package org.opendaylight.lispflowmapping.implementation.serializer;

import java.nio.ByteBuffer;
import java.util.ArrayList;

import org.apache.commons.lang3.BooleanUtils;
import org.opendaylight.lispflowmapping.implementation.lisp.exception.LispSerializationException;
import org.opendaylight.lispflowmapping.implementation.util.ByteUtil;
import org.opendaylight.lispflowmapping.implementation.util.NumberUtil;
import org.opendaylight.yang.gen.v1.lispflowmapping.rev131031.MapRegister;
import org.opendaylight.yang.gen.v1.lispflowmapping.rev131031.eidtolocatorrecords.EidToLocatorRecord;
import org.opendaylight.yang.gen.v1.lispflowmapping.rev131031.mapregisternotification.MapRegisterBuilder;

/**
 * This class deals with deserializing map register from udp to the java object.
 */
public class MapRegisterSerializer {

    private static final MapRegisterSerializer INSTANCE = new MapRegisterSerializer();

    // Private constructor prevents instantiation from other classes
    private MapRegisterSerializer() {
    }

    public static MapRegisterSerializer getInstance() {
        return INSTANCE;
    }

    public ByteBuffer serialize(MapRegister mapRegister) {
        int size = Length.HEADER_SIZE;
        if (mapRegister.getAuthenticationData() != null) {
            size += mapRegister.getAuthenticationData().length;
        }
        for (EidToLocatorRecord eidToLocatorRecord : mapRegister.getEidToLocatorRecord()) {
            size += EidToLocatorRecordSerializer.getInstance().getSerializationSize(eidToLocatorRecord);
        }

        ByteBuffer registerBuffer = ByteBuffer.allocate(size);
        registerBuffer.put((byte) ((byte) (LispMessageEnum.MapRegister.getValue() << 4) | ByteUtil.boolToBit(
                BooleanUtils.isTrue(mapRegister.isProxyMapReply()), Flags.PROXY)));
        registerBuffer.position(registerBuffer.position() + Length.RES);
        registerBuffer.put(ByteUtil.boolToBit(BooleanUtils.isTrue(mapRegister.isWantMapNotify()), Flags.WANT_MAP_REPLY));
        registerBuffer.put((byte) mapRegister.getEidToLocatorRecord().size());
        registerBuffer.putLong(NumberUtil.asLong(mapRegister.getNonce()));
        registerBuffer.putShort(NumberUtil.asShort(mapRegister.getKeyId()));

        if (mapRegister.getAuthenticationData() != null) {
            registerBuffer.putShort((short) mapRegister.getAuthenticationData().length);
            registerBuffer.put(mapRegister.getAuthenticationData());
        } else {
            registerBuffer.putShort((short) 0);
        }
        for (EidToLocatorRecord eidToLocatorRecord : mapRegister.getEidToLocatorRecord()) {
            EidToLocatorRecordSerializer.getInstance().serialize(registerBuffer, eidToLocatorRecord);
        }
        registerBuffer.clear();
        return registerBuffer;
    }

    public MapRegister deserialize(ByteBuffer registerBuffer) {
        try {
            MapRegisterBuilder builder = new MapRegisterBuilder();
            builder.setEidToLocatorRecord(new ArrayList<EidToLocatorRecord>());

            builder.setProxyMapReply(ByteUtil.extractBit(registerBuffer.get(), Flags.PROXY));

            registerBuffer.position(registerBuffer.position() + Length.RES);
            builder.setWantMapNotify(ByteUtil.extractBit(registerBuffer.get(), Flags.WANT_MAP_REPLY));
            byte recordCount = (byte) ByteUtil.getUnsignedByte(registerBuffer);
            builder.setNonce(registerBuffer.getLong());
            builder.setKeyId(registerBuffer.getShort());
            short authenticationLength = registerBuffer.getShort();
            byte[] authenticationData = new byte[authenticationLength];
            registerBuffer.get(authenticationData);
            builder.setAuthenticationData(authenticationData);

            for (int i = 0; i < recordCount; i++) {
                builder.getEidToLocatorRecord().add(EidToLocatorRecordSerializer.getInstance().deserialize(registerBuffer));
            }
            registerBuffer.limit(registerBuffer.position());
            byte[] mapRegisterBytes = new byte[registerBuffer.position()];
            registerBuffer.position(0);
            registerBuffer.get(mapRegisterBytes);
            return builder.build();
        } catch (RuntimeException re) {
            throw new LispSerializationException("Couldn't deserialize Map-Register (len=" + registerBuffer.capacity() + ")", re);
        }

    }

    private interface Flags {
        byte PROXY = 0x08;
        byte WANT_MAP_REPLY = 0x01;
    }

    private interface Length {
        int HEADER_SIZE = 16;
        int RES = 1;
    }
}