/*
 * Copyright (c) 2013 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.parser.impl.message.update;

import com.google.common.base.Preconditions;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import org.opendaylight.protocol.bgp.parser.AttributeFlags;
import org.opendaylight.protocol.bgp.parser.BGPDocumentedException;
import org.opendaylight.protocol.bgp.parser.BGPError;
import org.opendaylight.protocol.bgp.parser.BGPParsingException;
import org.opendaylight.protocol.bgp.parser.spi.AttributeParser;
import org.opendaylight.protocol.bgp.parser.spi.AttributeSerializer;
import org.opendaylight.protocol.bgp.parser.spi.NlriRegistry;
import org.opendaylight.protocol.concepts.Ipv4Util;
import org.opendaylight.protocol.concepts.Ipv6Util;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.Ipv4Prefix;
import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.Ipv6Prefix;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.update.PathAttributes;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.update.PathAttributesBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.multiprotocol.rev130919.PathAttributes2;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.multiprotocol.rev130919.PathAttributes2Builder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.multiprotocol.rev130919.destination.destination.type.DestinationIpv4Case;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.multiprotocol.rev130919.destination.destination.type.DestinationIpv6Case;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.multiprotocol.rev130919.update.path.attributes.MpUnreachNlri;
import org.opendaylight.yangtools.yang.binding.DataObject;

public final class MPUnreachAttributeParser implements AttributeParser, AttributeSerializer {
    public static final int TYPE = 15;
    public static final int MAX_ATTR_LENGTH_FOR_SINGLE_BYTE = 127;

    private final NlriRegistry reg;

    public MPUnreachAttributeParser(final NlriRegistry reg) {
        this.reg = Preconditions.checkNotNull(reg);
    }

    @Override
    public void parseAttribute(final ByteBuf buffer, final PathAttributesBuilder builder) throws BGPDocumentedException {
        try {
            final PathAttributes2 a = new PathAttributes2Builder().setMpUnreachNlri(this.reg.parseMpUnreach(buffer)).build();
            builder.addAugmentation(PathAttributes2.class, a);
        } catch (final BGPParsingException e) {
            throw new BGPDocumentedException("Could not parse MP_UNREACH_NLRI", BGPError.OPT_ATTR_ERROR, e);
        }
    }

    @Override
    public void serializeAttribute(DataObject attribute, ByteBuf byteAggregator) {
        PathAttributes pathAttributes = (PathAttributes) attribute;
        PathAttributes2 pathAttributes2 = pathAttributes.getAugmentation(PathAttributes2.class);
        if (pathAttributes2 == null) {
            return;
        }
        MpUnreachNlri mpUnreachNlri = pathAttributes2.getMpUnreachNlri();
        ByteBuf unreachBuffer = Unpooled.buffer();
        this.reg.serializeMpUnReach(mpUnreachNlri, unreachBuffer);

        if (mpUnreachNlri.getWithdrawnRoutes() != null) {
            if (mpUnreachNlri.getWithdrawnRoutes().getDestinationType() instanceof DestinationIpv4Case) {
                DestinationIpv4Case destinationIpv4Case = (DestinationIpv4Case) mpUnreachNlri.getWithdrawnRoutes().getDestinationType();
                if (destinationIpv4Case.getDestinationIpv4().getIpv4Prefixes() != null) {
                    for (Ipv4Prefix ipv4Prefix : destinationIpv4Case.getDestinationIpv4().getIpv4Prefixes()) {
                        unreachBuffer.writeByte(Ipv4Util.getPrefixLength(ipv4Prefix.getValue()));
                        unreachBuffer.writeBytes(Ipv4Util.bytesForPrefixByPrefixLength(ipv4Prefix));
                    }
                }
            }
            if (mpUnreachNlri.getWithdrawnRoutes().getDestinationType() instanceof DestinationIpv6Case) {
                DestinationIpv6Case destinationIpv6Case = (DestinationIpv6Case) mpUnreachNlri.getWithdrawnRoutes().getDestinationType();
                if (destinationIpv6Case.getDestinationIpv6().getIpv6Prefixes() != null) {
                    for (Ipv6Prefix ipv6Prefix : destinationIpv6Case.getDestinationIpv6().getIpv6Prefixes()) {
                        unreachBuffer.writeByte(Ipv4Util.getPrefixLength(ipv6Prefix.getValue()));
                        unreachBuffer.writeBytes(Ipv6Util.bytesForPrefixByPrefixLength(ipv6Prefix));
                    }
                }
            }
        }
        if (unreachBuffer.writerIndex() > MAX_ATTR_LENGTH_FOR_SINGLE_BYTE) {
            byteAggregator.writeByte(AttributeFlags.OPTIONAL | AttributeFlags.EXTENDED);
            byteAggregator.writeByte(TYPE);
            byteAggregator.writeShort(unreachBuffer.writerIndex());
        } else {
            byteAggregator.writeByte(AttributeFlags.OPTIONAL);
            byteAggregator.writeByte(TYPE);
            byteAggregator.writeByte(unreachBuffer.writerIndex());
        }
        byteAggregator.writeBytes(unreachBuffer);
    }
}