package nettools

import (
	"encoding/base64"
	"encoding/hex"
	"log"
	"math/big"
	"net"
	"net/http"
	"time"

	"golang.org/x/net/proxy"
)

// BasicAuth encodes BasicAuth header
func BasicAuth(username, password string) map[string]string {
	return map[string]string{
		"Authorization": "Basic " + base64.StdEncoding.EncodeToString([]byte(username+":"+password)),
	}
}

// IP returns IP address from requester
func IP(r *http.Request) (net.IP, error) {
	realip := r.Header.Get("x-forwarded-for")
	if realip != "" {
		return net.ParseIP(realip), nil
	}
	ip, _, err := net.SplitHostPort(r.RemoteAddr)
	if err != nil {
		return nil, err
	}
	return net.ParseIP(ip), nil
}

// Inet6Aton Encodes ip address to hex
func Inet6Aton(ip net.IP) string {
	ipv4 := false
	if ip.To4() != nil {
		ipv4 = true
	}
	ipInt := big.NewInt(0)
	if ipv4 {
		ipInt.SetBytes(ip.To4())
		ipHex := hex.EncodeToString(ipInt.Bytes())
		return ipHex
	}
	ipInt.SetBytes(ip.To16())
	ipHex := hex.EncodeToString(ipInt.Bytes())
	return ipHex
}

// Inet6AtonDecode decodes ip address from hex
func Inet6AtonDecode(ipHex string) (ip net.IP) {
	hex, err := hex.DecodeString(ipHex)
	if err != nil {
		log.Println(err)
		return net.ParseIP("0.0.0.0")
	}
	return net.IP(hex)
}

// Hostname returns hostname
func Hostname(ip net.IP) (hostname string) {
	names, err := net.LookupAddr(ip.String())
	if err != nil {
		return "unknown host"
	}
	return names[0]
}

// Proxy connect to proxy server using SOCKS5
func Proxy(network, address string, auth *proxy.Auth) (client *http.Client, err error) {
	dialer, err := proxy.SOCKS5(network, address, auth, proxy.Direct)
	if err != nil {
		return nil, err
	}
	tr := &http.Transport{Dial: dialer.Dial}
	return &http.Client{
		Transport: tr,
		Timeout:   time.Second * 10,
	}, nil
}