Design pattern for rescourceful feed?

Hi. I would love to have some feedback on a controller used by a feed page in an app that I was building. Im going into a similar project now and feel that this approach is lacking in so many ways. But im still not sure how to design a good index method...

What I need: *Filter on specific attributes *Sort on some attribute *Load x entries *Be able to pick up after the x entries and load x more... (I have considered the pagination, but not convinced since it might break consistensy if the rescource is updated while browsning??)

Okay, so heres my old code (the rescource is a "Trade"):

public function index(Request $request)
{   
    $validator = $this->indexValidator($request->all());                
    if ($validator->fails()) {
        return Response::json([
            'errors' =>  $validator->errors()->all()            
        ], 422);
    } else {        
        $take = intval($request->numberOfTrades) ?: 10;
        $id = intval($request->id) ?: 2147483647; // ~INT limit for 32-bit builds.
        $query = \App\Trade::where('id','<',$id);
        // APPLY SEARCH FILTERS
        $query = $this->applyFilters($query,$request);
        $query->take($take)->orderBy('id','desc');
        //$query->orderBy('id','desc');
        $trades = $query->get();
        
        return Response::json(
            $this->transformCollection($trades)            
        ,200);                          
    }                       
}

private function applyFilters($query, $request)
{
    // Search area
    if ($request->has('radius')) {            
        $lat = $request->lat;
        $lng = $request->lng;
        $radius = $request->radius;            
        $dLat = $this->getDLat();
        $dLng = $this->getDLng($lat);
        // apply search radius (approximating with BBOX)
        $query->where('lat','>',$lat-$radius*$dLat);
        $query->where('lat','<',$lat+$radius*$dLat);
        $query->where('lng','>',$lng-$radius*$dLng);
        $query->where('lng','<',$lng+$radius*$dLng);
    }
    // Search by tags
    if ($request->has('tags')) {
        $tags = $request->tags;
        // SEARCH BY SINGLE TAG IMPLEMENTED ONLY!
        $query->where('tags','LIKE','%' . $tags . '%');            
               
    }
    // Show only free/non free trades
    if ($request->has('free')) {
        //TODO            
    }
    return $query;        
}

Any advice is welcome. Thanks!