<?php

declare(strict_types=1);

namespace Sarcio\WordPress\Cache;

use Sarcio\Shim\RouteSetCache;

/**
 * Route-set cache on WordPress transients — the fallback when APCu is absent,
 * which is most shared hosting. With a persistent object cache (Redis,
 * Memcached) this is as good as APCu: one memory hit per request, shared across
 * every FPM worker. Without one it falls back to the options table, which is why
 * `Plugin` prefers APCu whenever it is available.
 *
 * Staleness is safe by protocol: a retired patch that lingers in the cache only
 * costs one extra `evaluate`, and the sidecar answers `proceed` for a route with
 * no live ops.
 */
final class TransientRouteSetCache implements RouteSetCache
{
    public function __construct(private readonly string $key = 'sarcio_routeset')
    {
    }

    public function forget(): void
    {
        delete_transient($this->key);
    }

    public function get(): ?array
    {
        $value = get_transient($this->key);
        if (!is_array($value)) {
            return null;
        }
        return array_values(array_filter($value, 'is_string'));
    }

    public function set(array $routes, int $ttlSeconds): void
    {
        set_transient($this->key, array_values(array_filter($routes, 'is_string')), max(1, $ttlSeconds));
    }
}