Calculator Controller

<?php

namespace AppBundle\Controller;

use AppBundle\Form\CalculatorType;
use AppBundle\Model\Calculator;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Symfony\Component\HttpFoundation\Request;

class CalculatorController extends Controller
{
    /**
     * @param Request $request
     * @Route("/calculator", name="calculator_index")
     * @return \Symfony\Component\HttpFoundation\Response
     */
    public function indexAction(Request $request)
    {
        $calculator = new Calculator();
        $form = $this->createForm(CalculatorType::class, $calculator);
        $form->handleRequest($request);
        $sum = 0;
        if($form->isValid() && $form->isSubmitted()){
            $calcService = new \AppBundle\Service\Calculator();
            $leftOperand = $calculator->getFirstNumber();
            $rightOperand = $calculator->getSecondNumber();
            $operator = $calculator->getOperator();



            switch ($operator){
                case '+':
                    $sum = $leftOperand + $rightOperand;
                    break;
                case '-':
                    $sum = $leftOperand - $rightOperand;
                    break;
                case '*':
                    $sum = $leftOperand * $rightOperand;
                    break;
                case '/':
                    $sum = $leftOperand / $rightOperand;
                    break;
                case '^':
                    $sum = pow($leftOperand , $rightOperand) ;
                    break;
            }
            return $this->render('calculator/index.html.twig', [
                'form'=>$form->createView(),
                'sum'=>$sum,
                'calculator'=>$calculator
            ]);
        }
        return $this->render('calculator/index.html.twig' ,[
            'form'=>$form->createView(),
            'sum'=>$sum,
            'calculator'=>$calculator
        ]);
    }

}