invoiceninja/app/PaymentDrivers/CheckoutCom/Utilities.php

<?php

/**
 * Invoice Ninja (https://invoiceninja.com)
 *
 * @link https://github.com/invoiceninja/invoiceninja source repository
 *
 * @copyright Copyright (c) 2020. Invoice Ninja LLC (https://invoiceninja.com)
 *
 * @license https://opensource.org/licenses/AAL
 */

namespace App\PaymentDrivers\CheckoutCom;

trait Utilities
{
    public function getPublishableKey()
    {
        return $this->company_gateway->getConfigField('publicApiKey');
    }

    public function convertToCheckoutAmount($amount, $currency)
    {
        $cases = [
            'option_1' => ['BIF', 'DJF', 'GNF', 'ISK', 'KMF', 'XAF', 'CLF', 'XPF', 'JPY', 'PYG', 'RWF', 'KRW', 'VUV', 'VND', 'XOF'],
            'option_2' => ['BHD', 'IQD', 'JOD', 'KWD', 'LYD', 'OMR', 'TND'],
        ];

        // https://docs.checkout.com/resources/calculating-the-value#Calculatingthevalue-Option1:Thefullvaluefullvalue
        if (in_array($currency, $cases['option_1'])) {
            return round($amount);
        }

        // https://docs.checkout.com/resources/calculating-the-value#Calculatingthevalue-Option2:Thevaluedividedby1000valuediv1000
        if (in_array($currency, $cases['option_2'])) {
            return round($amount * 1000);
        }

        // https://docs.checkout.com/resources/calculating-the-value#Calculatingthevalue-Option3:Thevaluedividedby100valuediv100
        return round($amount * 100);
    } 
}