WIP

app/Http/Controllers/Api/V1/Filters/FilterController.php

@@ -106,6 +106,23 @@ class FilterController extends Controller
                 ->get();
         }
 
+        if ($this->shouldFilterByChannel()) {
+            $channelId = (int) $this->request->channel_id;
+
+            return DB::table('brands')
+                ->select('brands.id', 'brands.name')
+                ->join('products', 'products.brand_id', '=', 'brands.id')
+                ->join('product_has_relations', 'products.id', '=', 'product_has_relations.product_id')
+                ->where('product_has_relations.productable_type', 'channel')
+                ->where('product_has_relations.productable_id', $channelId)
+                ->where('products.is_visible', true)
+                ->whereNull('products.parent_id')
+                ->where('products.stock', '>', 0)
+                ->groupBy('brands.id', 'brands.name', 'brands.sort_order')
+                ->orderBy('brands.sort_order')
+                ->get();
+        }
+
         return Brand::query()->where('is_visible', true)->ordered()->get(['id', 'name']);
     }