book.module

<?php
// $Id$

/**
 * Implementation of hook_node_name().
 */
function book_node_name($node) {
  return t('book page');
}

/**
 * Implementation of hook_perm().
 */
function book_perm() {
  return array('maintain books');
}

/**
 * Implementation of hook_access().
 */
function book_access($op, $node) {
  global $user;

  if ($op == 'view') {
    /*
    ** Everyone can access all published book pages whether these pages
    ** are still waiting for approval or not.  We might not always want
    ** to display pages that are waiting for approval, but we take care
    ** of that problem in the book_view() function.
    */

    return $node->status;
  }

  if ($op == 'create') {
    /*
    ** Only registered users can create book pages.  Given the nature
    ** of the book module this is considered to be a good/safe idea.
    */

    return user_access('maintain books');
  }

  if ($op == 'update') {
    /*
    ** Only registered users can update book pages.  Given the nature
    ** of the book module this is considered to be a good/safe idea.
    ** One can only update a book page if there are no suggested updates
    ** of that page waiting for approval, when it is not a PHP-page and
    ** as long as the "create new revision"-bit is set.  That is, only
    ** updates that don't overwrite the current or pending information
    ** are allowed.
    */

    return user_access('maintain books') && !$node->moderate && !$node->format && $node->revision;
  }
}

/**
 * Implementation of hook_link().
 */
function book_link($type, $node = 0, $main = 0) {

  $links = array();

  if ($type == 'page' && user_access('access content')) {
    $links[] = l(t('books'), 'book', array('title' => t('Read and contribute to the collaborative books.')));
  }

  if ($type == 'node' && $node->type == 'book') {
    if (book_access('update', $node)) {
      $links[] = l(t('edit this page'), "node/$node->nid/edit", array('title' => t('Suggest an update for this book page.')));
    }
    if (!$main) {
      $links[] = l(t('printer-friendly version'), "book/print/$node->nid", array('title' => t('Show a printer-friendly version of this book page and its sub-pages.')));
    }
  }

  return $links;
}

/**
 * Implementation of hook_menu().
 */
function book_menu() {
  $items = array();

  $items[] = array('path' => 'node/add/book', 'title' => t('book page'),
    'access' => user_access('maintain books'));
  $items[] = array('path' => 'admin/node/book', 'title' => t('books'),
    'callback' => 'book_admin',
    'access' => user_access('administer nodes'),
    'weight' => 4);
  $items[] = array('path' => 'admin/node/book/orphan', 'title' => t('orphan pages'),
    'callback' => 'book_admin_orphan',
    'access' => user_access('administer nodes'),
    'weight' => 8);
  $result = db_query('SELECT n.nid, n.title FROM {node} n INNER JOIN {book} b ON n.nid = b.nid WHERE b.parent = 0 ORDER BY b.weight, n.title');
  while ($book = db_fetch_object($result)) {
    $items[] = array('path' => 'admin/node/book/'. $book->nid, 'title' => t('"%title" book', array('%title' => $book->title)));
  }
  $items[] = array('path' => 'book', 'title' => t('books'),
    'callback' => 'book_render',
    'access' => user_access('access content'),
    'type' => MENU_SUGGESTED_ITEM);
  $items[] = array('path' => 'book/view', 'title' => t('view'),
    'callback' => 'book_view_page',
    'access' => user_access('access content'),
    'type' => MENU_CALLBACK);
  $items[] = array('path' => 'book/print', 'title' => t('printer-friendly version'),
    'callback' => 'book_print',
    'access' => user_access('access content'),
    'type' => MENU_CALLBACK);

  return $items;
}

/**
 * Implementation of hook_block().
 *
 * Displays the book table of contents in a block when a node is being
 * viewed using a "book/view" path.
 */
function book_block($op = 'list', $delta = 0) {

  // Only display this block when the user is browsing a book:
  if (arg(0) == 'book' && arg(1) == 'view' && $nid = arg(2)) {
    $page = db_fetch_object(db_query('SELECT n.nid, n.title, b.parent FROM {node} n INNER JOIN {book} b ON n.nid = b.nid WHERE n.nid = %d', $nid));

    $path = book_location($page);
    $path[] = $page;

    foreach ($path as $key => $node) {
      $expand[] = $node->nid;
    }

    $title = $path[0]->title;
    $table = book_tree($expand[0], 5, $expand);
  }

  if ($op == 'list') {
    $block[0]['info'] = t('Book navigation');
  }
  else {
    $block['subject'] = $title;
    $block['content'] = $table;
  }

   return $block;
}

/**
 * Implementation of hook_load().
 */
function book_load($node) {
  global $user;

  $book = db_fetch_object(db_query('SELECT format, parent, weight, log FROM {book} WHERE nid = %d', $node->nid));

  if (arg(1) == 'edit' && !user_access('administer nodes')) {
    /*
    ** If a user is about to update a book page, we overload some
    ** fields to reflect the changes.
    */

    if ($user->uid) {
      $book->uid = $user->uid;
      $book->name = $user->name;
    }
    else {
      $book->uid = 0;
      $book->name = '';
    }
  }

  /*
  ** We set the revision field to indicate that we have to create
  ** a new revision when updating this book page.  We enable this
  ** always such that the "edit this page" links appear.
  */

  $book->revision = 1;

  return $book;
}

/**
 * Implementation of hook_insert().
 */
function book_insert($node) {
  db_query("INSERT INTO {book} (nid, format, parent, weight, log) VALUES (%d, %d, %d, %d, '%s')", $node->nid, $node->format, $node->parent, $node->weight, $node->log);
}

/**
 * Implementation of hook_update().
 */
function book_update($node) {
  db_query("UPDATE {book} SET format = %d, parent = %d, weight = %d, log = '%s' WHERE nid = %d", $node->format, $node->parent, $node->weight, $node->log, $node->nid);
}

/**
 * Implementation of hook_delete().
 */
function book_delete(&$node) {
  db_query('DELETE FROM {book} WHERE nid = %d', $node->nid);
}

/**
 * Implementation of hook_validate().
 */
function book_validate(&$node) {
  if ($node->format && user_access('create php content')) {
    // Do not filter PHP code. Do not auto-extract a teaser.
    $node->teaser = $node->body;
  }
  else {
    $node->format = 0;
  }

  // Set default values for non-administrators.
  if (!user_access('administer nodes')) {
    $node->format = 0;
    $node->weight = 0;
    $node->revision = 1;
  }
}

/**
 * Implementation of hook_form().
 */
function book_form(&$node) {
  global $user;

  $op = $_POST['op'];
  $output = form_select(t('Parent'), 'parent', $node->parent, book_toc(), t('The parent subject or category the page belongs in.'));

  if (function_exists('taxonomy_node_form')) {
    $output .= implode('', taxonomy_node_form('book', $node));
  }

  $output .= form_textarea(t('Body'), 'body', $node->body, 60, 20, filter_tips_short());
  $output .= form_textarea(t('Log message'), 'log', $node->log, 60, 5, t('An explanation of the additions or updates being made to help the group understand your motivations.'));

  if (user_access('administer nodes')) {
    $output .= form_weight(t('Weight'), 'weight', $node->weight, 15, t('The heavier pages will sink and the lighter pages will be positioned nearer the top.'));
    if (user_access('create php content')) {
      $output .= form_radios('Type', 'format', $node->format, array(0 => 'HTML / text', 1 => 'PHP'));
    }
  }
  else {
    /*
    ** If a regular user updates a book page, we create a new revision
    ** authored by that user:
    */

    $output .= form_hidden('revision', 1);
  }

  return $output;
}

/**
 * Implementation of hook_node_link().
 */
function book_node_link($node = 0) {
  global $user;

  $op = $_POST['op'];
  $edit = $_POST['edit'];

  if ($node->type != 'book') {

    if ($edit['nid']) {
      $node = node_load(array('nid' => $edit['nid']));
    }

    if ($op == t('Add to book outline')) {
      db_query('INSERT INTO {book} (nid, parent, weight) VALUES (%d, %d, %d)', $node->nid, $edit['parent'], $edit['weight']);
      drupal_set_message(t('added the node to the book.'));
    }

    if ($op == t('Update book outline')) {
      db_query('UPDATE {book} SET parent = %d, weight = %d WHERE nid = %d', $edit['parent'], $edit['weight'], $node->nid);
      drupal_set_message(t('updated the book outline.'));
    }

    if ($op == t('Remove from book outline')) {
      db_query('DELETE FROM {book} WHERE nid = %d', $node->nid);
      drupal_set_message(t('removed the node form the book.'));
    }

    $output .= '<h3>'. t('Edit book outline for node "%booktitle"', array('%booktitle' => "<em>$node->title</em>")) .'</h3>';

    if ($edit['nid']) {
      $page = db_fetch_object(db_query('SELECT * FROM {book} WHERE nid = %d', $node->nid));

      $output .= form_select(t('Parent'), 'parent', $page->parent, book_toc(), t('The parent subject or category the page belongs in.'));
      $output .= form_weight(t('Weight'), 'weight', $node->weight, 15, t('The heavier pages will sink and the lighter pages will be positioned nearer the top.'));

      if ($page->nid) {
        $output .= form_submit(t('Update book outline'));
        $output .= form_submit(t('Remove from book outline'));
      }
      else {
        $output .= form_submit(t('Add to book outline'));
      }

    }
    else {
      $output .= form_submit(t('Edit book outline'));
    }

    $output .= form_hidden('nid', $node->nid);

    return form($output, 'post', url('admin/node/book'));
  }
}

/**
 * Return the the most recent revision that matches the specified conditions.
 */
function book_revision_load($page, $conditions = array()) {

  $revisions = array_reverse(node_revision_list($page));

  foreach ($revisions as $revision) {

    /*
    ** Extract the specified revision:
    */

    $node = node_revision_load($page, $revision);

    /*
    ** Check to see if the conditions are met:
    */

    $status = 1;

    foreach ($conditions as $key => $value) {
      if ($node->$key != $value) {
        $status = 0;
      }
    }

    if ($status) {
      return $node;
    }
  }
}

/**
 * Return the path (call stack) to a certain book page.
 */
function book_location($node, $nodes = array()) {
  // TODO: eliminate the recursion

  $parent = db_fetch_object(db_query('SELECT n.nid, n.title, b.parent FROM {node} n INNER JOIN {book} b ON n.nid = b.nid WHERE n.nid = %d', $node->parent));
  if ($parent->title) {
    $nodes = book_location($parent, $nodes);
    array_push($nodes, $parent);
  }
  return $nodes;
}

function book_location_down($node, $nodes = array()) {
  // TODO: eliminate the recursion

  $last_direct_child = db_fetch_object(db_query('SELECT n.nid, n.title, b.parent FROM {node} n INNER JOIN {book} b ON n.nid = b.nid WHERE b.parent = %d ORDER BY b.weight DESC, n.title DESC', $node->nid));
  if ($last_direct_child) {
    array_push($nodes, $last_direct_child);
    $nodes = book_location_down($last_direct_child, $nodes);
  }
  return $nodes;
}

/**
 * Fetch the node object of the previous page of the book.
 */
function book_prev($node) {
  // if the parent is zero, we are at the start of a book so there is no previous
  if ($node->parent == 0) {
    return NULL;
  }

  // previous on the same level
  $direct_above = db_fetch_object(db_query("SELECT n.nid, n.title FROM {node} n INNER JOIN {book} b ON n.nid = b.nid WHERE b.parent = %d AND n.status = 1 AND (n.moderate = 0 OR n.revisions != '') AND (b.weight < %d OR (b.weight = %d AND n.title < '%s')) ORDER BY b.weight DESC, n.title DESC", $node->parent, $node->weight, $node->weight, $node->title));
  if ($direct_above) {
    // get last leaf of $above
    $path = book_location_down($direct_above);

    return $path ? (count($path) > 0 ? array_pop($path) : NULL) : $direct_above;
  }
  else {
    // direct parent
    $prev = db_fetch_object(db_query("SELECT n.nid, n.title FROM {node} n INNER JOIN {book} b ON n.nid = b.nid WHERE n.nid = %d AND n.status = 1 AND (n.moderate = 0 OR n.revisions != '')", $node->parent));
    return $prev;
  }
}

/**
 * Fetch the node object of the next page of the book.
 */
function book_next($node) {
  // get first direct child
  $child = db_fetch_object(db_query("SELECT n.nid, n.title FROM {node} n INNER JOIN {book} b ON n.nid = b.nid WHERE b.parent = %d AND n.status = 1 AND (n.moderate = 0 OR n.revisions != '') ORDER BY b.weight ASC, n.title ASC", $node->nid));
  if ($child) {
    return $child;
  }

  // no direct child: get next for this level or any parent in this book
  array_push($path = book_location($node), $node); // path to top-level node including this one

  while (($leaf = array_pop($path)) && count($path)) {
    $next = db_fetch_object(db_query("SELECT n.nid, n.title FROM {node} n INNER JOIN {book} b ON n.nid = b.nid WHERE b.parent = %d AND n.status = 1 AND (n.moderate = 0 OR n.revisions != '') AND (b.weight > %d OR (b.weight = %d AND n.title > '%s')) ORDER BY b.weight ASC, n.title ASC", $leaf->parent, $leaf->weight, $leaf->weight, $leaf->title));
    if ($next) {
      return $next;
    }
  }
}

/**
 * Implementation of hook_content().
 */
function book_content($node, $teaser = FALSE) {
  $op = $_POST['op'];

  /*
  ** Always display the most recently approved revision of a node
  ** (if any) unless we have to display this page in the context of
  ** the moderation queue.
  */

  if ($op != t('Preview') && $node->moderate && arg(0) != 'queue') {
    $revision = book_revision_load($node, array('moderate' => 0, 'status' => 1));

    if ($revision) {
      $node = $revision;
    }
  }

  /*
  ** Extract the page body.  If body is dynamic (using PHP code), the body
  ** will be generated.
  */

  if ($node->format == 1) {
    // Make sure only authorized users can preview PHP pages.
    if ($op == t('Preview') && !user_access('create php content')) {
      return;
    }

    ob_start();
    eval($node->body);
    $node->teaser = $node->body = ob_get_contents();
    ob_end_clean();
  }
  else {
    $node = node_prepare($node, $teaser);
  }

  return $node;
}

/**
 * Implementation of hook_view().
 *
 * If not displayed on the main page, we render the node as a page in the
 * book with extra links to the previous and next pages.
 */
function book_view($node, $teaser = FALSE, $page = FALSE) {
  $node = book_content($node, $teaser);

  $output = '';

  if ($teaser) {
    $output .= theme('node', $node, $teaser, $page);
  }
  else {
    if ($node->moderate) {
      $node->body = $node->body . '<div class="log"><div class="title">'. t('Log') .":</div>$node->log</div>";
    }
    // Add the navigation and the breadcrumb if we view a page
    if ($page) {
      $node = book_navigation($node);
      // Print the breadcrumb
      menu_set_location($node->breadcrumb);
    }
    // Print the node
    $output .= theme('node', $node, $teaser, $page);
  }

  return $output;
}

/**
 * Present a view of a node as a book page.
 */
function book_show($node, $cid) {
  $output = '';

  if (node_access('view', $node)) {

    if ($node->type == 'book') {
      $output .= book_view($node, 0, 1);
    }
    else {

      if (node_hook($node, 'content')) {
        $node = node_invoke($node, 'content');

        /*
        ** Add the book navigation if the node is in the book.
        */

        $book = db_fetch_object(db_query('SELECT * FROM {book} WHERE nid = %d', $node->nid));

        if ($book) {
          foreach ($book as $key => $value) {
            $node->$key = $value;
          }
          $node = book_navigation($node);
        }

        /*
        ** make $node->type a book. This is for the links.
        */

        $node->type = 'book';

        /*
        ** View the node
        */
        menu_set_location($node->breadcrumb);
        $output .= theme('node', $node, 0, 1);
      }
      else {

        /*
        ** We can't get the content of the node and just view the node.
        ** We don't add breadcrumbs or links.
        */
        $output .= node_view($node, 0, 1);
      }
    }
    if (function_exists('comment_render') && $node->comment) {
      $output .= comment_render($node, $cid);
    }

    /*
    ** Update the history table, stating that this user viewed this node.
    */
    node_tag_new($node->nid);
  }
  else {
    $output .= message_access();
  }
  return $output;
}

/**
 * Prepares both the custom breadcrumb trail and the forward/backward
 * navigation for a node presented as a book page.
 */
function book_navigation($node) {
  $path = book_location($node);

  /*
  ** Construct the breadcrumb:
  */

  $node->breadcrumb = array(); // Overwrite the trail with a book trail.
  foreach ($path as $level) {
    $node->breadcrumb[] = array('path' => 'book/view/'. $level->nid, 'title' =>  $level->title);
  }
  $node->breadcrumb[] = array('path' => 'book/view/'. $node->nid);

  if ($node->nid) {
    $output .= '<div class="book">';

    if ($tree = book_tree($node->nid)) {
      $output .= '<div class="tree">'. book_tree($node->nid) .'</div>';
    }

    if ($prev = book_prev($node)) {
      $links .= '<div class="prev">';
      $links .= l(t('previous'), "book/view/$prev->nid", array('title' => t('View the previous page.')));
      $links .= '</div>';
      $titles .= "<div class=\"prev\">$prev->title</div>";
    }
    else {
      $links .= '<div class="prev">&nbsp;</div>'; // make an empty div to fill the space
    }
    if ($next = book_next($node)) {
      $links .= '<div class="next">';
      $links .= l(t('next'), "book/view/$next->nid", array('title' => t('View the next page.')));
      $links .= '</div>';
      $titles .= "<div class=\"next\">$next->title</div>";
    }
    else {
      $links .= '<div class="next">&nbsp;</div>'; // make an empty div to fill the space
    }
    if ($node->parent) {
      $links .= '<div class="up">';
      $links .= l(t('up'), "book/view/$node->parent", array('title' => t("View this page's parent section.")));
      $links .= '</div>';
    }

    $output .= '<div class="nav">';
    $output .= " <div class=\"links\">$links</div>";
    $output .= " <div class=\"titles\">$titles</div>";
    $output .= '</div>';
    $output .= '</div>';
  }

  $node->body = $node->body.$output;

  return $node;
}

function book_toc_recurse($nid, $indent, $toc, $children) {

  if ($children[$nid]) {
    foreach ($children[$nid] as $foo => $node) {
      $toc[$node->nid] = "$indent $node->title";
      $toc = book_toc_recurse($node->nid, "$indent--", $toc, $children);
    }
  }

  return $toc;
}

function book_toc($parent = 0, $indent = '', $toc = array()) {
  $result = db_query('SELECT n.nid, n.title, b.parent FROM {node} n INNER JOIN {book} b ON n.nid = b.nid WHERE n.status = 1 ORDER BY b.weight, n.title');

  while ($node = db_fetch_object($result)) {
    if (!$children[$node->parent]) {
      $children[$node->parent] = array();
    }
    array_push($children[$node->parent], $node);
  }

  /*
  ** If the user is an administrator, add the top-level book page;
  ** only administrators can start new books.
  */

  if (user_access('administer nodes')) {
    $toc[0] = '<'. t('top-level') .'>';
  }

  $toc = book_toc_recurse($parent, $indent, $toc, $children);

  return $toc;
}

function book_tree_recurse($nid, $depth, $children, $unfold = array()) {
  if ($depth > 0) {
    if ($children[$nid]) {
      foreach ($children[$nid] as $foo => $node) {
        if (in_array($node->nid, $unfold)) {
          if ($tree = book_tree_recurse($node->nid, $depth - 1, $children, $unfold)) {
            $output .= '<li class="expanded">';
            $output .= l($node->title, "book/view/$node->nid");
            $output .= "<ul>$tree</ul>";
            $output .= '</li>';
          }
          else {
            $output .= '<li class="leaf">'. l($node->title, "book/view/$node->nid") .'</li>';
          }
        }
        else {
          if ($tree = book_tree_recurse($node->nid, 1, $children)) {
            $output .= '<li class="collapsed">'. l($node->title, "book/view/$node->nid") .'</li>';
          }
          else {
            $output .= '<li class="leaf">'. l($node->title, "book/view/$node->nid") .'</li>';
          }
        }
      }
    }
  }

  return $output;
}

function book_tree($parent = 0, $depth = 3, $unfold = array()) {
  $result = db_query('SELECT n.nid, n.title, b.parent FROM {node} n INNER JOIN {book} b ON n.nid = b.nid WHERE n.status = 1 AND n.moderate = 0 ORDER BY b.weight, n.title');

  while ($node = db_fetch_object($result)) {
    $list = $children[$node->parent] ? $children[$node->parent] : array();
    array_push($list, $node);
    $children[$node->parent] = $list;
  }

  if ($tree = book_tree_recurse($parent, $depth, $children, $unfold)) {
    return "<ul>$tree</ul>";
  }
}

/**
 * Menu callback; prints a listing of all books.
 */
function book_render() {

  $result = db_query('SELECT n.nid FROM {node} n INNER JOIN {book} b ON n.nid = b.nid WHERE b.parent = 0 AND n.status = 1 AND (n.moderate = 0 OR n.revisions IS NOT NULL) ORDER BY b.weight, n.title');

  while ($page = db_fetch_object($result)) {
    // load the node:
    $node = node_load(array('nid' => $page->nid));

    if ($node) {
      // take the most recent approved revision, extract the page and check output:
      $node = book_content($node);
      // output the content:
      $output .= '<div class="book">';
      $output .= '<div class="title">'. l($node->title, "book/view/$node->nid") .'</div>';
      $output .= '<div class="body">'. $node->teaser .'</div>';
      $output .= '</div>';
    }
  }

  drupal_set_title(t('Books'));
  print theme('page', $output);
}

/**
 * Menu callback; prints a node as a book page, complete with navigation.
 */
function book_view_page($nid = 0, $cid = 0) {
  $node = node_load(array('nid' => $nid));
  $output = book_show($node, $cid);
  print theme('page', $output, $node->title);
}

/**
 * Menu callback; generates printer-friendly book page will all descendants.
 */
function book_print($nid = 0, $depth = 1) {
  global $base_url;
  $result = db_query('SELECT n.nid FROM {node} n INNER JOIN {book} b ON n.nid = b.nid WHERE n.status = 1 AND n.nid = %d AND (n.moderate = 0 OR n.revisions IS NOT NULL) ORDER BY b.weight, n.title', $nid);

  while ($page = db_fetch_object($result)) {
    // load the node:
    $node = node_load(array('nid' => $page->nid));

    if ($node) {
      // output the content:
      if (node_hook($node, 'content')) {
        $node = node_invoke($node, 'content');
      }
      $output .= "<h1 id=\"$node->nid\" name=\"$node->nid\" class=\"book-h$depth\">$node->title</h1>";

      if ($node->body) {
        $output .= $node->body;
      }
    }
  }

  $output .= book_print_recurse($nid, $depth);

  $html = "<html><head><title>$node->title</title>";
  $html .= "<base href=\"$base_url/\" />";
  $html .= "<style type=\"text/css\">\n@import url(misc/print.css);\n</style>";
  $html .= '</head><body>'. $output .'</body></html>';

  print $html;
}

function book_print_recurse($parent = '', $depth = 1) {
  $result = db_query("SELECT n.nid FROM {node} n INNER JOIN {book} b ON n.nid = b.nid WHERE n.status = 1 AND b.parent = '$parent' AND (n.moderate = 0 OR n.revisions IS NOT NULL) ORDER BY b.weight, n.title");

  while ($page = db_fetch_object($result)) {
    // load the node:
    $node = node_load(array('nid' => $page->nid));

    // take the most recent approved revision:
    if ($node->moderate) {
      $node = book_revision_load($node, array('moderate' => 0, 'status' => 1));
    }

    if ($node) {
      // output the content:
      if (node_hook($node, 'content')) {
        $node = node_invoke($node, 'content');
      }
      $output .= "<h1 id=\"$node->nid\" name=\"$node->nid\" class=\"book-h$depth\">$node->title</h1>";

      if ($node->body) {
        $output .= '<ul>'. $node->body .'</ul>';
      }

      $output .= book_print_recurse($node->nid, $depth + 1);
    }
  }

  return $output;
}

function book_admin_view_line($node, $depth = 0) {
  return array("<div style=\"padding-left: ". (25 * $depth) ."px;\">". form_textfield(NULL, "$node->nid][title", $node->title, 64, 255) ."</div>", form_weight(NULL, "$node->nid][weight", $node->weight), l(t("view node"), "node/$node->nid"), l(t("edit node"), "node/$node->nid/edit"), l(t("delete node"), "admin/node/delete/$node->nid"));
}

function book_admin_view_book($nid, $depth = 1) {
  $result = db_query("SELECT n.nid FROM {node} n INNER JOIN {book} b ON n.nid = b.nid WHERE b.parent = %d ORDER BY b.weight, n.title", $nid);

  while ($node = db_fetch_object($result)) {
    $node = node_load(array("nid" => $node->nid));
    $rows[] = book_admin_view_line($node, $depth);
    $rows = array_merge($rows, book_admin_view_book($node->nid, $depth + 1));
  }

  return $rows;
}

/**
 * Display an administrative view of the hierarchy of a book.
 */
function book_admin_view($nid, $depth = 0) {
  if ($nid) {
    $node = node_load(array("nid" => $nid));

    $output .= "<h3>$node->title</h3>";

    $header = array(t("title"), t("weight"), array("data" => t("operations"), "colspan" => 3));
    $rows[] = book_admin_view_line($node);
    $rows = array_merge($rows, book_admin_view_book($nid));

    $output .= theme("table", $header, $rows);
    $output .= form_submit(t("Save book pages"));

    return form($output);
  }
}

function book_admin_save($nid, $edit = array()) {
  if ($nid) {
    $book = node_load(array("nid" => $nid));

    foreach ($edit as $nid => $value) {
      /*
      ** Check to see whether the title needs updating:
      */

      $title = db_result(db_query("SELECT title FROM {node} WHERE nid = %d", $nid));
      if ($title != $value["title"]) {
        db_query("UPDATE {node} SET title = '%s' WHERE nid = %d", $value["title"], $nid);
      }

      /*
      ** Check to see whether the weight needs updating:
      */

      $weight = db_result(db_query("SELECT weight FROM {book} WHERE nid = %d", $nid));
      if ($weight != $value["weight"]) {
        db_query("UPDATE {book} SET weight = %d WHERE nid = %d", $value["weight"], $nid);
      }
    }

    $message = t('updated book "%title"', array('%title' => $book->title));
    watchdog('special', $message);

    return $message;
  }
}

/**
 * Menu callback; displays a listing of all orphaned book pages.
 */
function book_admin_orphan() {
  $result = db_query("SELECT n.nid, n.title, n.status, b.parent FROM {node} n INNER JOIN {book} b ON n.nid = b.nid");

  while ($page = db_fetch_object($result)) {
    $pages[$page->nid] = $page;
  }

  if ($pages) {
    $output .= "<h3>Orphan pages</h3>";
    $header = array(t("title"), t("weight"), array("data" => t("operations"), "colspan" => 3));
    foreach ($pages as $nid => $node) {
      if ($node->parent && empty($pages[$node->parent])) {
        $rows[] = book_admin_view_line($node, $depth);
        $rows = array_merge($rows, book_admin_view_book($node->nid, $depth + 1));
      }
    }
    $output .= theme("table", $header, $rows);
  }

  print theme("page", $output);
}