package main

import (
	"flag"
	"fmt"
	"io/ioutil"
	"net"
	"net/http"
	"os"
	"strings"
)

var (
	serverMode bool
	addr       string
	port       string
	envP       string
	host       string
	envHost    string
)

func init() {
	envP = os.Getenv("MYIP_PORT")
	envHost = os.Getenv("MYIP_HOST")

	flag.BoolVar(&serverMode, "s", false, "run in server mode")
	flag.StringVar(&host, "u", "kumoly.io", "hostname to ask for")
	flag.StringVar(&port, "p", "5080", "port to listen|connect")
	flag.StringVar(&addr, "b", "0.0.0.0", "the address the server binds on")
}

func usage() {
	fmt.Fprintf(os.Stderr, "Usage: myip [options]\n")
	flag.PrintDefaults()
}

func main() {
	flag.Parse()
	if envP != "" {
		port = envP
	}
	if envHost != "" {
		host = envHost
	}

	if serverMode {
		http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
			ip := r.Header.Get("X-Real-Ip")
			if ip == "" {
				ip = r.Header.Get("X-Forwarded-For")
			}
			if ip == "" {
				var err error
				ip, _, err = net.SplitHostPort(r.RemoteAddr)
				if err != nil {
					ip = r.RemoteAddr
				}
			}
			fmt.Fprint(w, ip+"\n")
		})

		err := http.ListenAndServe(addr+":"+port, nil)
		if err != nil {
			fmt.Println(err)
			os.Exit(1)
		}

	} else {
		res, err := http.Get("http://" + host + ":" + port)
		if err != nil {
			fmt.Println(err)
			os.Exit(2)
		}
		body, err := ioutil.ReadAll(res.Body)
		res.Body.Close()
		if err != nil {
			fmt.Println(err)
			os.Exit(3)
		}
		fmt.Println(strings.TrimRight(string(body), "\r\n"))
	}
}