package eth

import (
	"log"

	"github.com/google/gopacket"
	"github.com/google/gopacket/pcap"
	"github.com/gorilla/websocket"
)

const (
	interfaceName = "eth0"
)

type Eth struct {
	Handle *pcap.Handle
}

func Init() *Eth {
	handle, err := pcap.OpenLive(interfaceName, 1600, true, pcap.BlockForever)
	if err != nil {
		log.Fatal("打开驱动器失败: ", err)
		return nil
	}
	return &Eth{Handle: handle}
}

/**
 * 抓取网卡的数据，并写入WebSocket
 */
func (eth *Eth) EthernetPacketsToWs(wsConn *websocket.Conn) error {

	packetSource := gopacket.NewPacketSource(eth.Handle, eth.Handle.LinkType())
	for packet := range packetSource.Packets() {
		wsConn.WriteMessage(websocket.BinaryMessage, packet.Data())
	}
	return nil
}

/**
 * 将ws的数据写入网卡
 */
func (eth *Eth) WsToEthernet(wsConn *websocket.Conn) {
	for {
		_, p, err := wsConn.ReadMessage()
		if err != nil {
			return
		}
		err = eth.Handle.WritePacketData(p)
		if err != nil {
			log.Fatal(err)
		}
	}
}