<?php
/**
 * (c) Copyright Ascensio System SIA 2023
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

require dirname(__FILE__) . '/config.php';

/**
 * Check if the request is an AJAX request
 *
 * @return bool
 */
function isAjax()
{
    return isset($_SERVER['HTTP_X_REQUESTED_WITH'])
        && mb_strtolower($_SERVER['HTTP_X_REQUESTED_WITH']) == 'xmlhttprequest';
}

/**
 * Get the http origin
 *
 * @return string
 */
function getHttpOrigin()
{
    $origin = '';
    if (!empty($_SERVER['HTTP_ORIGIN'])) {
        $origin = $_SERVER['HTTP_ORIGIN'];
    }
    return $origin;
}

/**
 * Set headers that prevent caching in all the browsers
 *
 * @return void
 */
function nocacheHeaders()
{
    $headers = [
        'Expires' => 'Wed, 11 Jan 1984 05:00:00 GMT',
        'Cache-Control' => 'no-cache, must-revalidate, max-age=0',
        'Pragma' => 'no-cache',
    ];
    $headers['Last-Modified'] = false;

    unset($headers['Last-Modified']);

    // In PHP 5.3+, make sure we are not sending a Last-Modified header.
    if (function_exists('header_remove')) {
        @header_remove('Last-Modified');
    } else {
        // In PHP 5.2, send an empty Last-Modified header, but only as a
        // last resort to override a header already sent. #WP23021
        foreach (headers_list() as $header) {
            if (0 === mb_stripos($header, 'Last-Modified')) {
                $headers['Last-Modified'] = '';
                break;
            }
        }
    }

    foreach ($headers as $name => $field_value) {
        @header("{$name}: {$field_value}");
    }
}