package local

import (
	//"github.com/davecgh/go-spew/spew"
	"errors"
	"log"
	"runtime"
	"strings"

	"github.com/gravitl/netmaker/netclient/ncutils"
)

func SetIPForwarding() error {
	os := runtime.GOOS
	var err error
	switch os {
	case "linux":
		err = SetIPForwardingLinux()
	case "darwin":
		err = SetIPForwardingMac()
	default:
		err = errors.New("This OS is not supported")
	}
	return err
}

func SetIPForwardingLinux() error {
	out, err := ncutils.RunCmd("sysctl net.ipv4.ip_forward", true)
	if err != nil {
		log.Println("WARNING: Error encountered setting ip forwarding. This can break functionality.")
		return err
	} else {
		s := strings.Fields(string(out))
		if s[2] != "1" {
			_, err = ncutils.RunCmd("sysctl -w net.ipv4.ip_forward=1", true)
			if err != nil {
				log.Println("WARNING: Error encountered setting ip forwarding. You may want to investigate this.")
				return err
			}
		}
	}
	return nil
}

func SetIPForwardingMac() error {
	_, err := ncutils.RunCmd("sysctl -w net.inet.ip.forwarding=1", true)
	if err != nil {
		log.Println("WARNING: Error encountered setting ip forwarding. This can break functionality.")
	}
	return err
}

func IsWGInstalled() bool {
	out, err := ncutils.RunCmd("wg help", true)
	if err != nil {
		return false
	}
	return strings.Contains(out, "Available subcommand")
}

func GetMacIface(addr string) (string, error) {
	out, err := ncutils.RunCmd("route get "+addr, false)
	var iface string
	if err != nil {
		return iface, errors.New(string(out))
	}
	for _, line := range strings.Split(strings.TrimSuffix(string(out), "\n"), "\n") {
		if strings.Contains(line, "interface: ") {
			iface = getLineAfter(string(out), "interface: ")
			iface = strings.Split(iface, "\n")[0]
			break
		}
	}
	if iface == "" {
		err = errors.New("could not find iface for ip addr " + addr)
	}
	return iface, err
}

func getLineAfter(value string, a string) string {
	// Get substring after a string.
	pos := strings.LastIndex(value, a)
	if pos == -1 {
		return ""
	}
	adjustedPos := pos + len(a)
	if adjustedPos >= len(value) {
		return ""
	}
	return value[adjustedPos:len(value)]
}

func HasNetwork(network string) bool {

	if ncutils.IsWindows() {
		return ncutils.FileExists(ncutils.GetNetclientPathSpecific() + "netconfig-" + network)
	}
	return ncutils.FileExists("/etc/systemd/system/netclient-"+network+".timer") ||
		ncutils.FileExists(ncutils.GetNetclientPathSpecific()+"netconfig-"+network)
}