package utils

import(
	
	"GolangLearnPractice1/day11/communicate/common/message"
	"encoding/binary"
	"encoding/json"
	"errors"
	"fmt"
	"net"
)
type Transfer struct{
	Conn net.Conn
	Buf [8096]byte
}
func (this *Transfer)WritePkg(data []byte) (err error) {
	var pkgLen uint32
	pkgLen = uint32(len(data))
	binary.BigEndian.PutUint32(this.Buf[0:4], pkgLen)
	//fmt.Println("the length of the message is ",pkgLen)

	n, err := this.Conn.Write(this.Buf[:4])
	if n != 4 || err != nil {
		fmt.Println("conn.Write(buf) failed ,err=", err)
		return
	}

	n, err = this.Conn.Write(data)
	if n != int(pkgLen) || err != nil {
		fmt.Println("conn.Write(bytes) fail", err)
		return
	}
	return
}
func (this *Transfer)ReadPkg() (mes message.Message, err error) {
	
	//fmt.Println("wait reading....")

	n, err := this.Conn.Read(this.Buf[:4])
	if n != 4 || err != nil {
		err = errors.New("read pkg header failed")
		return
	}

	var pkgLen uint32
	pkgLen = binary.BigEndian.Uint32(this.Buf[:4])

	n, err = this.Conn.Read(this.Buf[:pkgLen])
	if n != int(pkgLen) || err != nil {
		err = errors.New("read pkg content failed")
		return
	}

	err = json.Unmarshal(this.Buf[:pkgLen], &mes)
	if err != nil {
		err = errors.New("Unmarshal pkg body failed")
		return
	}

	return
}