package main

import (
	"context"
	"flag"
	"fmt"
	"log"
	"net/http"
	"os"
	"os/signal"
	"path/filepath"
	"syscall"
)

var tftpDir string

func main() {
	var studentsFile string

	var lc loginChecker

	var bind = flag.String("bind", ":8081", "Bind port/socket")
	flag.StringVar(&studentsFile, "students", "./students.csv", "Path to a CSV file containing students list")
	flag.StringVar(&ARPTable, "arp", ARPTable, "Path to ARP table")
	flag.StringVar(&tftpDir, "tftpdir", "/var/tftp/", "Path to TFTPd directory")
	flag.StringVar(&loginSalt, "loginsalt", "adelina", "secret used in login HMAC")

	flag.BoolVar(&lc.noAuth, "noauth", false, "don't perform password check")
	flag.StringVar(&lc.ldapAddr, "ldaphost", "auth.cri.epita.fr", "LDAP host")
	flag.IntVar(&lc.ldapPort, "ldapport", 636, "LDAP port")
	flag.BoolVar(&lc.ldapIsTLS, "ldaptls", false, "Is LDAP connection LDAPS?")
	flag.StringVar(&lc.ldapBase, "ldapbase", "dc=epita,dc=net", "LDAP base")
	flag.StringVar(&lc.ldapBindUsername, "ldapbindusername", "", "LDAP user to use in order to perform bind (optional if search can be made anonymously)")
	flag.StringVar(&lc.ldapBindPassword, "ldapbindpassword", "", "Password for the bind user")
	flag.Parse()

	var err error

	// Sanitize options
	log.Println("Checking paths...")
	if tftpDir, err = filepath.Abs(tftpDir); err != nil {
		log.Fatal(err)
	}

	lc.students, err = readStudentsList(studentsFile)
	if err != nil {
		log.Fatal(err)
	}

	// Prepare graceful shutdown
	interrupt := make(chan os.Signal, 1)
	signal.Notify(interrupt, os.Interrupt, syscall.SIGHUP)
	signal.Notify(interrupt, os.Interrupt, syscall.SIGTERM)
	signal.Notify(interrupt, os.Interrupt, syscall.SIGINT)

	srv := &http.Server{
		Addr: *bind,
	}

	log.Println("Registering handlers...")
	mux := http.NewServeMux()
	mux.HandleFunc("/", Index)
	mux.Handle("/login", lc)
	mux.HandleFunc("/logout", logout)
	http.HandleFunc("/", mux.ServeHTTP)

	// Serve content
	go func() {
		log.Fatal(srv.ListenAndServe())
	}()
	log.Println(fmt.Sprintf("Ready, listening on %s", *bind))

	// Wait shutdown signal
	mloop: for {
		switch <-interrupt {
		case syscall.SIGHUP:
			log.Println("Reloading students files...")
			if lc.students, err = readStudentsList(studentsFile); err != nil {
				log.Println("Error during students.csv reload:", err)
			}
		case syscall.SIGTERM:
			break mloop;
		case syscall.SIGINT:
			break mloop;
		}
	}

	log.Print("The service is shutting down...")
	srv.Shutdown(context.Background())
	log.Println("done")
}