/**
  * Completely whipe all Membership data from Database.
  *
  * Note: This function is not used currently...
  *
  * @since  1.0.0
  */
 private static function cleanup_db()
 {
     global $wpdb;
     $sql = array();
     $trash_ids = array();
     // Delete membership meta-data from users.
     $users = MS_Model_Member::get_members();
     foreach ($users as $user) {
         $user->delete_all_membership_usermeta();
         $user->save();
     }
     // Determine IDs of Membership Pages.
     $page_types = MS_Model_Pages::get_page_types();
     foreach ($page_types as $type => $name) {
         $page_id = MS_Model_Pages::get_setting($type);
         $trash_ids[] = $page_id;
     }
     /**
      * Delete all plugin settings.
      * Settings are saved by classes that extend MS_Model_option
      */
     foreach (MS_Model_Gateway::get_gateways() as $option) {
         $option->delete();
     }
     MS_Factory::load('MS_Model_Addon')->delete();
     MS_Factory::load('MS_Model_Pages')->delete();
     MS_Factory::load('MS_Model_Settings')->delete();
     /**
      * Delete transient data
      * Transient data is saved by classed that extend MS_Model_Transient
      */
     MS_Factory::load('MS_Model_Simulate')->delete();
     /**
      * Delete all plugin content.
      * Content is saved by classes that extend MS_Model_CustomPostType
      */
     $ms_posttypes = array(MS_Model_Communication::get_post_type(), MS_Model_Event::get_post_type(), MS_Model_Invoice::get_post_type(), MS_Model_Transactionlog::get_post_type(), MS_Model_Membership::get_post_type(), MS_Model_Relationship::get_post_type(), MS_Addon_Coupon_Model::get_post_type(), MS_Addon_Invitation_Model::get_post_type());
     foreach ($ms_posttypes as $type) {
         $sql[] = $wpdb->prepare("DELETE FROM {$wpdb->posts} WHERE post_type = %s;", $type);
     }
     // Remove orphaned post-metadata.
     $sql[] = "\n\t\tDELETE FROM {$wpdb->postmeta}\n\t\tWHERE NOT EXISTS (\n\t\t\tSELECT 1 FROM {$wpdb->posts} tmp WHERE tmp.ID = post_id\n\t\t);\n\t\t";
     // Clear all WP transient cache.
     $sql[] = "\n\t\tDELETE FROM {$wpdb->options}\n\t\tWHERE option_name LIKE '_transient_%';\n\t\t";
     foreach ($sql as $s) {
         $wpdb->query($s);
     }
     // Move Membership pages to trash.
     foreach ($trash_ids as $id) {
         wp_delete_post($id, true);
     }
     // Clear all data from WP Object cache.
     wp_cache_flush();
     // Redirect to the main page.
     wp_safe_redirect(MS_Controller_Plugin::get_admin_url());
     exit;
 }