package org.kne.cloud.network.perf;

import java.io.EOFException;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.ReadableByteChannel;
import java.nio.channels.WritableByteChannel;

import org.kne.cloud.network.NetworkPacket;
import org.kne.cloud.network.klalb.KLALBPacket;

public class TESTNPacket extends KLALBPacket {

	private static final int HEADER_LENGTH = 3;

	// 核心：一个线程私有的 65535 字节大缓存，生命周期与线程同寿
	private static final ThreadLocal<ByteBuffer> BENCH_BUFFER =
			ThreadLocal.withInitial(() -> ByteBuffer.allocate(65535));

	// 不再持有 ByteBuffer，只记录长度
	private int payloadLength;

	@Override
	public long getTotalLength() {
		return HEADER_LENGTH + payloadLength;
	}

	// 发送端构造
	public TESTNPacket(int limit) {
		super(TESTN, HEADER_LENGTH);
		this.payloadLength = limit;
	}

	// 接收端构造（从已有的 ByteBuffer 解析）
	public TESTNPacket(ByteBuffer bb) {
		super(bb, HEADER_LENGTH);
		this.payloadLength = klalbHeader.getChar(1);
	}

	public int getPayloadLength() {
		return payloadLength;
	}

	@Override
	public void writeToChannel(WritableByteChannel dto) throws IOException {
		// 1. 写入包头（包含 payloadLength）
		klalbHeader.putChar(1, (char) payloadLength);
		super.writeToChannel(dto);

		// 2. 如果有 payload，借用 ThreadLocal 缓冲区并写出去
		if (payloadLength > 0) {
			ByteBuffer buf = BENCH_BUFFER.get();
			buf.clear();
			buf.limit(payloadLength); // 限制到指定长度

			// 直接写出，里面的数据是上一次残留的或者全 0，对于烤机无所谓
			dto.write(buf);
		}
	}

	@Override
	public void readFromChannel(ReadableByteChannel din) throws IOException {
		// 1. 读包头
		super.readFromChannel(din);
		this.payloadLength = klalbHeader.getChar(1);

		// 2. 如果有 payload，借用缓冲区接收数据
		if (payloadLength > 0) {
			ByteBuffer buf = BENCH_BUFFER.get();
			buf.clear();
			buf.limit(payloadLength);

			// 循环读满（使用你现有的 KNEChannels 工具或手动循环）
			while (buf.hasRemaining()) {
				if (din.read(buf) == -1) {
					throw new EOFException("连接提前断开，未能读满 TESTN 载荷");
				}
			}
			// 数据读完直接丢弃，缓冲区不保存，下一次 clear() 时会自动覆盖
		}
	}

	@Override
	public String toString() {
		return "TESTN[" + payloadLength + "]";
	}
}