/*
 * Copyright 2014-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.onlab.packet;

import java.nio.ByteBuffer;
import java.util.Arrays;

/**
 *
 *
 */
public class LLDPTLV {

    public static final int MAX_LENGTH = 0x1ff;

    protected byte type;
    protected short length;
    protected byte[] value;

    @Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("[");
        sb.append("type= ");
        sb.append(type);
        sb.append("length= ");
        sb.append(length);
        sb.append("value= ");
        sb.append(Arrays.toString(value));
        sb.append("]");
        return sb.toString();
    }

    /**
     * @return the type
     */
    public byte getType() {
        return this.type;
    }

    /**
     * @param type
     *            the type to set
     * @return this
     */
    public LLDPTLV setType(final byte type) {
        this.type = type;
        return this;
    }

    /**
     * @return the length
     */
    public short getLength() {
        return this.length;
    }

    /**
     * @param length
     *            the length to set
     * @return this
     */
    public LLDPTLV setLength(final short length) {
        this.length = length;
        return this;
    }

    /**
     * @return the value
     */
    public byte[] getValue() {
        return this.value;
    }

    /**
     * @param value
     *            the value to set
     * @return this
     */
    public LLDPTLV setValue(final byte[] value) {
        this.value = value;
        return this;
    }

    public byte[] serialize() {
        // type = 7 bits
        // info string length 9 bits, each value == byte
        // info string
        final short scratch = (short) ((0x7f & this.type) << 9 | 0x1ff & this.length);
        final byte[] data = new byte[2 + this.length];
        final ByteBuffer bb = ByteBuffer.wrap(data);
        bb.putShort(scratch);
        if (this.value != null) {
            bb.put(this.value);
        }
        return data;
    }

    public LLDPTLV deserialize(final ByteBuffer bb) throws DeserializationException {
        if (bb.remaining() < 2) {
            throw new DeserializationException(
                    "Not enough bytes to deserialize TLV type and length");
        }
        short typeLength;
        typeLength = bb.getShort();
        this.type = (byte) (typeLength >> 9 & 0x7f);
        this.length = (short) (typeLength & 0x1ff);

        if (this.length > 0) {
            this.value = new byte[this.length];

            // if there is an underrun just toss the TLV
            if (bb.remaining() < this.length) {
                throw new DeserializationException(
                        "Remaining bytes are less then the length of the TLV");
            }
            bb.get(this.value);
        }

        return this;
    }

    /*
     * (non-Javadoc)
     *
     * @see java.lang.Object#hashCode()
     */
    @Override
    public int hashCode() {
        final int prime = 1423;
        int result = 1;
        result = prime * result + this.length;
        result = prime * result + this.type;
        result = prime * result + Arrays.hashCode(this.value);
        return result;
    }

    /*
     * (non-Javadoc)
     *
     * @see java.lang.Object#equals(java.lang.Object)
     */
    @Override
    public boolean equals(final Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (!(obj instanceof LLDPTLV)) {
            return false;
        }
        final LLDPTLV other = (LLDPTLV) obj;
        if (this.length != other.length) {
            return false;
        }
        if (this.type != other.type) {
            return false;
        }
        if (!Arrays.equals(this.value, other.value)) {
            return false;
        }
        return true;
    }
}