sdis1819-t4g14

package main.java.utils;

import main.java.file.FileChunk;

import main.java.file.FileChunkID;

import main.java.file.FileID;

import main.java.peer.Peer;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.net.*;

import java.security.MessageDigest;

import java.util.Enumeration;

import java.util.regex.Pattern;

import static main.java.utils.Constants.*;

public class Utilities {

    public static String sha256(String base) {

        try{

            MessageDigest digest = MessageDigest.getInstance("SHA-256");

            byte[] hash = digest.digest(base.getBytes("UTF-8"));

            StringBuffer hexString = new StringBuffer();

            for (int i = 0; i < hash.length; i++) {

                String hex = Integer.toHexString(0xff & hash[i]);

                if(hex.length() == 1) hexString.append('0');

                hexString.append(hex);

            }

            return hexString.toString();

        } catch(Exception ex){

            throw new RuntimeException(ex);

        }

    }

    public static InetAddress getLocalAddress() throws IOException

    {

        MulticastSocket socket = new MulticastSocket();

        socket.setTimeToLive(0);

        InetAddress addr = InetAddress.getByName("225.0.0.0");

        socket.joinGroup(addr);

        byte[] bytes = new byte[0];

        DatagramPacket packet = new DatagramPacket(bytes, bytes.length, addr,

                socket.getLocalPort());

        socket.send(packet);

        socket.receive(packet);

        socket.close();

        return packet.getAddress();

    }

    public static boolean validateAccessPoint(String peerAP) {

        Pattern pattern;

        pattern = Pattern.compile("^([0-9]{1,3}\\.){3}[0-9]{1,3}(\\/([A-Z]|[a-z])+)?$");

        if(!pattern.matcher(peerAP).matches()) {

            System.out.println("Invalid Access Point!");

            return false;

        }

        return true;

    }

    //TODO: CONFIRM MESSAGES ARE AS SPECIFIED IN DOCUMENT <- IMPORTANT FOR INTEROPERABILITY

    public static byte[] messageConstructor(String protocol, FileChunk chunk, FileChunkID chunkID, FileID fileID) {

        String message = "default";

        byte[] msgToSend = new byte[0];

        //TODO: chunkgetChunkData() only works for txt. message could be byte[]?

        switch (protocol) {

            case "PUTCHUNK":

                message = PUTCHUNK + MESSAGE_SEPARATOR;

                message += Peer.getProtocolVersion() + MESSAGE_SEPARATOR;

                message += Peer.getID() + MESSAGE_SEPARATOR;

                message += chunk.getFileID() + MESSAGE_SEPARATOR;

                message += chunk.getChunkNo() + MESSAGE_SEPARATOR;

                message += chunk.getReplicationDegree() + MESSAGE_SEPARATOR;

                message += CRLF + CRLF;

                msgToSend = concatBytes(message.getBytes(), chunk.getChunkData());

                break;

            case "STORED":

                message = STORED + MESSAGE_SEPARATOR;

                message += Peer.getProtocolVersion() + MESSAGE_SEPARATOR;

                message += Peer.getID() + MESSAGE_SEPARATOR;

                message += chunkID.getFileID() + MESSAGE_SEPARATOR;

                message += chunkID.getChunkNumber() + MESSAGE_SEPARATOR;

                message += CRLF + CRLF;

                msgToSend = message.getBytes();

                break;

            case "REMOVED":

                message = REMOVED + MESSAGE_SEPARATOR;

                message += Peer.getProtocolVersion() + MESSAGE_SEPARATOR;

                message += Peer.getID() + MESSAGE_SEPARATOR;

                message += chunkID.getFileID() + MESSAGE_SEPARATOR;

                message += chunkID.getChunkNumber() + MESSAGE_SEPARATOR;

                message += CRLF + CRLF;

                msgToSend = message.getBytes();

                break;

            case "DELETE":

                message = DELETE + MESSAGE_SEPARATOR;

                message += Peer.getProtocolVersion() + MESSAGE_SEPARATOR;

                message += Peer.getID() + MESSAGE_SEPARATOR;

                message += fileID.toString() + MESSAGE_SEPARATOR;

                message += CRLF+CRLF;

                msgToSend = message.getBytes();

                break;

            case "GETCHUNK":

                message = GETCHUNK + MESSAGE_SEPARATOR;

                message += Peer.getProtocolVersion() + MESSAGE_SEPARATOR;

                message += Peer.getID() + MESSAGE_SEPARATOR;

                message += chunkID.getFileID() + MESSAGE_SEPARATOR;

                message += chunkID.getChunkNumber() + MESSAGE_SEPARATOR;

                message += CRLF + CRLF;

                msgToSend = message.getBytes();

                break;

            case "CHUNK":

                message = CHUNK + MESSAGE_SEPARATOR;

                message += Peer.getProtocolVersion() + MESSAGE_SEPARATOR;

                message += Peer.getID() + MESSAGE_SEPARATOR;

                message += chunk.getFileID().toString() + MESSAGE_SEPARATOR;

                message += chunkID.getChunkNumber() + MESSAGE_SEPARATOR;

                message += CRLF + CRLF;

                msgToSend = concatBytes(message.getBytes(), chunk.getChunkData());

                break;

        }

        return msgToSend;

    }

    public static byte[] concatBytes(byte[] a, byte[] b) {

        int aLen = a.length;

        int bLen = b.length;

        byte[] c = new byte[aLen + bLen];

        System.arraycopy(a, 0, c, 0, aLen);

        System.arraycopy(b, 0, c, aLen, bLen);

        return c;

    }

}