CourseWork/app/Http/Controllers/GradeSubjectController.php

<?php

namespace App\Http\Controllers;

use App\Http\Requests\GradeSubjectPostRequest;
use App\Models\Grade;
use App\Models\Subject;
use App\Services\ServiceInterface;
use Illuminate\Http\RedirectResponse;
use Illuminate\View\View;

class GradeSubjectController extends Controller
{
    public function create(Grade $grade): View
    {
        return view('grade-subject.create', [
            'grade' => $grade,
            'subjects' => Subject::all(),
        ]);
    }

    public function store(GradeSubjectPostRequest $request, Grade $grade): RedirectResponse
    {
        $grade->subjects()->syncWithoutDetaching($request->subject_id);

        return redirect()->route('grades.show', $grade);
    }

    public function edit(Grade $grade, Subject $subject): View
    {
        return view('grade-subject.edit', [
            'grade' => $grade,
            'updateSubject' => $subject,
            'subjects' => Subject::all(),
        ]);
    }

    public function update(GradeSubjectPostRequest $request, Grade $grade, Subject $subject): RedirectResponse
    {
        $grade->subjects()->detach($subject);
        $grade->subjects()->attach($request->subject_id);

        return redirect()->route('grades.show', $grade);
    }

    public function destroy(Grade $grade, Subject $subject): RedirectResponse
    {
        $grade->subjects()->detach($subject);

        return redirect()->route('grades.show', $grade);
    }
}