<?php

namespace Stemcell\Catalog\Observer;

use Magento\Framework\Event\Observer;
use Magento\Framework\Event\ObserverInterface;

/**
 * 解决下拉多选属性值没被保存的问题
 */
class MultiselectAttributeSave implements ObserverInterface
{
    public function execute(Observer $observer)
    {
        /* @var $controller \Magento\Catalog\Controller\Adminhtml\Product\Save */
        $controller = $observer->getEvent()->getData('controller');
        $data = $controller->getRequest()->getParam('product');

        /* @var $product \Magento\Catalog\Model\Product */
        $product = $observer->getEvent()->getData('product');

        $hasDiff = false;
        foreach ($product->getAttributes() as $attribute) {
            if ($attribute->getFrontendInput() === 'multiselect' && isset($data[$attribute->getAttributeCode()])) {

                $requestData = is_string($data[$attribute->getAttributeCode()])?
                    $data[$attribute->getAttributeCode()]:implode(',', $data[$attribute->getAttributeCode()]);

                if (!empty($requestData)) {
                    $product->setData($attribute->getAttributeCode(), $requestData);
                    $hasDiff = true;
                }
            }
        }
        if ($hasDiff) {
            $product->save();
        }
    }
}