<?php if(!(isset($_SESSION['username']))): ?>
                <P class="lead">No has iniciado sesión <a href="login.php">Inicia sesión</a>
                    </P>

            <?php else: ?>
                <p class="lead">Has iniciado sesión como <?php if(isset($_SESSION['username'])) echo $_SESSION['username']; ?>


 <?php endif ?>

function rememberMe($user_id){
    $encryptCookieData = base64_encode("UaQteh5i4y3dntstemYODEC{$user_id}");
    // Cookie set to expire in about 30 days
    setcookie("rememberUserCookie", $encryptCookieData, time()+60*60*24*100, "/");
}

/**
 * checked if the cookie used is same with the encrypted cookie
 * @param $db, database connection link
 * @return bool, true if the user cookie is valid
 */
function isCookieValid($db){
    $isValid = false;
    if (isset($_COOKIE['rememberUserCookie'])) {

        /**
         * Decode cookies and extract user ID
         */
        $decryptCookieData = base64_decode($_COOKIE['rememberUserCookie']);
        $user_id = explode("UaQteh5i4y3dntstemYODEC", $decryptCookieData);
        $userID = $user_id[1];

        /**
         * check if id retrieved from the cookie exist in the database
         * */
        $sqlQuery = "SELECT * FROM users WHERE id = :id";
        $statement = $db->prepare($sqlQuery);
        $statement->execute(array(':id' => $userID));

        if($row = $statement->fetch()){
            $id = $row['id'];
            $username = $row['username'];

            /**
             * Create the user session variable
             */
            $_SESSION['id'] = $id;
            $_SESSION['username'] = $username;
            $isValid = true;
        }else{
            /**
             * cookie ID is invalid destroy session and logout user
             */
            $isValid = false;
            signout();
        }
    }
    return $isValid;
}

/**
 * kill all sessions, cookies and regenrate session ID
 * Redirect to index page after all
 */
function signout(){
    unset($_SESSION['username']);
    unset($_SESSION['id']);

   if(isset($_COOKIE['rememberUserCookie'])){
        unset($_COOKIE['rememberUserCookie']);
        setcookie('rememberUserCookie', null, -1, '/');
    }
    session_destroy();
    session_regenerate_id(true);
    redirectTo('index');
}

/**
 *
 * @return bool, true if all good
 */
function guard(){

    $isValid = true;
    $inactive = 60 * 15; //15 mins
    $fingerprint = md5($_SERVER['REMOTE_ADDR'] . $_SERVER['HTTP_USER_AGENT']);

    if((isset($_SESSION['fingerprint']) && $_SESSION['fingerprint'] != $fingerprint)){
        $isValid = false;
        signout();
    }else if((isset($_SESSION['last_active']) && (time() - $_SESSION['last_active']) > $inactive) && $_SESSION['username']){
        $isValid = false;
        signout();
    }else{
        $_SESSION['last_active'] = time();
    }

    return $isValid;
}

function isValidImage($file){
    $form_errors = array();

    //split file name into an array using the dot (.)
    $part = explode(".", $file);

    //target the last element in the array
    $extension = end($part);

    switch(strtolower($extension)){
        case 'jpg':
        case 'gif':
        case 'bmp':
        case 'png':

        return $form_errors;
    }

    $form_errors[] = $extension . " is not a valid image extension";
    return $form_errors;
}


function _token(){
    $randonToken = base64_encode(openssl_random_pseudo_bytes(32));
    //$randonToken = md5(uniqid(rand(), true))." md5";

    return $_SESSION['token'] = $randonToken;
}

function validate_token($requestToken){
    if(isset($_SESSION['token']) && $requestToken === $_SESSION['token']){
        unset($_SESSION['token']);

        return true;
    }

    return false;
}

function prepLogin ($id, $username, $remember){
    $_SESSION['id'] = $id;
    $_SESSION['username'] = $username;

    $fingerprint = md5($_SERVER['REMOTE_ADDR'] . $_SERVER['HTTP_USER_AGENT']);
    $_SESSION['last_active'] = time();
    $_SESSION['fingerprint'] = $fingerprint;

    if($remember === "yes"){
        rememberMe($id);
    }
    //call sweet alert
    echo $welcome = "<script type="text/javascript">
                            swal({
                            title: "Welcome back $username!",
                            text: "You're being logged in.",
                            type: 'success',
                            timer: 3000,
                            showConfirmButton: false });
                            setTimeout(function(){
                               window.location.href = 'index.php';
                            }, 3000);
                        </script>";
}