package VMSConnection.Encoding;

import VMSConnection.Utils.ByteHelper;

import java.io.IOException;
import java.nio.channels.SocketChannel;

/*
 * @Author: Wang Feng
 * @Description:
 * @Version: 1.0.0
 * @Date: 19:47 2021/6/24
 * @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 BC_Encoder {
    /**
     * Encode 将消息编码: 加一个长度头
     * @param message
     * @return
     */
    public static byte[] Encode(byte[] message){
        byte[] length= ByteHelper.int32ToByteArray(message.length);
        byte[] pkg=new byte[4+ message.length];
        System.arraycopy(length,0,pkg,0,4);
        System.arraycopy(message,0,pkg,4,message.length);
        return pkg;
    }

    /**
     * 解码消息：去掉长度头
     * @param channel
     * @return
     */
    public static byte[] DecodeTcp(SocketChannel channel){
        if(!channel.isConnected()){
            // 重新连接
            try {
                System.out.println("DecodeTcp-重新连接: "+channel.getRemoteAddress());
                channel.connect(channel.getRemoteAddress());
            } catch (IOException e) {
                e.printStackTrace();
                return null;
            }
        }
        System.out.println("start read...");
        // 读取消息的长度
        byte[] buf=new byte[4];
        try {
            int revL=channel.socket().getInputStream().read(buf);
//            channel.read(ByteBuffer.wrap(buf));
            if(revL<0){
                System.out.println("read len < 0");
                return null;
            }
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
        int length=ByteHelper.byteArrayToInt32(buf);
        System.out.println("read 111: "+length);
        // 读取真正的消息数据
        byte[] pkg=new byte[length];
        try {
            int revL=channel.socket().getInputStream().read(pkg);
            if(revL<0){
                System.out.println("read len < 0");
                return null;
            }
        } catch (IOException e) {
            e.printStackTrace();
            return null;
        }
        System.out.println("read 222: "+new String(pkg));
        return pkg;
    }
}