/*
 * 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.annotations.VisibleForTesting;
import com.google.common.primitives.UnsignedBytes;
import io.netty.buffer.ByteBuf;
import java.util.Arrays;
import org.opendaylight.protocol.bgp.parser.BGPDocumentedException;
import org.opendaylight.protocol.bgp.parser.BGPError;
import org.opendaylight.protocol.util.ByteArray;
import org.opendaylight.protocol.util.Ipv4Util;
import org.opendaylight.protocol.util.ReferenceCache;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.path.attributes.ExtendedCommunities;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.path.attributes.ExtendedCommunitiesBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.Community;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.ShortAsNumber;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.extended.community.extended.community.AsSpecificExtendedCommunityCaseBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.extended.community.extended.community.Inet4SpecificExtendedCommunityCaseBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.extended.community.extended.community.OpaqueExtendedCommunityCaseBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.extended.community.extended.community.RouteOriginExtendedCommunityCaseBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.extended.community.extended.community.RouteTargetExtendedCommunityCaseBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.extended.community.extended.community.as.specific.extended.community._case.AsSpecificExtendedCommunityBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.extended.community.extended.community.inet4.specific.extended.community._case.Inet4SpecificExtendedCommunityBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.extended.community.extended.community.opaque.extended.community._case.OpaqueExtendedCommunityBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.extended.community.extended.community.route.origin.extended.community._case.RouteOriginExtendedCommunityBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.types.rev130919.extended.community.extended.community.route.target.extended.community._case.RouteTargetExtendedCommunityBuilder;

/**
 * Parser for Extended Communities Path Attribute.
 */
public final class CommunitiesParser {

    protected static final int EXTENDED_COMMUNITY_LENGTH = 8;

    protected static final int COMMUNITY_LENGTH = 4;

    private static final int AS_LOCAL_ADMIN_LENGTH = 4;

    private static final int INET_LOCAL_ADMIN_LENGTH = 2;

    protected static final short AS_TYPE_TRANS = 0;

    protected static final short AS_TYPE_NON_TRANS = 40;

    protected static final short INET_TYPE_TRANS = 1;

    protected static final short INET_TYPE_NON_TRANS = 41;

    protected static final short OPAQUE_TYPE_TRANS = 3;

    protected static final short OPAQUE_TYPE_NON_TRANS = 43;

    protected static final short ROUTE_TYPE_ONLY = 2;

    protected static final short ROUTE_TARGET_SUBTYPE = 2;

    protected static final short ROUTE_ORIGIN_SUBTYPE = 3;

    private static final byte[] NO_EXPORT = new byte[] { (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0x01 };

    private static final byte[] NO_ADVERTISE = new byte[] { (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0x02 };

    private static final byte[] NO_EXPORT_SUBCONFED = new byte[] { (byte) 0xFF, (byte) 0xFF, (byte) 0xFF, (byte) 0x03 };

    private CommunitiesParser() {

    }

    /**
     * Parse known Community, if unknown, a new one will be created.
     *
     * @param refCache
     *
     * @param bytes byte array to be parsed
     * @return new Community
     * @throws BGPDocumentedException
     */
    static Community parseCommunity(final ReferenceCache refCache, final ByteBuf buffer) throws BGPDocumentedException {
        if (buffer.readableBytes() != COMMUNITY_LENGTH) {
            throw new BGPDocumentedException("Community with wrong length: " + buffer.readableBytes(), BGPError.OPT_ATTR_ERROR);
        }
        byte[] body = ByteArray.getBytes(buffer, COMMUNITY_LENGTH);
        if (Arrays.equals(body, NO_EXPORT)) {
            return CommunityUtil.NO_EXPORT;
        } else if (Arrays.equals(body, NO_ADVERTISE)) {
            return CommunityUtil.NO_ADVERTISE;
        } else if (Arrays.equals(body, NO_EXPORT_SUBCONFED)) {
            return CommunityUtil.NO_EXPORT_SUBCONFED;
        }
        return CommunityUtil.create(refCache, buffer.readUnsignedShort(), buffer.readUnsignedShort());
    }

    /**
     * Parse Extended Community according to their type.
     *
     * @param bytes byte array to be parsed
     * @return new Specific Extended Community
     * @throws BGPDocumentedException if the type is not recognized
     */
    @VisibleForTesting
    public static ExtendedCommunities parseExtendedCommunity(final ReferenceCache refCache, final ByteBuf buffer)
            throws BGPDocumentedException {
        final int type = UnsignedBytes.toInt(buffer.readByte());
        final int subType = UnsignedBytes.toInt(buffer.readByte());

        final ExtendedCommunitiesBuilder comm = new ExtendedCommunitiesBuilder();
        switch (type) {
        case AS_TYPE_TRANS:
            comm.setCommType(AS_TYPE_TRANS);
            if (subType == ROUTE_TARGET_SUBTYPE) {
                comm.setCommSubType(ROUTE_TARGET_SUBTYPE).setExtendedCommunity(
                        new RouteTargetExtendedCommunityCaseBuilder().setRouteTargetExtendedCommunity(
                                new RouteTargetExtendedCommunityBuilder().setGlobalAdministrator(
                                        new ShortAsNumber((long) buffer.readUnsignedShort())).setLocalAdministrator(
                                        ByteArray.readBytes(buffer, AS_LOCAL_ADMIN_LENGTH)).build()).build());
            } else if (subType == ROUTE_ORIGIN_SUBTYPE) {
                comm.setCommSubType(ROUTE_ORIGIN_SUBTYPE).setExtendedCommunity(
                        new RouteOriginExtendedCommunityCaseBuilder().setRouteOriginExtendedCommunity(
                                new RouteOriginExtendedCommunityBuilder().setGlobalAdministrator(
                                        new ShortAsNumber((long) buffer.readUnsignedShort())).setLocalAdministrator(
                                        ByteArray.readBytes(buffer, AS_LOCAL_ADMIN_LENGTH)).build()).build());
            } else {
                comm.setExtendedCommunity(new AsSpecificExtendedCommunityCaseBuilder().setAsSpecificExtendedCommunity(
                        new AsSpecificExtendedCommunityBuilder().setTransitive(false).setGlobalAdministrator(
                                new ShortAsNumber((long) buffer.readUnsignedShort())).setLocalAdministrator(
                                ByteArray.readBytes(buffer, AS_LOCAL_ADMIN_LENGTH)).build()).build());
            }
            break;
        case AS_TYPE_NON_TRANS:
            comm.setCommType(AS_TYPE_NON_TRANS).setExtendedCommunity(
                    new AsSpecificExtendedCommunityCaseBuilder().setAsSpecificExtendedCommunity(
                            new AsSpecificExtendedCommunityBuilder().setTransitive(true).setGlobalAdministrator(
                                    new ShortAsNumber((long) buffer.readUnsignedShort())).setLocalAdministrator(
                                    ByteArray.readBytes(buffer, AS_LOCAL_ADMIN_LENGTH)).build()).build());
            break;
        case ROUTE_TYPE_ONLY:
            comm.setCommType(ROUTE_TYPE_ONLY);
            if (subType == ROUTE_TARGET_SUBTYPE) {
                comm.setCommSubType(ROUTE_TARGET_SUBTYPE).setExtendedCommunity(
                        new RouteTargetExtendedCommunityCaseBuilder().setRouteTargetExtendedCommunity(
                                new RouteTargetExtendedCommunityBuilder().setGlobalAdministrator(
                                        new ShortAsNumber((long) buffer.readUnsignedShort())).setLocalAdministrator(
                                        ByteArray.readBytes(buffer, AS_LOCAL_ADMIN_LENGTH)).build()).build());
            } else if (subType == ROUTE_ORIGIN_SUBTYPE) {
                comm.setCommSubType(ROUTE_ORIGIN_SUBTYPE).setExtendedCommunity(
                        new RouteOriginExtendedCommunityCaseBuilder().setRouteOriginExtendedCommunity(
                                new RouteOriginExtendedCommunityBuilder().setGlobalAdministrator(
                                        new ShortAsNumber((long) buffer.readUnsignedShort())).setLocalAdministrator(
                                        ByteArray.readBytes(buffer, AS_LOCAL_ADMIN_LENGTH)).build()).build());
            } else {
                throw new BGPDocumentedException("Could not parse Extended Community subtype: " + subType, BGPError.OPT_ATTR_ERROR);
            }
            break;
        case INET_TYPE_TRANS:
            comm.setCommType(INET_TYPE_TRANS);
            if (subType == ROUTE_TARGET_SUBTYPE) {
                comm.setCommSubType(ROUTE_TARGET_SUBTYPE).setExtendedCommunity(
                        new RouteTargetExtendedCommunityCaseBuilder().setRouteTargetExtendedCommunity(
                                new RouteTargetExtendedCommunityBuilder().setGlobalAdministrator(
                                        new ShortAsNumber((long) buffer.readUnsignedShort())).setLocalAdministrator(
                                        ByteArray.readBytes(buffer, AS_LOCAL_ADMIN_LENGTH)).build()).build());
            } else if (subType == ROUTE_ORIGIN_SUBTYPE) {
                comm.setCommSubType(ROUTE_ORIGIN_SUBTYPE).setExtendedCommunity(
                        new RouteOriginExtendedCommunityCaseBuilder().setRouteOriginExtendedCommunity(
                                new RouteOriginExtendedCommunityBuilder().setGlobalAdministrator(
                                        new ShortAsNumber((long) buffer.readUnsignedShort())).setLocalAdministrator(
                                        ByteArray.readBytes(buffer, AS_LOCAL_ADMIN_LENGTH)).build()).build());
            } else {
                comm.setExtendedCommunity(new Inet4SpecificExtendedCommunityCaseBuilder().setInet4SpecificExtendedCommunity(
                        new Inet4SpecificExtendedCommunityBuilder().setTransitive(false).setGlobalAdministrator(
                                Ipv4Util.addressForBytes(ByteArray.readBytes(buffer, Ipv4Util.IP4_LENGTH))).setLocalAdministrator(
                                ByteArray.readBytes(buffer, INET_LOCAL_ADMIN_LENGTH)).build()).build());
            }
            break;
        case INET_TYPE_NON_TRANS:
            comm.setCommType(INET_TYPE_NON_TRANS).setExtendedCommunity(
                    new Inet4SpecificExtendedCommunityCaseBuilder().setInet4SpecificExtendedCommunity(
                            new Inet4SpecificExtendedCommunityBuilder().setTransitive(true).setGlobalAdministrator(
                                    Ipv4Util.addressForBytes(ByteArray.readBytes(buffer, Ipv4Util.IP4_LENGTH))).setLocalAdministrator(
                                    ByteArray.readBytes(buffer, INET_LOCAL_ADMIN_LENGTH)).build()).build());
            break;
        case OPAQUE_TYPE_TRANS:
            comm.setCommType(OPAQUE_TYPE_TRANS).setExtendedCommunity(
                    new OpaqueExtendedCommunityCaseBuilder().setOpaqueExtendedCommunity(
                            new OpaqueExtendedCommunityBuilder().setTransitive(false).setValue(ByteArray.readAllBytes(buffer)).build()).build());
            break;
        case OPAQUE_TYPE_NON_TRANS:
            comm.setCommType(OPAQUE_TYPE_NON_TRANS).setExtendedCommunity(
                    new OpaqueExtendedCommunityCaseBuilder().setOpaqueExtendedCommunity(
                            new OpaqueExtendedCommunityBuilder().setTransitive(true).setValue(ByteArray.readAllBytes(buffer)).build()).build());
            break;
        default:
            throw new BGPDocumentedException("Could not parse Extended Community type: " + type, BGPError.OPT_ATTR_ERROR);
        }

        return comm.build();
    }
}