<?php
declare(strict_types=1);

namespace Esun\CustomerCoupon\Observer;

use Esun\CustomerCoupon\Block\Adminhtml\Form\CustomerSelect;
use Magento\Framework\Event\Observer;
use Magento\Framework\Event\ObserverInterface;
use Magento\Framework\View\LayoutInterface;

class AddCustomerSelectToCouponForm implements ObserverInterface
{
    public function __construct(private readonly LayoutInterface $layout)
    {
    }

    public function execute(Observer $observer): void
    {
        $form = $observer->getData('form');
        $fieldset = $form ? $form->getElement('information_fieldset') : null;
        if (!$fieldset || $form->getElement('customer_ids')) {
            return;
        }

        $html = $this->layout->createBlock(CustomerSelect::class)
            ->setTemplate('Esun_CustomerCoupon::form/customer-select.phtml')
            ->toHtml();

        $fieldset->addField(
            'customer_ids',
            'note',
            [
                'label' => __('Assigned Customers'),
                'text' => $html,
                'note' => __('When customers are selected, one unique coupon is generated for each customer.'),
            ],
            'dash'
        );
    }
}