<?php
// $Id: legacy.module,v 1.8 2006/02/21 18:46:54 dries Exp $

/**
 * @file
 * Provides legacy handlers for upgrades from older Drupal installations.
 */

/**
 * Implementation of hook_help().
 */
function legacy_help($section) {
  switch ($section) {
    case 'admin/help#legacy':
      $output = '<p>'. t('The legacy module provides legacy handlers for upgrades from older installations.  These handlers help automatically redirect references to pages from old installations and prevent <em>page not found</em> errors for your site.') .'</p>';
      $output .= '<p>'. t('The legacy module handles legacy style taxonomy page, taxonomy feed, and blog feed paths.  It also handles URL upgrades from Drupal 4.1.   It rewrites old-style URLs to new-style URLs (clean URLs). ') .'</p>';
      $output .= t('<p>Example Mappings:</p>
<ul>
<li><em>taxonomy/page/or/52,97</em> to <em>taxonomy/term/52+97</em>.</li>
<li><em>taxonomy/feed/or/52,97</em> to <em>taxonomy/term/52+97/0/feed</em>.</li>
<li><em>blog/feed/52</em> to <em>blog/52/feed</em>.</li>
<li><em>node/view/52</em> to <em>node/52</em>.</li>
<li><em>book/view/52</em> to <em>node/52</em>.</li>
<li><em>user/view/52</em> to <em>user/52</em>.</li>
</ul>
');
      $output .= '<p>'. t('Legacy module has no configurable options.') .'</p>';
      $output .= '<p>'. t('For more information please read the configuration and customization handbook <a href="%legacy">Legacy page</a>.', array('%legacy' => 'http://drupal.org/handbook/modules/legacy/')) .'</p>';
      return $output;
    case 'admin/modules#description':
      return t('Provides legacy handlers for upgrades from older Drupal installations.');
  }
}

/**
 * Implementation of hook_menu().
 *
 * Registers menu paths used in earlier Drupal versions.
 */
function legacy_menu($may_cache) {
  $items = array();

  if ($may_cache) {
    // Map "taxonomy/page/or/52,97" to "taxonomy/term/52+97".
    $items[] = array('path' => 'taxonomy/page', 'title' => t('taxonomy'),
      'callback' => 'legacy_taxonomy_page',
      'access' => TRUE, 'type' => MENU_CALLBACK);

    // Map "taxonomy/feed/or/52,97" to "taxonomy/term/52+97/0/feed".
    $items[] = array('path' => 'taxonomy/feed', 'title' => t('taxonomy'),
      'callback' => 'legacy_taxonomy_feed',
      'access' => TRUE, 'type' => MENU_CALLBACK);

    // Map "blog/feed/52" to "blog/52/feed".
    $items[] = array('path' => 'blog/feed', 'title' => t('blog'),
      'callback' => 'legacy_blog_feed',
      'access' => TRUE, 'type' => MENU_CALLBACK);
  }
  else {
    // Map "node/view/52" to "node/52".
    $items[] = array('path' => 'node/view', 'title' => t('view'),
      'callback' => 'drupal_goto',
      'callback arguments' => array('node/'. arg(2), NULL, NULL),
      'access' => TRUE, 'type' => MENU_CALLBACK);

    // Map "book/view/52" to "node/52".
    $items[] = array('path' => 'book/view', 'title' => t('view'),
      'callback' => 'drupal_goto',
      'callback arguments' => array('node/'. arg(2), NULL, NULL),
      'access' => TRUE, 'type' => MENU_CALLBACK);

    // Map "user/view/52" to "user/52".
    $items[] = array('path' => 'user/view', 'title' => t('view'),
      'callback' => 'drupal_goto',
      'callback arguments' => array('user/'. arg(2), NULL, NULL),
      'access' => TRUE, 'type' => MENU_CALLBACK);
  }

  return $items;
}

/**
 * Menu callback; redirects users to new taxonomy page paths.
 */
function legacy_taxonomy_page($operation = 'or', $str_tids = '') {
  if ($operation == 'or') {
    $str_tids = str_replace(',', '+', $str_tids);
  }
  drupal_goto('taxonomy/term/'. $str_tids);
}

/**
 * Menu callback; redirects users to new taxonomy feed paths.
 */
function legacy_taxonomy_feed($operation = 'or', $str_tids = '') {
  if ($operation == 'or') {
    $str_tids = str_replace(',', '+', $str_tids);
  }
  drupal_goto('taxonomy/term/'. $str_tids .'/0/feed');
}

/**
 * Menu callback; redirects users to new blog feed paths.
 */
function legacy_blog_feed($str_uid = '') {
  // if URL is of form blog/feed/52 redirect
  // if URL is of form blog/feed we have to call blog_feed_last().
  if (is_numeric($str_uid)) {
    drupal_goto('blog/'. $str_uid .'/feed');
  }
  else {
    module_invoke('blog', 'feed_last');
  }
}

/**
 * Implementation of hook_filter(). Handles URL upgrades from Drupal 4.1.
 */
function legacy_filter($op, $delta = 0, $format = -1, $text = '') {
  switch ($op) {
    case 'list':
      return array(t('Legacy filter'));

    case 'description':
      return t('Replaces URLs from Drupal 4.1 (and lower) with updated equivalents.');

    case 'process':
      return _legacy_filter_old_urls($text, $format);

    case 'settings':
      return;

    default:
      return $text;
  }
}

/**
 * Rewrite legacy URLs.
 *
 * This is a *temporary* filter to rewrite old-style URLs to new-style
 * URLs (clean URLs).  Currently, URLs are being rewritten dynamically
 * (ie. "on output"), however when these rewrite rules have been tested
 * enough, we will use them to permanently rewrite the links in node
 * and comment bodies.
 */
function _legacy_filter_old_urls($text) {
  if (!variable_get('rewrite_old_urls', 0)) {
    return $text;
  }

  global $base_url;

  $end = substr($base_url, 12);

  if (variable_get('clean_url', '0') == '0') {
    // Relative URLs:

    // rewrite 'node.php?id=<number>[&cid=<number>]' style URLs:
    $text = eregi_replace("\"(node)\.php\?id=([[:digit:]]+)(&cid=)?([[:digit:]]*)", "\"?q=\\1/view/\\2/\\4", $text);

    // rewrite 'module.php?mod=<name>{&<op>=<value>}' style URLs:
    $text = ereg_replace("\"module\.php\?(&?[[:alpha:]]+=([[:alnum:]]+))(&?[[:alpha:]]+=([[:alnum:]]+))(&?[[:alpha:]]+=([[:alnum:]]+))", "\"?q=\\2/\\4/\\6" , $text);
    $text = ereg_replace("\"module\.php\?(&?[[:alpha:]]+=([[:alnum:]]+))(&?[[:alpha:]]+=([[:alnum:]]+))", "\"?q=\\2/\\4", $text);
    $text = ereg_replace("\"module\.php\?(&?[[:alpha:]]+=([[:alnum:]]+))", "\"?q=\\2", $text);

    // Absolute URLs:

    // rewrite 'node.php?id=<number>[&cid=<number>]' style URLs:
    $text = eregi_replace("$end/(node)\.php\?id=([[:digit:]]+)(&cid=)?([[:digit:]]*)", "$end/?q=\\1/view/\\2/\\4", $text);

    // rewrite 'module.php?mod=<name>{&<op>=<value>}' style URLs:
    $text = ereg_replace("$end/module\.php\?(&?[[:alpha:]]+=([[:alnum:]]+))(&?[[:alpha:]]+=([[:alnum:]]+))(&?[[:alpha:]]+=([[:alnum:]]+))", "$end/?q=\\2/\\4/\\6" , $text);
    $text = ereg_replace("$end/module\.php\?(&?[[:alpha:]]+=([[:alnum:]]+))(&?[[:alpha:]]+=([[:alnum:]]+))", "$end/?q=\\2/\\4", $text);
    $text = ereg_replace("$end/module\.php\?(&?[[:alpha:]]+=([[:alnum:]]+))", "\"$end/?q=\\2", $text);
  }
  else {
    // Relative URLs:

    // Rewrite 'node.php?id=<number>[&cid=<number>]' style URLs:
    $text = eregi_replace("\"(node)\.php\?id=([[:digit:]]+)(&cid=)?([[:digit:]]*)", "\"\\1/view/\\2/\\4", $text);

    // Rewrite 'module.php?mod=<name>{&<op>=<value>}' style URLs:
    $text = ereg_replace("\"module\.php\?(&?[[:alpha:]]+=([[:alnum:]]+))(&?[[:alpha:]]+=([[:alnum:]]+))(&?[[:alpha:]]+=([[:alnum:]]+))", "\"\\2/\\4/\\6", $text);
    $text = ereg_replace("\"module\.php\?(&?[[:alpha:]]+=([[:alnum:]]+))(&?[[:alpha:]]+=([[:alnum:]]+))", "\"\\2/\\4", $text);
    $text = ereg_replace("\"module\.php\?(&?[[:alpha:]]+=([[:alnum:]]+))", "\"\\2", $text);

    // Absolute URLs:

    // Rewrite 'node.php?id=<number>[&cid=<number>]' style URLs:
    $text = eregi_replace("$end/(node)\.php\?id=([[:digit:]]+)(&cid=)?([[:digit:]]*)", "$end/\\1/view/\\2/\\4", $text);

    // Rewrite 'module.php?mod=<name>{&<op>=<value>}' style URLs:
    $text = ereg_replace("$end/module\.php\?(&?[[:alpha:]]+=([[:alnum:]]+))(&?[[:alpha:]]+=([[:alnum:]]+))(&?[[:alpha:]]+=([[:alnum:]]+))", "$end/\\2/\\4/\\6", $text);
    $text = ereg_replace("$end/module\.php\?(&?[[:alpha:]]+=([[:alnum:]]+))(&?[[:alpha:]]+=([[:alnum:]]+))", "$end/\\2/\\4", $text);
    $text = ereg_replace("$end/module\.php\?(&?[[:alpha:]]+=([[:alnum:]]+))", "$end/\\2", $text);
  }

  return $text;
}