<?php
namespace Stemcell\ChineseDirectory\Observer\Order\Address;

use Magento\Framework\DataObject\Copy\Config;
use Magento\Framework\Event\Observer;
use Magento\Framework\Event\ObserverInterface;
use Magento\Quote\Model\Quote;
use Magento\Sales\Model\Order;

class AttachExtensionAttributeObserver implements ObserverInterface
{
    /**
     * @var Config
     */
    protected Config $fieldsetConfig;

    public function __construct(
        Config $config
    ) {
        $this->fieldsetConfig = $config;
    }

    public function execute(Observer $observer)
    {
        /* @var $order Order */
        $order = $observer->getData('order');

        /* @var $quote Quote */
        $quote = $observer->getData('quote');
        $aspect = 'to_order_address';
        $fields = $this->fieldsetConfig->getFieldset('sales_convert_quote_address');
        $extensionAttributes = $quote->getShippingAddress()->getExtensionAttributes();
        $orderAddress = $order->getShippingAddress();
        foreach ($fields as $code => $node) {
            if (empty($node[$aspect])) {
                continue;
            }
            $method = 'get' . str_replace('_', '', ucwords($code, '_'));
            if (method_exists($extensionAttributes, $method) && $extensionAttributes->$method()) {
                $orderAddress->setData($code, $extensionAttributes->$method());
            }
        }
    }
}