<?php

declare(strict_types=1);

if (!defined('ABSPATH')) {
    exit;
}

final class TheDotDevAgenticBridge_Readiness_Sitemap
{
    /**
     * @return array{status: string, root: string, error: string}
     */
    public static function validate_body(string $body): array
    {
        if ($body === '') {
            return ['status' => 'invalid', 'root' => '', 'error' => 'empty body'];
        }

        if (stripos($body, '<html') !== false) {
            return ['status' => 'invalid', 'root' => '', 'error' => 'html body'];
        }

        if (!class_exists('DOMDocument')) {
            return ['status' => 'unknown', 'root' => '', 'error' => 'parser unavailable'];
        }

        $previous = libxml_use_internal_errors(true);
        $doc = new DOMDocument();
        $loaded = @$doc->loadXML($body, LIBXML_NONET | LIBXML_COMPACT);
        libxml_clear_errors();
        libxml_use_internal_errors($previous);

        if (!$loaded) {
            return ['status' => 'invalid', 'root' => '', 'error' => 'malformed xml'];
        }

        $root = strtolower((string) $doc->documentElement?->nodeName);
        if (!in_array($root, ['urlset', 'sitemapindex'], true)) {
            return ['status' => 'invalid', 'root' => $root, 'error' => 'unexpected root'];
        }

        return ['status' => 'valid', 'root' => $root, 'error' => ''];
    }
}