<?php

/*
 *
 *  ____            _        _   __  __ _                  __  __ ____
 * |  _ \ ___   ___| | _____| |_|  \/  (_)_ __   ___      |  \/  |  _ \
 * | |_) / _ \ / __| |/ / _ \ __| |\/| | | '_ \ / _ \_____| |\/| | |_) |
 * |  __/ (_) | (__|   <  __/ |_| |  | | | | | |  __/_____| |  | |  __/
 * |_|   \___/ \___|_|\_\___|\__|_|  |_|_|_| |_|\___|     |_|  |_|_|
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * @author PocketMine Team
 * @link http://www.pocketmine.net/
 *
 *
*/

declare(strict_types=1);

/**
 * Implementation of the Source RCON Protocol to allow remote console commands
 * Source: https://developer.valvesoftware.com/wiki/Source_RCON_Protocol
 */
namespace pocketmine\network\rcon;

use pocketmine\command\RemoteConsoleCommandSender;
use pocketmine\Server;
use pocketmine\snooze\SleeperNotifier;
use pocketmine\utils\TextFormat;
use function max;
use function socket_bind;
use function socket_close;
use function socket_create;
use function socket_create_pair;
use function socket_getsockname;
use function socket_last_error;
use function socket_listen;
use function socket_set_block;
use function socket_strerror;
use function socket_write;
use function trim;
use const AF_INET;
use const AF_UNIX;
use const SOCK_STREAM;
use const SOCKET_ENOPROTOOPT;
use const SOCKET_EPROTONOSUPPORT;
use const SOL_TCP;

class RCON{
	/** @var Server */
	private $server;
	/** @var resource */
	private $socket;

	/** @var RCONInstance */
	private $instance;

	/** @var resource */
	private $ipcMainSocket;
	/** @var resource */
	private $ipcThreadSocket;

	/**
	 * @param Server $server
	 * @param string $password
	 * @param int    $port
	 * @param string $interface
	 * @param int    $maxClients
	 *
	 * @throws \RuntimeException
	 */
	public function __construct(Server $server, string $password, int $port = 19132, string $interface = "0.0.0.0", int $maxClients = 50){
		$this->server = $server;
		$this->server->getLogger()->info("Starting remote control listener");
		if($password === ""){
			throw new \RuntimeException("Empty password");
		}

		$this->socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);

		if($this->socket === false or !@socket_bind($this->socket, $interface, $port) or !@socket_listen($this->socket)){
			throw new \RuntimeException(trim(socket_strerror(socket_last_error())));
		}

		socket_set_block($this->socket);

		$ret = @socket_create_pair(AF_UNIX, SOCK_STREAM, 0, $ipc);
		if(!$ret){
			$err = socket_last_error();
			if(($err !== SOCKET_EPROTONOSUPPORT and $err !== SOCKET_ENOPROTOOPT) or !@socket_create_pair(AF_INET, SOCK_STREAM, 0, $ipc)){
				throw new \RuntimeException(trim(socket_strerror(socket_last_error())));
			}
		}

		[$this->ipcMainSocket, $this->ipcThreadSocket] = $ipc;

		$notifier = new SleeperNotifier();
		$this->server->getTickSleeper()->addNotifier($notifier, function() : void{
			$response = new RemoteConsoleCommandSender();
			$this->server->dispatchCommand($response, $this->instance->cmd);

			$this->instance->response = TextFormat::clean($response->getMessage());
			$this->instance->synchronized(function(RCONInstance $thread){
				$thread->notify();
			}, $this->instance);
		});
		$this->instance = new RCONInstance($this->socket, $password, (int) max(1, $maxClients), $this->server->getLogger(), $this->ipcThreadSocket, $notifier);

		socket_getsockname($this->socket, $addr, $port);
		$this->server->getLogger()->info("RCON running on $addr:$port");
	}

	public function stop() : void{
		$this->instance->close();
		socket_write($this->ipcMainSocket, "\x00"); //make select() return
		$this->instance->quit();

		@socket_close($this->socket);
		@socket_close($this->ipcMainSocket);
		@socket_close($this->ipcThreadSocket);
	}
}