package comm

import (
	"fmt"
	"log"
	"net"
	"os"
	"path/filepath"
	"strings"
	"time"
)

func GetFreePort() (int, error) {
	addr, err := net.ResolveTCPAddr("tcp", "localhost:0")
	if err != nil {
		return 0, err
	}

	l, err := net.ListenTCP("tcp", addr)
	if err != nil {
		return 0, err
	}
	defer l.Close()
	return l.Addr().(*net.TCPAddr).Port, nil
}

func GetLocalIpByName(adapterName string) net.IP {

	ifaces, err := net.Interfaces()
	// handle err
	if err != nil {
		log.Println("No network:", err)
		return nil
	}

	for _, i := range ifaces {
		if strings.Contains(i.Name, adapterName) {
			addrs, err := i.Addrs()
			if err != nil {
				log.Println("No IP:", err)
				return nil
			}

			for _, addr := range addrs {
				var ip net.IP
				switch v := addr.(type) {
				case *net.IPNet:
					log.Println("IPNET")
					ip = v.IP
				case *net.IPAddr:
					log.Println("IPAddr")
					ip = v.IP
				}
				if ip[0] == 0 {
					log.Println("Get device:", i.Name)
					return ip
				}
			}
		}
	}

	return nil
}

func IsExist(path string) bool {
	_, err := os.Stat(path)
	if err != nil {
		if os.IsExist(err) {
			return true
		}
		if os.IsNotExist(err) {
			return false
		}
		fmt.Println(err)
		return false
	}
	return true
}

func CreateSessionId() string {
	t := time.Now()
	date := t.Format("20060102150405")
	return fmt.Sprintf("s%s-%d", date, t.Nanosecond())
}

func GetCurrentDir() string {
	dir, err := filepath.Abs(filepath.Dir(os.Args[0]))
	if err != nil {
		return ""
	}
	return strings.Replace(dir, "\\", "/", -1)
}