/**
  * Initialize a new instance of the WordPress Auto-Update class
  *
  * @param string $current_version
  * @param string $update_path
  * @param string $plugin_slug
  */
 function __construct($current_version, $update_path, $plugin_slug)
 {
     // Set the class public variables
     $this->current_version = $current_version;
     $this->update_path = $update_path;
     $this->plugin_slug = $plugin_slug;
     $t = explode('/', $plugin_slug);
     $this->slug = str_replace('.php', '', $t[1]);
     // define the alternative API for updating checking
     add_filter('pre_set_site_transient_update_plugins', array(&$this, 'check_update'));
     // Define the alternative response for information checking
     add_filter('plugins_api', array(&$this, 'check_info'), 10, 3);
     add_action('in_plugin_update_message-' . vc_plugin_name(), array(&$this, 'addUpgradeMessageLink'));
 }

 /**
  * Downloads new VC from Envato marketplace and unzips into temporary directory.
  *
  * @param $reply
  * @param $package
  * @param $updater
  *
  * @return mixed|string|WP_Error
  */
 public function upgradeFilterFromEnvato($reply, $package, $updater)
 {
     global $wp_filesystem;
     if (isset($updater->skin->plugin) && $updater->skin->plugin === vc_plugin_name() || isset($updater->skin->plugin_info) && $updater->skin->plugin_info['Name'] === $this->title) {
         $updater->strings['download_envato'] = __('Downloading package from envato market...', 'js_composer');
         $updater->skin->feedback('download_envato');
         $package_filename = 'js_composer.zip';
         $res = $updater->fs_connect(array(WP_CONTENT_DIR));
         if (!$res) {
             return new WP_Error('no_credentials', __("Error! Can't connect to filesystem", 'js_composer'));
         }
         $username = vc_settings()->get('envato_username');
         $api_key = vc_settings()->get('envato_api_key');
         $purchase_code = vc_settings()->get('js_composer_purchase_code');
         if (!vc_license()->isActivated() || empty($username) || empty($api_key) || empty($purchase_code)) {
             return new WP_Error('no_credentials', __('To receive automatic updates license activation is required. Please visit <a href="' . admin_url('admin.php?page=vc-updater') . '' . '" target="_blank">Settings</a> to activate your Visual Composer.', 'js_composer'));
         }
         $json = wp_remote_get($this->envatoDownloadPurchaseUrl($username, $api_key, $purchase_code));
         $result = json_decode($json['body'], true);
         if (!isset($result['download-purchase']['download_url'])) {
             return new WP_Error('no_credentials', __('Error! Envato API error', 'js_composer') . (isset($result['error']) ? ': ' . $result['error'] : '.'));
         }
         $result['download-purchase']['download_url'];
         $download_file = download_url($result['download-purchase']['download_url']);
         if (is_wp_error($download_file)) {
             return $download_file;
         }
         $upgrade_folder = $wp_filesystem->wp_content_dir() . 'uploads/js_composer_envato_package';
         if (is_dir($upgrade_folder)) {
             $wp_filesystem->delete($upgrade_folder);
         }
         $result = unzip_file($download_file, $upgrade_folder);
         if ($result && is_file($upgrade_folder . '/' . $package_filename)) {
             return $upgrade_folder . '/' . $package_filename;
         }
         return new WP_Error('no_credentials', __('Error on unzipping package', 'js_composer'));
     }
     return $reply;
 }

 /**
  * Shows message on Wp plugins page with a link for updating from envato.
  */
 public function addUpgradeMessageLink()
 {
     $username = vc_settings()->get('envato_username');
     $api_key = vc_settings()->get('envato_api_key');
     $purchase_code = vc_settings()->get('js_composer_purchase_code');
     echo '<style type="text/css" media="all">tr#wpbakery-visual-composer + tr.plugin-update-tr a.thickbox + em { display: none; }</style>';
     if (empty($username) || empty($api_key) || empty($purchase_code)) {
         echo ' <a href="' . $this->url . '">' . __('Download new version from CodeCanyon.', 'js_composer') . '</a>';
     } else {
         // update.php?action=upgrade-plugin&plugin=testimonials-widget%2Ftestimonials-widget.php&_wpnonce=6178d48b6e
         // echo '<a href="' . wp_nonce_url( admin_url( 'plugins.php?vc_action=vc_upgrade' ) ) . '">' . __( 'Update Visual Composer now.', 'js_composer' ) . '</a>';
         echo '<a href="' . wp_nonce_url(admin_url('update.php?action=upgrade-plugin&plugin=' . vc_plugin_name()), 'upgrade-plugin_' . vc_plugin_name()) . '">' . __('Update Visual Composer now.', 'js_composer') . '</a>';
     }
 }

 /**
  * Gets updater instance.
  *
  * @return Vc_Updater
  */
 public function updater()
 {
     if (!isset($this->factory['updater'])) {
         do_action('vc_before_init_updater');
         require_once $this->path('UPDATERS_DIR', 'class-vc-updater.php');
         $updater = new Vc_Updater();
         require_once vc_path_dir('UPDATERS_DIR', 'class-vc-updating-manager.php');
         $updater->setUpdateManager(new Vc_Updating_Manager(WPB_VC_VERSION, $updater->versionUrl(), vc_plugin_name()));
         $this->factory['updater'] = $updater;
         do_action('vc_after_init_updater');
     }
     return $this->factory['updater'];
 }

 /**
  * Disables the VC updater function
  *
  * @since  3.0.0
  */
 public function disable_updater()
 {
     // Make sure theme mode is enabled
     if (!$this->vc_theme_mode) {
         return;
     }
     /**
      * Remove update pre_download filter
      *
      * @see Vc_Updater
      *
      */
     if (empty($GLOBALS['wp_filter']['upgrader_pre_download'])) {
         return;
     } else {
         $filters = $GLOBALS['wp_filter']['upgrader_pre_download'];
     }
     // Loop through filter
     foreach ($filters as $priority => $filter) {
         foreach ($filter as $identifier => $function) {
             if (is_array($function) and is_a($function['function'][0], 'Vc_Updater') and 'upgradeFilterFromEnvato' === $function['function'][1]) {
                 remove_filter('upgrader_pre_download', array($function['function'][0], 'upgradeFilterFromEnvato'), $priority);
             }
         }
     }
     /**
      * Remove Updater message in plugins list
      *
      * @see Vc_Updating_Manager
      *
      */
     if (!function_exists('vc_plugin_name')) {
         return;
     }
     $tag = 'in_plugin_update_message-' . vc_plugin_name();
     if (empty($GLOBALS['wp_filter'][$tag])) {
         return;
     } else {
         $filters = $GLOBALS['wp_filter'][$tag];
     }
     // Return if filters are empty
     if (empty($filters)) {
         return;
     }
     // Loop through filter
     foreach ($filters as $priority => $filter) {
         foreach ($filter as $identifier => $function) {
             if (is_array($function) and is_a($function['function'][0], 'Vc_Updating_Manager') and 'check_update' === $function['function'][1]) {
                 remove_filter($tag, array($function['function'][0], 'check_update'), $priority);
             }
         }
     }
 }

 /**
  * Disables the VC updater function
  *
  * @since  3.0.0
  */
 public function disable_updater()
 {
     // Get Globals
     global $GLOBALS;
     /**
      * Remove update pre_download filter
      *
      * @see Vc_Updater
      *
      */
     if (!empty($GLOBALS['wp_filter']['upgrader_pre_download'])) {
         $filters = $GLOBALS['wp_filter']['upgrader_pre_download'];
         if (!empty($filters) && is_array($filters)) {
             foreach ($filters as $priority => $filter) {
                 foreach ($filter as $identifier => $function) {
                     if (is_array($function) and is_a($function['function'][0], 'Vc_Updater') and 'upgradeFilterFromEnvato' === $function['function'][1]) {
                         remove_filter('upgrader_pre_download', array($function['function'][0], 'upgradeFilterFromEnvato'), $priority);
                     }
                 }
             }
         }
     }
     /**
      * Remove Updater message in plugins list
      *
      * @see Vc_Updating_Manager
      *
      */
     if (function_exists('vc_plugin_name')) {
         $tag = 'in_plugin_update_message-' . vc_plugin_name();
         if (!empty($GLOBALS['wp_filter'][$tag])) {
             $filters = $GLOBALS['wp_filter'][$tag];
             if (!empty($filters) && is_array($filters)) {
                 foreach ($filters as $priority => $filter) {
                     foreach ($filter as $identifier => $function) {
                         if (is_array($function) and is_a($function['function'][0], 'Vc_Updating_Manager') and 'check_update' === $function['function'][1]) {
                             remove_filter($tag, array($function['function'][0], 'check_update'), $priority);
                         }
                     }
                 }
             }
         }
     }
 }