/*
 * Copyright (c) 2015 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.linkstate.impl.attribute.sr;

import static org.opendaylight.protocol.bgp.linkstate.impl.attribute.sr.binding.sid.sub.tlvs.SIDParser.SID_TYPE;

import com.google.common.collect.ImmutableMap;
import io.netty.buffer.ByteBuf;
import io.netty.buffer.Unpooled;
import java.util.Map;
import org.opendaylight.protocol.util.BitArray;
import org.opendaylight.protocol.util.Ipv6Util;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.segment.routing.ext.rev200120.sid.label.index.SidLabelIndex;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.segment.routing.ext.rev200120.sid.label.index.sid.label.index.Ipv6AddressCase;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.segment.routing.ext.rev200120.sid.label.index.sid.label.index.Ipv6AddressCaseBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.segment.routing.ext.rev200120.sid.label.index.sid.label.index.LocalLabelCase;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.segment.routing.ext.rev200120.sid.label.index.sid.label.index.LocalLabelCaseBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.segment.routing.ext.rev200120.sid.label.index.sid.label.index.SidCase;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.segment.routing.ext.rev200120.sid.label.index.sid.label.index.SidCaseBuilder;
import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.network.concepts.rev131125.MplsLabel;
import org.opendaylight.yangtools.yang.common.Uint32;
import org.opendaylight.yangtools.yang.common.netty.ByteBufUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public final class SidLabelIndexParser {
    private static final Logger LOG = LoggerFactory.getLogger(SidLabelIndexParser.class);
    private static final int LABEL_MASK = 0xfffff;

    private SidLabelIndexParser() {

    }

    public enum Size {
        LABEL(3), SID(4), IPV6_ADD(16);
        private static final Map<Integer, Size> VALUE_MAP;

        static {
            final ImmutableMap.Builder<java.lang.Integer, Size> b = ImmutableMap.builder();
            for (final Size enumItem : Size.values()) {
                b.put(enumItem.length, enumItem);
            }
            VALUE_MAP = b.build();
        }

        private final int length;

        Size(final int length) {
            this.length = length;
        }

        public static Size forValue(final int value) {
            return VALUE_MAP.get(value);
        }
    }

    public static ByteBuf serializeSidValue(final SidLabelIndex tlv) {
        if (tlv instanceof Ipv6AddressCase) {
            return Ipv6Util.byteBufForAddress(((Ipv6AddressCase) tlv).getIpv6Address());
        } else if (tlv instanceof LocalLabelCase) {
            return Unpooled.copyMedium(((LocalLabelCase) tlv).getLocalLabel().getValue().intValue() & LABEL_MASK);
        } else if (tlv instanceof SidCase) {
            return Unpooled.copyInt(((SidCase) tlv).getSid().intValue());
        }
        return null;
    }

    static SidLabelIndex parseSidSubTlv(final ByteBuf buffer) {
        final int type = buffer.readUnsignedShort();
        if (type != SID_TYPE) {
            LOG.warn("Unexpected type in SID/index/label field, expected {}, actual {}, ignoring it", SID_TYPE, type);
            return null;
        }
        final int length = buffer.readUnsignedShort();
        return parseSidLabelIndex(Size.forValue(length), buffer);
    }

    public static SidLabelIndex parseSidLabelIndex(final Size length, final ByteBuf buffer) {
        switch (length) {
            case LABEL:
                return new LocalLabelCaseBuilder().setLocalLabel(new MplsLabel(readLabel(buffer))).build();
            case SID:
                return new SidCaseBuilder().setSid(ByteBufUtils.readUint32(buffer)).build();
            case IPV6_ADD:
                return new Ipv6AddressCaseBuilder().setIpv6Address(Ipv6Util.addressForByteBuf(buffer)).build();
            default:
                return null;
        }
    }

    private static Uint32 readLabel(final ByteBuf buffer) {
        return Uint32.valueOf(buffer.readUnsignedMedium() & LABEL_MASK);
    }

    /**
     * Parses SID/Label/Index value into appropriate type based on V-Flag and L-Flag
     * values. This method is required as some device-side implementations
     * incorrectly encode SID/Label/Index value using wrong type e.g. Label type to
     * encode an Index value (V-Flag=false, L-Flag=false).
     *
     * @param length length of SID/Label/Index value
     * @param buffer buffer containing SID/Label/Index value
     * @param isValue V-Flag value
     * @param isLocal L-Flag value
     * @return SID/Label/Index value parsed into the appropriate type
     */
    public static SidLabelIndex parseSidLabelIndexByFlags(final Size length, final ByteBuf buffer,
            final boolean isValue, final boolean isLocal) {
        switch (length) {
            case LABEL:
                return getSidLabelIndexByFlags(readLabel(buffer), isValue, isLocal);
            case SID:
                return getSidLabelIndexByFlags(ByteBufUtils.readUint32(buffer), isValue, isLocal);
            case IPV6_ADD:
                return new Ipv6AddressCaseBuilder().setIpv6Address(Ipv6Util.addressForByteBuf(buffer)).build();
            default:
                return null;
        }
    }

    private static SidLabelIndex getSidLabelIndexByFlags(final Uint32 sidLabelIndex, final boolean isValue,
            final boolean isLocal) {
        if (isValue && isLocal) {
            return new LocalLabelCaseBuilder().setLocalLabel(new MplsLabel(sidLabelIndex)).build();
        } else if (!isValue && !isLocal) {
            return new SidCaseBuilder().setSid(sidLabelIndex).build();
        } else {
            return null;
        }
    }

    static void setFlags(final SidLabelIndex tlv, final BitArray flags, final int value, final int local) {
        if (tlv instanceof LocalLabelCase) {
            flags.set(value, Boolean.TRUE);
            flags.set(local, Boolean.TRUE);
        } else if (tlv instanceof SidCase) {
            flags.set(value, Boolean.FALSE);
            flags.set(local, Boolean.FALSE);
        } else if (tlv instanceof Ipv6AddressCase) {
            flags.set(value, Boolean.TRUE);
            flags.set(local, Boolean.FALSE);
        }
    }
}