public function action_parse_sites()
    {
        $directory = APPPATH . 'logs/parser/';
        $threads_count = 20;
        
        /**================ Map ================*/
        if (!file_exists($directory . '1.dat'))
        {
            $db = Database::instance();
            $db_expr_null = DB::expr('NULL');
            
            $ids = DB::select('id')
                ->from('sites')
                ->where('description', 'IS', $db_expr_null)
                ->where('keywords', 'IS', $db_expr_null)
                ->or_where_open()
                ->where('description', '=', '')
                ->or_where('keywords', '=', '')
                ->or_where_close()
                ->execute($db)
                ->as_array(null, 'id');
            
            $ids_count = count($ids);
            $size = ceil($ids_count / $threads_count);
            
            for ($i = 0; $i < $threads_count; ++ $i)
            {
                file_put_contents($directory . ($i + 1) . '.dat', serialize(array_splice($ids, 0, $size)));
            }
        }
        
        for ($i = 0; $i < $threads_count; ++ $i)
        {
            if (file_exists($directory . ($i + 1) . '.dat') && !file_exists($directory . ($i + 1) . '.lock'))
            {
                $this->_log_parser($i + 1, 'Started');
                file_put_contents($directory . ($i + 1) . '.lock', '');
                $this->_log_parser($i + 1, 'Locked');
                
                try
                {
                    $ids = unserialize(file_get_contents($directory . ($i + 1) . '.dat'));
                    $this->_log_parser($i + 1, 'Retrieved ' . count($ids) . ' IDs');
                    $j = 0;

                    /** ================ Reduce ================*/
                    while (($id = array_shift($ids)) !== false)
                    {
                        $site = ORM::factory('site', $id);
                        
                        if (!$site->loaded())
                            continue;
                        
                        try
                        {
                            $result = $site->_get_content();

                            $is_available = $result['content'] !== null;

                            if ($is_available)
                            {
                                $description = $site->parse_description($result['content']);
                                $site->description = $description !== '' ? $description: null;
                                
                                $keywords = $site->parse_keywords($result['content']);
                                $site->keywords = $keywords !== '' ? $keywords : null;
                                
                                $site
                                    ->values([
                                        'is_available' => (int)$is_available,
                                        'last_pinged_at' => time(),
                                    ])
                                    ->update()
                                    ->clear();
                            }
                        }
                        catch (Curl_Exception $exception) {}
                        catch (ORM_Validation_Exception $exception)
                        {
                            Kohana::$log->add(Log::ERROR, Kohana_Exception::text($exception));
                            $strace = Kohana_Exception::text($exception) . "\n--\n" . $exception->getTraceAsString();
                            Kohana::$log->add(Log::STRACE, $strace);
                            Kohana::$log->write();

                            continue;
                        }
                        catch (ErrorException $exception)
                        {
                            if (strstr($exception->getMessage(), 'mb_convert_encoding') !== false)
                            {
                                Kohana::$log->add(Log::ERROR, Kohana_Exception::text($exception));
                                $strace = Kohana_Exception::text($exception) . "\n--\n" . $exception->getTraceAsString();
                                Kohana::$log->add(Log::STRACE, $strace);
                                Kohana::$log->write();
                                
                                continue;
                            }
                            else
                            {
                                throw $exception;
                            }
                        }
                        
                        ++ $j;
                        
                        if (!($j % 100))
                        {
                            $this->_log_parser($i + 1, $j . ' IDs processed');
                        }
                    }
                    
                    $this->_log_parser($i + 1, 'All IDs processed succesfully');
                    
                    unlink($directory . ($i + 1) . '.dat');
                    unlink($directory . ($i + 1) . '.lock');
                    
                    $this->_log_parser($i + 1, 'Service files removed');
                    break;
                }
                catch (Exception $exception)
                {
                    $this->_log_parser($i + 1, 'Unexpected exception [' . $exception->getCode() . ']: ' . $exception->getMessage());
                    
                    if (isset($ids) && !empty($ids))
                    {
                        file_put_contents($directory . ($i + 1) . '.dat', serialize($ids));
                        $this->_log_parser($i + 1, 'Unprocessed IDs stored (' . count($ids) . ' left)');
                    }
                    else
                    {
                        $this->_log_parser($i + 1, 'No IDs processed');
                    }
                    
                    unlink($directory . ($i + 1) . '.lock');
                    $this->_log_parser($i + 1, 'Unlocked' . PHP_EOL . PHP_EOL);
                    throw $exception;
                }
            }
        }
    }
    
    protected function _log_parser($thread, $message)
    {
        file_put_contents(APPPATH . 'logs/parser/' . $thread . '.log', '[ ' . date('d.m.Y H:i:s') . ' ] ' . $message . PHP_EOL, FILE_APPEND);
    }