/*
 * Copyright 2015-present Open Networking Laboratory
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.onosproject.bgpio.types;

import com.google.common.base.MoreObjects;
import org.jboss.netty.buffer.ChannelBuffer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.onosproject.bgpio.util.Constants;

import java.util.Objects;

/**
 * Provides MultiProtocolExtnCapabilityTlv.
 */
public class MultiProtocolExtnCapabilityTlv implements BgpValueType {

    /*
        0       7       15      23      31
        +-------+-------+-------+-------+
        |  AFI          | Res   |  SAFI |
        +-------+-------+-------+-------+

        Multiprotocol Extensions CAPABILITY TLV format
        REFERENCE : RFC 4760
     */
    protected static final Logger log = LoggerFactory
            .getLogger(MultiProtocolExtnCapabilityTlv.class);

    public static final byte TYPE = 1;
    public static final byte LENGTH = 4;

    private final short afi;
    private final byte res;
    private final byte safi;
    private final byte rpdSendReceive;

    /**
     * Constructor to initialize variables.
     * @param afi Address Family Identifiers
     * @param res reserved field
     * @param safi Subsequent Address Family Identifier
     */
    public MultiProtocolExtnCapabilityTlv(short afi, byte res, byte safi) {
        this.afi = afi;
        this.res = res;
        this.safi = safi;
        this.rpdSendReceive = Constants.RPD_CAPABILITY_SEND_VALUE;
    }

        /**
     * Constructor to initialize variables.
     * @param afi Address Family Identifiers
     * @param res reserved field
     * @param safi Subsequent Address Family Identifier
     * @param rpdSendReceive indicates whether the sender is
                                    (a) willing  to receive Route Policies via BGP FLowSpec from its peer (value 1).
                                    (b) would like to send Route Policies via BGP FLowSpec to its peer (value 2).
                                    (c) both (value 3).
     */
    public MultiProtocolExtnCapabilityTlv(short afi, byte res, byte safi, byte rpdSendReceive) {
        this.afi = afi;
        this.res = res;
        this.safi = safi;
        this.rpdSendReceive = rpdSendReceive;
    }

    /**
     * Returns object of MultiProtocolExtnCapabilityTlv.
     * @param afi Address Family Identifiers
     * @param res reserved field
     * @param safi Subsequent Address Family Identifier
     * @return object of MultiProtocolExtnCapabilityTlv
     */
    public static MultiProtocolExtnCapabilityTlv of(short afi, byte res,
                                                    byte safi) {
        return new MultiProtocolExtnCapabilityTlv(afi, res, safi);
    }

    /**
     * Returns afi Address Family Identifiers value.
     * @return afi Address Family Identifiers value
     */
    public short getAfi() {
        return afi;
    }

    /**
     * Returns res reserved field value.
     * @return res reserved field value
     */
    public byte getRes() {
        return res;
    }

    /**
     * Returns safi Subsequent Address Family Identifier value.
     * @return safi Subsequent Address Family Identifier value
     */
    public byte getSafi() {
        return safi;
    }

    @Override
    public short getType() {
        return TYPE;
    }

    @Override
    public int hashCode() {
        return Objects.hash(afi, res, safi);
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj instanceof MultiProtocolExtnCapabilityTlv) {
            MultiProtocolExtnCapabilityTlv other = (MultiProtocolExtnCapabilityTlv) obj;
            return Objects.equals(this.afi, other.afi)
                    && Objects.equals(this.res, other.res)
                    && Objects.equals(this.safi, other.safi);
        }
        return false;
    }

    @Override
    public int write(ChannelBuffer cb) {
        boolean isFsRpd = false;
        int iLenStartIndex = cb.writerIndex();
        cb.writeByte(TYPE);

        if ((afi == Constants.AFI_FLOWSPEC_RPD_VALUE) && (safi == Constants.SAFI_FLOWSPEC_RPD_VALUE)) {
            cb.writeByte(LENGTH + 1);
            isFsRpd = true;
        } else {
            cb.writeByte(LENGTH);
        }

        // write afi
        cb.writeShort(afi);

        // write res
        cb.writeByte(res);

        // write safi
        cb.writeByte(safi);

        if (isFsRpd) {
            // write Send/Receive (1 octet)
            cb.writeByte(rpdSendReceive);
        }

        return cb.writerIndex() - iLenStartIndex;
    }

    /**
     * Reads from channel buffer and returns object of MultiprotocolCapabilityTlv.
     * @param cb of type channel buffer
     * @return object of MultiProtocolExtnCapabilityTlv
     */
    public static BgpValueType read(ChannelBuffer cb) {
        short afi = cb.readShort();
        byte res = cb.readByte();
        byte safi = cb.readByte();

        if ((afi == Constants.AFI_FLOWSPEC_RPD_VALUE) && (safi == Constants.SAFI_FLOWSPEC_RPD_VALUE)) {
            return new MultiProtocolExtnCapabilityTlv(afi, res, safi, cb.readByte());
        }
        return new MultiProtocolExtnCapabilityTlv(afi, res, safi);
    }

    @Override
    public String toString() {
        return MoreObjects.toStringHelper(getClass())
                .add("Type", TYPE)
                .add("Length", LENGTH)
                .add("AFI", afi)
                .add("Reserved", res)
                .add("SAFI", safi).toString();
    }

    @Override
    public int compareTo(Object o) {
        // TODO Auto-generated method stub
        return 0;
    }
}