composer ile kütüphaneyi yüklediniz mi?
<?php defined('BASEPATH') or exit('No direct script access allowed');
if (!empty($payment_gateway) && $payment_gateway->name_key == "iyzico"):
require_once(APPPATH . 'third_party/iyzipay/vendor/autoload.php');
require_once(APPPATH . 'third_party/iyzipay/vendor/iyzico/iyzipay-php/IyzipayBootstrap.php');
IyzipayBootstrap::init();
$options = new \Iyzipay\Options();
$options->setApiKey($payment_gateway->public_key);
$options->setSecretKey($payment_gateway->secret_key);
if ($payment_gateway->environment == "sandbox") {
$options->setBaseUrl("https://sandbox-api.iyzipay.com");
} else {
$options->setBaseUrl("https://api.iyzipay.com");
}
$conversation_id = generate_short_unique_id();
$customer = get_cart_customer_data();başı bu tarz tabii devamını buraya eklemedim ama kütüphane ekli