Added helper file, replaced size file for human version as a helper method, next prev buttons for chapters.

app/Http/Controllers/ChapterController.php

@@ -10,9 +10,13 @@ class ChapterController extends Controller
     public function index(Chapter $chapter, SymfonyCastDlService $symfonyCastDlService)
     {
         $symfonyCastDlService->videoSize($chapter);
-        if($chapter->sync_offline){
+        if ($chapter->sync_offline) {
             $symfonyCastDlService->downloadFile($chapter);
         }
-        return view('chapter.index', compact('chapter'));
+        $chapters = $chapter->course->chapters;
+
+        $next = $chapters->where('order', '>', $chapter->order)->first();
+        $prev = $chapters->where('order', '<', $chapter->order)->sortByDesc('order')->first();
+        return view('chapter.index', compact('chapter', 'chapters', 'prev', 'next'));
     }
 }