<?php
namespace Relay\Multisite;

use Relay\Support\RelayError;
use Relay\Support\SiteInfo;

/** The network's subsites: listing them, and creating one for a site coming in (spec 2026-10-16 §5.4). */
final class Subsites
{
    /** @return array[] {id, name, url, main, available}, main site first */
    public static function list(): array
    {
        if (!is_multisite()) {
            return [];
        }
        $out = [];
        foreach (get_sites(['number' => 0, 'network_id' => get_current_network_id()]) as $site) {
            $id = (int) $site->blog_id;
            $out[] = [
                'id' => $id,
                'name' => SiteInfo::plain_name((string) get_blog_option($id, 'blogname')),
                'url' => untrailingslashit((string) get_blog_option($id, 'home')),
                'main' => is_main_site($id),
                'available' => !((int) $site->archived || (int) $site->deleted || (int) $site->spam),
            ];
        }
        usort($out, static fn ($a, $b) => [$b['main'], $a['id']] <=> [$a['main'], $b['id']]);
        return $out;
    }

    /**
     * Where a new subsite at $address would live: a path under the network's domain on a subdirectory network
     * ("https://net.test/client1/"), a subdomain or any other domain on a subdomain network. Refuses addresses
     * that aren't valid there or are taken.
     *
     * @return array{domain: string, path: string}
     */
    public static function parse_address(string $address): array
    {
        $network = get_network();
        $address = trim($address);
        if (!preg_match('#^https?://#i', $address)) {
            $address = 'https://' . $address;
        }
        $parts = wp_parse_url($address);
        $domain = strtolower((string) ($parts['host'] ?? ''));
        if (isset($parts['port'])) {
            $domain .= ':' . (int) $parts['port'];
        }
        $path = '/' . trim(strtolower((string) ($parts['path'] ?? '')), '/') . '/';
        $path = $path === '//' ? '/' : $path;
        $bad = static function (string $why): RelayError {
            return new RelayError('subsite.bad_address', esc_html($why), esc_html(is_subdomain_install()
                /* translators: %s: network domain */
                ? sprintf(__('Use a subdomain such as client.%s, or a domain of its own.', 'siterelay'), get_network()->domain)
                /* translators: %s: example address */
                : sprintf(__('Use one word after the network\'s address, such as %s.', 'siterelay'), 'https://' . get_network()->domain . get_network()->path . 'client/')));
        };
        if (!preg_match('/^[a-z0-9.-]+(:[0-9]+)?$/', $domain) || strpos($domain, '.') === false && strpos($domain, 'localhost') !== 0) {
            /* translators: %s: address */
            throw $bad(esc_html(sprintf(__('%s is not a valid address.', 'siterelay'), $address)));
        }
        if (is_subdomain_install()) {
            if ($path !== '/') {
                throw $bad(esc_html__('On this network a subsite has an address of its own, without a folder.', 'siterelay'));
            }
        } else {
            $slug = trim(substr($path, strlen($network->path)), '/');
            if ($domain !== $network->domain || strpos($path, $network->path) !== 0 || !preg_match('/^[a-z0-9-]+$/', $slug)) {
                /* translators: %s: network address */
                throw $bad(esc_html(sprintf(__('On this network a subsite lives in one folder under %s.', 'siterelay'), 'https://' . $network->domain . $network->path)));
            }
            if (in_array($slug, get_subdirectory_reserved_names(), true)) {
                /* translators: %s: folder name */
                throw $bad(esc_html(sprintf(__('“%s” is reserved by WordPress.', 'siterelay'), $slug)));
            }
        }
        if (domain_exists($domain, $path, (int) $network->id)) {
            throw new RelayError(
                'subsite.address_taken',
                /* translators: %s: address */
                esc_html(sprintf(__('A subsite already uses %s.', 'siterelay'), $domain . $path)),
                esc_html__('Choose that subsite to replace it, or another address.', 'siterelay')
            );
        }
        return ['domain' => $domain, 'path' => $path];
    }

    /** Create the subsite (WordPress fills it with its default content, which the job then replaces). */
    public static function create(string $address, string $title, int $user_id): int
    {
        $where = self::parse_address($address);
        $id = wp_insert_site([
            'domain' => $where['domain'],
            'path' => $where['path'],
            'network_id' => get_current_network_id(),
            'title' => $title !== '' ? $title : $where['domain'] . $where['path'],
            'user_id' => $user_id > 0 ? $user_id : (int) get_current_user_id(),
        ]);
        if (is_wp_error($id)) {
            /* translators: %s: WordPress' error message */
            throw new RelayError('subsite.create_failed', esc_html(sprintf(__('WordPress could not create the subsite: %s', 'siterelay'), $id->get_error_message())));
        }
        return (int) $id;
    }
}