App\Http\Controllers\AccountController::changePlan PHP Method

    public function changePlan()
    {
        $user = Auth::user();
        $account = $user->account;
        $company = $account->company;
        $plan = Input::get('plan');
        $term = Input::get('plan_term');
        $numUsers = Input::get('num_users');
        if ($plan != PLAN_ENTERPRISE) {
            $numUsers = 1;
        }
        $planDetails = $account->getPlanDetails(false, false);
        $newPlan = ['plan' => $plan, 'term' => $term, 'num_users' => $numUsers];
        $newPlan['price'] = Utils::getPlanPrice($newPlan);
        $credit = 0;
        if (!empty($planDetails['started']) && $plan == PLAN_FREE) {
            // Downgrade
            $refund_deadline = clone $planDetails['started'];
            $refund_deadline->modify('+30 days');
            if ($plan == PLAN_FREE && $refund_deadline >= date_create()) {
                if ($payment = $account->company->payment) {
                    $ninjaAccount = $this->accountRepo->getNinjaAccount();
                    $paymentDriver = $ninjaAccount->paymentDriver();
                    $paymentDriver->refundPayment($payment);
                    Session::flash('message', trans('texts.plan_refunded'));
                    \Log::info("Refunded Plan Payment: {$account->name} - {$user->email}");
                } else {
                    Session::flash('message', trans('texts.updated_plan'));
                }
            }
        }
        $hasPaid = false;
        if (!empty($planDetails['paid']) && $plan != PLAN_FREE) {
            $hasPaid = true;
            $time_used = $planDetails['paid']->diff(date_create());
            $days_used = $time_used->days;
            if ($time_used->invert) {
                // They paid in advance
                $days_used *= -1;
            }
            $days_total = $planDetails['paid']->diff($planDetails['expires'])->days;
            $percent_used = $days_used / $days_total;
            $credit = $planDetails['plan_price'] * (1 - $percent_used);
        }
        if ($newPlan['price'] > $credit) {
            $invitation = $this->accountRepo->enablePlan($newPlan, $credit);
            if ($hasPaid) {
                return Redirect::to('view/' . $invitation->invitation_key);
            } else {
                return Redirect::to('payment/' . $invitation->invitation_key);
            }
        } else {
            if ($plan != PLAN_FREE) {
                $company->plan_term = $term;
                $company->plan_price = $newPlan['price'];
                $company->num_users = $numUsers;
                $company->plan_expires = date_create()->modify($term == PLAN_TERM_MONTHLY ? '+1 month' : '+1 year')->format('Y-m-d');
            }
            $company->plan = $plan;
            $company->save();
            return Redirect::to('settings/account_management');
        }
    }