<?php
// @codingStandardsIgnoreFile
/**
 * IP utilities.
 *
 * Copyright: © 2009-2011
 * {@link http://websharks-inc.com/ WebSharks, Inc.}
 * (coded in the USA)
 *
 * Released under the terms of the GNU General Public License.
 * You should have received a copy of the GNU General Public License,
 * along with this software. In the main directory, see: /licensing/
 * If not, see: {@link http://www.gnu.org/licenses/}.
 *
 * @since 161110
 */
if (!class_exists('c_ws_plugin__s2member_utils_ip')) {
    /**
     * IP utilities.
     *
     * @since 161110
     */
    class c_ws_plugin__s2member_utils_ip
    {
        /**
         * Get the current visitor's real IP address.
         *
         * @since 161110 IP utilities.
         *
         * @return string Real IP address, else `unknown` on failure.
         *
         * @note This supports both IPv4 and IPv6 addresses.
         * @note See my tests against this here: http://3v4l.org/fVWUp
         */
        public static function current()
        {
            static $ip; // Static cache.

            if ($ip !== null) {
                return $ip;
            }
            $sources = array(
                'HTTP_CF_CONNECTING_IP',
                'HTTP_CLIENT_IP',
                'HTTP_X_FORWARDED_FOR',
                'HTTP_X_FORWARDED',
                'HTTP_X_CLUSTER_CLIENT_IP',
                'HTTP_FORWARDED_FOR',
                'HTTP_FORWARDED',
                'HTTP_VIA',
                'REMOTE_ADDR',
            );
            $sources                = apply_filters('ws_plugin__s2member_current_ip_sources', $sources);
            $prioritize_remote_addr = apply_filters('ws_plugin__s2member_current_ip_prioritize_remote_addr', false);

            if (!empty($_SERVER['REMOTE_ADDR']) && $prioritize_remote_addr) {
                if (($_valid_public_ip = self::valid_public((string) $_SERVER['REMOTE_ADDR']))) {
                    return $ip = $_valid_public_ip;
                } // unset($_valid_public_ip); // Housekeeping.
            }
            foreach ($sources as $_key => $_source) {
                if (!empty($_SERVER[$_source])) { // Exists?
                    if (($_valid_public_ip = self::valid_public((string) $_SERVER[$_source]))) {
                        return $ip = $_valid_public_ip;
                    }
                } // unset($_key, $_source, $_valid_public_ip); // Housekeeping.
            }
            if (!empty($_SERVER['REMOTE_ADDR'])) {
                return $ip = strtolower((string) $_SERVER['REMOTE_ADDR']);
            }
            return $ip = 'unknown'; // Not possible.
        }

        /**
         * Gets a valid/public IP address.
         *
         * @since 161110 IP utilities.
         *
         * @param string $list_of_possible_ips A single IP, or a comma-delimited list of IPs.
         *
         * @return string A valid/public IP address (if one is found), else an empty string.
         *
         * @note This supports both IPv4 and IPv6 addresses.
         * @note See my tests against this here: http://3v4l.org/fVWUp
         */
        public static function valid_public($list_of_possible_ips)
        {
            if (!$list_of_possible_ips || !is_string($list_of_possible_ips)) {
                return ''; // Empty or invalid data.
            } elseif (!($list_of_possible_ips = trim($list_of_possible_ips))) {
                return ''; // Not possible; i.e., empty string.
            }
            foreach (preg_split('/[\s;,]+/', $list_of_possible_ips, -1, PREG_SPLIT_NO_EMPTY) as $_key => $_possible_ip) {
                if (($_valid_public_ip = filter_var(strtolower($_possible_ip), FILTER_VALIDATE_IP, FILTER_FLAG_NO_PRIV_RANGE | FILTER_FLAG_NO_RES_RANGE))) {
                    return $_valid_public_ip; // A valid public IPv4 or IPv6 address.
                }
            } // unset($_key, $_possible_ip, $_valid_public_ip); // Housekeeping.

            return ''; // Default return value.
        }
    }
}