<?php
// $Id$

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

/**
 * Implementation of hook_help().
 */
function menu_help($path, $arg) {
  switch ($path) {
    case 'admin/help#menu':
      $output = t('<p>Menus are a collection of links (menu items) used to navigate a website. The menu module provides an interface to control and customize the powerful menu system that comes with Drupal. Menus are primarily displayed as a hierarchical list of links using Drupal\'s highly flexible <a href="@admin-block">blocks</a> feature. Each menu automatically creates a block of the same name. By default, new menu items are placed inside a built-in menu labelled %navigation, but administrators can also create custom menus.</p>
<p>Drupal themes generally provide out-of-the-box support for two menus commonly labelled %primary-links and %secondary-links. These are sets of links which are usually displayed in the header or footer of each page (depending on the currently active theme).</p>
Menu administration tabs:
<ul>
  <li>On the administer menu page, administrators can "edit" to change the title, description, parent or weight of a menu item. Under the "operations" column, click on "enable/disable" to toggle a menu item on or off. Only menu items which are enabled are displayed in the corresponding menu block. Note that the default menu items generated by the menu module cannot be deleted, only disabled.</li>
  <li>Use the "add menu" tab to submit a title for a new custom menu. Once submitted, the menu will appear in a list toward the bottom of the administer menu page underneath the main navigation menu. Under the menu name there will be links to edit or delete the menu, and a link to add new items to the menu.</li>
  <li>Use the "add menu item" tab to create new links in either the navigation or a custom menu (such as a primary/secondary links menu). Select the parent item to place the new link within an existing menu structure. For top level menu items, choose the name of the menu in which the link is to be added.</li>
</ul>', array('%navigation' => 'Navigation', '%primary-links' => 'Primary links', '%secondary-links' => 'Secondary links', '@admin-block' => url('admin/build/block'), '@menu-settings' => url('admin/build/menu/settings')));
      $output .= '<p>'. t('For more information please read the configuration and customization handbook <a href="@menu">Menu page</a>.', array('@menu' => 'http://drupal.org/handbook/modules/menu/')) .'</p>';
      return $output;
    case 'admin/build/menu':
      return '<p>'. t('Menus are a collection of links (menu items) used to navigate a website. The list(s) below display the currently available menus along with their menu items. Select an operation from the list to manage each menu or menu item.', array('@admin-settings-menus' => url('admin/build/menu/settings'), '@admin-block' => url('admin/build/block'))) .'</p>';
    case 'admin/build/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/build/block'))) .'</p>';
    case 'admin/build/menu/item/add':
      return '<p>'. t('Enter the title, path, position and the weight for your new menu item.') .'</p>';
  }
}

/**
 * Implementation of hook_perm().
 */
function menu_perm() {
  return array('administer menu');
}

/**
 * Implementation of hook_menu().
 */
function menu_menu() {
  $items['admin/build/menu'] = array(
    'title' => 'Menus',
    'description' => "Control your site's navigation menu, primary links and secondary links. as well as rename and reorganize menu items.",
    'page callback' => 'menu_overview_page',
    'access callback' => 'user_access',
    'access arguments' => array('administer menu'),
  );

  $items['admin/build/menu/list'] = array(
    'title' => 'List menus',
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => -10);
  $items['admin/build/menu/add'] = array(
    'title' => 'Add menu',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('menu_edit_menu', 'add'),
    'type' => MENU_LOCAL_TASK);
  $items['admin/build/menu/settings'] = array(
    'title' => 'Settings',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('menu_configure'),
    'type' => MENU_LOCAL_TASK,
    'weight' => 5);

  $items['admin/build/menu-customize/%menu'] = array(
    'title' => 'Customize menu',
    'page callback' => 'menu_overview',
    'page arguments' => array(3),
    'title callback' => 'menu_overview_title',
    'title arguments' => array(3),
    'access arguments' => array('administer menu'),
    'type' => MENU_CALLBACK);
  $items['admin/build/menu-customize/%menu/list'] = array(
    'title' => 'List items',
    'weight' => -10,
    'type' => MENU_DEFAULT_LOCAL_TASK);
  $items['admin/build/menu-customize/%menu/add'] = array(
    'title' => 'Add item',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('menu_edit_item', 'add', NULL, 3),
    'type' => MENU_LOCAL_TASK);
  $items['admin/build/menu-customize/%menu/edit'] = array(
    'title' => 'Edit menu',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('menu_edit_menu', 'edit', 3),
    'type' => MENU_LOCAL_TASK);
  $items['admin/build/menu-customize/%menu/delete'] = array(
    'title' => 'Delete menu',
    'page callback' => 'menu_delete_menu_page',
    'page arguments' => array(3),
    'type' => MENU_CALLBACK);
  $items['admin/build/menu/item/%menu_link/disable'] = array(
    'title' => 'Disable menu item',
    'page callback' => 'menu_flip_item',
    'page arguments' => array(TRUE, 4),
    'type' => MENU_CALLBACK);
  $items['admin/build/menu/item/%menu_link/enable'] = array(
    'title' => 'Enable menu item',
    'page callback' => 'menu_flip_item',
    'page arguments' => array(FALSE, 4),
    'type' => MENU_CALLBACK);
  $items['admin/build/menu/item/%menu_link/edit'] = array(
    'title' => 'Edit menu item',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('menu_edit_item', 'edit', 4, NULL),
    'type' => MENU_CALLBACK);
  $items['admin/build/menu/item/%menu_link/reset'] = array(
    'title' => 'Reset menu item',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('menu_reset_item_confirm', 4),
    'type' => MENU_CALLBACK);
  $items['admin/build/menu/item/%menu_link/delete'] = array(
    'title' => 'Delete menu item',
    'page callback' => 'menu_item_delete_page',
    'page arguments' => array(4),
    'type' => MENU_CALLBACK);

  return $items;
}

/**
 * Implementation of hook_enable()
 *
 *  Add a link for each custom menu.
 */
function menu_enable() {
  menu_rebuild();
  $result = db_query("SELECT * FROM {menu_custom}");
  $link['module'] = 'menu';
  $link['plid'] = db_result(db_query("SELECT mlid from {menu_links} WHERE menu_name = 'navigation' AND link_path = 'admin/build/menu'"));
  $link['router_path'] = 'admin/build/menu-customize/%';

  while ($menu = db_fetch_array($result)) {
    $link['mlid'] = 0;
    $link['link_title'] = $menu['title'];
    $link['link_path'] = 'admin/build/menu-customize/'. $menu['menu_name'];
    menu_link_save($link);
  }
  menu_cache_clear_all();
}

/**
 * Title callback for the menu overview page and links.
 */
function menu_overview_title($menu) {
  return t('!menu_title (overview)', array('!menu_title' => $menu['title']));
}

/**
 * Load the data for a single custom menu.
 */
function menu_load($menu_name) {
  return db_fetch_array(db_query("SELECT * FROM {menu_custom} WHERE menu_name = '%s'", $menu_name));
}

/**
 * Menu callback which shows an overview page of all the custom menus and their descriptions.
 */
function menu_overview_page() {
  $result = db_query("SELECT * FROM {menu_custom} ORDER BY title");
  $content = array();
  while ($menu = db_fetch_array($result)) {
    $menu['href'] = 'admin/build/menu-customize/'. $menu['menu_name'];
    $menu['options'] = array();
    $content[] = $menu;
  }
  return theme('admin_block_content', $content);
}

/**
 * Shows for one menu the menu items accessible to the current user and relevant operations.
 */
function menu_overview($menu) {

  $header = array(t('Menu item'), t('Expanded'), array('data' => t('Operations'), 'colspan' => '3'));
  $sql ="
    SELECT m.load_functions, m.to_arg_functions, m.access_callback, m.access_arguments, m.page_callback, m.page_arguments, m.title, m.title_callback, m.title_arguments, m.type, ml.*
    FROM {menu_links} ml LEFT JOIN {menu_router} m ON m.path = ml.router_path
    WHERE ml.menu_name = '%s'
    ORDER BY p1 ASC, p2 ASC, p3 ASC, p4 ASC, p5 ASC, p6 ASC, p7 ASC, p8 ASC, p9 ASC";
  $sql_count = "SELECT COUNT(*) FROM {menu_links} ml WHERE menu_name = '%s'";
  $result = pager_query($sql, 200, 0, $sql_count, $menu['menu_name']);
  $tree = menu_tree_data($result);
  $node_links = array();
  menu_tree_collect_node_links($tree, $node_links);
  menu_tree_check_access($tree, $node_links);
  $rows = _menu_overview_tree($tree);
  $output = theme('table', $header, $rows);
  $output .= theme('pager', NULL, 200, 0);
  return $output;
}

/**
 * Recursive helper function for menu_overview().
 */
function _menu_overview_tree($tree) {
  static $rows = array();
  foreach ($tree as $data) {
    $title = '';
    $item = $data['link'];
    // Don't show callbacks; these have $item['hidden'] < 0.
    if ($item && $item['hidden'] >= 0) {
      $title = str_repeat('&nbsp;&nbsp;', $item['depth'] - 1) . ($item['depth'] > 1 ? '-&nbsp;' : '');
      $title .= l($item['title'], $item['href'], $item['options']);
      // Populate the operations field.
      $operations = array();
      // Set the edit column.
      $operations[] = array('data' => l(t('edit'), 'admin/build/menu/item/'. $item['mlid'] .'/edit'));
      if ($item['hidden']) {
        $title .= ' ('. t('disabled') .')';
        $class = 'menu-disabled';
        $operations[] = array('data' => l(t('enable'), 'admin/build/menu/item/'. $item['mlid'] .'/enable'));
      }
      else {
        $class = 'menu-enabled';
        $operations[] = array('data' => l(t('disable'), 'admin/build/menu/item/'. $item['mlid'] .'/disable'));
      }
      // Only items created by the menu module can be deleted.
      if ($item['module'] == 'menu') {
        $operations[] = array('data' => l(t('delete'), 'admin/build/menu/item/'. $item['mlid'] .'/delete'));
      }
      // Set the reset column.
      elseif ($item['module'] == 'system' && $item['customized']) {
        $operations[] = array('data' => l(t('reset'), 'admin/build/menu/item/'. $item['mlid'] .'/reset'));
      }
      else {
        $operations[] = array('data' => '');
      }
      $row = array(
        array('data' => $title, 'class' => $class),
        array('data' => ($item['has_children'] ? (($item['expanded']) ? t('Yes') : t('No')) : ''), 'class' => $class),
      );
      foreach ($operations as $operation) {
        $operation['class'] = $class;
        $row[] = $operation;
      }
      $rows[] = $row;
    }
    if ($data['below']) {
      _menu_overview_tree($data['below']);
    }
  }
  return $rows;
}

/**
 * Menu callback; enable/disable a menu link.
 *
 * @param $hide
 *   TRUE to not show in the menu tree. FALSE to make the item and its children
 *   reappear in menu tree.
 * @param $item
 *    The menu item.
 */
function menu_flip_item($hide, $item) {

  $item['hidden'] = (bool)$hide;
  $item['customized'] = 1;
  menu_link_save($item);
  drupal_set_message($hide ? t('The menu item has been disabled.') : t('The menu item has been enabled.'));
  drupal_goto('admin/build/menu-customize/'. $item['menu_name']);
}

/**
 * Menu callback; Build the menu link editing form.
 */
function menu_edit_item(&$form_state, $type, $item, $menu) {

  if ($type == 'add' || empty($item)) {
    // This is an add form, initialize the menu link.
    $item = array('link_title' => '', 'mlid' => 0, 'plid' => 0, 'menu_name' => $menu['menu_name'], 'weight' => 0,  'link_path' => '', 'options' => array(), 'module' => 'menu', 'expanded' => 0, 'hidden' => 0, 'has_children' => 0);
  }
  foreach (array('link_path', 'mlid', 'module', 'hidden', 'has_children', 'options') as $key) {
    $form[$key] = array('#type' => 'value', '#value' => $item[$key]);
  }
  // Any item created or edited via this interface is considered "customized".
  $form['customized'] = array('#type' => 'value', '#value' => 1);
  $form['original_item'] = array('#type' => 'value', '#value' => $item);

  if ($item['module'] == 'menu') {
    $form['link_path'] = array(
      '#type' => 'textfield',
      '#title' => t('Path'),
      '#default_value' => $item['link_path'],
      '#description' => t('The path this menu item links to. This can be an internal Drupal path such as %add-node or an external URL such as %drupal. Enter %front to link to the front page.', array('%front' => '<front>', '%add-node' => 'node/add', '%drupal' => 'http://drupal.org')),
      '#required' => TRUE,
    );
    $form['delete'] = array(
      '#type' => 'submit',
      '#value' => t('Delete'),
      '#access' => $item['mlid'],
      '#submit' => array('menu_item_delete_submit'),
      '#weight' => 10,
    );
  }
  else {
    $form['_path'] = array(
      '#type' => 'item',
      '#title' => t('Path'),
      '#description' => l($item['link_title'], $item['href'], $item['options']),
    );
  }
  $form['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.'),
    '#required' => TRUE,
  );
  $form['description'] = array(
    '#type' => 'textarea',
    '#title' => t('Description'),
    '#default_value' => isset($item['options']['attributes']['title']) ? $item['options']['attributes']['title'] : '',
    '#rows' => 1,
    '#description' => t('The description displayed when hovering over a menu item.'),
  );
  $form['expanded'] = array(
    '#type' => 'checkbox',
    '#title' => t('Expanded'),
    '#default_value' => $item['expanded'],
    '#description' => t('If selected and this menu item has children, the menu will always appear expanded.'),
  );

  // 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 = 'navigation:0';
  }
  $form['parent'] = array(
    '#type' => 'select',
    '#title' => t('Parent item'),
    '#default_value' => $default,
    '#options' => $options,
  );
  $form['weight'] = array(
    '#type' => 'weight',
    '#title' => t('Weight'),
    '#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.'),
  );
  $form['submit'] = array('#type' => 'submit', '#value' => t('Save'));


  return $form;
}

/**
 * Validate form values for a menu link being added or edited.
 */
function menu_edit_item_validate($form, &$form_state) {
  $item = $form_state['values'];
  if (!trim($item['link_path']) || !menu_valid_path($item)) {
    form_set_error('link_path', t("The path '@link_path' is either invalid or you do not have access to it.", array('@link_path' => $item['link_path'])));
  }
}

/**
 * Submit function for the delete button on the menu item editing form.
 */
function menu_item_delete_submit($form, &$form_state) {
  $form_state['redirect'] = 'admin/build/menu/item/'. $form_state['values']['mlid'] .'/delete';
}

/**
 * Process menu and menu item add/edit form submissions.
 */
function menu_edit_item_submit($form, &$form_state) {
  $form_state['values']['options']['attributes']['title'] = $form_state['values']['description'];
  list($form_state['values']['menu_name'], $form_state['values']['plid']) = explode(':', $form_state['values']['parent']);
  if (!menu_link_save($form_state['values'])) {
    drupal_set_message(t('There was an error saving the menu link.'), 'error');
  }
  $form_state['redirect'] = 'admin/build/menu-customize/'. $form_state['values']['menu_name'];
}

/**
 * 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) {

  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']);
  }
  return $options;
}

/**
 * Recursive helper function for menu_parent_options().
 */
function _menu_parents_recurse($tree, $menu_name, $indent, &$options, $exclude) {
  foreach ($tree as $data) {
    if ($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'] && $data['link']['depth'] < MENU_MAX_DEPTH - 1) {
        _menu_parents_recurse($data['below'], $menu_name, $indent .'--', $options, $exclude);
      }
    }
  }
}

/**
 * Menu callback; Build the form that handles the adding/editing of a custom menu.
 */
function menu_edit_menu(&$form_state, $type, $menu = array()) {
  if ($type == 'edit') {
    $form['menu_name'] = array('#type' => 'value', '#value' => $menu['menu_name']);
    $form['#insert'] = FALSE;
    $form['delete'] = array(
      '#type' => 'submit',
      '#value' => t('Delete'),
      '#access' => !in_array($menu['menu_name'], menu_list_system_menus()),
      '#submit' => array('menu_custom_delete_submit'),
      '#weight' => 10,
    );
  }
  else {
    $menu = array('menu_name' => '', 'title' => '', 'description' => '');
    $form['menu_name'] = array(
      '#type' => 'textfield',
      '#title' => t('Menu name'),
      '#description' => t('The machine-readable name of this menu. This text will be used for constructing the URL of the <em>menu overview</em> page for this menu. This name may consist of only of lowercase letters, numbers, and hyphens, and must be unique.'),
      '#required' => TRUE,
    );
    $form['#insert'] = TRUE;
  }
  $form['#title'] = $menu['title'];
  $form['title'] = array(
    '#type' => 'textfield',
    '#title' => t('Title'),
    '#default_value' => $menu['title'],
    '#required' => TRUE,
  );
  $form['description'] = array(
    '#type' => 'textarea',
    '#title' => t('Description'),
    '#default_value' => $menu['description'],
  );
  $form['submit'] = array(
    '#type' => 'submit',
    '#value' => t('Save'),
  );

  return $form;
}

/**
 * Submit function for the 'Delete' button on the menu editing form.
 */
function menu_custom_delete_submit($form, &$form_state) {
  $form_state['redirect'] = 'admin/build/menu-customize/'. $form_state['values']['menu_name'] .'/delete';
}

/**
 * Menu callback; check access and get a confirm form for deletion of a custom menu.
 */
function menu_delete_menu_page($menu) {
  // System-defined menus may not be deleted.
  if (in_array($menu['menu_name'], menu_list_system_menus())) {
    drupal_access_denied();
    return;
  }
  return drupal_get_form('menu_delete_menu_confirm', $menu);
}

/**
 * Build a confirm form for deletion of a custom menu.
 */
function menu_delete_menu_confirm(&$form_state, $menu) {
  $form['#menu'] = $menu;
  $caption = '';
  $num_links = db_result(db_query("SELECT COUNT(*) FROM {menu_links} WHERE menu_name = '%s'", $menu['menu_name']));
  if ($num_links) {
    $caption .= '<p>'. format_plural($num_links, '<strong>Warning:</strong> There is currently 1 menu item in %title. It will be deleted (system-defined items will be reset).', '<strong>Warning:</strong> There are currently @count menu items in %title. They will be deleted (system-defined items will be reset).', array('%title' => $menu['title'])) .'</p>';
  }
  $caption .= '<p>'. t('This action cannot be undone.') .'</p>';
  return confirm_form($form, t('Are you sure you want to delete the custom menu %title?', array('%title' => $menu['title'])), 'admin/build/menu-customize/'. $menu['menu_name'], $caption, t('Delete'));
}

/**
 * Delete a custom menu and all items in it.
 */
function menu_delete_menu_confirm_submit($form, &$form_state) {
  $menu = $form['#menu'];
  $form_state['redirect'] = 'admin/build/menu';
  // System-defined menus may not be deleted - only menus defined by this module.
  if (in_array($menu['menu_name'], menu_list_system_menus())  || !db_result(db_query("SELECT COUNT(*) FROM {menu_custom} WHERE menu_name = '%s'", $menu['menu_name']))) {
    return;
  }
  // Reset all the menu links defined by the system via hook_menu.
  $result = db_query("SELECT * FROM {menu_links} ml INNER JOIN {menu_router} m ON ml.router_path = m.path WHERE ml.menu_name = '%s' AND ml.module = 'system' ORDER BY m.number_parts ASC", $menu['menu_name']);
  while ($item = db_fetch_array($result)) {
    menu_reset_item($item);
  }
  // Delete all links to the overview page for this menu.
  $result = db_query("SELECT mlid FROM {menu_links} ml WHERE ml.link_path = '%s'", 'admin/build/menu-customize/'. $menu['menu_name']);
  while ($m = db_fetch_array($result)) {
    menu_link_delete($m['mlid']);
  }
  // Delete all the links in the menu and the menu from the list of custom menus.
  db_query("DELETE FROM {menu_links} WHERE menu_name = '%s'", $menu['menu_name']);
  db_query("DELETE FROM {menu_custom} WHERE menu_name = '%s'", $menu['menu_name']);
  // Delete all the blocks for this menu.
  db_query("DELETE FROM {blocks} WHERE module = 'menu' AND delta = '%s'", $menu['menu_name']);
  db_query("DELETE FROM {blocks_roles} WHERE module = 'menu' AND delta = '%s'", $menu['menu_name']);
  menu_cache_clear_all();
  cache_clear_all();
  $t_args = array('%title' => $menu['title']);
  drupal_set_message(t('The custom menu %title has been deleted.', $t_args));
  watchdog('menu', 'Deleted custom menu %title and all its menu items.', $t_args, WATCHDOG_NOTICE);
}

/**
 * Validates the human and machine-readable names when adding or editing a menu.
 */
function menu_edit_menu_validate($form, &$form_state) {
  $item = $form_state['values'];
  if (preg_match('/[^a-z0-9-]/', $item['menu_name'])) {
    form_set_error('menu_name', t('Menu name may consist only of lowercase letters, numbers, and hyphens.'));
  }
  if ($form['#insert']) {
    // We will add 'menu-' to the menu name to help avoid name-space conflicts.
    $item['menu_name'] = 'menu-'. $item['menu_name'];
    if (db_result(db_query("SELECT menu_name FROM {menu_custom} WHERE menu_name = '%s'", $item['menu_name'])) ||
      db_result(db_query_range("SELECT menu_name FROM {menu_links} WHERE menu_name = '%s'", $item['menu_name'], 0, 1))) {
      form_set_error('menu_name', t('Menu already exists'));
    }
  }
}

/**
 * Submit function for adding or editing a custom menu.
 */
function menu_edit_menu_submit($form, &$form_state) {
  $menu = $form_state['values'];
  $path = 'admin/build/menu-customize/';
  if ($form['#insert']) {
    // Add 'menu-' to the menu name to help avoid name-space conflicts.
    $menu['menu_name'] = 'menu-'. $menu['menu_name'];
    $link['link_title'] = $menu['title'];
    $link['link_path'] = $path . $menu['menu_name'];
    $link['router_path'] = $path .'%';
    $link['module'] = 'menu';
    $link['plid'] = db_result(db_query("SELECT mlid from {menu_links} WHERE menu_name = 'navigation' AND link_path = 'admin/build/menu'"));
    menu_link_save($link);
    db_query("INSERT INTO {menu_custom} (menu_name, title, description) VALUES ('%s', '%s', '%s')", $menu['menu_name'], $menu['title'], $menu['description']);
  }
  else {
    db_query("UPDATE {menu_custom} SET title = '%s', description = '%s' WHERE menu_name = '%s'", $menu['title'], $menu['description'], $menu['menu_name']);
    $result = db_query("SELECT mlid FROM {menu_links} WHERE link_path = '%s'", $path . $menu['menu_name']);
    while ($m = db_fetch_array($result)) {
      $link = menu_link_load($m['mlid']);
      $link['link_title'] = $menu['title'];
      menu_link_save($link);
    }
  }
  $form_state['redirect'] = $path . $menu['menu_name'];
}

/**
 * Menu callback; Check access and present a confirm form for deleting a menu link.
 */
function menu_item_delete_page($item) {
  // Links defined via hook_menu may not be deleted.
  if ($item['module'] == 'system') {
    drupal_access_denied();
    return;
  }
  return drupal_get_form('menu_item_delete_form', $item);
}

/**
 * Build a confirm form for deletion of a single menu link.
 */
function menu_item_delete_form(&$form_state, $item) {
  $form['#item'] = $item;
  return confirm_form($form, t('Are you sure you want to delete the custom menu item %item?', array('%item' => $item['link_title'])), 'admin/build/menu-customize/'. $item['menu_name']);
}

/**
 * Process menu delete form submissions.
 */
function menu_item_delete_form_submit($form, &$form_state) {
  $item = $form['#item'];
  menu_link_delete($item['mlid']);
  $t_args = array('%title' => $item['link_title']);
  drupal_set_message(t('The menu item %title has been deleted.', $t_args));
  watchdog('menu', 'Deleted menu item %title.', $t_args, WATCHDOG_NOTICE);
  $form_state['redirect'] = 'admin/build/menu-customize/'. $item['menu_name'];
}

/**
 * Menu callback; reset a single modified item.
 */
function menu_reset_item_confirm(&$form_state, $item) {
  $form['item'] = array('#type' => 'value', '#value' => $item);
  return confirm_form($form, t('Are you sure you want to reset the item %item to its default values?', array('%item' => $item['link_title'])), 'admin/build/menu-customize/'. $item['menu_name'], t('Any customizations will be lost. This action cannot be undone.'), t('Reset'));
}

/**
 * Process menu reset item form submissions.
 */
function menu_reset_item_confirm_submit($form, &$form_state) {
  $item = $form_state['values']['item'];
  $new_item = menu_reset_item($item);
  drupal_set_message(t('The menu item was reset to its default settings.'));
  $form_state['redirect'] = 'admin/build/menu-customize/'. $new_item['menu_name'];
}

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

/**
 * Implementation of hook_block().
 */
function menu_block($op = 'list', $delta = 0) {
  $custom_menus = menu_get_menus(FALSE);
  if ($op == 'list') {
    $blocks = array();
    foreach ($custom_menus as $name => $title) {
      // Default "Navigation" block is handled by user.module.
      $blocks[$name]['info'] = check_plain($title);
    }
    return $blocks;
  }
  else if ($op == 'view') {
    $data['subject'] = check_plain($custom_menus[$delta]);
    $data['content'] = menu_tree($delta);
    return $data;
  }
}

/**
 * Implementation of hook_nodeapi().
 */
function menu_nodeapi(&$node, $op) {
  switch ($op) {
    case 'insert':
    case 'update':
      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');
          }
        }
      }
      break;
    case 'delete':
      // Delete all menu module links that point to this node.
      $result = db_query("SELECT mlid FROM {menu_links} WHERE link_path = 'node/%d' AND module = 'menu'", $node->nid);
      while ($m = db_fetch_array($result)) {
        menu_link_delete($m['mlid']);
      }
      break;
    case 'prepare':
      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', 'navigation');
        $item = array();
        if (isset($node->nid)) {
          // Give priority to the default menu
          $mlid = db_result(db_query_range("SELECT mlid FROM {menu_links} WHERE link_path = 'node/%d' AND menu_name = '%s' AND module = 'menu' ORDER BY mlid ASC", $node->nid, $menu_name, 0, 1));
          // Check all menus if a link does not exist in the default menu.
          if (!$mlid) {
            $mlid = db_result(db_query_range("SELECT mlid FROM {menu_links} WHERE link_path = 'node/%d' AND module = 'menu' ORDER BY mlid ASC", $node->nid, 0, 1));
          }
          if ($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);
      }
      break;
  }
}

/**
 * Implementation of hook_form_alter(). Adds menu item fields to the node form.
 */
function menu_form_alter(&$form, $form_state, $form_id) {
  if (isset($form['#node']) && $form['#node']->type .'_node_form' == $form_id) {
    // 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,
      '#tree' => TRUE,
      '#weight' => -2,
    );
    $item = $form['#node']->menu;

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

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

    $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 = 'navigation:0';
    }
    $form['menu']['parent'] = array(
      '#type' => 'select',
      '#title' => t('Parent item'),
      '#default_value' => $default,
      '#options' => $options,
    );
    $form['#submit'][] = 'menu_node_form_submit';

    $form['menu']['weight'] = array(
      '#type' => 'weight',
      '#title' => t('Weight'),
      '#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 = menu_list_system_menus();
  $sql = 'SELECT * FROM {menu_custom}';
  if (!$all) {
    $sql .= ' WHERE menu_name NOT IN ('. implode(',', array_fill(0, count($system_menus), "'%s'")) .')';
  }
  $sql .= ' ORDER BY title';
  $result = db_query($sql, $system_menus);
  $rows = array();
  while ($r = db_fetch_array($result)) {
    $rows[$r['menu_name']] = $r['title'];
  }
  return $rows;
}

/**
 * Menu callback; Build the form presenting menu configuration options.
 */
function menu_configure() {
  $form['intro'] = array(
    '#type' => 'item',
    '#value' => t('The menu module allows on-the-fly creation of menu links in the content authoring forms. The following option sets the default menu in which a new link will be added.'),
  );

  $authoring_options = menu_get_menus();
  $form['menu_default_node_menu'] = array('#type' => 'select',
    '#title' => t('Default menu for content'),
    '#default_value' => variable_get('menu_default_node_menu', 'navigation'),
    '#options' => $authoring_options,
    '#description' => t('Choose the menu to be the default in the menu options in the content authoring form.'),
  );

  return system_settings_form($form);
}

/**
 * Validates the path of a menu link being created or edited.
 *
 * @return
 *   TRUE if it is a valid path AND the current user has access permission,
 *   FALSE otherwise.
 */
function menu_valid_path($form_item) {
  $item = array();
  $path = $form_item['link_path'];
  if ($path == '<front>' || menu_path_is_external($path)) {
    $item = array('access' => TRUE);
  }
  elseif (preg_match('/\/\%/', $path)) {
    // Path is dynamic (ie 'user/%'), so check directly against menu_router table.
    if ($item = db_fetch_array(db_query("SELECT * FROM {menu_router} where path = '%s' ", $path))) {
      $item['link_path']  = $form_item['link_path'];
      $item['link_title'] = $form_item['link_title'];
      $item['external']   = FALSE;
      $item['options'] = '';
      _menu_link_translate($item);
    }
  }
  else {
    $item = menu_get_item($path);
  }
  return $item && $item['access'];
}