<?php
namespace Relay\Restore;

/**
 * Loads the site the way a visitor and wp-admin would, right after a restore switched it over. A server
 * error or WordPress' "critical error" page means the restored site is broken (for example a plugin in the
 * backup needs a newer PHP than this server runs). When the site can't be reached at all (loopback requests
 * blocked, timeouts), the result is "unknown" rather than "broken".
 */
final class SiteCheck
{
    public const OK = 'ok';
    public const BROKEN = 'broken';
    public const UNKNOWN = 'unknown';

    /**
     * $blog_id: a subsite of this network (its front page and its admin-ajax), else this site.
     *
     * @return array{status: string, detail: string}
     */
    public static function run(int $blog_id = 0): array
    {
        $unknown = '';
        $urls = $blog_id > 0 ? [get_home_url($blog_id, '/'), get_admin_url($blog_id, 'admin-ajax.php')] : [home_url('/'), admin_url('admin-ajax.php')];
        foreach ($urls as $url) {
            $response = wp_remote_get(add_query_arg('relay-check', (string) time(), $url), [
                'timeout' => 15,
                'redirection' => 3,
                'sslverify' => false,
                'headers' => ['Cache-Control' => 'no-cache'],
            ]);
            if (is_wp_error($response)) {
                $unknown = $url . ': ' . $response->get_error_message();
                continue;
            }
            $code = (int) wp_remote_retrieve_response_code($response);
            $body = (string) wp_remote_retrieve_body($response);
            if ($code >= 500 || stripos($body, 'There has been a critical error on this website') !== false) {
                /* translators: 1: URL, 2: HTTP status code */
                return ['status' => self::BROKEN, 'detail' => sprintf(__('%1$s answered HTTP %2$d', 'siterelay'), $url, $code)];
            }
        }
        return $unknown === '' ? ['status' => self::OK, 'detail' => ''] : ['status' => self::UNKNOWN, 'detail' => $unknown];
    }
}