SENG302/src/main/java/seng302/Networking/BinaryMessageDecoder.java

package seng302.Networking;

import seng302.Networking.MessageDecoders.*;
import seng302.Networking.Utils.*;

import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.Arrays;
import java.util.zip.CRC32;

/**
 * Created by hba56 on 21/04/17.
 */
public class BinaryMessageDecoder {
    private byte[] fullMessage;
    private byte[] header;
    private byte[] message;
    private byte[] crc;

    private byte headerSync1;
    private byte headerSync2;
    private byte headerMessageType;
    private byte[] headerTimeStamp;
    private byte[] headerSourceID;
    private byte[] headerMessageLength;


    public BinaryMessageDecoder(byte[] fullMessage) {
        this.fullMessage = fullMessage;
    }

    public AC35Data decode() throws IndexOutOfBoundsException{
        //get the header
        this.header = Arrays.copyOfRange(this.fullMessage, 0, 15);

        this.headerSync1 = this.header[0];
        this.headerSync2 = this.header[1];
        this.headerMessageType = this.header[2];
        this.headerTimeStamp = Arrays.copyOfRange(this.header, 3, 9);
        this.headerSourceID = Arrays.copyOfRange(this.header, 9, 13);
        this.headerMessageLength = Arrays.copyOfRange(this.header, 13, 15);

        if (15 > this.fullMessage.length - 4){
            //System.err.println("Message is too short.");
            return null;
        }
        //get message
        this.message = Arrays.copyOfRange(this.fullMessage, 15, this.fullMessage.length - 4);

        //get crc
        this.crc = Arrays.copyOfRange(this.fullMessage, this.fullMessage.length - 4, fullMessage.length);


        CRC32 crc = new CRC32();
        crc.reset();
        crc.update(this.fullMessage);

        //run through the checks
        if (this.message.length != twoByteToInt(this.headerMessageLength) && this.message.length != twoByteToIntBE(this.headerMessageLength)){
            System.err.println("message length in header does not equal the message length");
            System.err.println("message length in header: " + twoByteToInt(this.headerMessageLength));
            System.err.println("message length: " + this.message.length);
            return null;
        }else if(this.headerSync1 != 0x47){
            System.err.println("Sync byte 1 is wrong");
            return null;
        }else if(this.headerSync2 !=(byte) 0x83){
            System.err.println("Sync byte 2 is wrong");
            return null;
        }/*else if(crc.getValue() != 0){
            //todo check crc
            System.err.println("CRC is not 0 and is instead:" + crc.getValue());
            return;
        }*/

        MessageType mType = MessageType.valueOf(this.headerMessageType);
        AC35Data data = null;

        switch(mType){
            case HEARTBEAT:
                System.out.println("HeartBeat Message!");
                data = new Heartbeat();
                break;
            case RACESTATUS:
                System.out.println("Race Status Message");
                RaceStatusDecoder rsdecoder = new RaceStatusDecoder(this.message);
                data = new RaceStatus(rsdecoder.getTime(), rsdecoder.getRace(), rsdecoder.getRaceState(), rsdecoder.getStartTime(), rsdecoder.getRaceWindDir(), rsdecoder.getRaceWindSpeed(), rsdecoder.getRaceType(), rsdecoder.getBoats());
                break;
            case DISPLAYTEXTMESSAGE:
                System.out.println("Display Text Message");
                //no decoder for this.
                break;
            case XMLMESSAGE:
                System.out.println("XML Message!");
                XMLMessageDecoder xmdecoder = new XMLMessageDecoder(this.message);
                xmdecoder.decode();
                data = new XMLMessage(xmdecoder.getAckNumber(), xmdecoder.getTimeStamp(), xmdecoder.getXmlMsgSubType(), xmdecoder.getSequenceNumber(), xmdecoder.getXmlMsgLength(), xmdecoder.getXmlMessageInputSource());
                break;
            case RACESTARTSTATUS:
                System.out.println("Race Start Status Message");
                RaceStartStatusDecoder rssDecoder = new RaceStartStatusDecoder(this.message);
                data = new RaceStartStatus(rssDecoder.getTime(), rssDecoder.getAck(), rssDecoder.getStartTime(), rssDecoder.getRaceID(), rssDecoder. getNotification());
                break;
            case YACHTEVENTCODE:
                System.out.println("Yacht Action Code!");
                //no decoder
                break;
            case YACHTACTIONCODE:
                System.out.println("Yacht Action Code!");
                //no decoder
                break;
            case CHATTERTEXT:
                System.out.println("Chatter Text Message!");
                //no decoder
                break;
            case BOATLOCATION:
                System.out.println("Boat Location Message!");
                BoatLocationDecoder blDecoder = new BoatLocationDecoder(this.message);
                data = blDecoder.getMessage();
                break;
            case MARKROUNDING:
                System.out.println("Mark Rounding Message!");
                MarkRoundingDecoder mrDecoder = new MarkRoundingDecoder(this.message);
                data = mrDecoder.getMarkRounding();
                break;
            case COURSEWIND:
                System.out.println("Couse Wind Message!");
                CourseWindDecoder cwDecoder = new CourseWindDecoder(this.message);
                data =new CourseWinds(cwDecoder.getMessageVersionNumber(), cwDecoder.getByteWindID(), cwDecoder.getLoopMessages());
                break;
            case AVGWIND:
                System.out.println("Average Wind Message!");
                AverageWindDecoder awDecoder = new AverageWindDecoder(this.message);
                data = awDecoder.getAverageWind();
                break;
            default:
                System.out.println("Broken Message!");
                break;
        }

        return data;
    }


    private short bytesToShort(byte[] bytesShort){
        ByteBuffer wrapped = ByteBuffer.wrap(bytesShort);
        short num = wrapped.getShort();
        return num;
    }

    private int bytesToInt(byte[] bytesInt){
        ByteBuffer wrapped = ByteBuffer.wrap(bytesInt);
        int num = wrapped.getInt();
        return num;
    }

    private int twoByteToInt(byte[] bytesInt){
        byte[] bytes = new byte[2];
        bytes[1] = bytesInt[0];
        bytes[0] = bytesInt[1];
        int num = ByteBuffer.wrap(bytes).getShort();

        return num;
    }

    private int twoByteToIntBE(byte[] bytesInt){
        ByteBuffer byteBuffer = ByteBuffer.allocate(4);
        byteBuffer.order(ByteOrder.BIG_ENDIAN);
        byteBuffer.put((byte)0);
        byteBuffer.put((byte)0);
        byteBuffer.put(bytesInt);
        int num = byteBuffer.getInt(0);
        return num;
    }

    private long bytesToLong(byte[] bytesLong){
        ByteBuffer byteBuffer = ByteBuffer.allocate(8);
        byteBuffer.order(ByteOrder.BIG_ENDIAN);
        byteBuffer.put((byte)0);
        byteBuffer.put((byte)0);
        byteBuffer.put(bytesLong[0]);
        byteBuffer.put(bytesLong[1]);
        byteBuffer.put(bytesLong[2]);
        byteBuffer.put(bytesLong[3]);
        byteBuffer.put(bytesLong[4]);
        byteBuffer.put(bytesLong[5]);
        long longVal = byteBuffer.getLong(0);
        return longVal;
    }

    public long getTimeStamp() {
        return bytesToLong(this.headerTimeStamp);
    }

    public int getSourceID() {
        return bytesToInt(this.headerSourceID);
    }

    public short getMessageLength() {
        return bytesToShort(this.headerMessageLength);
    }

    public int getMessageType(){
        return (int) this.headerMessageType;
    }

    public byte[] getMessage() {
        return message;
    }
}