<?php

/*

 * Enano - an open-source CMS capable of wiki functions, Drupal-like sidebar blocks, and everything in between

 * pageprocess.php - intelligent retrieval of pages

 * Copyright (C) 2006-2007 Dan Fuhry

 *

 * This program is Free Software; you can redistribute and/or modify it under the terms of the GNU General Public License

 * as published by the Free Software Foundation; either version 2 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 details.

 */

/**

 * Class to handle fetching page text (possibly from a cache) and formatting it.

 * @package Enano

 * @subpackage UI

 * @copyright 2007 Dan Fuhry

 * @license GNU General Public License <http://www.gnu.org/licenses/gpl.html>

 */

class PageProcessor

{

  /**

   * Page ID and namespace of the page handled by this instance

   * @var string

   */

  var $page_id;

  var $namespace;

  /**

   * The title of the page sent to the template parser

   * @var string

   */

  var $title = '';

  /**

   * The information about the page(s) we were redirected from

   * @var array

   */

  var $redirect_stack = array();

  /**

   * The revision ID (history entry) to send. If set to 0 (the default) then the most recent revision will be sent.

   * @var int

   */

  var $revision_id = 0;

  /**

   * Unsanitized page ID.

   * @var string

   */

  var $page_id_unclean;

  /**

   * Tracks if the page we're loading exists in the database or not.

   * @var bool

   */

  var $page_exists = false;

  /**

   * Permissions!

   * @var object

   */

  var $perms = null;

  /**

   * The SHA1 hash of the user-inputted password for the page

   * @var string

   */

  var $password = '';

  /**

   * Switch to track if redirects are allowed. Defaults to true.

   * @var bool

   */

  var $allow_redir = true;

  /**

   * If this is set to true, this will call the header and footer funcs on $template when render() is called.

   * @var bool

   */

  var $send_headers = false;

  /**

   * Cache the fetched text so we don't fetch it from the DB twice.

   * @var string

   */

  var $text_cache = '';

  /**

   * Debugging information to track errors. You can set enable to false to disable sending debug information.

   * @var array

   */

  var $debug = array(

      'enable' => false,

      'works'  => false

    );

  /**

   * Constructor.

   * @param string The page ID (urlname) of the page

   * @param string The namespace of the page

   * @param int Optional. The revision ID to send.

   */

  function __construct( $page_id, $namespace, $revision_id = 0 )

  {

    global $db, $session, $paths, $template, $plugins; // Common objects

    // See if we can get some debug info

    if ( function_exists('debug_backtrace') && $this->debug['enable'] )

    {

      $this->debug['works'] = true;

      $this->debug['backtrace'] = enano_debug_print_backtrace(true);

    }

    // First things first - check page existence and permissions

    if ( !isset($paths->nslist[$namespace]) )

    {

      $this->send_error('The namespace "' . htmlspecialchars($namespace) . '" does not exist.');

    }

    if ( !is_int($revision_id) )

      $revision_id = 0;

    $this->_setup( $page_id, $namespace, $revision_id );

  }

  /**

   * The main method to send the page content. Also responsible for checking permissions and calling the statistics counter.

   * @param bool If true, the stat counter is called. Defaults to false.

   */

  function send( $do_stats = false )

  {

    global $db, $session, $paths, $template, $plugins; // Common objects

    if ( !$this->perms->get_permissions('read') )

    {

      $this->err_access_denied();

      return false;

    }

    $pathskey = $paths->nslist[ $this->namespace ] . $this->page_id;

    $strict_no_headers = false;

    if ( isset($paths->pages[$pathskey]) )

    {

      if ( $paths->pages[$pathskey]['special'] == 1 )

      {

        $this->send_headers = false;

        $strict_no_headers = true;

      }

      if ( isset($paths->pages[$pathskey]['password']) )

      {

        if ( $paths->pages[$pathskey]['password'] != '' && $paths->pages[$pathskey]['password'] != sha1('') )

        {

          $password =& $paths->pages[$pathskey]['password'];

          if ( $this->password != $password )

          {

            $this->err_wrong_password();

            return false;

          }

        }

      }

    }

    if ( $this->page_exists && $this->namespace != 'Special' && $this->namespace != 'Admin' && $do_stats )

    {

      doStats($this->page_id, $this->namespace);

    }

    if ( $this->namespace == 'Special' || $this->namespace == 'Admin' )

    {

      if ( !$this->page_exists )

      {

        redirect( makeUrl(getConfig('main_page')), 'Can\'t find special page', 'The special or administration page you requested does not exist. You will now be transferred to the main page.', 2 );

      }

      $func_name = "page_{$this->namespace}_{$this->page_id}";

      if ( function_exists($func_name) )

      {

        return @call_user_func($func_name);

      }

      else

      {

        $title = 'Page backend not found';

        $message = "The administration page you are looking for was properly registered using the page API, but the backend function

                    (<tt>$fname</tt>) was not found. If this is a plugin page, then this is almost certainly a bug with the plugin.";

        if ( $this->send_headers )

        {

          $template->tpl_strings['PAGE_NAME'] = $title;

          $template->header();

          echo "<p>$message</p>";

          $template->footer();

        }

        else

        {

          echo "<h2>$title</h2>

                <p>$message</p>";

        }

        return false;

      }

    }

    else if ( $this->namespace == 'User' && strpos($this->page_id, '/') === false )

    {

      $this->_handle_userpage();

    }

    else if ( ( $this->namespace == 'Template' || $this->namespace == 'System' ) && $this->page_exists )

    {

      $this->header();

      $text = $this->fetch_text();

      $text = preg_replace('/<noinclude>(.*?)<\/noinclude>/is', '\\1', $text);

      $text = preg_replace('/<nodisplay>(.*?)<\/nodisplay>/is', '', $text);

      $text = RenderMan::render( $text );

      echo $text;

      $this->footer();

    }

    else if ( $this->namespace == 'Anonymous' )

    {

      $uri = scriptPath . '/' . $this->page_id;

      if ( !$this->send_headers )

      {

        $sep = ( strstr($uri, '?') ) ? '&' : '?';

        $uri .= "{$sep}noheaders";

      }

      redirect( $uri, '', '', 0 );

    }

    else if ( !$this->page_exists )

    {

      // Perhaps this is hooked?

      ob_start();

      $code = $plugins->setHook('page_not_found');

      foreach ( $code as $cmd )

      {

        eval($cmd);

      }

      $ob = ob_get_contents();

      if ( empty($ob) )

      {

        $this->err_page_not_existent();

      }

      else

      {

        // Something sent content, so we'll assume the page exist...ed at least according to the plugin

        if ( $this->namespace != 'Special' && $this->namespace != 'Admin' && $do_stats )

        {

          doStats($this->page_id, $this->namespace);

        }

      }

    }

    else // (disabled for compatibility reasons) if ( in_array($this->namespace, array('Article', 'User', 'Project', 'Help', 'File', 'Category')) && $this->page_exists )

    {

      // Send as regular page

      // die($this->page_id);

      $text = $this->fetch_text();

      if ( $text == 'err_no_text_rows' )

      {

        $this->err_no_rows();

        return false;

      }

      else

      {

        $redirect = ( isset($_GET['redirect']) ) ? $_GET['redirect'] : 'YES YOU IDIOT';

        if ( preg_match('/^#redirect \[\[([^\]]+)\]\]/i', $text, $match) && $redirect != 'no' )

        {

          // Redirect page!

          $page_to = sanitize_page_id($match[1]);

          $page_id_data = RenderMan::strToPageID($page_to);

          if ( count($this->redirect_stack) >= 3 )

          {

            $this->render( (!$strict_no_headers), '<div class="usermessage"><b>The maximum number of internal redirects has been exceeded.</b></div>' );

          }

          else

          {

            $result = $this->_handle_redirect($page_id_data[0], $page_id_data[1]);

            if ( $result !== true )

            {

              // There was some error during the redirect process - usually an infinite redirect

              $this->render( (!$strict_no_headers), '<div class="usermessage"><b>' . $result . '</b></div>' );

            }

          }

        }

        else

        {

          $this->render( (!$strict_no_headers) );

        }

      }

    }

  }

  /**

   * Sets internal variables.

   * @access private

   */

  function _setup($page_id, $namespace, $revision_id)

  {

    global $db, $session, $paths, $template, $plugins; // Common objects

    $page_id_cleaned = sanitize_page_id($page_id);

    $this->page_id = $page_id_cleaned;

    $this->namespace = $namespace;

    $this->revision_id = $revision_id;

    $this->page_id_unclean = dirtify_page_id($page_id);