HETNiX.COM - WHMCS Hook: Receive notification after Invoice

<?php
/**
 * WHMCS Invoice Payment Notification
 *
 * Please upload this file to your whmcs includes/hooks folder and name it ipaid.php
 * This code is free and opensource. Feel free to customize it as you need/like
 *
 * @author     HETNiX SRL <office@hetnix.com>
 * @date       17th of July 2015
 * @version    1.0.0
 * @link       https://www.hetnix.com/
 */


if (!defined("WHMCS"))
    die("This file cannot be accessed directly");

function ipaid_notif($vars) {

    $invoiceid = $vars['invoiceid'];

$qry1=mysql_query("SELECT * FROM tblinvoices WHERE id = $invoiceid") or die(mysql_error());
$strx=mysql_fetch_assoc($qry1);
$clidx=$strx['userid'];
$cldtls=mysql_query("SELECT * FROM tblclients WHERE id = $clidx") or die(mysql_error());
$dox=mysql_fetch_assoc($cldtls);


if ($clidx > 0) {

    switch ($strx['paymentmethod']) {

    case 'banktransfer':
        $fnpmth = "Bank Transfer Gateway";
        break;
    case 'paypal':
        $fnpmth = "PayPal Gateway";
        break;



    }

    $toj="**YOUREMAIL@MAILBOX.COM**";
    $subj="Payment received - ".$strx['total']." CURRENCY_CODE - Invoice ".$invoiceid;
    $bodj="Invoice ".$invoiceid." received a payment today of ".$strx['total']." CURRENCY_CODE\nDetails: ".$dox['firstname']." ".$dox['lastname']." paid invoice using ".$fnpmth." today.\n\nView Invoice: http://www.yourdomain.com/whmcs/admin/invoices.php?action=edit&id=".$invoiceid."\n";
    $headersj = 'From: **FROMEMAIL@MAILBOX.COM**' . "\r\n" .
    'Reply-To: **REPLYEMAIL@MAILBOX.COM**' . "\r\n" .
    'X-Mailer: PHP/' . phpversion();
    mail($toj, $subj, $bodj, $headersj);

}

}

add_hook("InvoicePaid",1,"ipaid_notif");

?>