<?php
/**
 * @file
 * Pluggable system to provide advanced help facilities for Drupal and modules.
 *
 * Modules utilizing this help system should create a 'help' directory in their
 * module. Inside that directory place MODULENAME.help.ini which will be
 * formatted like this:
 *
 * @code
 * [buses]
 * title = "How buses are tied into the system"
 * file = buses
 *
 * [TOPIC_ID]
 * title = "Title of topic"
 * file = filename of topic, without the .html extension
 * weight = the importance of the topic on the index page
 * parent = the optional topic parent to use in the breadcrumb.
 * Can be either topic or module%topic
 * @endcode
 *
 * All topics are addressed by the module that provides the topic, and the topic
 * id. Links may be embedded as in the following example:
 *
 * @code
 * $output .= theme('advanced_help_topic', $module, $topic);
 * @endcode
 *
 * Link to other topics using <a href="topic:module/topic">. (Using
 * this format ensures the popup status remains consistent for all
 * links.)
 */

/**
 * Implements hook_menu().
 */
function advanced_help_menu() {
  // View help topic index.
  //
  // This is structured little oddly so that POTX can handle the translation.
  if (module_exists('help')) {
    $items['admin/advanced_help'] = array(
      'title' => 'Advanced help',
      'page callback' => 'advanced_help_index_page',
      'access arguments' => array('view advanced help index'),
      'weight' => 9,
    );
  }
  else {
    $items['admin/advanced_help'] = array(
      'title' => 'Help',
      'page callback' => 'advanced_help_index_page',
      'access arguments' => array('view advanced help index'),
      'weight' => 9,
    );
  }
  $items['advanced_help/search/%'] = array(
    'title' => 'Search help',
    'page callback' => 'advanced_help_search_view',
    'page arguments' => array('advanced_help'),
    'access arguments' => array('view advanced help index'),
  );

  // View help topic.
  $items['help/%/%'] = array(
    'page callback' => 'advanced_help_topic_page',
    'page arguments' => array(1, 2),
    'access arguments' => array('view advanced help topic'),
    'type' => MENU_CALLBACK,
  );

  return $items;
}

/**
 * Implements hook_menu_alter().
 */
function advanced_help_menu_alter(&$callbacks) {
  // We need to fix the menu item provided by search module to restrict access.
  $callbacks['search/advanced_help/%menu_tail']['access callback'] = 'user_access';
  $callbacks['search/advanced_help/%menu_tail']['access arguments'] = array('view advanced help index');
}

/**
 * Implements hook_theme().
 */
function advanced_help_theme() {
  $hooks['advanced_help_topic'] = array(
    'variables' => array(
      'module' => NULL,
      'topic'  => NULL,
      'type'   => 'icon',
    ),
  );

  $hooks['advanced_help_popup'] = array(
    'render element' => 'content',
    'template' => 'advanced-help-popup',
  );

  return $hooks;
}

/**
 * Helper function to sort topics.
 */
function advanced_help_uasort($id_a, $id_b) {
  $topics = advanced_help_get_topics();
  list($module_a, $topic_a) = $id_a;
  $a = $topics[$module_a][$topic_a];
  list($module_b, $topic_b) = $id_b;
  $b = $topics[$module_b][$topic_b];

  $a_weight = isset($a['weight']) ? $a['weight'] : 0;
  $b_weight = isset($b['weight']) ? $b['weight'] : 0;
  if ($a_weight != $b_weight) {
    return ($a_weight < $b_weight) ? -1 : 1;
  }

  if ($a['title'] != $b['title']) {
    return ($a['title'] < $b['title']) ? -1 : 1;
  }
  return 0;
}

/* Helper function for grabbing search keys. Function is missing in D7.
 *
 * http://api.drupal.org/api/function/search_get_keys/6
 */
function advanced_help_search_get_keys() {
  static $return;
  if (!isset($return)) {
    // Extract keys as remainder of path
    // Note: support old GET format of searches for existing links.
    $path = explode('/', $_GET['q'], 3);
    $keys = empty($_REQUEST['keys']) ? '' : $_REQUEST['keys'];
    $return = count($path) == 3 ? $path[2] : $keys;
  }
  return $return;
}

/**
 * Page callback for advanced help search.
 */
function advanced_help_search_view() {
  if (!module_exists('search')) {
    return drupal_not_found();
  }

  $breadcrumb[] = advanced_help_l(t('Help'), 'admin/advanced_help');

  if (!isset($_POST['form_id'])) {
    $keys = advanced_help_search_get_keys();
    // Only perform search if there is non-whitespace search term:
    $results = '';
    if (trim($keys)) {
      $search_results = search_data($keys, 'advanced_help');
      $search_results = drupal_render($search_results);
      // Collect the search results:
      $results = array(
        '#type' => 'markup',
        '#markup' => $search_results,
      );
    }

    // Construct the search form.
    $output['advanced_help_search_form'] = drupal_get_form('advanced_help_search_form', $keys);
    $output['results'] = $results;

  }
  else {
    $output = drupal_get_form('advanced_help_search_form', empty($keys) ? '' : $keys);
  }

  $popup = !empty($_GET['popup']) && user_access('view advanced help popup');
  if ($popup) {
    // Prevent devel module from spewing.
    $GLOBALS['devel_shutdown'] = FALSE;
    // Suppress admin_menu.
    module_invoke('admin_menu', 'suppress');
    drupal_set_breadcrumb(array_reverse($breadcrumb));
    print theme('advanced_help_popup', array('content' => $output));
    return;
  }

  $breadcrumb = array_merge(drupal_get_breadcrumb(), array_reverse($breadcrumb));
  drupal_set_breadcrumb($breadcrumb);
  return $output;
}

/**
 * Page callback to view the advanced help topic index.
 *
 * @param string $module
 *   Name of the module.
 *
 * @return array
 *   Returns module index.
 */
function advanced_help_index_page($module = '') {
  $topics = advanced_help_get_topics();
  $settings = advanced_help_get_settings();

  $output = array();
  // Print a search widget.
  $output['advanced_help_search'] = module_exists('search')
    ? drupal_get_form('advanced_help_search_form') : t('Enable the search module to search help.');

  $breadcrumb = array();
  if ($module) {
    if (empty($topics[$module])) {
      return drupal_not_found();
    }

    advanced_help_get_topic_hierarchy($topics);
    $items = advanced_help_get_tree($topics, $topics[$module]['']['children']);

    $breadcrumb[] = advanced_help_l(t('Help'), 'admin/advanced_help');

    drupal_set_title(t('@module help index', array('@module' => advanced_help_get_module_name($module))));
    $output['items-module'] = array(
      '#theme' => 'item_list',
      '#items' => $items,
    );
  }
  else {
    // Print a module index.
    $modules = array();
    $result = db_query('SELECT * FROM {system}');
    foreach ($result as $info) {
      $module_info = unserialize($info->info);
      $modules[$info->name] = $module_info['name'];
    }

    asort($modules);

    $items = array();
    foreach ($modules as $module => $module_name) {
      if (!empty($topics[$module]) && empty($settings[$module]['hide'])) {
        if (isset($settings[$module]['index name'])) {
          $name = $settings[$module]['index name'];
        }
        elseif (isset($settings[$module]['name'])) {
          $name = $settings[$module]['name'];
        }
        else {
          $name = t($module_name);
        }
        $items[] = advanced_help_l($name, "admin/advanced_help/$module");
      }
    }

    drupal_set_title(t('Module help index'));
    $output['items-nomodule'] = array(
      '#theme' => 'item_list',
      '#items' => $items,
    );
  }

  $popup = !empty($_GET['popup']) && user_access('view advanced help popup');
  if ($popup) {
    // Prevent devel module from spewing.
    $GLOBALS['devel_shutdown'] = FALSE;
    // Suppress admin_menu.
    module_invoke('admin_menu', 'suppress');
    drupal_set_breadcrumb(array_reverse($breadcrumb));
    print theme('advanced_help_popup', array('content' => $output));
    return;
  }

  $breadcrumb = array_merge(drupal_get_breadcrumb(), array_reverse($breadcrumb));
  drupal_set_breadcrumb($breadcrumb);
  return $output;
}

/**
 * Build a tree of advanced help topics.
 *
 * @param array $topics
 *   Topics.
 * @param array $topic_ids
 *   Topic Ids.
 * @param int $max_depth
 *   Maximum depth for subtopics.
 * @param int $depth
 *   Default depth for subtopics.
 *
 * @return array
 *   Returns list of topics/subtopics.
 */
function advanced_help_get_tree($topics, $topic_ids, $max_depth = -1, $depth = 0) {
  uasort($topic_ids, 'advanced_help_uasort');
  $items = array();
  foreach ($topic_ids as $info) {
    list($module, $topic) = $info;
    $item = advanced_help_l($topics[$module][$topic]['title'], "help/$module/$topic");
    if (!empty($topics[$module][$topic]['children']) && ($max_depth == -1 || $depth < $max_depth)) {
      $item .= theme('item_list', array(
        'items' => advanced_help_get_tree($topics, $topics[$module][$topic]['children'], $max_depth, $depth + 1),
      ));
    }

    $items[] = $item;
  }

  return $items;
}

/**
 * Build a hierarchy for a single module's topics.
 */
function advanced_help_get_topic_hierarchy(&$topics) {
  foreach ($topics as $module => $module_topics) {
    foreach ($module_topics as $topic => $info) {
      $parent_module = $module;
      // We have a blank topic that we don't want parented to itself.
      if (!$topic) {
        continue;
      }

      if (empty($info['parent'])) {
        $parent = '';
      }
      elseif (strpos($info['parent'], '%')) {
        list($parent_module, $parent) = explode('%', $info['parent']);
        if (empty($topics[$parent_module][$parent])) {
          // If it doesn't exist, top level.
          $parent = '';
        }
      }
      else {
        $parent = $info['parent'];
        if (empty($module_topics[$parent])) {
          // If it doesn't exist, top level.
          $parent = '';
        }
      }

      if (!isset($topics[$parent_module][$parent]['children'])) {
        $topics[$parent_module][$parent]['children'] = array();
      }
      $topics[$parent_module][$parent]['children'][] = array($module, $topic);
      $topics[$module][$topic]['_parent'] = array($parent_module, $parent);
    }
  }
}

/**
 * Implements hook_form_system_modules_alter().
 *
 * Add advanced help links to the modules page.
 */
function advanced_help_form_system_modules_alter(&$form, &$form_state) {
  if (!isset($form['modules'])) {
    return;
  }
  $advanced_help_modules = drupal_map_assoc(array_keys(advanced_help_get_topics()));
  foreach (element_children($form['modules']) as $group) {
    foreach (element_children($form['modules'][$group]) as $module) {
      if (isset($advanced_help_modules[$module])) {
        $form['modules'][$group][$module]['links']['help'] = array(
          '#type' => 'link',
          '#title' => t('Help'),
          '#href' => "admin/advanced_help/$module",
          '#options' => array(
            'attributes' => array(
              'class' => array('module-link', 'module-link-help'),
              'title' => t('Help'),
            ),
          ),
        );
      }
    }
  }
}

/**
 * Form builder callback to build the search form.
 *
 * Load search/search.pages so that its template preprocess functions are
 * visible and can be invoked.
 */
function advanced_help_search_form($form, &$form_state, $keys = '') {
  module_load_include('inc', 'search', 'search.pages');
  $form = search_form($form, $form_state, 'admin/advanced_help', $keys, 'advanced_help', t('Search help'));

  $form['basic']['inline']['submit']['#validate'] = array('search_form_validate');
  $form['basic']['inline']['submit']['#submit'] = array('advanced_help_search_form_submit');

  return $form;
}

/**
 * Process a search form submission.
 */
function advanced_help_search_form_submit($form, &$form_state) {
  $keys = empty($form_state['values']['processed_keys']) ? $form_state['values']['keys'] : $form_state['values']['processed_keys'];
  if ($keys == '') {
    form_set_error('keys', t('Please enter some keywords.'));
    return;
  }

  $popup = !empty($_GET['popup']) && user_access('view advanced help popup');

  if ($popup) {
    $form_state['redirect'] = array('advanced_help/search/' . $keys, array('query' => array('popup' => 'true')));
  }
  else {
    $form_state['redirect'] = 'advanced_help/search/' . $keys;
  }
}

/**
 * Small helper function to get a module's proper name.
 *
 * @param string $module
 *   Name of the module.
 *
 * @return string
 *   Returns module's descriptive name.
 */
function advanced_help_get_module_name($module) {
  $settings = advanced_help_get_settings();
  if (isset($settings[$module]['name'])) {
    $name = $settings[$module]['name'];
  }
  else {
    $info = db_query("SELECT s.info FROM {system} s WHERE s.name = :name",
      array(':name' => $module))
      ->fetchField();
    $info = unserialize($info);
    $name = t($info['name']);
  }
  return $name;
}

/**
 * Page callback to view a help topic.
 */
function advanced_help_topic_page($module, $topic) {
  $info = advanced_help_get_topic($module, $topic);
  if (!$info) {
    return drupal_not_found();
  }

  $popup = !empty($_GET['popup']) && user_access('view advanced help popup');

  drupal_set_title($info['title']);

  // Set up breadcrumb.
  $breadcrumb = array();

  $parent = $info;
  $pmodule = $module;

  // Loop checker.
  $checked = array();
  while (!empty($parent['parent'])) {
    if (strpos($parent['parent'], '%')) {
      list($pmodule, $ptopic) = explode('%', $parent['parent']);
    }
    else {
      $ptopic = $parent['parent'];
    }

    if (!empty($checked[$pmodule][$ptopic])) {
      break;
    }
    $checked[$pmodule][$ptopic] = TRUE;

    $parent = advanced_help_get_topic($pmodule, $ptopic);
    if (!$parent) {
      break;
    }

    $breadcrumb[] = advanced_help_l($parent['title'], "help/$pmodule/$ptopic");
  }

  $breadcrumb[] = advanced_help_l(advanced_help_get_module_name($pmodule), "admin/advanced_help/$pmodule");
  $breadcrumb[] = advanced_help_l(t('Help'), "admin/advanced_help");

  $output = advanced_help_view_topic($module, $topic, $popup);
  if (empty($output)) {
    $output = t('Missing help topic.');
  }

  if ($popup) {
    // Prevent devel module from spewing.
    $GLOBALS['devel_shutdown'] = FALSE;
    // Suppress admin_menu.
    module_invoke('admin_menu', 'suppress');
    drupal_set_breadcrumb(array_reverse($breadcrumb));
    print theme('advanced_help_popup', array('content' => $output));
    return;
  }

  drupal_add_css(drupal_get_path('module', 'advanced_help') . '/help.css');
  $breadcrumb[] = l(t('Home'), '');
  drupal_set_breadcrumb(array_reverse($breadcrumb));
  return $output;
}

/**
 * Implements hook_permission().
 */
function advanced_help_permission() {
  return array(
    'view advanced help topic' => array('title' => t('View help topics')),
    'view advanced help popup' => array('title' => t('View help popups')),
    'view advanced help index' => array('title' => t('View help index')),
  );
}

/**
 * Display a help icon with a link to view the topic in a popup.
 *
 * @param array $variables
 *   An associative array containing:
 *   - module: The module that owns this help topic.
 *   - topic: The identifier for the topic
 *   - type
 *     - 'icon' to display the question mark icon
 *     - 'title' to display the topic's title
 *     - any other text to display the text. Be sure to t() it!
 */
function theme_advanced_help_topic($variables) {
  $module = $variables['module'];
  $topic  = $variables['topic'];
  $type   = $variables['type'];

  $info = advanced_help_get_topic($module, $topic);
  if (!$info) {
    return;
  }

  switch ($type) {
    case 'icon':
      $text = '<span>' . t('Help') . '</span>';
      $class = 'advanced-help-link';
      break;

    case 'title':
      $text = $info['title'];
      $class = 'advanced-help-title';
      break;

    default:
      $class = 'advanced-help-title';
      $text = $type;
      break;
  }

  if (user_access('view advanced help popup')) {
    drupal_add_css(drupal_get_path('module', 'advanced_help') . '/help-icon.css');
    return l($text, "help/$module/$topic", array(
      'attributes' => array(
        'class' => $class,
        'onclick' => "var w=window.open(this.href, 'advanced_help_window', 'width=" . $info['popup width'] . ",height=" . $info['popup height'] . ",scrollbars,resizable'); w.focus(); return false;",
        'title' => $info['title'],
      ),
      'query' => array('popup' => TRUE),
      'html' => TRUE)
    );
  }
  else {
    return l($text, "help/$module/$topic", array(
      'attributes' => array(
        'class' => $class,
        'title' => $info['title'],
      ),
      'html' => TRUE)
    );
  }
}

/**
 * Load and render a help topic.
 */
function advanced_help_get_topic_filename($module, $topic) {
  $info = advanced_help_get_topic_file_info($module, $topic);
  if ($info) {
    return "./$info[path]/$info[file]";
  }
}
/**
 * Load and render a help topic.
 */
function advanced_help_get_topic_file_info($module, $topic) {
  global $language;

  $info = advanced_help_get_topic($module, $topic);
  if (empty($info)) {
    return;
  }

  // Search paths:
  $paths = array(
    // Allow theme override.
    path_to_theme() . '/help',
    // Translations.
    drupal_get_path('module', $module) . "/translations/help/$language->language",
    // In same directory as .inc file.
    $info['path'],
  );

  foreach ($paths as $path) {
    if (file_exists("./$path/$info[file]")) {
      return array('path' => $path, 'file' => $info['file']);
    }
  }
}

/**
 * Load and render a help topic.
 *
 * @param string $module
 *   Name of the module.
 * @param string $topic
 *   Name of the topic.
 * @param boolean $popup
 *   Whether to show in popup or not.
 *
 * @return string
 *   Returns formatted topic.
 */
function advanced_help_view_topic($module, $topic, $popup = FALSE) {
  $file_info = advanced_help_get_topic_file_info($module, $topic);
  if ($file_info) {
    $info = advanced_help_get_topic($module, $topic);
    $file = "./$file_info[path]/$file_info[file]";

    $output = file_get_contents($file);
    if (isset($info['readme file']) && $info['readme file']) {
      // Readme files are treated as plain text: filter accordingly.
      $output = check_plain($output);
    }

    // Make some exchanges. The strtr is because url() translates $ into %24
    // but we need to change it back for the regex replacement.
    //
    // Change 'topic:' to the URL for another help topic.
    if ($popup) {
      $output = preg_replace('/href="topic:([^"]+)"/', 'href="' . strtr(url('help/$1', array('query' => array('popup' => 'true'))), array('%24' => '$')) . '"', $output);
      $output = preg_replace('/src="topic:([^"]+)"/', 'src="' .  strtr(url('help/$1', array('query' => array('popup' => 'true'))), array('%24' => '$')) . '"', $output);
      $output = preg_replace('/&topic:([^"]+)&/', strtr(url('help/$1', array('query' => array('popup' => 'true'))), array('%24' => '$')), $output);
    }
    else {
      $output = preg_replace('/href="topic:([^"]+)"/', 'href="' . strtr(url('help/$1'), array('%24' => '$')) . '"', $output);
      $output = preg_replace('/src="topic:([^"]+)"/', 'src="' . strtr(url('help/$1'), array('%24' => '$')) . '"', $output);
      $output = preg_replace('/&topic:([^"]+)&/', strtr(url('help/$1'), array('%24' => '$')), $output);
    }

    global $base_path;

    // Change 'path:' to the URL to the base help directory.
    $output = preg_replace('/href="path:([^"]+)"/', 'href="' . $base_path . $info['path'] . '/$1"', $output);
    $output = preg_replace('/src="path:([^"]+)"/', 'src="' . $base_path . $info['path'] . '/$1"', $output);
    $output = str_replace('&path&', $base_path . $info['path'] . '/', $output);

    // Change 'trans_path:' to the URL to the actual help directory.
    $output = preg_replace('/href="trans_path:([^"]+)"/', 'href="' . $base_path . $file_info['path'] . '/$1"', $output);
    $output = preg_replace('/src="trans_path:([^"]+)"/', 'src="' . $base_path . $file_info['path'] . '/$1"', $output);
    $output = str_replace('&trans_path&', $base_path . $file_info['path'] . '/', $output);

    // Change 'base_url:' to the URL to the site.
    $output = preg_replace('/href="base_url:([^"]+)"/', 'href="' . strtr(url('$1'), array('%24' => '$')) . '"', $output);
    $output = preg_replace('/src="base_url:([^"]+)"/', 'src="'   . strtr(url('$1'), array('%24' => '$')) . '"', $output);
    $output = preg_replace('/&base_url&([^"]+)"/', strtr(url('$1'), array('%24' => '$')) . '"', $output);

    // Run the line break filter if requested.
    if (!empty($info['line break'])) {
      // Remove the header since it adds an extra <br /> to the filter.
      $output = preg_replace('/^<!--[^\n]*-->\n/', '', $output);

      $output = _filter_autop($output);
    }

    if (!empty($info['navigation'])) {
      $topics = advanced_help_get_topics();
      advanced_help_get_topic_hierarchy($topics);
      if (!empty($topics[$module][$topic]['children'])) {
        $items = advanced_help_get_tree($topics, $topics[$module][$topic]['children']);
        $output .= theme('item_list', array('items' => $items));
      }

      list($parent_module, $parent_topic) = $topics[$module][$topic]['_parent'];
      if ($parent_topic) {
        $parent = $topics[$module][$topic]['_parent'];
        $up = "help/$parent[0]/$parent[1]";
      }
      else {
        $up = "admin/advanced_help/$module";
      }

      $siblings = $topics[$parent_module][$parent_topic]['children'];
      uasort($siblings, 'advanced_help_uasort');
      $prev = $next = NULL;
      $found = FALSE;
      foreach ($siblings as $sibling) {
        list($sibling_module, $sibling_topic) = $sibling;
        if ($found) {
          $next = $sibling;
          break;
        }
        if ($sibling_module == $module && $sibling_topic == $topic) {
          $found = TRUE;
          continue;
        }
        $prev = $sibling;
      }

      if ($prev || $up || $next) {
        $navigation = '<div class="help-navigation clear-block">';

        if ($prev) {
          $navigation .= advanced_help_l('<< ' . $topics[$prev[0]][$prev[1]]['title'], "help/$prev[0]/$prev[1]", array('attributes' => array('class' => 'help-left')));
        }
        if ($up) {
          $navigation .= advanced_help_l(t('Up'), $up, array('attributes' => array('class' => $prev ? 'help-up' : 'help-up-noleft')));
        }
        if ($next) {
          $navigation .= advanced_help_l($topics[$next[0]][$next[1]]['title'] . ' >>', "help/$next[0]/$next[1]", array('attributes' => array('class' => 'help-right')));
        }

        $navigation .= '</div>';

        $output .= $navigation;
      }
    }

    if (!empty($info['css'])) {
      drupal_add_css($info['path'] . '/' . $info['css']);
    }

    $output = '<div class="advanced-help-topic">' . $output . '</div>';
    drupal_alter('advanced_help_topic', $output, $popup);
    return $output;
  }
}

/**
 * Get the information for a single help topic.
 */
function advanced_help_get_topic($module, $topic) {
  $topics = advanced_help_get_topics();
  if (!empty($topics[$module][$topic])) {
    return $topics[$module][$topic];
  }
}

/**
 * Search the system for all available help topics.
 */
function advanced_help_get_topics() {
  $cache = _advanced_help_parse_ini();
  return $cache['topics'];
}

/**
 * Returns advanced help settings.
 */
function advanced_help_get_settings() {
  $cache = _advanced_help_parse_ini();
  return $cache['settings'];
}

/**
 * Funtion to parse ini / txt files.
 */
function _advanced_help_parse_ini() {
  static $cache = NULL;

  if (!isset($cache)) {
    $cache = array('topics' => array(), 'settings' => array());

    $help_path = drupal_get_path('module', 'advanced_help') . '/modules';
    foreach (module_list() as $module) {
      $module_path = drupal_get_path('module', $module);
      $info = array();
      if (file_exists("$module_path/help/$module.help.ini")) {
        $path = "$module_path/help";
        $info = parse_ini_file("./$module_path/help/$module.help.ini", TRUE);
      }
      elseif (file_exists("$help_path/$module/$module.help.ini")) {
        $path = "$help_path/$module";
        $info = parse_ini_file("./$help_path/$module/$module.help.ini", TRUE);
      }
      elseif (!file_exists("$module_path/help")) {
        // Look for one or more README files.
        $files = file_scan_directory("./$module_path",
          '/^(README|readme).*\.(txt|TXT)$/', array('recurse' => FALSE));
        $path = "./$module_path";
        foreach ($files as $name => $fileinfo) {
          $info[$fileinfo->filename] = array(
            'line break' => TRUE,
            'readme file' => TRUE,
            'file' => $fileinfo->filename,
            'title' => $fileinfo->name,
          );
        }
      }

      if (!empty($info)) {
        // Get translated titles:
        global $language;
        $translation = array();
        if (file_exists("$module_path/translations/help/$language->language/$module.help.ini")) {
          $translation = parse_ini_file("$module_path/translations/help/$language->language/$module.help.ini", TRUE);
        }

        $cache['settings'][$module] = array();
        if (!empty($info['advanced help settings'])) {
          $cache['settings'][$module] = $info['advanced help settings'];
          unset($info['advanced help settings']);

          // Check translated strings for translatable global settings.
          if (isset($translation['advanced help settings']['name'])) {
            $cache['settings']['name'] = $translation['advanced help settings']['name'];
          }
          if (isset($translation['advanced help settings']['index name'])) {
            $cache['settings']['index name'] = $translation['advanced help settings']['index name'];
          }

        }

        foreach ($info as $name => $topic) {
          // Each topic should have a name, a title, a file and path.
          $file = !empty($topic['file']) ? $topic['file'] : $name;
          $cache['topics'][$module][$name] = array(
            'name' => $name,
            'title' => !empty($translation[$name]['title']) ? $translation[$name]['title'] : $topic['title'],
            'weight' => isset($topic['weight']) ? $topic['weight'] : 0,
            'parent' => isset($topic['parent']) ? $topic['parent'] : 0,
            'popup width' => isset($topic['popup width']) ? $topic['popup width'] : 500,
            'popup height' => isset($topic['popup height']) ? $topic['popup height'] : 500,
            // Require extension.
            'file' => isset($topic['readme file']) ? $file : $file . '.html',
            // Not in .ini file.
            'path' => $path,
            'line break' => isset($topic['line break']) ? $topic['line break'] : (isset($cache['settings'][$module]['line break']) ? $cache['settings'][$module]['line break'] : FALSE),
            'navigation' => isset($topic['navigation']) ? $topic['navigation'] : (isset($cache['settings'][$module]['navigation']) ? $cache['settings'][$module]['navigation'] : TRUE),
            'css' => isset($topic['css']) ? $topic['css'] : (isset($cache['settings'][$module]['css']) ? $cache['settings'][$module]['css'] : NULL),
            'readme file' => isset($topic['readme file']) ? $topic['readme file'] : FALSE,
          );
        }
      }
    }
    drupal_alter('advanced_help_topic_info', $cache);
  }
  return $cache;
}

/**
 * Implements hook_search_info().
 *
 * @return array
 *   Returns title for the tab on search page & path component after 'search/'.
 */
function advanced_help_search_info() {
  return array(
    'title' => t('Help'),
    'path' => 'advanced_help',
  );
}

/**
 * Implements hook_search_execute().
 */
function advanced_help_search_execute($keys = NULL) {
  $topics = advanced_help_get_topics();

  $query = db_select('search_index', 'i', array('target' => 'slave'))
    ->extend('SearchQuery')
    ->extend('PagerDefault');
  $query->join('advanced_help_index', 'ahi', 'i.sid = ahi.sid');
  $query->searchExpression($keys, 'help');

  // Only continue if the first pass query matches.
  if (!$query->executeFirstPass()) {
    return array();
  }

  $results = array();

  $find = $query->execute();
  foreach ($find as $item) {
    $sids[] = $item->sid;
  }

  $query = db_select('advanced_help_index', 'ahi');
  $result = $query
    ->fields('ahi')
    ->condition('sid', $sids, 'IN')
    ->execute();

  foreach ($result as $sid) {
    // Guard against removed help topics that are still indexed.
    if (empty($topics[$sid->module][$sid->topic])) {
      continue;
    }
    $info = $topics[$sid->module][$sid->topic];
    $text = advanced_help_view_topic($sid->module, $sid->topic);
    $results[] = array(
      'link' => advanced_help_url("help/$sid->module/$sid->topic"),
      'title' => $info['title'],
      'snippet' => search_excerpt($keys, $text),
    );
  }
  return $results;
}

/**
 * Implements hook_search_reset().
 */
function advanced_help_search_reset() {
  variable_del('advanced_help_last_cron');
}

/**
 * Implements hook_search_status().
 */
function advanced_help_search_status() {
  $topics = advanced_help_get_topics();
  $total = 0;
  foreach ($topics as $module => $module_topics) {
    foreach ($module_topics as $topic => $info) {
      $file = advanced_help_get_topic_filename($module, $topic);
      if ($file) {
        $total++;
      }
    }
  }

  $last_cron = variable_get('advanced_help_last_cron', array('time' => 0));
  $indexed = 0;
  if ($last_cron['time'] != 0) {
    $indexed = db_query("SELECT COUNT(*) FROM {search_dataset} sd WHERE sd.type = 'help' AND sd.sid IS NOT NULL AND sd.reindex = 0")->fetchField();
  }
  return array('remaining' => $total - $indexed, 'total' => $total);
}

/**
 * Gets search id for each topic.
 *
 * Get or create an sid (search id) that correlates to each topic for
 * the search system.
 */
function advanced_help_get_sids(&$topics) {
  global $language;
  $result = db_query("SELECT * FROM {advanced_help_index} WHERE language = :language",
    array(':language' => $language->language));
  foreach ($result as $sid) {
    if (empty($topics[$sid->module][$sid->topic])) {
      db_query("DELETE FROM {advanced_help_index} WHERE sid = :sid",
        array(':sid' => $sid->sid));
    }
    else {
      $topics[$sid->module][$sid->topic]['sid'] = $sid->sid;
    }
  }
}

/**
 * Implements hook_update_index().
 */
function advanced_help_update_index() {
  global $language;

  // If we got interrupted by limit, this will contain the last module
  // and topic we looked at.
  $last = variable_get('advanced_help_last_cron', array('time' => 0));
  $limit = intval(variable_get('search_cron_limit', 100));
  $topics = advanced_help_get_topics();
  advanced_help_get_sids($topics);

  $count = 0;

  foreach ($topics as $module => $module_topics) {
    // Fast forward if necessary.
    if (!empty($last['module']) && $last['module'] != $module) {
      continue;
    }

    foreach ($module_topics as $topic => $info) {
      // Fast forward if necessary.
      if (!empty($last['topic']) && $last['topic'] != $topic) {
        continue;
      }

      // If we've been looking to catch up, and we have, reset so we
      // stop fast forwarding.
      if (!empty($last['module'])) {
        unset($last['topic']);
        unset($last['module']);
      }

      $file = advanced_help_get_topic_filename($module, $topic);
      if ($file && (empty($info['sid']) || filemtime($file) > $last['time'])) {
        if (empty($info['sid'])) {
          $info['sid'] = db_insert('advanced_help_index')
            ->fields(array(
              'module' => $module,
              'topic'  => $topic,
              'language' => $language->language,
            ))
            ->execute();
        }

        search_index($info['sid'], 'help', '<h1>' . $info['title'] . '</h1>' . file_get_contents($file));
        $count++;
        if ($count >= $limit) {
          $last['topic'] = $topic;
          $last['module'] = $module;
          // Don't change time if we stop.
          variable_set('advanced_help_last_cron', $last);
          return;
        }
      }
    }
  }

  variable_set('advanced_help_last_cron', array('time' => time()));
}

/**
 * Fill in a bunch of page variables for our specialized popup page.
 */
function template_preprocess_advanced_help_popup(&$variables) {
  // Add favicon.
  if (theme_get_setting('toggle_favicon')) {
    drupal_add_html_head('<link rel="shortcut icon" href="' . check_url(theme_get_setting('favicon')) . '" type="image/x-icon" />');
  }

  global $theme;
  // Construct page title.
  if (drupal_get_title()) {
    $head_title = array(
      strip_tags(drupal_get_title()),
      variable_get('site_name', 'Drupal'),
    );
  }
  else {
    $head_title = array(variable_get('site_name', 'Drupal'));
    if (variable_get('site_slogan', '')) {
      $head_title[] = variable_get('site_slogan', '');
    }
  }

  drupal_add_css(drupal_get_path('module', 'advanced_help') . '/help-popup.css');
  drupal_add_css(drupal_get_path('module', 'advanced_help') . '/help.css');

  $variables['head_title']        = implode(' | ', $head_title);
  $variables['base_path']         = base_path();
  $variables['front_page']        = url();
  $variables['breadcrumb']        = theme('breadcrumb', array('breadcrumb' => drupal_get_breadcrumb()));
  $variables['feed_icons']        = drupal_get_feeds();
  $variables['head']              = drupal_get_html_head();
  $variables['language']          = $GLOBALS['language'];
  $variables['language']->dir     = $GLOBALS['language']->direction ? 'rtl' : 'ltr';
  $variables['logo']              = theme_get_setting('logo');
  $variables['messages']          = theme('status_messages');
  $variables['site_name']         = (theme_get_setting('toggle_name') ? variable_get('site_name', 'Drupal') : '');
  $variables['css']               = drupal_add_css();
  $css = drupal_add_css();

  // Remove theme css.
  foreach ($css as $media => $types) {
    if (isset($css[$media]['theme'])) {
      $css[$media]['theme'] = array();
    }
  }

  $variables['styles']            = drupal_get_css($css);
  $variables['scripts']           = drupal_get_js();
  $variables['title']             = drupal_get_title();

  // This function can be called either with a render array or
  // an already rendered string.
  if (is_array($variables['content'])) {
    $variables['content'] = drupal_render($variables['content']);
  }
  // Closure should be filled last.
  $variables['closure']           = theme('closure');
}

/**
 * Format a link but preserve popup identity.
 */
function advanced_help_l($text, $dest, $options = array()) {
  $popup = !empty($_GET['popup']) && user_access('view advanced help popup');
  if ($popup) {
    if (empty($options['query'])) {
      $options['query'] = array();
    }

    if (is_array($options['query'])) {
      $options['query'] += array('popup' => TRUE);
    }
    else {
      $options['query'] += '&popup=TRUE';
    }
  }

  return l($text, $dest, $options);
}

/**
 * Format a URL but preserve popup identity.
 */
function advanced_help_url($dest, $options = array()) {
  $popup = !empty($_GET['popup']) && user_access('view advanced help popup');
  if ($popup) {
    if (empty($options['query'])) {
      $options['query'] = array();
    }

    $options['query'] += array('popup' => TRUE);
  }

  return url($dest, $options);
}
