<?php

namespace alveolata\server;

require_once(DIR_ALVEOLATA . '/log/functions.php');


/**
 * @author Christian Fraß <frass@greenscale.de>
 */
class struct_subject/*<type_input,type_output>*/
{
	
	/**
	 * @var int
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public $port;
	
	
	/**
	 * @var function<type_input,type_output>
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public $handler;
	
	
	/**
	 * whether a global handler for the operating systems interrupt signal (SIGINT) shall be installed for stopping the
	 *     server gracfully
	 * 
	 * @var boolean
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public $install_killhandler;
	
	
	/**
	 * procedure to be executed on start
	 * 
	 * @var function<tuple<>,void>
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public $on_starting;
	
	
	/**
	 * procedure to be executed on stop
	 * 
	 * @var function<tuple<>,void>
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public $on_stopping;
	
	
	/**
	 * procedure to be executed on start
	 * 
	 * @var function<tuple<>,void>
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public $on_started;
	
	
	/**
	 * procedure to be executed on stop
	 * 
	 * @var function<tuple<>,void>
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public $on_stopped;
	
	
	/**
	 * @var any
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public $socket;
	
	
	/**
	 * whether the server is supposed to shutdown
	 * 
	 * @var boolean
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public $run;
	
	
	/**
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public function __construct(
		int $port,
		\Closure $handler,
		bool $install_killhandler,
		\Closure $on_starting,
		\Closure $on_stopping,
		\Closure $on_started,
		\Closure $on_stopped
	)
	{
		$this->port = $port;
		$this->handler = $handler;
		$this->install_killhandler = $install_killhandler;
		$this->on_starting = $on_starting;
		$this->on_stopping = $on_stopping;
		$this->on_started = $on_started;
		$this->on_stopped = $on_stopped;
		$this->socket = null;
		$this->run = false;
	}
	
}


/**
 * @param int $port
 * @param function<type_input,type_output> $handler
 * @param boolean $install_killhandler
 * @param function<tuple<>,void> [$on_starting]
 * @param function<tuple<>,void> [$on_stopping]
 * @param function<tuple<>,void> [$on_started]
 * @param function<tuple<>,void> [$on_stopped]
 * @return struct_subject<type_input,type_output>
 * @author Christian Fraß <frass@greenscale.de>
 */
function make(
	int $port,
	\Closure $handler,
	bool $install_killhandler = false,
	\Closure $on_starting = null,
	\Closure $on_stopping = null,
	\Closure $on_started = null,
	\Closure $on_stopped = null
) : struct_subject
{
	if ($on_starting === null) {
		$on_starting = function () {
			\alveolata\log\info('starting server …');
		};
	}
	if ($on_stopping === null) {
		$on_stopping = function () {
			\alveolata\log\info('stopping server …');
		};
	}
	if ($on_started === null) {
		$on_started = function () {
			\alveolata\log\info('server started');
		};
	}
	if ($on_stopped === null) {
		$on_stopped = function () {
			\alveolata\log\info('server stopped');
		};
	}
	return (
		new struct_subject(
			$port,
			$handler,
			$install_killhandler,
			$on_starting,
			$on_stopping,
			$on_started,
			$on_stopped
		)
	);
}


/**
 * @param struct_subject<type_input,type_output> $subject
 * @author Christian Fraß <frass@greenscale.de>
 */
function killhandler(
	struct_subject/*<type_input,type_output>*/ $subject
) : void
{
	\alveolata\log\warning(
		'killhandler for server won\'t work'
	);
	/*
	\pcntl_signal(
		SIGINT,
		function ($signo) use (&$subject) {stop($subject);}
	);
	 */
}


/**
 * @param struct_subject<type_input,type_output> $subject
 * @author Christian Fraß <frass@greenscale.de>
 */
function stop/*<type_input,type_output>*/(
	struct_subject/*<type_input,type_output>*/ $subject
) : void
{
	($subject->on_stopping)();
	if (! ($subject->socket === null)) {
		\socket_shutdown($subject->socket);
	}
	$subject->run = false;
}


/**
 * @param struct_subject<type_input, type_output> $subject
 * @author Christian Fraß <frass@greenscale.de>
 */
function start/*<type_input, type_output>*/(
	struct_subject/*<type_input, type_output>*/ $subject
) : void
{
	$conf = [
		'host' => 'localhost',
		'max_connections' => 7,
		'buffer_length' => 2048,
	];
	($subject->on_starting)();
	if ($subject->install_killhandler) {
		killhandler($subject);
	}
	$subject->run = true;
	$socket = \socket_create(
		AF_INET,
		SOCK_STREAM,
		SOL_TCP
	);
	// \socket_set_nonblock($socket);
	\socket_bind(
		$socket,
		$conf['host'],
		$subject->port
	);
	\socket_listen(
		$socket,
		$conf['max_connections']
	);
	($subject->on_started)();
	while ($subject->run) {
		$subject->socket = $request = \socket_accept(
			$socket
		);
		/*if ($request === false) {
			usleep(125000);
		}
		else {*/
			$input = \socket_read(
				$request,
				$conf['buffer_length']
			);
			$output = ($subject->handler)($input);
			$bytes = \socket_write(
				$request,
				$output,
				strlen($output)
			);
			$successful = ($bytes !== false);
			if (! $successful) {
				\error_log('could not write to socket; shutting down server');
				break;
			}
		/*}*/
	}
	\socket_close(
		$request
	);
	\socket_close(
		$socket
	);
	($subject->on_stopped)();
}

 ?>