<?php
// MemcachedProviderLegacy.php
// Created: 2024-04-10
// Updated: 2024-04-10

namespace Index\Cache\Memcached;

use InvalidArgumentException;
use Memcache;
use Index\Net\{DnsEndPoint,IPEndPoint,UnixEndPoint};

/**
 * Legacy Memcached provider implementation.
 */
class MemcachedProviderLegacy extends MemcachedProvider {
    private Memcache $memcache;
    private string $prefix;
    private bool $persistent;
    private bool $compress;

    public function __construct(MemcachedProviderInfo $providerInfo) {
        $this->prefix = $providerInfo->getPrefixKey();
        $this->compress = $providerInfo->shouldEnableCompression();
        $this->persistent = $providerInfo->isPersistent();
        $this->memcache = new Memcache;

        foreach($providerInfo->getEndPoints() as $endPointInfo) {
            if($endPointInfo[0] instanceof UnixEndPoint) {
                $host = 'unix://' . $endPointInfo->getPath();
                $port = 0;
            } elseif($endPointInfo[0] instanceof DnsEndPoint) {
                $host = $endPointInfo->getHost();
                $port = $endPointInfo->getPort();
            } elseif($endPointInfo[0] instanceof IPEndPoint) {
                $host = $endPointInfo->getAddress()->getCleanAddress();
                $port = $endPointInfo->getPort();
            } else throw new InvalidArgumentException('One of the servers specified in $providerInfo is not a supported endpoint.');

            $this->memcache->addServer($host, $port, $this->persistent, $endPointInfo[1]);
        }
    }

    public function get(string $key): mixed {
        $value = $this->memcache->get($this->prefix . $key);
        return $value === false ? null : unserialize($value);
    }

    public function set(string $key, mixed $value, int $ttl = 0): void {
        if($ttl < 0)
            throw new InvalidArgumentException('$ttl must be equal to or greater than 0.');
        if($ttl > MemcachedProvider::MAX_TTL)
            throw new InvalidArgumentException('$ttl may not be greater than 30 days.');
        if($value === null)
            return;

        $serialised = serialize($value);
        $flags = 0;
        if($this->compress && strlen($serialised) > 100)
            $flags |= MEMCACHE_COMPRESSED;

        $this->memcache->set($this->prefix . $key, $serialised, $flags, $ttl);
    }

    public function delete(string $key): void {
        $this->memcache->delete($this->prefix . $key);
    }

    public function touch(string $key, int $ttl = 0): void {
        $this->set($key, $this->get($key), $ttl);
    }

    public function increment(string $key, int $amount = 1): int {
        $key = $this->prefix . $key;
        $result = $this->memcache->increment($key, $amount);
        if($result === false) { // @phpstan-ignore-line: PHP documentation states increment returns int|false
            $result = $amount;
            $this->memcache->set($key, serialize($result), 0);
        }

        return $result;
    }

    public function decrement(string $key, int $amount = 1): int {
        $key = $this->prefix . $key;
        $result = $this->memcache->decrement($key, $amount);
        if($result === false) { // @phpstan-ignore-line: PHP documentation states decrement returns int|false
            $result = $amount * -1;
            $this->memcache->set($key, serialize($result), 0);
        }

        return $result;
    }

    public function close(): void {
        if(!$this->persistent)
            $this->memcache->close();
    }
}