package seng302.Networking;


import seng302.Networking.Utils.MessageType;

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

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

    private byte headerSync1 = (byte) 0x47;
    private byte headerSync2 = (byte) 0x83;
    private byte headerMessageType;
    private long headerTimeStamp;
    private int headerSourceID;
    private short headerMessageLength;

    public BinaryMesageEncoder(MessageType headerMessageType, long headerTimeStamp, int headerSourceID, short headerMessageLength, byte[] message) {
        //set the header
        this.headerMessageType = headerMessageType.getValue();
        this.headerTimeStamp = headerTimeStamp;
        this.headerSourceID = headerSourceID;
        this.headerMessageLength = headerMessageLength;

        ByteBuffer tempHeaderByteBuffer = ByteBuffer.allocate(15);
        tempHeaderByteBuffer.put(this.headerSync1);
        tempHeaderByteBuffer.put(this.headerSync2);
        tempHeaderByteBuffer.put(this.headerMessageType);
        tempHeaderByteBuffer.put(longToSixBytes(this.headerTimeStamp));
        tempHeaderByteBuffer.putInt(this.headerSourceID);
        tempHeaderByteBuffer.put(shortToBytes(this.headerMessageLength));


        this.header = tempHeaderByteBuffer.array();

        //set the message
        this.message = message;

        //set full message
        ByteBuffer tempMessageByteBuffer = ByteBuffer.allocate(19 + this.headerMessageLength);
        tempMessageByteBuffer.put(this.header);
        tempMessageByteBuffer.put(this.message);

        CRC32 crc = new CRC32();
        crc.reset();
        byte[] messageAndHeader = new byte[this.header.length + this.message.length];
        System.arraycopy(this.header, 0, messageAndHeader, 0, this.header.length);
        System.arraycopy(this.message, 0, messageAndHeader, this.header.length, this.message.length);
        crc.update(messageAndHeader);
        //System.out.println(Arrays.toString(messageAndHeader));

        tempMessageByteBuffer.put(intToBytes((int) crc.getValue()));
        this.fullMessage = tempMessageByteBuffer.array();


    }

    private byte[] longToSixBytes(long x) {
        ByteBuffer buffer = ByteBuffer.allocate(Long.BYTES);
        buffer.putLong(x);
        return Arrays.copyOfRange(buffer.array(), 2, 8);
    }

    private byte[] shortToBytes(short x) {
        ByteBuffer buffer = ByteBuffer.allocate(Short.BYTES);
        buffer.putShort(x);
        return buffer.array();
    }

    private byte[] intToBytes(int x) {
        ByteBuffer buffer = ByteBuffer.allocate(Integer.BYTES);
        buffer.putInt(x);
        return buffer.array();
    }

    public byte[] getFullMessage() {
        return fullMessage;
    }
}