/*
 * Copyright (c) 2016 Cisco Systems, Inc. and others.  All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 */
package org.opendaylight.protocol.bgp.evpn.impl.extended.communities;

import com.google.common.base.Preconditions;
import com.google.common.primitives.UnsignedBytes;
import io.netty.buffer.ByteBuf;
import org.opendaylight.protocol.util.BitArray;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.evpn.rev200120.NormalizationType;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.evpn.rev200120.OperationalMode;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.evpn.rev200120.evpn.routes.evpn.routes.evpn.route.attributes.extended.communities.extended.community.Layer2AttributesExtendedCommunityCase;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.evpn.rev200120.evpn.routes.evpn.routes.evpn.route.attributes.extended.communities.extended.community.Layer2AttributesExtendedCommunityCaseBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.evpn.rev200120.layer._2.attributes.extended.community.Layer2AttributesExtendedCommunity;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.evpn.rev200120.layer._2.attributes.extended.community.Layer2AttributesExtendedCommunityBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev200120.extended.community.ExtendedCommunity;
import org.opendaylight.yangtools.yang.common.netty.ByteBufUtils;

public class Layer2AttributesExtCom extends AbstractExtendedCommunities {
    // TODO: TBD BY IANA
    private static final int SUBTYPE = 4;
    private static final int FLAGS_SIZE = 16;
    private static final int BACKUP_PE_OFFSET = 15;
    private static final int PRIMARY_PE_OFFSET = 14;
    private static final int CONTROL_WORD_OFFSET = 13;
    private static final int MODE_OF_OPERATION = 11;
    private static final int NORMALIZATION_TYPE = 9;
    private static final int RESERVED = 2;
    private static final int THREE_BITS_SHIFT = 3;
    private static final int FIVE_BITS_SHIFT = 5;

    private static short getFlagShort(final BitArray flags, final int index) {
        short opMode = 0;
        opMode |= flags.get(index + 1) ? 1 : 0;
        opMode |= (flags.get(index) ? 1 : 0) << 1;
        return opMode;
    }

    @Override
    public ExtendedCommunity parseExtendedCommunity(final ByteBuf body) {
        final BitArray flags = BitArray.valueOf(body, FLAGS_SIZE);

        final Layer2AttributesExtendedCommunityBuilder builder = new Layer2AttributesExtendedCommunityBuilder()
                .setBackupPe(flags.get(BACKUP_PE_OFFSET))
                .setPrimaryPe(flags.get(PRIMARY_PE_OFFSET))
                .setControlWord(flags.get(CONTROL_WORD_OFFSET))

                .setModeOfOperation(OperationalMode.forValue(getFlagShort(flags, MODE_OF_OPERATION)))
                .setOperatingPer(NormalizationType.forValue(getFlagShort(flags, NORMALIZATION_TYPE)))

                .setL2Mtu(ByteBufUtils.readUint16(body));
        body.skipBytes(RESERVED);
        return new Layer2AttributesExtendedCommunityCaseBuilder()
                .setLayer2AttributesExtendedCommunity(builder.build()).build();
    }

    @Override
    public void serializeExtendedCommunity(final ExtendedCommunity extendedCommunity, final ByteBuf body) {
        Preconditions.checkArgument(extendedCommunity instanceof Layer2AttributesExtendedCommunityCase,
                "The extended community %s is not EsImportRouteExtendedCommunityCaseCase type.",
                extendedCommunity);
        final Layer2AttributesExtendedCommunity extCom = ((Layer2AttributesExtendedCommunityCase) extendedCommunity)
                .getLayer2AttributesExtendedCommunity();
        final BitArray flags = new BitArray(FLAGS_SIZE);
        flags.set(PRIMARY_PE_OFFSET, extCom.getPrimaryPe());
        flags.set(BACKUP_PE_OFFSET, extCom.getBackupPe());
        flags.set(CONTROL_WORD_OFFSET, extCom.getControlWord());

        final byte[] res = flags.array();
        byte aux = 0;
        final OperationalMode modeOfOperation = extCom.getModeOfOperation();
        if (modeOfOperation != null) {
            aux = UnsignedBytes.checkedCast(modeOfOperation.getIntValue());
            aux = (byte) (aux << THREE_BITS_SHIFT);
            res[res.length - 1] = (byte) (res[res.length - 1] | aux);
        }

        final NormalizationType normalizationType = extCom.getOperatingPer();
        if (normalizationType != null) {
            aux = UnsignedBytes.checkedCast(normalizationType.getIntValue());
            aux = (byte) (aux << FIVE_BITS_SHIFT);
            res[res.length - 1] = (byte) (res[res.length - 1] | aux);
        }
        body.writeShort(res[res.length - 1]);
        ByteBufUtils.writeOrZero(body, extCom.getL2Mtu());
        body.writeZero(RESERVED);
    }

    @Override
    public int getSubType() {
        return SUBTYPE;
    }
}