<?php
namespace Relay\Support;

use Relay\Database\Db;
use Relay\Multisite\Scope;

/** What one site tells another about itself in a handshake. */
final class SiteInfo
{
    /** Where a site's uploads and wp-content are (optional; AutoPairs maps them). */
    public const FOLDERS = ['uploads_url', 'uploads_dir', 'content_url', 'alt_uploads_url', 'alt_content_url'];

    /**
     * This site; on a network, the network (its main site) with "network" => {subdomain}. Besides its addresses and
     * path it tells where its uploads and wp-content live, so the other site can map those too (spec 2026-10-16 §4).
     */
    public static function current(Db $db): array
    {
        $info = self::of($db, Scope::site(), $db->prefix());
        if (is_multisite()) {
            $info['network'] = ['subdomain' => is_subdomain_install()];
        }
        return $info;
    }

    /**
     * A site Relay moves: this single site or one subsite of this network, with the table prefix its tables have in
     * flight — the base prefix for a subsite that leaves its network (single-site shape), its own for one that is
     * written to. A subsite also says its id.
     */
    public static function of(Db $db, Scope $scope, string $prefix): array
    {
        global $wp_version, $wpdb;
        $info = [
            'name' => $scope->name,
            'site_url' => $scope->site_url,
            'home_url' => $scope->home_url,
            'path' => $scope->path,
            'prefix' => $prefix,
            'wp' => (string) $wp_version,
            'php' => PHP_VERSION,
            'mysql' => $db->server_version(),
            'charset' => (string) $wpdb->charset,
            'relay' => RELAY_VERSION,
        ];
        foreach (self::FOLDERS as $key) {
            $value = $scope->urls()[$key] ?? '';
            if ($value !== '') {
                $info[$key] = $value;
            }
        }
        if ($scope->is_subsite()) {
            $info['subsite'] = $scope->blog_id;
        }
        return $info;
    }

    /**
     * A peer's site info from a request or response, checked and reduced to plain strings (and its optional parts).
     *
     * @param mixed $data as the other site sent it
     */
    public static function from_peer($data): array
    {
        $out = [];
        foreach (['name', 'site_url', 'home_url', 'path', 'prefix', 'wp', 'php', 'mysql', 'charset', 'relay'] as $field) {
            $out[$field] = is_scalar($data[$field] ?? null) ? mb_substr((string) $data[$field], 0, 255) : '';
        }
        $out['name'] = self::plain_name($out['name']);
        if (!preg_match('#^https?://#i', $out['site_url']) || !preg_match('#^https?://#i', $out['home_url']) || !preg_match('/^[A-Za-z0-9_]{1,40}$/', $out['prefix'])) {
            throw new RelayError('remote.bad_request', esc_html__('The other site sent incomplete site details.', 'siterelay'));
        }
        foreach (self::FOLDERS as $key) {
            $value = is_string($data[$key] ?? null) ? mb_substr($data[$key], 0, 1024) : '';
            if ($value !== '' && ($key === 'uploads_dir' || preg_match('#^https?://#i', $value))) {
                $out[$key] = $value;
            }
        }
        if (is_int($data['subsite'] ?? null) && $data['subsite'] > 0) {
            $out['subsite'] = $data['subsite'];
        }
        if (is_array($data['network'] ?? null)) {
            $out['network'] = ['subdomain' => !empty($data['network']['subdomain'])];
        }
        return $out;
    }

    /** A site name as people typed it: WordPress keeps it HTML-escaped ("Moroff &amp; Partners"), and older sites send it so. */
    public static function plain_name(string $stored): string
    {
        return html_entity_decode($stored, ENT_QUOTES | ENT_HTML5, 'UTF-8');
    }

    /** Whether two addresses are the same site: scheme, letter case and a trailing slash don't count. */
    public static function same_address(string $a, string $b): bool
    {
        $key = static function (string $url): string {
            $p = wp_parse_url(trim($url));
            if (!is_array($p) || empty($p['host'])) {
                return '';
            }
            return strtolower($p['host']) . (isset($p['port']) ? ':' . $p['port'] : '') . rtrim($p['path'] ?? '', '/');
        };
        $first = $key($a);
        return $first !== '' && $first === $key($b);
    }

    /**
     * Stops a connection whose other end is this site (its own connection string): pulling or pushing a site
     * onto itself copies nothing new and loses whatever is saved there while it runs.
     */
    public static function refuse_this_site(array $peer): void
    {
        if (self::same_address((string) ($peer['home_url'] ?? ''), home_url())) {
            throw new RelayError(
                'connection.self',
                /* translators: %s: this site's address */
                esc_html(sprintf(__('This connection string belongs to this site (%s).', 'siterelay'), home_url())),
                esc_html__('Use the connection string from Access keys on the other site, the one you want to copy from or to.', 'siterelay')
            );
        }
    }
}