<?php

namespace Kash;

use Psr\SimpleCache\CacheInterface;

class ApcuCache implements CacheInterface
{
    const DEFAULT_NS_SEPARATOR = ':';

    public function __construct(
        protected string $namespace,
        protected int $ttl,
    ) {}

    public function get(string $key, mixed $default = null): mixed
    {
        $value = apcu_fetch($this->fullkey($key), $status);

        return $status === true ? $value : $default;
    }

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

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

    public function clear() : bool
    {
        return apcu_clear_cache();
    }

    public function getMultiple(iterable $keys, mixed $default = null): iterable
    {
        $nsKeys = $this->fullkey($keys);

        $result = apcu_fetch($nsKeys);

        return array_combine(array_map(fn($e) => substr($e, strlen($this->namespace) + strlen(static::DEFAULT_NS_SEPARATOR)), $nsKeys), $result) + array_fill_keys($keys, $default);
    }

    public function setMultiple(iterable $values, null|int|\DateInterval $ttl = null): bool
    {
        $list = array_combine(array_map( [$this, 'prependNamespace' ], array_keys($values), $values);

        $result = apcu_store($list, $this->ttl($ttl));

        return in_array($result, [ [], true ], true);
    }

    public function deleteMultiple(iterable $keys): bool
    {
        return apcu_delete($this->fullkey($keys)) === [];
    }

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

    protected function handleTTL(null|int|\DateInterval $ttl) : int
    {
        if ($ttl instanceof \DateInterval) {
            $ttl = (new \DateTime)->add($ttl)->getTimestamp() - (new \DateTime)->getTimestamp();
        }

        $ttl ??= $this->ttl;

        return (int) $ttl;
    }

    protected function fullkey(string|array $key) : string|array
    {
        return is_array($key) ? array_map([ $this, 'prependNamespace' ], $key) : $this->prependNamespace($key);
    }

    protected function prependNamespace(string $key) : string
    {
        return $this->namespace . static::DEFAULT_NS_SEPARATOR . $key;
    }
}