package main

import (
	"fmt"
	"net/http"
	"net/http/httputil"
	"os"
	"strings"
	"time"

	"github.com/VividCortex/godaemon"
	"gopkg.in/alecthomas/kingpin.v2"
)

var (
	routedHostnames map[string]int
	// Sites are the enabled sites
	Sites []Site
	// HTTPClient is the http client
	HTTPClient http.Client
)

var (
	logFileLoc = kingpin.Flag("log", "Location of the log file").Default("stdout").String()
	daemonize  = kingpin.Flag("daemon", "If daemonized, the program will run in the background.").Default("false").Bool()
	sitesLoc   = kingpin.Flag("sites_dir", "Location of site files").Short('h').Default("/etc/hostsplitter/").String()
	bindAddr   = kingpin.Flag("bind", "Bind address").Short('b').Default(":80").String()
)

func main() {
	HTTPClient = http.Client{}

	kingpin.Parse()

	fmt.Println("Starting hostsplitter")

	if *logFileLoc != "stdout" {
		logFile, err := os.OpenFile(*logFileLoc, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0640)
		defer logFile.Close()
		if err != nil {
			fmt.Println("error opening file: %v", err)
		}
		fmt.Println("Using ", *logFileLoc, " for logging")
		//log.SetOutput(logFile)
	}

	if *daemonize {
		fmt.Println("Daemonizing... Bye Bye")
		godaemon.MakeDaemon(&godaemon.DaemonAttr{})
	}

	LoadConfig()

	go SignalHandler()

	r := new(revProx)
	fmt.Println(http.ListenAndServe(*bindAddr, r))
}

type revProx struct{}

func (p *revProx) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	if i, ok := routedHostnames[string(r.Host)]; ok {
		reverseProxy := new(httputil.ReverseProxy)
		reverseProxy.Director = func(r *http.Request) {
			r.Header.Set("X-Hostsplitter-Secret", Sites[i].Secret)
			r.Header.Set("Host", r.Host)
			r.URL.Scheme = "http"
			r.URL.Host = Sites[i].GetBackend()
			r.RequestURI = ""
			HTTPLogger(r, http.StatusOK)
		}
		reverseProxy.ServeHTTP(w, r)
	} else {
		HTTPLogger(r, http.StatusBadRequest)
		w.WriteHeader(http.StatusBadRequest)
		w.Write([]byte("Bad Request"))
	}
}

const apacheFormatPattern = "%s - - [%s] \"%s %s %s\" %d %d \"%s\" \"%s\" %.4f\n"

// HTTPLogger logs an http request
func HTTPLogger(r *http.Request, status int) {
	if *logFileLoc != "stdout" {
		logFile, err := os.OpenFile(*logFileLoc, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0640)
		defer logFile.Close()
		if err != nil {
			fmt.Println("error opening file: %v", err)
		}

		timeFormatted := time.Now().Format("02/Jan/2006 03:04:05")
		clientIP := r.RemoteAddr
		if colon := strings.LastIndex(clientIP, ":"); colon != -1 {
			clientIP = clientIP[:colon]
		}

		referer := r.Referer()
		if referer == "" {
			referer = "-"
		}

		userAgent := r.UserAgent()
		if userAgent == "" {
			userAgent = "-"
		}

		fmt.Fprint(logFile, fmt.Sprintf(
			apacheFormatPattern,
			clientIP,
			timeFormatted,
			r.Method,
			r.RequestURI,
			r.Proto,
			status,
			0,
			referer,
			userAgent,
			0.00,
		))
	}
}