package netTools //main //
 
import (
	"fmt"
	"net"
	"strconv"
	"strings"
	"time"
)
 
func smain() {
	lis,err := net.Listen("tcp",":1789")
	if err != nil {
		fmt.Println(err)
	}
	defer lis.Close()
	for {
		con,_ := lis.Accept()
		go handler(con)
	}
}
 
func handler(con net.Conn) {
	defer con.Close()
	buf := make([]byte,20)
	n,_ := con.Read(buf)
	fmt.Println(string(buf[:n]))
	con.Write(buf)
	con.Write(buf)
}
 
//func main() {
//	buf,err := Telnet([]string{"w_Hello World","r_50","r_30"},"127.0.0.1:1789",20)
//	fmt.Println(err)
//	fmt.Println(string(buf))
//}
 
func PortIsOpen(ip string,timeout int) bool {
	con,err := net.DialTimeout("tcp",ip,time.Duration(timeout))
	if err != nil {
		return false
	}
	con.Close()
	return true
}
 
func Telnet(action []string,ip string,timeout int) (buf []byte,err error) {
	con,time.Duration(timeout)*time.Second)
	if err != nil {
		return
	}
	defer con.Close()
	con.SetReadDeadline(time.Now().Add(time.Second * 5))
	for _,v := range action {
		l := strings.SplitN(v,"_",2)
		if len(l) < 2 {
			return
		}
		switch l[0] {
		case "r":
			var n int
			n,err = strconv.Atoi(l[1])
			if err != nil {
				return
			}
			p := make([]byte,n)
			n,err = con.Read(p)
			if err != nil {
				return
			}
			buf = append(buf,p[:n]...)
			fmt.Println(buf)
		case "w":
			_,err = con.Write([]byte(l[1]))
		}
	}
	return
}