AjaxRequestCustomFieldKeys.php

<?php

namespace AC\Controller;

use AC\Ajax;
use AC\Helper\Select;
use AC\Helper\Select\Generic\GroupFormatter\BlogSite;
use AC\Helper\Select\Generic\GroupFormatter\VisibilityType;
use AC\Helper\Select\Generic\Groups;
use AC\Meta\Query;
use AC\Registerable;
use AC\Request;
use AC\Response;

class AjaxRequestCustomFieldKeys implements Registerable
{

    public function register(): void
    {
        $this->get_ajax_handler()->register();
    }

    private function get_ajax_handler(): Ajax\Handler
    {
        $handler = new Ajax\Handler();
        $handler
            ->set_action('ac_custom_field_options')
            ->set_callback([$this, 'ajax_get_custom_fields']);

        return $handler;
    }

    public function ajax_get_custom_fields(): void
    {
        $this->get_ajax_handler()->verify_request();

        $request = new Request();
        $response = new Response\Json();

        $post_type = $request->get('post_type');

        $query = new Query($request->get('meta_type'));

        $query->select('meta_key')
              ->distinct()
              ->order_by('meta_key');

        if ($post_type) {
            $query->where_post_type($post_type);
        }

        $formatter = is_multisite()
            ? new BlogSite()
            : new VisibilityType();

        $meta_keys = $query->get();

        $options = Select\Options::create_from_array(
            array_combine($meta_keys, $meta_keys)
        );
        $options = new Groups($options, $formatter);

        $select = new Select\Response($options);

        $response
            ->set_parameters($select())
            ->success();
    }

}