<?php
// $Id: menutrails.module,v 1.2.2.3 2009-07-24 16:57:52 sun Exp $


/**
 * @file
 * Menutrails allows the assigment of "trails" which will keep menu items
 * active for individual node views.
 */

/**
 * Implementation of hook_menu().
 *
 * For settings page.
 */
function menutrails_menu($may_cache) {
  $items = array();
  if ($may_cache) {
    $items[] = array(
      'path' => 'admin/settings/menutrails',
      'title' => t('Menu Trails'),
      'description' => t('Configure your menu trails.'),
      'callback' => 'drupal_get_form',
      'callback arguments' => array('menutrails_settings_form'),
      'access' => user_access('administer site configuration'),
      'type' => MENU_NORMAL_ITEM,
    );
  }
  return $items;
}

/**
 * Implementation of hook_nodeapi().
 *
 * This will evaluate individual nodes when being viewed and take the necessary
 * steps to set the active_trail for menus.
 *
 * This will retain menu state at the node/view level. For instance, forum nodes
 * would maintain an active trail to the forum menu item.
 */
// TODO: this too cries out for an admin configuration screen
function menutrails_nodeapi(&$node, $op, $a3 = NULL, $page = FALSE) {
  if ($op == 'view' && $page == TRUE) {
    $location = menutrails_node_location($node);
    menu_set_location($location);
  }
}

/**
 * Determine the menu location of a node.
 *
 * Inspired by _menu_get_active_trail().
 */
function menutrails_node_location($node) {
  // This should only fire if the menu isn't already active.
  $item = menu_get_item(NULL, 'node/'. $node->nid);
  // type = 4 is for a callback
  if ($item['type'] == 4) {
    $type_trails = variable_get('menutrails_node_types', array());
    $mid         = $type_trails[$node->type];
    $term_trails = variable_get('menutrails_terms', array());
    if (isset($node->taxonomy)) {
      foreach ($node->taxonomy as $tid => $term) {
        if ($term_trails[$tid] > 0) {
          $mid = $term_trails[$tid];
        }
      }
    }
    if ($mid > 0) {
      // Follow the parents up the chain to get the trail.
      while ($mid && ($item = menu_get_item($mid))) {
        $location[] = $item;
        $mid = $mid = $item['pid'];
      }
      $location = array_reverse($location);
      $location[] = array('path' => 'node/'. $node->nid, 'title' => $node->title);
    }
    return $location;
  }
}

/**
 * This implements the same functionality as the nodeapi, but for comment urls.
 */
function menutrails_comment($comment, $op) {
  if ($op == 'form' && arg(0) == 'comment') {
    $node       = node_load($comment['nid']['#value']);
    $location   = menutrails_node_location($node);
    $location[] = array('path' => "comment/reply/$node->nid");
    menu_set_location($location);
  }
}

/**
 * Form builder function for settings.
 *
 * This is where menutrails rules are set. The interface here could definitely
 * stand for some improvement. It's especially unhelpful for tagging
 * vocabularies with lots and lots of terms.
 */
function menutrails_settings_form() {
  $options = array('NONE');
  $options = $options + menu_parent_options($item['mid'], variable_get('menu_parent_items', 0)); 
  $node_types = node_get_types('names');
  $node_trails = variable_get('menutrails_node_types', array());
  if (module_exists('taxonomy')) {
    $vocabs = taxonomy_get_vocabularies();
  }
  $term_trails = variable_get('menutrails_terms', array());

  $form['description'] = array(
    '#type' => 'markup',
    '#weight' => '-100',
    '#value' => t('Use these settings to configure the "menu trails" for your nodes. This determines what menu items are activated when viewing an individual node. For instance, if you have a menu item for "Blog," you may want to have all blog posts fall under that menu.'),
    '#prefix' => '<p>',
    '#suffix' => '</p>',
  );
  $form['order'] = array(
    '#type' => 'markup',
    '#weight' => '-99',
    '#value' => t('<p>Menu trials are evaluated in the following order:</p> <ol><li>Node type</li><li>Taxonomy category</li><li>Node-specific menu setting</li></ol><p>In other words, category-based menu trails override node-type, and specific settings made on the node itself override both. Category-based menu trails are evaluated by weight in the order shown here, so settings in lower vocabularies take precidence.</p>'),
  );
  $form['menutrails_node_types'] = array(
    '#tree' => TRUE,
    '#type' => 'fieldset',
    '#collapsible' => TRUE,
    '#collapsed' => TRUE,
    '#title' => t('Menu trails by node type'),
  );
  foreach ($node_types as $key => $value) {
    $form['menutrails_node_types'][$key] = array('#type' => 'select',
      '#title' => t('Parent item for') ." $value",
      '#default_value' => $node_trails[$key],
      '#options' => $options,
    );
  }
  if (isset($vocabs)) {
    foreach ($vocabs as $vocab) {
      $form[$vocab->vid]['menutrails_terms'] = array(
        '#tree' => TRUE,
        '#type' => 'fieldset',
        '#collapsible' => TRUE,
        '#collapsed' => TRUE,
        '#title' => t('Menu trails by category:') ." $vocab->name",
      );
      $terms = taxonomy_get_tree($vocab->vid);
      foreach ($terms as $term) {
        $form[$vocab->vid]['menutrails_terms'][$term->tid] = array('#type' => 'select',
          '#title' => t('Parent item for') ." $term->name",
          '#default_value' => $term_trails[$term->tid],
          '#options' => $options,
        );
      }
    }
  }

  return system_settings_form($form);
}

/***
 * This is an example _phptemplate_variables() implementation.
 *
 * You need to add this code (or something like it) to your template.php file
 * for this module to do anything useful. Obviously in template.php you don't
 * want the code commented out.
 */

/*
function _phptemplate_variables($hook, $vars = array()) {
  switch ($hook) {
    case 'page': // page is where menu comes into play
      // set the primary links
      $vars['primary_links'] = menutrails_primary_links(1);
      // you may want to also override secondary_links
      $vars['secondary_links'] = menutrails_primary_links(2);
      break;
  }
}
*/

/**
 * SUBSTITUTE MENU FUNCTIONS
 */

/**
 * This is a substitute function for menu_primary_links()
 *
 * The important difference is a different criteria for determining if an item
 * is "active" or not, and the use of our own _menu_item() function to make use
 * of that active status.
 */
function menutrails_primary_links($start_level = 1, $pid = 0) {
  if (!module_exists('menu')) {
    return NULL;
  }
  if (!$pid) {
    $pid = variable_get('menu_primary_menu', 0);
  }
  if (!$pid) {
    return NULL;
  }

  if ($start_level < 1) {
    $start_level = 1;
  }

  if ($start_level > 1) {
    $trail = _menu_get_active_trail_in_submenu($pid);
    if (!$trail) {
      return NULL;
    }
    else {
      $pid = $trail[$start_level - 1];
    }
  }

  $menu = menu_get_menu();
  $links = array();
  // Custom data for use down the line
  $trail = _menu_get_active_trail();
  if ($pid && is_array($menu['visible'][$pid]) && isset($menu['visible'][$pid]['children'])) {
    $count = 1;
    foreach ($menu['visible'][$pid]['children'] as $cid) {
      $index = "menu-$start_level-$count-$pid";
      // this needs to be unset
      unset($active);
      // changed from menu_in_active_subtrail
      if (in_array($cid, $trail)) {
        $index .= "-active";
        // we use this below
        $active = TRUE;
      }
      // use $active
      $links[$index] = menutrails_item_link($cid, FALSE, $active);
      $count++;
    }
  }

  // Special case - provide link to admin/build/menu if primary links is empty.
  if (empty($links) && $start_level == 1 && $pid == variable_get('menu_primary_menu', 0) && user_access('administer menu')) {
    $links['1-1'] = array(
      'title' => t('Edit primary links'),
      'href' => 'admin/build/menu',
    );
  }

  return $links;
}

/**
 * This is a substitute function for menu_item_link()
 *
 * The important difference is that this will pick up the $active bit from the
 * function above, and assign the "active" class to the link if it is present.
 */
function menutrails_item_link($mid, $theme = TRUE, $active = FALSE) {
  $item      = menu_get_item($mid);
  $link_item = $item;
  $link      = '';
  while ($link_item['type'] & MENU_LINKS_TO_PARENT) {
    $link_item = menu_get_item($link_item['pid']);
  }

  if ($theme) {
    $link = theme('menu_item_link', $item, $link_item);
  }
  else {
    $link = array(
      'title' => $item['title'],
      'href' => $link_item['path'],
      'attributes' => !empty($item['description']) ? array('title' => $item['description']) : array(),
    );
    if ($active) {
      $link['attributes']['class'] = 'active';
    }
  }
  $link['mid'] = $mid;
  return $link;
}