<?php

/**
 * Gelato Library
 *
 * This source file is part of the Gelato Library. More information,
 * documentation and tutorials can be found at http://gelato.monstra.org
 *
 * @package     Gelato
 *
 * @author      Romanenko Sergey / Awilum <awilum@msn.com>
 * @copyright   2012-2014 Romanenko Sergey / Awilum <awilum@msn.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

class Session
{
    /**
     * Starts the session.
     *
     *  <code>
     *      Session::start();
     *  </code>
     *
     */
    public static function start()
    {
        // Is session already started?
        if ( ! session_id()) {

            // Start the session
            return @session_start();
        }

        // If already started
        return true;
    }

    /**
     * Deletes one or more session variables.
     *
     *  <code>
     *      Session::delete('user');
     *  </code>
     *
     */
    public static function delete()
    {
        // Loop all arguments
        foreach (func_get_args() as $argument) {

            // Array element
            if (is_array($argument)) {

                // Loop the keys
                foreach ($argument as $key) {

                    // Unset session key
                    unset($_SESSION[(string) $key]);
                }
            } else {

                // Remove from array
                unset($_SESSION[(string) $argument]);
            }
        }
    }

    /**
     * Destroys the session.
     *
     *  <code>
     *      Session::destroy();
     *  </code>
     *
     */
    public static function destroy()
    {
        // Destroy
        if (session_id()) {
            session_unset();
            session_destroy();
            $_SESSION = array();
        }

    }

    /**
     * Checks if a session variable exists.
     *
     *  <code>
     *      if (Session::exists('user')) {
     * 			// Do something...
     *  	}
     *  </code>
     *
     * @return boolean
     */
    public static function exists()
    {
        // Start session if needed
        if ( ! session_id()) Session::start();

        // Loop all arguments
        foreach (func_get_args() as $argument) {

            // Array element
            if (is_array($argument)) {

                // Loop the keys
                foreach ($argument as $key) {

                    // Does NOT exist
                    if ( ! isset($_SESSION[(string) $key])) return false;
                }
            } else {

                // Does NOT exist
                if ( ! isset($_SESSION[(string) $argument])) return false;
            }
        }

        return true;
    }

    /**
     * Gets a variable that was stored in the session.
     *
     *  <code>
     *      echo Session::get('user');
     *  </code>
     *
     * @param  string $key The key of the variable to get.
     * @return mixed
     */
    public static function get($key)
    {
        // Start session if needed
        if ( ! session_id()) self::start();

        // Redefine key
        $key = (string) $key;

        // Fetch key
        if (Session::exists((string) $key)) return $_SESSION[(string) $key];

        // Key doesn't exist
        return null;
    }


    /**
     * Returns the sessionID.
     *
     *  <code>
     *      echo Session::getSessionId();
     *  </code>
     *
     * @return string
     */
    public static function getSessionId()
    {
        if ( ! session_id()) Session::start();
        return session_id();
    }


    /**
     * Stores a variable in the session.
     *
     *  <code>
     *      Session::set('user', 'Awilum');
     *  </code>
     *
     * @param string $key   The key for the variable.
     * @param mixed  $value The value to store.
     */
    public static function set($key, $value)
    {
        // Start session if needed
        if ( ! session_id()) self::start();

        // Set key
        $_SESSION[(string) $key] = $value;
    }

}