package main

import (
	"fmt"
	"io"
	"log"
	"net"
	"net/http"
)

func main() {
	http.HandleFunc("/", getIP)
	fmt.Println("listening on port 3000")
	http.ListenAndServe(":3000", nil)
}

func getIP(w http.ResponseWriter, req *http.Request) {
	ip, _, err := net.SplitHostPort(req.RemoteAddr)
	if err != nil {
		handleError(w, err, "Could not get IP address from request")
		return
	}
	io.WriteString(w, ip+"\n")
	log.Printf("Give response IP %s\n", ip)
}

func handleError(resp http.ResponseWriter, err error, message string) {
	resp.WriteHeader(http.StatusBadRequest)
	io.WriteString(resp, message)
	log.Printf("Error handling request: %s (%s)", message, err)
}