<?php

namespace alveolata\session;

// require_once(DIR_ALVEOLATA . '/definitions.php');
require_once(DIR_ALVEOLATA . '/session/interface.php');


/**
 * @author Christian Fraß <frass@greenscale.de>
 */
class struct_subject_cgi {
	
	/**
	 * @var string
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public $id;
	
	
	/**
	 * @param string $id
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public function __construct(
		string $id
	)
	{
		$this->id = $id;
	}
	
}


/**
 * @param struct_subject_cgi $subject
 * @param string $key
 * @throw \Exception if no such key
 * @author Christian Fraß <frass@greenscale.de>
 */
function _cgi_keycheck(
	struct_subject_cgi $subject,
	string $key
) : void
{
	// \session_id($subject->id);
	if (! array_key_exists($key, $_SESSION)) {
		$message = sprintf('no key "%s"', $key);
		throw (new \Exception($message));
	}
}


/**
 * @author Christian Fraß <frass@greenscale.de>
 */
function cgi_set_dir(
	string $path
) : void
{
	ini_set('session.save_path', $path);
}


/**
 * @author Christian Fraß <frass@greenscale.de>
 */
function cgi_begin(
) : struct_subject_cgi
{
	\session_start();
	$id = \session_id();
	$subject = new struct_subject_cgi($id);
	return $subject;
}


/**
 * @author Christian Fraß <frass@greenscale.de>
 */
function cgi_get(
	string $id
) : struct_subject_cgi
{
	$subject = (new struct_subject_cgi($id));
	\session_id($id);
	\session_start();
	return $subject;
}


/**
 * @author Christian Fraß <frass@greenscale.de>
 */
function cgi_id(
	struct_subject_cgi $subject
) : string
{
	return $subject->id;
}


/**
 * @implementation
 * @author Christian Fraß <frass@greenscale.de>
 */
function cgi_read(
	struct_subject_cgi $subject,
	string $key
) : string
{
	_cgi_keycheck($subject, $key);
	// \session_id($subject->id);
	$value = $_SESSION[$key];
	return $value;
}


/**
 * @implementation
 * @author Christian Fraß <frass@greenscale.de>
 */
function cgi_write(
	struct_subject_cgi $subject,
	string $key,
	string $value
) : void
{
	// \session_id($subject->id);
	$_SESSION[$key] = $value;
}


/**
 * @implementation
 * @author Christian Fraß <frass@greenscale.de>
 */
function cgi_remove(
	struct_subject_cgi $subject,
	string $key
) : void
{
	_cgi_keycheck($subject, $key);
	// \session_id($subject->id);
	unset($_SESSION[$key]);
}


/**
 * @implementation
 * @author Christian Fraß <frass@greenscale.de>
 */
function cgi_end(
	struct_subject_cgi $subject
) : void
{
	// \session_id($subject->id);
	\session_destroy();
}


/**
 * @author Christian Fraß <frass@greenscale.de>
 */
class implementation_cgi implements interface_session {
	
	/**
	 * @var struct_subject_cgi
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	private $subject;
	
	
	/**
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	private function __construct(struct_subject_cgi $subject) {$this->subject = $subject;}
	
	
	/**
	 * implementations
	 * 
	 * @author Christian Fraß <frass@greenscale.de>
	 */
	public static function begin() : interface_session {return (new implementation_cgi(cgi_begin()));}
	public static function get(string $id) : interface_session {return (new implementation_cgi(cgi_get($id)));}
	public function id() : string {return cgi_id($this->subject);}
	public function read(string $key) : string {return cgi_read($this->subject, $key);}
	public function write(string $key, string $value) : void {cgi_write($this->subject, $key, $value);}
	public function remove(string $key) : void {cgi_remove($this->subject, $key);}
	public function end() : void {cgi_end($this->subject);}
	
}

 ?>