woocommerce-module/retailcrm/include/api/class-wc-retailcrm-proxy.php

<?php
/**
 * RetailCRM Integration.
 *
 * @package  WC_Retailcrm_Proxy
 * @category Integration
 * @author   RetailCRM
 */

if ( ! class_exists( 'WC_Retailcrm_Proxy' ) ) :

    /**
     * Class WC_Retailcrm_Proxy
     */
    class WC_Retailcrm_Proxy
    {
        public function __construct($api_url, $api_key, $api_vers = 'v4')
        {
            $this->logger = new WC_Logger();

            if ( ! class_exists( 'WC_Retailcrm_Client_V3' ) ) {
                include_once( __DIR__ . '/class-wc-retailcrm-client-v3.php' );
            }

            if ( ! class_exists( 'WC_Retailcrm_Client_V4' ) ) {
                include_once( __DIR__ . '/class-wc-retailcrm-client-v4.php' );
            }

            if ( ! class_exists( 'WC_Retailcrm_Client_V5' ) ) {
                include_once( __DIR__ . '/class-wc-retailcrm-client-v5.php' );
            }

            if ($api_url && $api_key) {
                switch ($api_vers) {
                    case 'v3':
                        $this->retailcrm = new WC_Retailcrm_Client_V3($api_url, $api_key);
                        break;

                    case 'v4':
                        $this->retailcrm = new WC_Retailcrm_Client_V4($api_url, $api_key);
                        break;

                    case 'v5':
                        $this->retailcrm = new WC_Retailcrm_Client_V5($api_url, $api_key);
                        break;                    
                }
            }
        }

        public function __call($method, $arguments)
        {
        try {
            $response = call_user_func_array(array($this->retailcrm, $method), $arguments);
            
            if ($response->isSuccessful()) {
                $result = ' Ok';
            } else {
                $result = sprintf(
                    $method ." : Error: [HTTP-code %s] %s",
                    $response->getStatusCode(),
                    $response->getErrorMsg()
                );

                if (isset($response['errors'])) {
                        foreach ($response['errors'] as $error) {
                        $result .= " $error";
                    }
                }
            }

                $this->logger->add('retailcrm', sprintf("[%s] %s", $method, $result));
            } catch (WC_Retailcrm_Exception_Curl $exception) {
                $this->logger->add('retailcrm', sprintf("[%s] %s - %s", $method, $exception->getMessage(), $result));
            } catch (WC_Retailcrm_Exception_Json $exception) {
                $this->logger->add('retailcrm', sprintf("[%s] %s - %s", $method, $exception->getMessage(), $result));
            } catch (InvalidArgumentException $exception) {
                $this->logger->add('retailcrm', sprintf("[%s] %s - %s", $method, $exception->getMessage(), $result));
            }

            return $response;    
        }
    }
endif;