer.toString(chunkN);

            break;

        case CHUNK:

            header += " " + Integer.toString(chunkN);

            break;

        case DELETE:

            // Nothing to add

            break;

        case REMOVED:

            header += " " + Integer.toString(chunkN);

            break;

        default:

            break;

        }

        // Finalize with double CRLF

        header += CRLF + CRLF;

    }

    // Pack a datagram from message

    public DatagramPacket packit(InetAddress address, int port) {

        byte[] headerBytes = header.getBytes();

        byte[] full = new byte[headerBytes.length + body.length];

        System.arraycopy(headerBytes, 0, full, 0, headerBytes.length);

        System.arraycopy(body, 0, full, headerBytes.length, body.length);

        DatagramPacket packet = new DatagramPacket(full, full.length, address, port);

        return packet;

    }

}