package utils

import (
        "encoding/binary"
        "log"
        "time"

        "net"
        "unicode/utf8"

        "github.com/google/gopacket"
        "github.com/google/gopacket/layers"
        "github.com/mdlayher/packet"
)

type SocketCall struct {
        conn    *packet.Conn
        Iface   *net.Interface
}


func splitData(message string) []string {
        data := []string{}
        maxPacketLength := 1449

        var i, j int

        for i, j = 0, maxPacketLength; j < len(message); i, j = j, j+maxPacketLength {
                for !utf8.RuneStart(message[j]) {
                        j--
                }
                data = append(data, message[i:j])
        }
        data = append(data, message[i:])

        return data
}

func GetAdapter() string {
	inetInterface := ""
	inetInterfaces, _ := net.Interfaces()
	if inetInterfaces[0].Name == "lo" {
		inetInterface = inetInterfaces[1].Name
	} else {
		inetInterface = inetInterfaces[0].Name
	}
	return inetInterface
}

func (c* SocketCall) SendPackage(buf gopacket.SerializeBuffer) error {
        _, err := c.conn.WriteTo(buf.Bytes(), &packet.Addr{HardwareAddr: layers.EthernetBroadcast})
        return err
}

func (c* SocketCall)SendData(message string) {
        iface, _ := net.InterfaceByName(GetAdapter())
        c.Iface = iface

        conn, err := packet.Listen(iface, packet.Raw, int(layers.EthernetTypeIPv4), nil)
        c.conn = conn

        if err != nil {
                log.Panic(err)
        }

        splitMessage := splitData(message)

        for i := 0; i < len(splitMessage); i++ {
                c.SendPackage(c.FileTransferPacket(splitMessage[i], uint16(i)))
                time.Sleep(20 * time.Microsecond)

        time.Sleep(200 * time.Microsecond)

        return
	}
}

func (c* SocketCall) saprusPayloadLength(pkt []byte) [2]byte{
        payloadLength := make([]byte, 2)
        var length [2]byte
        binary.BigEndian.PutUint16(payloadLength, uint16(len(pkt)))

        length[0] = payloadLength[0]
        length[1] = payloadLength[1]

        return length
}