/*
 * Copyright 2016-present Open Networking Foundation
 *
 * 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.pcepio.types;

import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;
import java.util.Objects;

import org.jboss.netty.buffer.ChannelBuffer;
import org.onosproject.pcepio.exceptions.PcepParseException;
import org.onosproject.pcepio.protocol.PcepVersion;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.base.MoreObjects;

/**
 * Provides Local TE Node Descriptors TLV which contains Node Descriptor Sub-TLVs.
 */
public class LocalNodeDescriptorsTlv implements PcepValueType {

    /* REFERENCE :draft-dhodylee-pce-pcep-ls-01, section 9.2.2
     *  0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |           Type=[TBD8]         |             Length            |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     //              Node Descriptor Sub-TLVs (variable)            //
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     Note: Length is including header here. Refer Routing Universe TLV.
     */

    private static final Logger log = LoggerFactory.getLogger(LocalNodeDescriptorsTlv.class);

    public static final short TYPE = (short) 65282;
    short hLength;

    public static final int TLV_HEADER_LENGTH = 4;
    // Node Descriptor Sub-TLVs (variable)
    private List<PcepValueType> llNodeDescriptorSubTLVs;

    /**
     * Constructor to initialize llNodeDescriptorSubTLVs.
     *
     * @param llNodeDescriptorSubTLVs List of PcepValueType
     */
    public LocalNodeDescriptorsTlv(List<PcepValueType> llNodeDescriptorSubTLVs) {
        this.llNodeDescriptorSubTLVs = llNodeDescriptorSubTLVs;
    }

    /**
     * Returns a new object of LocalNodeDescriptorsTLV.
     *
     * @param llNodeDescriptorSubTLVs linked list of Node Descriptor Sub TLVs
     * @return object of LocalNodeDescriptorsTLV
     */
    public static LocalNodeDescriptorsTlv of(final List<PcepValueType> llNodeDescriptorSubTLVs) {
        return new LocalNodeDescriptorsTlv(llNodeDescriptorSubTLVs);
    }

    /**
     * Returns Linked List of tlvs.
     *
     * @return llNodeDescriptorSubTLVs linked list of Node Descriptor Sub TLV
     */
    public List<PcepValueType> getllNodeDescriptorSubTLVs() {
        return llNodeDescriptorSubTLVs;
    }

    @Override
    public PcepVersion getVersion() {
        return PcepVersion.PCEP_1;
    }

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

    @Override
    public short getLength() {
        return hLength;
    }

    @Override
    public int hashCode() {
        return Objects.hash(llNodeDescriptorSubTLVs.hashCode());
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }

        /*
         * Here we have a list of Tlv so to compare each sub tlv between the object
         * we have to take a list iterator so one by one we can get each sub tlv object
         * and can compare them.
         * it may be possible that the size of 2 lists is not equal so we have to first check
         * the size, if both are same then we should check for the subtlv objects otherwise
         * we should return false.
         */
        if (obj instanceof LocalNodeDescriptorsTlv) {
            int countObjSubTlv = 0;
            int countOtherSubTlv = 0;
            boolean isCommonSubTlv = true;
            LocalNodeDescriptorsTlv other = (LocalNodeDescriptorsTlv) obj;
            Iterator<PcepValueType> objListIterator = ((LocalNodeDescriptorsTlv) obj).llNodeDescriptorSubTLVs
                    .iterator();
            countObjSubTlv = ((LocalNodeDescriptorsTlv) obj).llNodeDescriptorSubTLVs.size();
            countOtherSubTlv = other.llNodeDescriptorSubTLVs.size();
            if (countObjSubTlv != countOtherSubTlv) {
                return false;
            } else {
                while (objListIterator.hasNext() && isCommonSubTlv) {
                    PcepValueType subTlv = objListIterator.next();
                    isCommonSubTlv = Objects.equals(llNodeDescriptorSubTLVs.contains(subTlv),
                            other.llNodeDescriptorSubTLVs.contains(subTlv));
                }
                return isCommonSubTlv;
            }
        }
        return false;
    }

    @Override
    public int write(ChannelBuffer c) {
        int tlvStartIndex = c.writerIndex();
        c.writeShort(TYPE);
        int tlvLenIndex = c.writerIndex();
        hLength = 0;
        c.writeShort(0);

        ListIterator<PcepValueType> listIterator = llNodeDescriptorSubTLVs.listIterator();

        while (listIterator.hasNext()) {
            PcepValueType tlv = listIterator.next();
            if (tlv == null) {
                log.debug("TLV is null from subTlv list");
                continue;
            }
            tlv.write(c);

            // need to take care of padding
            int pad = tlv.getLength() % 4;

            if (0 != pad) {
                pad = 4 - pad;
                for (int i = 0; i < pad; ++i) {
                    c.writeByte((byte) 0);
                }
            }
        }
        hLength = (short) (c.writerIndex() - tlvStartIndex);
        c.setShort(tlvLenIndex, (hLength - TLV_HEADER_LENGTH));
        return c.writerIndex() - tlvStartIndex;
    }

    /**
     * Reads the channel buffer and returns object of AutonomousSystemTlv.
     *
     * @param c input channel buffer
     * @param hLength length of subtlvs.
     * @return object of AutonomousSystemTlv
     * @throws PcepParseException if mandatory fields are missing
     */
    public static PcepValueType read(ChannelBuffer c, short hLength) throws PcepParseException {

        // Node Descriptor Sub-TLVs (variable)
        List<PcepValueType> llNodeDescriptorSubTLVs = new LinkedList<>();

        ChannelBuffer tempCb = c.readBytes(hLength);

        while (TLV_HEADER_LENGTH <= tempCb.readableBytes()) {

            PcepValueType tlv;
            short hType = tempCb.readShort();
            int iValue = 0;
            short length = tempCb.readShort();

            switch (hType) {

            case AutonomousSystemSubTlv.TYPE:
                iValue = tempCb.readInt();
                tlv = new AutonomousSystemSubTlv(iValue);
                break;
            case BgpLsIdentifierSubTlv.TYPE:
                iValue = tempCb.readInt();
                tlv = new BgpLsIdentifierSubTlv(iValue);
                break;
            case OspfAreaIdSubTlv.TYPE:
                iValue = tempCb.readInt();
                tlv = new OspfAreaIdSubTlv(iValue);
                break;
            case IgpRouterIdSubTlv.TYPE:
                tlv = IgpRouterIdSubTlv.read(tempCb, length);
                break;

            default:
                throw new PcepParseException("Unsupported Sub TLV type :" + hType);
            }

            // Check for the padding
            int pad = length % 4;
            if (0 < pad) {
                pad = 4 - pad;
                if (pad <= tempCb.readableBytes()) {
                    tempCb.skipBytes(pad);
                }
            }

            llNodeDescriptorSubTLVs.add(tlv);
        }

        if (0 < tempCb.readableBytes()) {
            throw new PcepParseException("Sub Tlv parsing error. Extra bytes received.");
        }
        return new LocalNodeDescriptorsTlv(llNodeDescriptorSubTLVs);
    }

    @Override
    public String toString() {
        return MoreObjects.toStringHelper(getClass())
                .add("Type", TYPE)
                .add("Length", hLength)
                .add("NodeDescriptorSubTLVs", llNodeDescriptorSubTLVs)
                .toString();
    }
}