<?php
namespace Vichan\Data\Driver\Cache;

defined('TINYBOARD') or exit;


class MemcachedCacheDriver implements CacheDriver {
	use CacheDriverTrait;

	private \Memcached $inner;


	public function __construct(string $prefix, string $server_uri, int $server_port, int $server_weight) {
		$this->inner = new \Memcached();
		if (!$this->inner->setOption(\Memcached::OPT_BINARY_PROTOCOL, true)) {
			$err = $this->inner->getResultMessage();
			throw new \RuntimeException("Unable to set the memcached protocol: '$err'");
		}
		if (!$this->inner->setOption(\Memcached::OPT_PREFIX_KEY, $prefix)) {
			$err = $this->inner->getResultMessage();
			throw new \RuntimeException("Unable to set the memcached prefix: '$err'");
		}

		$maybe_unix_path = self::asUnixSocketPath($server_uri);
		$is_unix = $maybe_unix_path !== null;
		if ($is_unix) {
			$server_uri = $maybe_unix_path;
		}

		// Memcached keeps the server connections open across requests.
		$current_servers = $this->inner->getServerList();
		$found_in_curr = false;
		foreach ($current_servers as $curr) {
			// Ignore the port if the server is connected with a unix socket.
			if ($curr['host'] === $server_uri && ($is_unix || $curr['port'] === $server_port)) {
				$found_in_curr = true;
			}
		}

		if (!$found_in_curr) {
			if (!empty($current_servers)) {
				if (!$this->inner->resetServerList()) {
					$err = $this->inner->getResultMessage();
					throw new \RuntimeException("Unable to reset the memcached server list: '$err'");
				}
			}
			if (!$this->inner->addServer($server_uri, $server_port, $server_weight)) {
				$err = $this->inner->getResultMessage();
				throw new \RuntimeException("Unable to add memcached servers: '$err'");
			}
		}
	}

	public function get(string $key): mixed {
		$ret = $this->inner->get($key);
		// If the returned value is false but the retrival was a success, then the value stored was a boolean false.
		if ($ret === false && $this->inner->getResultCode() !== \Memcached::RES_SUCCESS) {
			return null;
		}
		return $ret;
	}

	public function set(string $key, mixed $value, mixed $expires = false): void {
		$this->inner->set($key, $value, (int)$expires);
	}

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

	public function flush(): void {
		$this->inner->flush();
	}
}