public static function filter($request)
    {

        $columns = $request->get('columns');
        $order = $request->get('order');

        $customers = self::select([
            'customers.id AS id',
            'customers.name AS name',
            'customers.phone AS phone',
            'customers.email AS email',
            'customers.address AS address',
            'customers.website AS website',
            'customers.comment AS comment',
            'customers.created_at AS created_at',
            'cs.name AS status',
            'ct.name AS type',
            'c.name AS city',
            'm.surname AS manager_surname',
            'm.name AS manager_name',
            'm.fathername AS manager_fathername'
        ])
            ->leftJoin('customers_statuses AS cs', function($q){
                $q->on(DB::raw('customers.status_id = cs.id'), DB::raw(''), DB::raw(''));
            })
            ->leftJoin('customers_types AS ct', function($q){
                $q->on(DB::raw('customers.type_id = ct.id'), DB::raw(''), DB::raw(''));
            })
            ->leftJoin('cities AS c', function($q){
                $q->on(DB::raw('customers.city_id = c.id'), DB::raw(''), DB::raw(''));
            })
            ->leftJoin('users AS m', function($q) {
                $q->on('customers.manager_id', '=', 'm.id');
            });

        if($columns){
            foreach($columns as $column){
                if(isset($column['search']['value']) && !empty($column['search']['value']) && $column['searchable'] == 'true'){
                    if(preg_match('#_at#', $column['name'])) {
                        $parts = explode('-', $column['search']['value']);
                        if (isset($parts[0]) && !empty($parts[0]) && isset($parts[1]) && !empty($parts[1])) {
                            $customers->whereBetween('customers.' . $column['name'], [(new Carbon($parts[0]))->format('Y-m-d'), (new Carbon($parts[1]))->format('Y-m-d')]);
                        } else if (isset($parts[0]) && !empty($parts[0])) {
                            $customers->where('customers.' . $column['name'], '>', (new Carbon($parts[0]))->format('Y-m-d'));
                        } else if (isset($parts[1]) && !empty($parts[1])) {
                            $customers->where('customers.' . $column['name'], '<', (new Carbon($parts[1]))->format('Y-m-d'));
                        }
                    }else if($column['name'] == 'name') {
                        $customers->where(function ($q) use ($column) {
                            $q->where('customers.name', 'LIKE', $column['search']['value'] . '%');
                        });
                    }else if($column['name'] == 'id'){
                        $customers->where('customers.' . $column['name'], '=', $column['search']['value']);
                    }else{
                        $customers->where($column['name'], '=', $column['search']['value']);
                    }
                }
            }
        }

        if(isset($columns[$order[0]['column']]['data']) && isset($order[0]['dir'])){
            if($columns[$order[0]['column']]['orderable'] == 'false'){
                $columns[$order[0]['column']]['data'] = 'id';
            }

            $customers->orderBy($columns[$order[0]['column']]['data'], $order[0]['dir']);
        }

        return $customers;

    }