<?php namespace phpSec\Common;
/**
  phpSec - A PHP security library

  @author    Audun Larsen <larsen@xqus.com>
  @copyright Copyright (c) Audun Larsen, 2011
  @link      https://github.com/phpsec/phpSec
  @license   http://opensource.org/licenses/mit-license.php The MIT License
  @package   phpSec
 */

class Session {

  /**

   * phpSec core Pimple container.

   */
  private $psl = null;

  private $sessIdRegen;

  private $savePath;

  private $name;

  private $keyCookie;

  private $secret;

  private $currID;

  private $newID;



  public $cryptAlgo = 'rijndael-256';

  public $cryptMode = 'cfb';

  /**

   * Constructor.

   *

   * @param \phpSec\Core $psl

   *   phpSec core Pimple container.

   */
  public function __construct($psl) {
    $this->psl = $psl;
    ini_set('session.save_handler', 'user');

    session_set_save_handler(
      array($this, 'open'),
      array($this, 'close'),
      array($this, 'read'),
      array($this, 'write'),
      array($this, 'destroy'),
      array($this, 'gc')
    );

    /* Since we set a session cookie on our session handler, disable the built-in cookies. */

    ini_set('session.use_cookies', 0);
  }

  /**
   * Start session.
   *
   * @param bool $regen
   *   Regenerate session ID or not.
   */
  public function start($regen = true) {
    $this->sessIdRegen = $regen;

    /* Start a new session. */

    session_start();


    /* Set UID. */

    $this->psl->getUid();
  }

  /**

   * Close a session.

   *

   * @return bool

   */
  public function close() {
    return true;
  }

  /**

   * Destroy/remove a session.

   *

   * @param string $id

   * @return bool

   */

  public function destroy($id) {
    $store  = $this->psl['store'];
    return $store->delete('session', $id);

  }

  /**

   * Do garbage collection.

   *

   * @param integer $ttl

   * @return bool

   */

  public function gc($ttl) {
    $store  = $this->psl['store'];

    $Ids = $store->listIds('session');

    foreach($Ids as $Id) {

      $data = $store->meta('session', $Id);

      if($data->time + $ttl < time()) {

        $store->delete('session', $Id);

      }

    }

    return true;
  }

  /**

   * Open a session.

   *

   * @param string $path

   * @param string $name

   * @return bool

   */

  public function open($path, $name) {
    $rand = $this->psl['crypt/rand'];

    /* Set some variables we need later. */

    $this->savePath  = $path;

    $this->name      = $name;

    $this->keyCookie = $name.'_secret';



    /* Set current and new ID. */

    if(isset($_COOKIE[$name])) {

      $this->currID = $_COOKIE[$name];

    } else {

      $this->currID = null;

    }

    if($this->sessIdRegen === true || $this->currID === null) {

      $this->newID = $rand->str(128, 'abcdefghijklmnopqrstuvwxyz1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ-_.!*#=%');

    } else {

      $this->newID = $this->currID;

    }



    /* Set cookie with new session ID. */

    $cookieParam = session_get_cookie_params();

    setcookie(

        $name,

        $this->newID,

        $cookieParam['lifetime'],

        $cookieParam['path'],

        $cookieParam['domain'],

        $cookieParam['secure'],

        $cookieParam['httponly']

    );



    /* If we don't have a encryption key, create one. */

    if(!isset($_COOKIE[$this->keyCookie])) {

      /* Create a secret used for encryption of session. */

      $this->setSecret();

    } else {

      $this->secret = base64_decode($_COOKIE[$this->keyCookie]);

    }

    return true;
  }

  /**

   * Read and decrypt a session.

   *

   * @param string $id

   * @return mixed

   */

  public function read($id) {
    $crypto = $this->psl['crypt/crypto'];

    $store  = $this->psl['store'];

    /* If no cookie is set, just drop it! */

    if(!isset($_COOKIE[$this->name])) {

      return false;

    }



    /* Read from store and decrypt. */

    try {

      $sessData = $store->read('session', $_COOKIE[$this->name]);



      if($sessData !== false ) {

        $return = $crypto->decrypt($sessData, $this->secret);

      } else {

        $return = false;

      }

      return $return;

    }  catch (\phpSec\Exception $e) {

      return false;

    }
  }

  /**

   * Encrypt and save a session.

   *

   * @param string $id

   * @param string $data

   * @return bool

   */

  public function write($id , $data) {
    $crypto = $this->psl['crypt/crypto'];
    $store  = $this->psl['store'];

    /* Encrypt session. */

    try {

      $crypto->_algo = $this->cryptAlgo;

      $crypto->_mode = $this->cryptMode;

      $encrypted = $crypto->encrypt($data, $this->secret);



      /* Destroy old session. */

      if($this->newID != $this->currID) {

        $this->destroy($this->currID);

      }



      /* Write new session, with new ID. */

      return $store->write('session', $this->newID, $encrypted);

    } catch (\phpSec\Exception $e) {

      return false;

    }
  }

  /**

   * Set the cookie with the secret.

   *

   * @return true

   */
  public function setSecret() {

    $rand = $this->psl['crypt/rand'];

    $this->secret = $rand->bytes(32);

    $cookieParam = session_get_cookie_params();

    setcookie(

        $this->keyCookie,

        base64_encode($this->secret),

        $cookieParam['lifetime'],

        $cookieParam['path'],

        $cookieParam['domain'],

        $cookieParam['secure'],

        $cookieParam['httponly']

    );

    return true;

  }
}