<?php
/**
 * Copyright © Magento, Inc. All rights reserved.
 * See COPYING.txt for license details.
 */
namespace Magento\Customer\Block\Adminhtml\Grid\Filter;

/**
 * Country customer grid column filter
 */
class Country extends \Magento\Backend\Block\Widget\Grid\Column\Filter\Select
{
    /**
     * @var \Magento\Directory\Model\ResourceModel\Country\CollectionFactory
     */
    protected $_collectionFactory;

    /**
     * @param \Magento\Backend\Block\Context $context
     * @param \Magento\Framework\DB\Helper $resourceHelper
     * @param \Magento\Directory\Model\ResourceModel\Country\CollectionFactory $collectionFactory
     * @param array $data
     */
    public function __construct(
        \Magento\Backend\Block\Context $context,
        \Magento\Framework\DB\Helper $resourceHelper,
        \Magento\Directory\Model\ResourceModel\Country\CollectionFactory $collectionFactory,
        array $data = []
    ) {
        $this->_collectionFactory = $collectionFactory;
        parent::__construct($context, $resourceHelper, $data);
    }

    /**
     * Return options
     *
     * @return array
     */
    protected function _getOptions()
    {
        $options = $this->_collectionFactory->load()->toOptionArray();
        array_unshift($options, ['value' => '', 'label' => __('All countries')]);
        return $options;
    }
}
