<?php
/**
 *  Copyright (C) 2011  Kai Dorschner
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * @author Kai Dorschner <the-hide@address.com>
 * @copyright Copyright 2011, Kai Dorschner
 * @license http://www.gnu.org/licenses/gpl.html GPLv3
 * @package mocovi
 */

class Session
{
	/**
	 * Start global session by using PHP session management.
	 *
	 * It additionally checks if the header is already sent
	 * and throws an exception if it is.
	 *
	 * @access public
	 * @static
	 * @return void
	 */
	public static function start()
	{
		if(!session_id())
			if(!headers_sent())
			{
				if(!session_start())
					throw new Exception('Session not started successfully.');
			}
			else
				throw new Exception('Session cannot be started. Headers already sent.');
	}

	/**
	 * Destroys a PHP session.
	 *
	 * It additionally deletes the session cookie (if the header is not already
	 * sent) and destroys every variable content relating to the session.
	 *
	 * @access public
	 * @static
	 * return void
	 */
	public static function destroy()
	{
		if(!headers_sent())
		{
			$params = session_get_cookie_params();
			setcookie
				( session_name()
				, ''
				, time() - 3600 // Set cookie valide time to the past (1h)
				, $params["path"]
				, $params["domain"]
				, $params["secure"]
				, $params["httponly"]
				);
		}
		session_unset();
		session_destroy();
	}

	/**
	 * Returns the value of a session var.
	 * 
	 * @access public
	 * @static
	 * @return String Session-var value
	 * @param string $name Name of the session var
	 */
	public static function get($name)
	{
		if(isset($_SESSION[$name]))
			return $_SESSION[$name];
		return false;
	}

	/**
	 * Sets/overwrites a session var.
	 * 
	 * @access public
	 * @static
	 * @return void
	 * @param string $name Name of the session var
	 * @param string $value New value of the session var
	 */
	public static function set($name, $value)
	{
		$_SESSION[$name] = $value;
	}

	/**
	 * Deletes a session var.
	 *
	 * @access public
	 * @static
	 * @return void
	 * @param string $name Name of the session var
	 */
	public static function delete($name)
	{
		unset($_SESSION[$name]);
	}

	/**
	 * Returns the current session ID.
	 *
	 * @access public
	 * @static
	 * @return string Session ID
	 */
	public static function id()
	{
		return session_id();
	}
}