<?php

declare(strict_types=1);

namespace base\mcp\service;

use Psr\SimpleCache\CacheInterface;
use think\cache\Driver;
use think\facade\Cache;

/**
 * think Cache 驱动的 PSR-16 薄适配器.
 *
 * mcp/sdk 的 Psr16SessionStore 需要 Psr\SimpleCache\CacheInterface 实现，
 * think cache Driver 方法集与 PSR-16 同形（get/set/delete/clear/has/*Multiple），
 * 本类只做签名收紧与 TTL 归一（int|DateInterval|null → 秒），全部转发给
 * defaultStore() 指定的 think 缓存 store。
 *
 * 子类（app 壳）覆写 defaultStore() 返回 'mcp_session' 等具体 store 名。
 */
class Psr16ThinkCacheBase implements CacheInterface
{
    protected Driver $driver;

    public function __construct(?Driver $driver = null)
    {
        $this->driver = $driver ?? Cache::store($this->defaultStore());
    }

    /**
     * 默认 think 缓存 store 名（子类覆写）.
     */
    protected function defaultStore(): string
    {
        return 'file';
    }

    public function get(string $key, mixed $default = null): mixed
    {
        return $this->driver->get($key, $default);
    }

    public function set(string $key, mixed $value, null|int|\DateInterval $ttl = null): bool
    {
        return (bool) $this->driver->set($key, $value, $this->normalizeTtl($ttl));
    }

    public function delete(string $key): bool
    {
        return (bool) $this->driver->delete($key);
    }

    public function clear(): bool
    {
        return (bool) $this->driver->clear();
    }

    public function getMultiple(iterable $keys, mixed $default = null): iterable
    {
        $keys = is_array($keys) ? $keys : iterator_to_array($keys, false);

        $result = [];
        foreach ($keys as $key) {
            $result[$key] = $this->driver->get($key, $default);
        }

        return $result;
    }

    public function setMultiple(iterable $values, null|int|\DateInterval $ttl = null): bool
    {
        $ttl = $this->normalizeTtl($ttl);

        $result = true;
        foreach ($values as $key => $value) {
            if (!$this->driver->set((string) $key, $value, $ttl)) {
                $result = false;
            }
        }

        return $result;
    }

    public function deleteMultiple(iterable $keys): bool
    {
        $result = true;
        foreach ($keys as $key) {
            if (!$this->driver->delete($key)) {
                $result = false;
            }
        }

        return $result;
    }

    public function has(string $key): bool
    {
        return (bool) $this->driver->has($key);
    }

    /**
     * PSR-16 TTL 归一为秒：DateInterval 折算秒数；null 视为 0（think 驱动默认有效期，0=永久）.
     */
    protected function normalizeTtl(null|int|\DateInterval $ttl): int
    {
        if ($ttl instanceof \DateInterval) {
            $now = new \DateTimeImmutable('@' . time());

            return max(0, $now->add($ttl)->getTimestamp() - $now->getTimestamp());
        }

        return max(0, (int) ($ttl ?? 0));
    }
}