if($_POST['action'] == 'call_this') {
    checkUser();
}

function checkUser() {
$url = 'myshopurl'; //code uses actual url
$key = 'mykey'; //code uses actual key
$debug =  true;
require_once('./PSWebServiceLibrary.php');

$webService = new PrestaShopWebservice($url, $key, $debug);
$COOKIE_KEY = 'mycookiekey'; //code uses actual cookie key
$password = $_REQUEST['password'];
$email = $_REQUEST['email'];

$optUser = array(
    'resource' => 'customers',
    'filter[email]' => '[' . $email . ']',
    'display' => '[id,email,lastname,firstname,passwd]'
);

$resultUser = ($webService->get($optUser));

$json = json_encode($resultUser);
echo $json;

foreach ($resultUser->customers->customer as $info) {


    $salt = substr($info->passwd, strrpos($info->passwd, ':') + 1, 2);

    $ZCpassword = md5($COOKIE_KEY . $password) . ':' . $salt;

    // Check if password comparison is true or false
    if (password_verify($password, $info->passwd) == true) {
        session_start();
        $response = array();
        $response['status'] = 'success';
        $response['message'] = "You did it!";
        setcookie("userId", $info->id);
        header('Content-type: application/json');
        echo json_encode($response);
    } else {
        $response = array();
        $response['status'] = 'error';
        $response['message'] = 'Wrong password';
        header('Content-type: application/json');
        echo json_encode($response);
    }
}