package main

import (
	"crypto/rand"
	"encoding/base64"
	"errors"
	"log"
	"net/http"
	"time"
)

type SessionData struct {
	username string
}

var (
	sessions = make(map[string]*SessionData)
)

func userOk(username, password string) bool {
	return (username == "Lamperi" && password == "paskaa")
}

func tryLogin(username, password string, longerTime bool) (http.Cookie, error) {
	if exists := userOk(username, password); !exists {
		return http.Cookie{},
			errors.New("The username or password you entered isn't correct.")
	}

	sid, err := randString(32)
	if err != nil {
		return http.Cookie{}, err
	}

	sessions[sid] = &SessionData{username}

	hours := time.Duration(1)
	if longerTime {
		hours = time.Duration(336)
	}

	loginCookie := http.Cookie{
		Name:     "id",
		Value:    sid,
		MaxAge:   int((time.Hour * hours).Seconds()),
		HttpOnly: true,
	}

	return loginCookie, nil
}

func getSession(req *http.Request) (*SessionData, error) {
	cookie, err := req.Cookie("id")
	if err != nil {
		return nil, err
	}

	session, exists := sessions[cookie.Value]
	if !exists {
		return nil, errors.New("Session expired from server")
	}
	return session, nil
}

func randString(size int) (string, error) {
	buf := make([]byte, size)

	if _, err := rand.Read(buf); err != nil {
		log.Println(err)
		return "", errors.New("Couldn't generate random string")
	}

	return base64.URLEncoding.EncodeToString(buf)[:size], nil
}