package main

import (
	"flag"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"strings"

	"github.com/gorilla/mux"
)

var (
	port      *int     // port the http server listens on
	usernames []string // list of usernames
)

func registerHTTPFlags() {
	port = flag.Int("port", 8081, "The port the http server should listen on")
}

func setupHTTPServer() http.Server {
	r := mux.NewRouter()

	r.HandleFunc("/", indexHandler)
	r.HandleFunc("/register", registerGetHandler).Methods("GET")
	r.HandleFunc("/register", registerPostHandler).Methods("POST")

	return http.Server{
		Addr:    fmt.Sprintf("0.0.0.0:%d", *port),
		Handler: r,
	}
}

// Host of the index file
func indexHandler(w http.ResponseWriter, r *http.Request) {
	readFileToReponse(w, "/index.html")
}

// Read register page
func registerGetHandler(w http.ResponseWriter, r *http.Request) {
	readFileToReponse(w, "/register.html")
}

// Process a registration
func registerPostHandler(w http.ResponseWriter, r *http.Request) {
	r.ParseForm()

	username := r.Form.Get("username")

	// test if the username has already been chosen
	if !isUniq(username) {
		log.Println("redirecting to usernameTaken")
		usernameTakenGetHandler(w, r)
		return
	}

	// add the new username to the list of usernames
	usernames = append(usernames, username)

	// generate a new accesscode
	accesscode := newAccessCode()
	log.Printf("Generated a new AccessCode for user %s: %s", username, accesscode)

	// redirect the user to the front page
	http.Redirect(w, r, "/", http.StatusTemporaryRedirect)
}

func usernameTakenGetHandler(w http.ResponseWriter, r *http.Request) {
	log.Println("[usernameTaken]")
	readFileToReponse(w, "/usernameTaken.html")
}

func isUniq(username string) bool {
	for _, user := range usernames {
		if username == user {
			return false
		}
	}
	return true
}

func readFileToReponse(w http.ResponseWriter, path string) {
	requestedFile := strings.Replace(path, "..", "", -1)

	contents, readError := ioutil.ReadFile(fmt.Sprintf("hosted/%s", requestedFile))

	if readError != nil {
		w.Write([]byte(fmt.Sprintf("unable to read %s", requestedFile)))
	} else {
		w.Write([]byte(contents))
	}
}