<?php
/*
 * Enano - an open-source CMS capable of wiki functions, Drupal-like sidebar blocks, and everything in between
 * Version 1.0 (Banshee)
 * 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 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;
  
  /**
   * 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.
   */
  
  function send()
  {
    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 ( $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' )
    {
      $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->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) )
      {
        $this->err_page_not_existent();
      }
    }
    else // (disabled for compatibility reasons) if ( in_array($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
      {
        $this->render( (!$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);
    
    $this->perms = $session->fetch_page_acl( $page_id, $namespace );
    
    // Exception for Admin: pages
    if ( $this->namespace == 'Admin' )
    {
      $fname = "page_Admin_{$this->page_id}";
    }
    
    // Does the page "exist"?
    if ( $paths->cpage['urlname_nons'] == $page_id && $paths->namespace == $namespace && !$paths->page_exists && ( $this->namespace != 'Admin' || ($this->namespace == 'Admin' && !function_exists($fname) ) ) )
    {
      $this->page_exists = false;
    }
    else if ( !isset( $paths->pages[ $paths->nslist[$namespace] . $page_id ] ) && ( $this->namespace == 'Admin' && !function_exists($fname) ) )
    {
      $this->page_exists = false;
    }
    else
    {
      $this->page_exists = true;
    }
    
    // Compatibility with older databases
    if ( strstr($this->page_id, '.2e') && !$this->page_exists )
    {
      $page_id = str_replace('.2e', '.', $page_id);
      
      if ( $paths->cpage['urlname_nons'] == $page_id && $paths->namespace == $namespace && !$paths->page_exists && ( $this->namespace != 'Admin' || ($this->namespace == 'Admin' && !function_exists($fname) ) ) )
      {
        $this->page_exists = false;
      }
      else if ( !isset( $paths->pages[ $paths->nslist[$namespace] . $page_id ] ) && ( $this->namespace == 'Admin' && !function_exists($fname) ) )
      {
        $this->page_exists = false;
      }
      else
      {
        $this->page_exists = true;
      }
      
    }
    
  }
  
  /**
   * Renders it all in one go, and echoes it out. This assumes that the text is in the DB.
   * @access private
   */
  
  function render($incl_inner_headers = true)
  {
    $text = $this->fetch_text();
    
    $this->header();
    if ( $incl_inner_headers )
    {
      display_page_headers();
    }
    
    if ( $this->revision_id )
    {
      echo '<div class="info-box" style="margin-left: 0; margin-top: 5px;"><b>Notice:</b><br />The page you are viewing was archived on '.date('F d, Y \a\t h:i a', $this->revision_id).'.<br /><a href="'.makeUrlNS($this->namespace, $this->page_id).'" onclick="ajaxReset(); return false;">View current version</a>  |  <a href="'.makeUrlNS($this->namespace, $this->pageid, 'do=rollback&amp;id='.$this->revision_id).'" onclick="ajaxRollback(\''.$this->revision_id.'\')">Restore this version</a></div><br />';
    }
    
    if ( $incl_inner_headers )
    {
      $text = '?>' . RenderMan::render($text);
    }
    else
    {
      $text = '?>' . $text;
      $text = preg_replace('/<nowiki>(.*?)<\/nowiki>/s', '\\1', $text);
    }
    // echo('<pre>'.htmlspecialchars($text).'</pre>');
    eval ( $text );
    
    if ( $incl_inner_headers )
    {
      display_page_footers();
    }
    
    $this->footer();
  }
  
  /**
   * Sends the page header, dependent on, of course, whether we're supposed to.
   */
  
  function header()
  {
    global $db, $session, $paths, $template, $plugins; // Common objects
    if ( $this->send_headers )
      $template->header();
  }
  
  /**
   * Sends the page footer, dependent on, of course, whether we're supposed to.
   */
  
  function footer()
  {
    global $db, $session, $paths, $template, $plugins; // Common objects
    if ( $this->send_headers )
      $template->footer();
  }
  
  /**
   * Fetches the raw, unfiltered page text.
   * @access public
   */
  
  function fetch_text()
  {
    global $db, $session, $paths, $template, $plugins; // Common objects
    
    if ( !empty($this->text_cache) )
    {
      return $this->text_cache;
    }
    
    if ( $this->revision_id > 0 && is_int($this->revision_id) )
    {
    
      $q = $db->sql_query('SELECT page_text, char_tag, date_string FROM '.table_prefix.'logs WHERE page_id=\'' . $this->page_id . '\' AND namespace=\'' . $this->namespace . '\' AND time_id=' . $this->revision_id . ';');
      if ( !$q )
      {
        $this->send_error('Error during SQL query.', true);
      }
      if ( $db->numrows() < 1 )
      {
        // Compatibility fix for old pages with dots in the page ID
        if ( strstr($this->page_id, '.2e') )
        {
          $db->free_result();
          $page_id = str_replace('.2e', '.', $this->page_id);
          $q = $db->sql_query('SELECT page_text, char_tag, date_string FROM '.table_prefix.'logs WHERE page_id=\'' . $page_id . '\' AND namespace=\'' . $this->namespace . '\' AND time_id=' . $this->revision_id . ';');
          if ( !$q )
          {
            $this->send_error('Error during SQL query.', true);
          }
          if ( $db->numrows() < 1 )
          {
            $this->page_exists = false;
            return 'err_no_text_rows';
          }
        }
        else
        {
          $this->page_exists = false;
          return 'err_no_text_rows';
        }
      }
      else
      {
        $row = $db->fetchrow();
      }
      
      $db->free_result();
      
    }
    else
    {
      
      $q = $db->sql_query('SELECT page_text, char_tag FROM '.table_prefix.'page_text WHERE page_id=\'' . $this->page_id . '\' AND namespace=\'' . $this->namespace . '\';');
      if ( !$q )
      {
        $this->send_error('Error during SQL query.', true);
      }
      if ( $db->numrows() < 1 )
      {
        // Compatibility fix for old pages with dots in the page ID
        if ( strstr($this->page_id, '.2e') )
        {
          $db->free_result();
          $page_id = str_replace('.2e', '.', $this->page_id);
          $q = $db->sql_query('SELECT page_text, char_tag FROM '.table_prefix.'page_text WHERE page_id=\'' . $page_id . '\' AND namespace=\'' . $this->namespace . '\';');
          if ( !$q )
          {
            $this->send_error('Error during SQL query.', true);
          }
          if ( $db->numrows() < 1 )
          {
            $this->page_exists = false;
            return 'err_no_text_rows';
          }
        }
        else
        {
          $this->page_exists = false;
          return 'err_no_text_rows';
        }
      }
      
      $row = $db->fetchrow();
      $db->free_result();
      
    }
    
    if ( !empty($row['char_tag']) )
    {
      // This page text entry uses the old text-escaping format
      $from = array(
          "{APOS:{$row['char_tag']}}",
          "{QUOT:{$row['char_tag']}}",
          "{SLASH:{$row['char_tag']}}"
        );
      $to = array("'", '"',  '\\');
      $row['page_text'] = str_replace($from, $to, $row['page_text']);
    }
    
    $this->text_cache = $row['page_text'];
    
    return $row['page_text'];
    
  }
  
  /**
   * Handles the extra overhead required for user pages.
   * @access private
   */
   
  function _handle_userpage()
  {
    global $db, $session, $paths, $template, $plugins; // Common objects
    
    if ( $this->page_id == $paths->cpage['urlname_nons'] && $this->namespace == $paths->namespace )
    {
      $page_name = ( isset($paths->cpage['name']) ) ? $paths->cpage['name'] : $this->page_id;
    }
    else
    {
      $page_name = ( isset($paths->pages[$this->page_id]) ) ? $paths->pages[$this->page_id]['name'] : $this->page_id;
    }
    
    $target_username = strtr($page_name, 
      Array(
        '_' => ' ',
        '<' => '&lt;',
        '>' => '&gt;'
        ));
    
    $target_username = preg_replace('/^' . preg_quote($paths->nslist['User']) . '/', '', $target_username);
    
    if ( ( $page_name == str_replace('_', ' ', $this->page_id) || $page_name == $paths->nslist['User'] . str_replace('_', ' ', $this->page_id) ) || !$this->page_exists )
    {
      $page_name = "$target_username's user page";
    }
    else
    {
      // User has a custom title for their userpage
      $page_name = $paths->pages[ $paths->nslist[$this->namespace] . $this->page_id ]['name'];
    }
    
    $template->tpl_strings['PAGE_NAME'] = htmlspecialchars($page_name);
    
    $q = $db->sql_query('SELECT u.username, u.user_id AS authoritative_uid, u.real_name, u.email, u.reg_time, x.*, COUNT(c.comment_id) AS n_comments
                           FROM '.table_prefix.'users u
                           LEFT JOIN '.table_prefix.'users_extra AS x
                             ON ( u.user_id = x.user_id OR x.user_id IS NULL ) 
                           LEFT JOIN '.table_prefix.'comments AS c
                             ON ( ( c.user_id=u.user_id AND c.approved=1 ) OR ( c.comment_id IS NULL AND c.approved IS NULL ) )
                           WHERE u.username=\'' . $db->escape($target_username) . '\'
                           GROUP BY u.user_id;');
    if ( !$q )
      $db->_die();
    
    $user_exists = true;
    
    if ( $db->numrows() < 1 )
    {
      $user_exists = false;
    }
    else
    {
      $userdata = $db->fetchrow();
      if ( $userdata['authoritative_uid'] == 1 )
      {
        // Hide data for anonymous user
        $user_exists = false;
        unset($userdata);
      }
    }
    
    $this->header();
    
    // if ( $send_headers )
    // {
    //  display_page_headers();
    // }
   
    // Start left sidebar: basic user info, latest comments
    
    if ( $user_exists ):
    
    echo '<table border="0" cellspacing="4" cellpadding="0" style="width: 100%;">';
    echo '<tr><td style="width: 150px;" valign="top">';
    
    echo '<div class="tblholder">
            <table border="0" cellspacing="1" cellpadding="4">';
    
    //
    // Main part of sidebar
    //
    
    // Basic user info
    
    echo '<tr><th class="subhead">All about ' . htmlspecialchars($target_username) . '</th></tr>';
    echo '<tr><td class="row3">Joined: ' . date('F d, Y h:i a', $userdata['reg_time']) . '</td></tr>';
    echo '<tr><td class="row1">Total comments: ' . $userdata['n_comments'] . '</td></tr>';
    
    if ( !empty($userdata['real_name']) )
    {
      echo '<tr><td class="row3">Real name: ' . $userdata['real_name'] . '</td></tr>';
    }
    
    // Comments
    
    echo '<tr><th class="subhead">' . htmlspecialchars($target_username) . '\'s latest comments</th></tr>';
    $q = $db->sql_query('SELECT page_id, namespace, subject, time FROM '.table_prefix.'comments WHERE name=\'' . $db->escape($target_username) . '\' AND approved=1 ORDER BY time DESC LIMIT 5;');
    if ( !$q )
      $db->_die();
    
    $comments = Array();
    $no_comments = false;
    
    if ( $row = $db->fetchrow() )
    {
      do 
      {
        $row['time'] = date('F d, Y', $row['time']);
        $comments[] = $row;
      }
      while ( $row = $db->fetchrow() );
    }
    else
    {
      $no_comments = true;
    }
    
    echo '<tr><td class="row3">';
    echo '<div style="border: 1px solid #000000; padding: 0px; margin: 0; max-height: 200px; clip: rect(0px,auto,auto,0px); overflow: auto; background-color: transparent;" class="tblholder">';
    
    echo '<table border="0" cellspacing="1" cellpadding="4">';
    $class = 'row1';
    
    $tpl = '<tr>
              <td class="{CLASS}">
                <a href="{PAGE_LINK}" <!-- BEGINNOT page_exists -->class="wikilink-nonexistent"<!-- END page_exists -->>{PAGE}</a><br />
                <small>Posted {DATE}<br /></small>
                <b><a href="{COMMENT_LINK}">{SUBJECT}</a></b>
              </td>
            </tr>';
    $parser = $template->makeParserText($tpl);
    
    if ( count($comments) > 0 )
    {
      foreach ( $comments as $comment )
      {
        $c_page_id = $paths->nslist[ $comment['namespace'] ] . sanitize_page_id($comment['page_id']);
        if ( isset($paths->pages[ $c_page_id ]) )
        {
          $parser->assign_bool(array(
            'page_exists' => true
            ));
          $page_title = $paths->pages[ $c_page_id ]['name'];
        }
        else
        {
          $parser->assign_bool(array(
            'page_exists' => false
            ));
          $page_title = htmlspecialchars(dirtify_page_id($c_page_id));
        }
        $parser->assign_vars(array(
            'CLASS' => $class,
            'PAGE_LINK' => makeUrlNS($comment['namespace'], sanitize_page_id($comment['page_id'])),
            'PAGE' => $page_title,
            'SUBJECT' => $comment['subject'],
            'DATE' => $comment['time'],
            'COMMENT_LINK' => makeUrlNS($comment['namespace'], sanitize_page_id($comment['page_id']), 'do=comments', true)
          ));
        $class = ( $class == 'row3' ) ? 'row1' : 'row3';
        echo $parser->run();
      }
    }
    else
    {
      echo '<tr><td class="' . $class . '">This user has not posted any comments.</td></tr>';
    }
    echo '</table>';
    
    echo '</div>';
    echo '</td></tr>';
            
    echo '  </table>
          </div>';
    
    echo '</td><td valign="top" style="padding: 0 10px;">';
    
    else:
    
    // Nothing for now
    
    endif;
    
    // User's own content
    
    $send_headers = $this->send_headers;
    $this->send_headers = false;
    
    if ( $this->page_exists )
    {
      $this->render();
    }
    else
    {
      $this->err_page_not_existent(true);
    }
    
    // Right sidebar
    
    if ( $user_exists ):
    
    echo '</td><td style="width: 150px;" valign="top">';
    
    echo '<div class="tblholder">
            <table border="0" cellspacing="1" cellpadding="4">';
    
    //
    // Main part of sidebar
    //
    
    // Contact information
    
    echo '<tr><th class="subhead">Get in touch</th></tr>';
    
    $class = 'row3';
    
    if ( $userdata['email_public'] == 1 )
    {
      $class = ( $class == 'row1' ) ? 'row3' : 'row1';
      global $email;
      $email_link = $email->encryptEmail($userdata['email']);
      echo '<tr><td class="'.$class.'">E-mail address: ' . $email_link . '</td></tr>';
    }
    
    $class = ( $class == 'row1' ) ? 'row3' : 'row1';
    if ( $session->user_logged_in )
    {
      echo '<tr><td class="'.$class.'">Send ' . htmlspecialchars($target_username) . ' a <a href="' . makeUrlNS('Special', 'PrivateMessages/Compose/to/' . $this->page_id, false, true) . '">Private Message</a>!</td></tr>';
    }
    else
    {
      echo '<tr><td class="'.$class.'">You could send ' . htmlspecialchars($target_username) . ' a private message if you were <a href="' . makeUrlNS('Special', 'Login/' . $paths->nslist[$this->namespace] . $this->page_id) . '">logged in</a>.</td></tr>';
    }
    
    if ( !empty($userdata['user_aim']) )
    {
      $class = ( $class == 'row1' ) ? 'row3' : 'row1';
      echo '<tr><td class="'.$class.'">AIM: ' . htmlspecialchars($userdata['user_aim']) . '</td></tr>';
    }
    
    if ( !empty($userdata['user_yahoo']) )
    {
      $class = ( $class == 'row1' ) ? 'row3' : 'row1';
      echo '<tr><td class="'.$class.'">Yahoo! IM: ' . htmlspecialchars($userdata['user_yahoo']) . '</td></tr>';
    }
    
    if ( !empty($userdata['user_msn']) )
    {
      $class = ( $class == 'row1' ) ? 'row3' : 'row1';
      $email_link = $email->encryptEmail($userdata['user_msn']);
      echo '<tr><td class="'.$class.'">WLM: ' . $email_link . '</td></tr>';
    }
    
    if ( !empty($userdata['user_xmpp']) )
    {
      $class = ( $class == 'row1' ) ? 'row3' : 'row1';
      $email_link = $email->encryptEmail($userdata['user_xmpp']);
      echo '<tr><td class="'.$class.'">XMPP/Jabber: ' . $email_link . '</td></tr>';
    }
    
    // Real life
    
    echo '<tr><th class="subhead">' . htmlspecialchars($target_username) . ' in real life</th></tr>';
    
    if ( !empty($userdata['user_location']) )
    {
      $class = ( $class == 'row1' ) ? 'row3' : 'row1';
      echo '<tr><td class="'.$class.'">Location: ' . htmlspecialchars($userdata['user_location']) . '</td></tr>';
    }
    
    if ( !empty($userdata['user_job']) )
    {
      $class = ( $class == 'row1' ) ? 'row3' : 'row1';
      echo '<tr><td class="'.$class.'">Job/occupation: ' . htmlspecialchars($userdata['user_job']) . '</td></tr>';
    }
    
    if ( !empty($userdata['user_hobbies']) )
    {
      $class = ( $class == 'row1' ) ? 'row3' : 'row1';
      echo '<tr><td class="'.$class.'">Enjoys: ' . htmlspecialchars($userdata['user_hobbies']) . '</td></tr>';
    }
    
    if ( empty($userdata['user_location']) && empty($userdata['user_job']) && empty($userdata['user_hobbies']) )
    {
      $class = ( $class == 'row1' ) ? 'row3' : 'row1';
      echo '<tr><td class="'.$class.'">' . htmlspecialchars($target_username) . ' hasn\'t posted any real-life contact information.</td></tr>';
    }
    
    echo '  </table>
          </div>';
          
    echo '</tr></table>';
    
    else:
    
    echo '<p>Additional information: user "' . htmlspecialchars($target_username) . '" does not exist.</p>';
    
    endif;
    
    // if ( $send_headers )
    // {
    //  display_page_footers();
    // }
    
    $this->send_headers = $send_headers;
    unset($send_headers);
    
    $this->footer();
    
  }
  
  /**
   * Send the error message to the user that the access to this page is denied.
   * @access private
   */
  
  function err_access_denied()
  {
    global $db, $session, $paths, $template, $plugins; // Common objects
    
    $ob = '';
    $template->tpl_strings['PAGE_NAME'] = 'Access denied';
      
    if ( $this->send_headers )
    {
      $ob .= $template->getHeader();
    }
    
    $ob .= '<div class="error-box"><b>Access to this page is denied.</b><br />This may be because you are not logged in or you have not met certain criteria for viewing this page.</div>';
    
    if ( $this->send_headers )
    {
      $ob .= $template->getFooter();
    }
    echo $ob;
  }
  
  /**
   * Send the error message to the user complaining that there weren't any rows.
   * @access private
   */
  
  function err_no_rows()
  {
    global $db, $session, $paths, $template, $plugins; // Common objects
    
    $title = 'No text rows';
    $message = 'While the page\'s existence was verified, there were no rows in the database that matched the query for the text. This may indicate a bug with the software; ask the webmaster for more information. The offending query was:<pre>' . $db->latest_query . '</pre>';
    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>";
    }
  }
  
  /**
   * Tell the user the page doesn't exist, and present them with their options.
   * @access private
   */
   
  function err_page_not_existent($userpage = false)
  {
    global $db, $session, $paths, $template, $plugins; // Common objects
    
    $this->header();
    header('HTTP/1.1 404 Not Found');
    if ( $userpage )
    {
      echo '<h3>There is no page with this title yet.</h3>
             <p>This user has not created his or her user page yet.';
    }
    else
    {
      echo '<h3>There is no page with this title yet.</h3>
             <p>You have requested a page that doesn\'t exist yet.';
    }
    if ( $session->get_permissions('create_page') )
    {
      echo ' You can <a href="'.makeUrlNS($this->namespace, $this->page_id, 'do=edit', true).'" onclick="ajaxEditor(); return false;">create this page</a>, or return to the <a href="'.makeUrl(getConfig('main_page')).'">homepage</a>.';
    }
    else
    {
      echo ' Return to the <a href="'.makeUrl(getConfig('main_page')).'">homepage</a>.</p>';
    }
    if ( $session->get_permissions('history_rollback') )
    {
      $e = $db->sql_query('SELECT * FROM ' . table_prefix . 'logs WHERE action=\'delete\' AND page_id=\'' . $this->page_id . '\' AND namespace=\'' . $this->namespace . '\' ORDER BY time_id DESC;');
      if ( !$e )
      {
        $db->_die('The deletion log could not be selected.');
      }
      if ( $db->numrows() > 0 )
      {
        $r = $db->fetchrow();
        echo '<p><b>This page was deleted on ' . $r['date_string'] . '.</b> The stated reason was:</p><blockquote>' . $r['edit_summary'] . '</blockquote><p>You can probably <a href="'.makeUrl($paths->page, 'do=rollback&amp;id='.$r['time_id']).'" onclick="ajaxRollback(\''.$r['time_id'].'\'); return false;">roll back</a> the deletion.</p>';
      }
      $db->free_result();
    }
    echo '<p>
            HTTP Error: 404 Not Found
          </p>';
    $this->footer();
  }
  
  /**
   * PHP 4 constructor.
   * @see PageProcessor::__construct()
   */
  
  function PageProcessor( $page_id, $namespace, $revision_id = 0 )
  {
    $this->__construct($page_id, $namespace, $revision_id);
  }
  
  /**
   * Send an error message and die. For debugging or critical technical errors only - nothing that would under normal circumstances be shown to the user.
   * @var string Error message
   * @var bool If true, send DBAL's debugging information as well
   */
   
  function send_error($message, $sql = false)
  {
    global $db, $session, $paths, $template, $plugins; // Common objects
    
    $content = "<p>$message</p>";
    $template->tpl_strings['PAGE_NAME'] = 'General error in page fetcher';
    
    if ( $this->debug['works'] )
    {
      $content .= $this->debug['backtrace'];
    }
    
    header('HTTP/1.1 500 Internal Server Error');
    
    $template->header();
    echo $content;
    $template->footer();
    
    $db->close();
    
    exit;
    
  }
  
} // class PageProcessor

?>