<?php
// $Id$

/**
 * @file
 * Allows administrators to customize the site navigation menu.
 */

/**
 * Maximum length of menu name as entered by the user. Database length is 32
 * and we add a menu- prefix.
 */
define('MENU_MAX_MENU_NAME_LENGTH_UI', 27);

/**
 * Implement hook_help().
 */
function menu_help($path, $arg) {
  switch ($path) {
    case 'admin/help#menu':
      $output = '<p>' . t("The menu module provides an interface to control and customize Drupal's powerful menu system. Menus are a hierarchical collection of links used to navigate a website.  Each menu is rendered in a block that may be positioned and displayed using Drupal's flexible block system. Five menus are provided by Drupal and are always present: <em>Navigation</em>, <em>Management</em>, <em>User menu</em>, <em>Main menu</em>, and <em>Secondary menu</em>. The <em>Management</em> menu contains links for administration and content creation, while the <em>Navigation</em> menu is the default location for site navigation links created by newly enabled modules. Both of these are often displayed in either the left or right sidebar. Most Drupal themes also provide support for the <em>Main links</em> and <em>Secondary links</em>, by displaying them in either the header or footer of each page. The <em>Main menu</em> is the default source for the <em>Main links</em> and the <em>User menu</em> is the default source for the <em>Secondary links</em>.  By default, the <em>User menu</em> has links to take the current user to their account or allow them to log out, while the <em>Main menu</em> and <em>Secondary menu</em> contain no menu links but may be configured to contain custom menu items specific to your site. You may create an unlimited number of additional menus, each of which will automatically have an associated block.") . '</p>';
      $output .= '<p>' . t('The <a href="@menu">menus page</a> displays all menus currently available on your site. Select a menu from this list to add or edit a menu link, or to rearrange links within the menu. Create new menus using the <a href="@add-menu">add menu page</a> (the block containing a new menu must also be enabled on the <a href="@blocks">blocks administration page</a>).', array('@menu' => url('admin/structure/menu'), '@add-menu' => url('admin/structure/menu/add'), '@blocks' => url('admin/structure/block'))) . '</p>';
      $output .= '<p>' . t('For more information, see the online handbook entry for <a href="@menu">Menu module</a>.', array('@menu' => 'http://drupal.org/handbook/modules/menu/')) . '</p>';
      return $output;
    case 'admin/structure/menu/add':
      return '<p>' . t('Enter the name for your new menu. Remember to enable the newly created block in the <a href="@blocks">blocks administration page</a>.', array('@blocks' => url('admin/structure/block'))) . '</p>';
    case 'admin/structure/menu/item/add':
      return '<p>' . t('Enter the title and path for your new menu link.') . '</p>';
  }
  if ($path == 'admin/structure/menu' && module_exists('block')) {
    return '<p>' . t('Each menu has a corresponding block that is managed on the <a href="@blocks">blocks administration page</a>.', array('@blocks' => url('admin/structure/block'))) . '</p>';
  }
}

/**
 * Implement hook_permission().
 */
function menu_permission() {
  return array(
    'administer menu' => array(
      'title' => t('Administer menu'),
      'description' => t('Manage menus and menu items.'),
    ),
  );
}

/**
 * Implement hook_menu().
 */
function menu_menu() {
  $items['admin/structure/menu'] = array(
    'title' => 'Menus',
    'description' => 'Add new menus to your site, edit existing menus, and rename and reorganize menu links.',
    'page callback' => 'menu_overview_page',
    'access callback' => 'user_access',
    'access arguments' => array('administer menu'),
  );
  $items['admin/structure/menu/list'] = array(
    'title' => 'List menus',
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => -10,
  );
  $items['admin/structure/menu/add'] = array(
    'title' => 'Add menu',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('menu_edit_menu', 'add'),
    'access arguments' => array('administer menu'),
    'type' => MENU_LOCAL_ACTION,
  );
  $items['admin/structure/menu/settings'] = array(
    'title' => 'Settings',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('menu_configure'),
    'access arguments' => array('administer menu'),
    'type' => MENU_LOCAL_TASK,
    'weight' => 5,
  );
  $items['admin/structure/menu-customize/%menu'] = array(
    'title' => 'Customize menu',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('menu_overview_form', 3),
    'title callback' => 'menu_overview_title',
    'title arguments' => array(3),
    'access arguments' => array('administer menu'),
    'type' => MENU_CALLBACK,
  );
  $items['admin/structure/menu-customize/%menu/list'] = array(
    'title' => 'List links',
    'weight' => -10,
    'type' => MENU_DEFAULT_LOCAL_TASK,
  );
  $items['admin/structure/menu-customize/%menu/add'] = array(
    'title' => 'Add link',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('menu_edit_item', 'add', NULL, 3),
    'access arguments' => array('administer menu'),
    'type' => MENU_LOCAL_ACTION,
  );
  $items['admin/structure/menu-customize/%menu/edit'] = array(
    'title' => 'Edit menu',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('menu_edit_menu', 'edit', 3),
    'access arguments' => array('administer menu'),
    'type' => MENU_LOCAL_TASK,
  );
  $items['admin/structure/menu-customize/%menu/delete'] = array(
    'title' => 'Delete menu',
    'page callback' => 'menu_delete_menu_page',
    'page arguments' => array(3),
    'access arguments' => array('administer menu'),
    'type' => MENU_CALLBACK,
  );
  $items['admin/structure/menu/item/%menu_link/edit'] = array(
    'title' => 'Edit menu link',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('menu_edit_item', 'edit', 4, NULL),
    'access arguments' => array('administer menu'),
    'type' => MENU_CALLBACK,
  );
  $items['admin/structure/menu/item/%menu_link/reset'] = array(
    'title' => 'Reset menu link',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('menu_reset_item_confirm', 4),
    'access arguments' => array('administer menu'),
    'type' => MENU_CALLBACK,
  );
  $items['admin/structure/menu/item/%menu_link/delete'] = array(
    'title' => 'Delete menu link',
    'page callback' => 'menu_item_delete_page',
    'page arguments' => array(4),
    'access arguments' => array('administer menu'),
    'type' => MENU_CALLBACK,
  );
  return $items;
}

/**
 * Implement hook_theme().
 */
function menu_theme() {
  return array(
    'menu_overview_form' => array(
      'file' => 'menu.admin.inc',
      'arguments' => array('form' => NULL),
    ),
    'menu_admin_overview' => array(
      'file' => 'menu.admin.inc',
      'arguments' => array('title' => NULL, 'name' => NULL, 'description' => NULL),
    ),
  );
}

/**
 * Implement hook_enable().
 *
 * Add a link for each custom menu.
 */
function menu_enable() {
  menu_rebuild();
  $base_link = db_query("SELECT mlid AS plid, menu_name from {menu_links} WHERE link_path = 'admin/structure/menu' AND module = 'system'")->fetchAssoc();
  $base_link['router_path'] = 'admin/structure/menu-customize/%';
  $base_link['module'] = 'menu';
  $result = db_query("SELECT * FROM {menu_custom}", array(), array('fetch' => PDO::FETCH_ASSOC));
  foreach ($result as $menu) {
    // $link is passed by reference to menu_link_save(), so we make a copy of $base_link.
    $link = $base_link;
    $link['mlid'] = 0;
    $link['link_title'] = $menu['title'];
    $link['link_path'] = 'admin/structure/menu-customize/' . $menu['menu_name'];
    $menu_link = db_query("SELECT mlid FROM {menu_links} WHERE link_path = :path AND plid = :plid", array(
      ':path' => $link['link_path'],
      ':plid' => $link['plid']
    ))
    ->fetchField();
    if (!$menu_link) {
      menu_link_save($link);
    }
  }
  menu_cache_clear_all();
}

/**
 * Title callback for the menu overview page and links.
 */
function menu_overview_title($menu) {
  return $menu['title'];
}

/**
 * Load the data for a single custom menu.
 */
function menu_load($menu_name) {
  return db_query("SELECT * FROM {menu_custom} WHERE menu_name = :menu", array(':menu' => $menu_name))->fetchAssoc();
}

/**
 * Return a list of menu items that are valid possible parents for the given menu item.
 *
 * @param $menus
 *   An array of menu names and titles, such as from menu_get_menus().
 * @param $item
 *   The menu item for which to generate a list of parents.
 *   If $item['mlid'] == 0 then the complete tree is returned.
 * @return
 *   An array of menu link titles keyed on the a string containing the menu name
 *   and mlid. The list excludes the given item and its children.
 */
function menu_parent_options($menus, $item) {
  // The menu_links table can be practically any size and we need a way to
  // allow contrib modules to provide more scalable pattern choosers.
  // hook_form_alter is too late in itself because all the possible parents are
  // retrieved here, unless menu_override_parent_selector is set to TRUE.
  if (variable_get('menu_override_parent_selector', FALSE)) {
    return array();
  }
  // If the item has children, there is an added limit to the depth of valid parents.
  if (isset($item['parent_depth_limit'])) {
    $limit = $item['parent_depth_limit'];
  }
  else {
    $limit = _menu_parent_depth_limit($item);
  }

  foreach ($menus as $menu_name => $title) {
    $tree = menu_tree_all_data($menu_name, NULL);
    $options[$menu_name . ':0'] = '<' . $title . '>';
    _menu_parents_recurse($tree, $menu_name, '--', $options, $item['mlid'], $limit);
  }
  return $options;
}

/**
 * Recursive helper function for menu_parent_options().
 */
function _menu_parents_recurse($tree, $menu_name, $indent, &$options, $exclude, $depth_limit) {
  foreach ($tree as $data) {
    if ($data['link']['depth'] > $depth_limit) {
      // Don't iterate through any links on this level.
      break;
    }
    if ($data['link']['mlid'] != $exclude && $data['link']['hidden'] >= 0) {
      $title = $indent . ' ' . truncate_utf8($data['link']['title'], 30, TRUE, FALSE);
      if ($data['link']['hidden']) {
        $title .= ' (' . t('disabled') . ')';
      }
      $options[$menu_name . ':' . $data['link']['mlid']] = $title;
      if ($data['below']) {
        _menu_parents_recurse($data['below'], $menu_name, $indent . '--', $options, $exclude, $depth_limit);
      }
    }
  }
}

/**
 * Reset a system-defined menu item.
 */
function menu_reset_item($item) {
  $new_item = _menu_link_build(menu_get_item($item['router_path']));
  foreach (array('mlid', 'has_children') as $key) {
    $new_item[$key] = $item[$key];
  }
  menu_link_save($new_item);
  return $new_item;
}

/**
 * Implement hook_block_list().
 */
function menu_block_list() {
  $menus = menu_get_menus(FALSE);

  $blocks = array();
  foreach ($menus as $name => $title) {
    // Default "Navigation" block is handled by user.module.
    $blocks[$name]['info'] = check_plain($title);
    // Menu blocks can't be cached because each menu item can have
    // a custom access callback. menu.inc manages its own caching.
    $blocks[$name]['cache'] = BLOCK_NO_CACHE;
  }
  return $blocks;
}

/**
 * Implement hook_block_view().
 */
function menu_block_view($delta = '') {
  $menus = menu_get_menus(FALSE);
  $data['subject'] = check_plain($menus[$delta]);
  $data['content'] = menu_tree($delta);
  return $data;
}

/**
 * Implement hook_node_insert().
 */
function menu_node_insert($node) {
  if (isset($node->menu)) {
    $item = &$node->menu;
    if (!empty($item['delete'])) {
      menu_link_delete($item['mlid']);
    }
    elseif (trim($item['link_title'])) {
      $item['link_title'] = trim($item['link_title']);
      $item['link_path'] = "node/$node->nid";
      if (!$item['customized']) {
        $item['options']['attributes']['title'] = trim($node->title);
      }
      if (!menu_link_save($item)) {
        drupal_set_message(t('There was an error saving the menu link.'), 'error');
      }
    }
  }
}

/**
 * Implement hook_node_update().
 */
function menu_node_update($node) {
  if (isset($node->menu)) {
    $item = &$node->menu;
    if (!empty($item['delete'])) {
      menu_link_delete($item['mlid']);
    }
    elseif (trim($item['link_title'])) {
      $item['link_title'] = trim($item['link_title']);
      $item['link_path'] = "node/$node->nid";
      if (!$item['customized']) {
        $item['options']['attributes']['title'] = trim($node->title);
      }
      if (!menu_link_save($item)) {
        drupal_set_message(t('There was an error saving the menu link.'), 'error');
      }
    }
  }
}

/**
 * Implement hook_node_delete().
 */
function menu_node_delete($node) {
  // Delete all menu module links that point to this node.
  $result = db_query("SELECT mlid FROM {menu_links} WHERE link_path = :path AND module = 'menu'", array(':path' => 'node/' . $node->nid), array('fetch' => PDO::FETCH_ASSOC));
  foreach ($result as $m) {
    menu_link_delete($m['mlid']);
  }
}

/**
 * Implement hook_node_prepare().
 */
function menu_node_prepare($node) {
  if (empty($node->menu)) {
    // Prepare the node for the edit form so that $node->menu always exists.
    $menu_name = variable_get('menu_default_node_menu', 'main-menu');
    $item = array();
    if (isset($node->nid)) {
      // Give priority to the default menu
      $mlid = db_query_range("SELECT mlid FROM {menu_links} WHERE link_path = :path AND menu_name = :menu_name AND module = 'menu' ORDER BY mlid ASC", array(
        ':path' => 'node/' . $node->nid,
        ':menu_name' => $menu_name,
      ), 0, 1)
      ->fetchField();
      // Check all menus if a link does not exist in the default menu.
      if (!$mlid) {
        $mlid = db_query_range("SELECT mlid FROM {menu_links} WHERE link_path = :path AND module = 'menu' ORDER BY mlid ASC", array(
          ':path' => 'node/' . $node->nid,
        ), 0, 1)
        ->fetchField();
      }
      if ($mlid) {
        $item = menu_link_load($mlid);
      }
    }
    // Set default values.
    $node->menu = $item + array('link_title' => '', 'mlid' => 0, 'plid' => 0, 'menu_name' => $menu_name, 'weight' => 0, 'options' => array(), 'module' => 'menu', 'expanded' => 0, 'hidden' => 0, 'has_children' => 0, 'customized' => 0);
  }
  // Find the depth limit for the parent select.
  if (!isset($node->menu['parent_depth_limit'])) {
    $node->menu['parent_depth_limit'] = _menu_parent_depth_limit($node->menu);
  }
}

/**
 * Find the depth limit for items in the parent select.
 */
function _menu_parent_depth_limit($item) {
  return MENU_MAX_DEPTH - 1 - (($item['mlid'] && $item['has_children']) ? menu_link_children_relative_depth($item) : 0);
}

/**
 * Implement hook_form_alter(). Adds menu item fields to the node form.
 */
function menu_form_alter(&$form, $form_state, $form_id) {
  if (!empty($form['#node_edit_form'])) {
    // Note - doing this to make sure the delete checkbox stays in the form.
    $form['#cache'] = TRUE;

    $form['menu'] = array(
      '#type' => 'fieldset',
      '#title' => t('Menu settings'),
      '#access' => user_access('administer menu'),
      '#collapsible' => TRUE,
      '#collapsed' => FALSE,
      '#group' => 'additional_settings',
      '#attached_js' => array(drupal_get_path('module', 'menu') . '/menu.js'),
      '#tree' => TRUE,
      '#weight' => -2,
      '#attributes' => array('class' => array('menu-item-form')),
    );
    $item = $form['#node']->menu;

    if ($item['mlid']) {
      // There is an existing link.
      $form['menu']['delete'] = array(
        '#type' => 'checkbox',
        '#title' => t('Delete this menu item.'),
      );
    }
    if (!$item['link_title']) {
      $form['menu']['#collapsed'] = TRUE;
    }

    foreach (array('mlid', 'module', 'hidden', 'has_children', 'customized', 'options', 'expanded', 'hidden', 'parent_depth_limit') as $key) {
      $form['menu'][$key] = array('#type' => 'value', '#value' => $item[$key]);
    }
    $form['menu']['#item'] = $item;

    $form['menu']['link_title'] = array('#type' => 'textfield',
      '#title' => t('Menu link title'),
      '#default_value' => $item['link_title'],
      '#description' => t('The link text corresponding to this item that should appear in the menu. Leave blank if you do not wish to add this post to the menu.'),
      '#required' => FALSE,
    );
    // Generate a list of possible parents (not including this item or descendants).
    $options = menu_parent_options(menu_get_menus(), $item);
    $default = $item['menu_name'] . ':' . $item['plid'];
    if (!isset($options[$default])) {
      $default = 'main-menu:0';
    }
    $form['menu']['parent'] = array(
      '#type' => 'select',
      '#title' => t('Parent item'),
      '#default_value' => $default,
      '#options' => $options,
      '#description' => t('The maximum depth for an item and all its children is fixed at !maxdepth. Some menu items may not be available as parents if selecting them would exceed this limit.', array('!maxdepth' => MENU_MAX_DEPTH)),
      '#attributes' => array('class' => array('menu-title-select')),
    );
    $form['#submit'][] = 'menu_node_form_submit';

    $form['menu']['weight'] = array(
      '#type' => 'weight',
      '#title' => t('Weight'),
      '#delta' => 50,
      '#default_value' => $item['weight'],
      '#description' => t('Optional. In the menu, the heavier items will sink and the lighter items will be positioned nearer the top.'),
    );
  }
}

/**
 * Decompose the selected menu parent option into the menu_name and plid.
 */
function menu_node_form_submit($form, &$form_state) {
  list($form_state['values']['menu']['menu_name'], $form_state['values']['menu']['plid']) = explode(':', $form_state['values']['menu']['parent']);
}

/**
 * Return an associative array of the custom menus names.
 *
 * @param $all
 *   If FALSE return only user-added menus, or if TRUE also include
 *   the menus defined by the system.
 * @return
 *   An array with the machine-readable names as the keys, and human-readable
 *   titles as the values.
 */
function menu_get_menus($all = TRUE) {
  $system_menus = array_keys(menu_list_system_menus());
  $query = db_select('menu_custom');
  $query->addField('menu_custom', 'menu_name', 'menu_name');
  $query->addField('menu_custom', 'title', 'title');
  if (!$all) {
    $query->condition('menu_name', $system_menus, 'NOT IN');
  }
  $query->orderBy('title');

  return $query->execute()->fetchAllKeyed();
}