package main

import (
	"flag"
	"log"
	"net"
	"net/http"
	"net/http/httputil"
	"net/url"
	"os"
)

type myConfig struct {
	MyURL  string
	MySock string
	Strip  string
	Log    bool
}

func logRequest(handler http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		log.Printf("%s %s %s\n", r.RemoteAddr, r.Method, r.URL)
		handler.ServeHTTP(w, r)
	})
}

func main() {
	var c myConfig

	flag.StringVar(&c.MyURL, "url", "", "URL to proxy to")
	flag.StringVar(&c.MySock, "unix", "", "Unix socket to listen on")
	flag.StringVar(&c.Strip, "strip", "", "Strip prefix from reqeusts")
	flag.BoolVar(&c.Log, "log", false, "Log requests to stdout")
	flag.Parse()

	if c.MySock == "" {
		log.Fatal("sock argument required")
	}
	rpURL, err := url.Parse(c.MyURL)
	if err != nil {
		log.Fatal(err)
	}

	if err := os.RemoveAll(c.MySock); err != nil {
		log.Fatal(err)
	}

	if c.Strip == "" {
		c.Strip = "/"
	}

	frontendProxy := httputil.NewSingleHostReverseProxy(rpURL)

	srv := &http.Server{}
	if c.Strip == "" {
		if c.Log {
			srv.Handler = logRequest(frontendProxy)
		} else {
			srv.Handler = frontendProxy
		}
	} else {
		if c.Log {
			srv.Handler = logRequest(http.StripPrefix(c.Strip, frontendProxy))

		} else {
			srv.Handler = http.StripPrefix(c.Strip, frontendProxy)
		}
	}

	unixListener, err := net.Listen("unix", c.MySock)
	os.Chmod(c.MySock, 0777)

	if err != nil {
		log.Fatal(err)
	}
	log.Fatal(srv.Serve(unixListener))
}