package component;

import encoding.*;

/*
 * @Author: Wang Feng
 * @Description: 表示 LpPacket 中的分片id TLV
 * @Version: 1.0.0
 * @Date: 20:45 2021/4/5
 * @Copyright: MIN-Group；国家重大科技基础设施——未来网络北大实验室；深圳市信息论与未来网络重点实验室
 */
public class LpPacketFragmentId implements TlvComponentBase,InitialAble,IEncodingAble{
    // 成员变量
    private long id;

    public LpPacketFragmentId(){
    }

    public LpPacketFragmentId(long id){
        this.setId(id);
    }

    // 函数
    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
        this.doInitial();
    }

    // 接口实现-变量区
    private boolean initial=false;

    // 接口实现-方法区
    @Override
    public void doInitial() {
        initial=true;
    }

    @Override
    public boolean isInitial() {
        return initial;
    }

    /**
     * 将 LpPacketFragmentId 线速编码为一个 TLV
     * @param encoder
     * @return
     */
    @Override
    public int wireEncode(Encoder encoder) throws ComponentException {
        try {
            int totalLength=0;

            // 编码 TLV-VALUE
            int tmpLen=encoder.prependNonNegativeInteger(this.id);
            if(tmpLen<0){
                return -1;
            }
            totalLength+=tmpLen;

            // 编码 TLV-TYPE
            tmpLen=encoder.prependVarNumber(new VlInt(totalLength));
            if(tmpLen<0){
                return -1;
            }
            totalLength+=tmpLen;

            // 编码 TLV-TYPE
            tmpLen=encoder.prependVarNumber(new VlInt(TLV.TlvLpPacketFragmentId));
            if(tmpLen<0){
                return -1;
            }
            totalLength+=tmpLen;

            return totalLength;
        } catch (EncoderException e) {
            throw new ComponentException("LpPacketFragmentId.wireEncode: "+e.getMessage());
        }
    }

    /**
     * 从 TLV Block 中解码一个 LpPacketFragmentId
     * @param block
     * @return
     */
    @Override
    public boolean wireDecode(Block block) throws ComponentException {
        try {
            // 检查 Type 是否正确
            if (!TLV.expectType(block.getType(), new VlInt(TLV.TlvLpPacketFragmentId))) {
                return false;
            }

            // 读取 value
            long value = TLV.readNonNegativeInteger(block.getValue(), 0, block.getLength().getVlIntValue2Int());
            if (value < 0) {
                return false;
            }
            this.setId(value);

            return true;
        } catch (TLVException | VlIntException e) {
            throw new ComponentException("LpPacketFragmentId.wireDecode: "+e.getMessage());
        }
    }
}