Done

app/Services/ArticleSelector.php

@@ -0,0 +1,30 @@
+<?php
+
+namespace App\Services;
+
+use App\Models\Category;
+use Illuminate\Support\Collection;
+
+class ArticleSelector
+{
+    public function forCategory(Category $category, int $limit = 10): Collection
+    {
+        $feeds = $category->feeds()->with([
+            'articles' => fn ($q) => $q->orderByDesc('published_at')->limit($limit),
+        ])->get();
+
+        // Round robin: take article[0] from every feed, then article[1] from every feed, etc.
+        $buckets = $feeds->map(fn ($feed) => $feed->articles->values());
+        $maxDepth = $buckets->max(fn ($b) => $b->count()) ?? 0;
+
+        $selected = collect();
+        for ($i = 0; $i < $maxDepth && $selected->count() < $limit; $i++) {
+            foreach ($buckets as $bucket) {
+                if ($selected->count() >= $limit) break;
+                if ($bucket->has($i)) $selected->push($bucket[$i]);
+            }
+        }
+
+        return $selected;
+    }
+}