<?php

/**
 *  NOTES
 *  Here are various notes I've taken about notable changes and/or ommissions
 *
 *  - Everything has been moved to admin/structure/nodequeue which seemed the
 *    most appropriate destination now that admin/content is out of the picture.
 *
 *  - None of the PagerQueries are working, they're all just normal queries for
 *    the time being.
 */

/**
 * @file
 * Maintains queues of nodes in arbitrary order.
 */

define('NODEQUEUE_OK', 0);
define('NODEQUEUE_INVALID_POSITION', 1);
define('NODEQUEUE_INVALID_NID', 2);
define('NODEQUEUE_DUPLICATE_POSITION', 3);

/* --- HOOKS ---------------------------------------------------------------- */

/**
 * Implements hook_permission().
 */
function nodequeue_permission() {
  return array(
    'administer nodequeue' => array(
      'title' => t('Administer nodequeue'),
      'description' => t('Administer the nodequeue module.'),
    ),
   'manipulate queues' => array(
      'title' => t('Manipulate queues'),
      'description' => t('Manipulate queues.'),
    ),
    'manipulate all queues' => array(
      'title' => t('Manipulate all queues'),
      'description' => t('Manipulate all queues.'),
    ),
  );
}

/**
 * Implements hook_init().
 *
 * Loads subsidiary includes for other modules.
 */
function nodequeue_init() {
  include_once DRUPAL_ROOT . '/' . drupal_get_path('module', 'nodequeue') . '/includes/nodequeue.actions.inc';
}

/**
 * Implements hook_menu().
 */
function nodequeue_menu() {
  $items = array();
  $admin_access = array('administer nodequeue');

  // administrative items
  $items['admin/structure/nodequeue'] = array(
    'title' => 'Nodequeues',
    'page callback' => 'nodequeue_view_queues',
    'access callback' => '_nodequeue_access_admin_or_manipulate',
    'description' => 'Create and maintain simple nodequeues.',
    'file' => 'includes/nodequeue.admin.inc',
    'type' => MENU_NORMAL_ITEM
  );
  $items['admin/structure/nodequeue/list'] = array(
    'title' => 'List',
    'page callback' => 'nodequeue_view_queues',
    'access callback' => '_nodequeue_access_admin_or_manipulate',
    'file' => 'includes/nodequeue.admin.inc',
    'weight' => -1,
    'type' => MENU_DEFAULT_LOCAL_TASK
  );
  $items['admin/structure/nodequeue/settings'] = array(
    'title' => 'Settings',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('nodequeue_admin_settings'),
    'access arguments' => $admin_access,
    'file' => 'includes/nodequeue.admin.inc',
    'type' => MENU_LOCAL_TASK
  );
  $items['nodequeue/autocomplete'] = array(
    'title' => 'Autocomplete',
    'page callback' => 'nodequeue_autocomplete',
    'access callback' => '_nodequeue_access_admin_or_manipulate',
    'file' => 'includes/nodequeue.admin.inc',
    'type' => MENU_CALLBACK
  );
  $info = nodequeue_api_info();
  foreach ($info as $key => $data) {
    $items['admin/structure/nodequeue/add/' . $key] = array(
      'title' => 'Add @type',
      'title arguments' => array('@type' => strtolower($data['title'])),
      'page callback' => 'drupal_get_form',
      'page arguments' => array('nodequeue_edit_queue_form', $key),
      'access arguments' => $admin_access,
      'file' => 'includes/nodequeue.admin.inc',
      'type' => MENU_LOCAL_ACTION
    );
  }
  $items['node/%node/nodequeue'] = array(
    'title' => '@tab',
    'title arguments' => array('@tab' => variable_get('nodequeue_tab_name', 'Nodequeue')),
    'page callback' => 'nodequeue_node_tab',
    'page arguments' => array(1),
    'access callback' => 'nodequeue_node_tab_access',
    'access arguments' => array(1),
    'file' => 'includes/nodequeue.admin.inc',
    'weight' => 5,
    'type' => MENU_LOCAL_TASK
  );

  // Administrative items for an individual queue.
  $items['admin/structure/nodequeue/%nodequeue'] = array(
    'page callback' => 'nodequeue_admin_view',
    'page arguments' => array(3),
    'access callback' => 'nodequeue_queue_access',
    'access arguments' => array(3),
    'file' => 'includes/nodequeue.admin.inc',
    'type' => MENU_CALLBACK
  );
  $items['admin/structure/nodequeue/%nodequeue/view'] = array(
    'title' => 'View',
    'page callback' => 'nodequeue_admin_view',
    'page arguments' => array(3),
    'access callback' => 'nodequeue_queue_access',
    'access arguments' => array(3),
    'file' => 'includes/nodequeue.admin.inc',
    'weight' => -10,
    'type' => MENU_DEFAULT_LOCAL_TASK
  );
  $items['admin/structure/nodequeue/%nodequeue/view/%subqueue'] = array(
    'title' => 'View',
    'page callback' => 'nodequeue_admin_view',
    'page arguments' => array(3, 5),
    'access callback' => 'nodequeue_queue_access',
    'access arguments' => array(3, 5),
    'file' => 'includes/nodequeue.admin.inc',
    'weight' => -10,
    'tab parent' => 'admin/structure/nodequeue/%',
    'type' => MENU_CALLBACK
  );
  // Actual administrative items.
  $items['admin/structure/nodequeue/%nodequeue/edit'] = array(
    'title' => 'Edit queue',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('nodequeue_edit_queue_form', 3),
    'access arguments' => $admin_access,
    'file' => 'includes/nodequeue.admin.inc',
    'type' => MENU_LOCAL_TASK
  );
  $items['admin/structure/nodequeue/%nodequeue/delete'] = array(
    'title' => 'Delete',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('nodequeue_admin_delete', 3),
    'access arguments' => $admin_access,
    'file' => 'includes/nodequeue.admin.inc',
    'weight' => 5,
    'type' => MENU_CALLBACK
  );
  $items['nodequeue/%nodequeue/add-node/%subqueue/%node'] = array(
    'page callback' => 'nodequeue_admin_add_node',
    'page arguments' => array(1, 3, 4),
    'access callback' => 'nodequeue_node_and_queue_access',
    'access arguments' => array(4, 1, 3),
    'file' => 'includes/nodequeue.admin.inc',
    'type' => MENU_CALLBACK
  );
  $items['nodequeue/%nodequeue/remove-node/%subqueue/%node'] = array(
    'page callback' => 'nodequeue_admin_remove_node',
    'page arguments' => array(1, 3, 4),
    'access callback' => 'nodequeue_node_and_queue_access',
    'access arguments' => array(4, 1, 3),
    'file' => 'includes/nodequeue.admin.inc',
    'type' => MENU_CALLBACK
  );
  $items["admin/structure/nodequeue/%nodequeue/clear/%subqueue"] = array(
    'title' => 'Clear',
    'page callback' => 'drupal_get_form',
    'page arguments' => array('nodequeue_clear_confirm', 3, 5),
    'access callback' => 'nodequeue_queue_access',
    'access arguments' => array(3, 5),
    'file' => 'includes/nodequeue.admin.inc',
    'type' => MENU_CALLBACK
  );

  return $items;
}

/**
 * Helper function for a _menu_translate() bug.
 */
function subqueue_to_arg() {
  return '';
}

/**
 * Implements hook_admin_paths().
 */
function nodequeue_admin_paths() {
  if (variable_get('node_admin_theme')) {
    $paths = array(
      'node/*/nodequeue' => TRUE,
    );
    return $paths;
  }
}

/**
 * Implements hook_node_delete.
 */
function nodequeue_node_delete($node) {
  // If a node is being deleted, ensure it's also removed from any queues.
  $result = db_query("SELECT qid, sqid FROM {nodequeue_nodes} WHERE nid =:nid", array(
    ':nid' => $node->nid,
  ));
  foreach ($result as $obj) {
    // If the queue is being tracked by translation set and the node is part
    // of a translation set, don't delete the queue record.
    // Instead, data will be updated in the 'translation_change' op, below.
    $queues = nodequeue_load_queues(array($obj->qid));
    $queue = array_shift($queues);
    if (!$queue->i18n || (isset($node->tnid) && empty($node->tnid))) {
      // This removes by nid, not position, because if we happen to have a
      // node in a queue twice, the 2nd position would be wrong.
      nodequeue_subqueue_remove_node($obj->sqid, $node->nid);
    }
  }
}

/**
 * Implements hook_node_view().
 */
function nodequeue_node_view($node, $view_mode) {
  $links = nodequeue_node_links($node);
  if (!empty($links)) {
    $node->content['links']['nodequeue'] = array(
      '#links' => $links,
      '#theme' => 'links__node__nodequeue',
    );
  }
}

/**
 * Implementats hook_forms().
 */
function nodequeue_forms($form_id) {
  $forms = array();
  if (strpos($form_id, 'nodequeue_arrange_subqueue_form_') === 0) {
    $forms[$form_id] = array(
      'callback' => 'nodequeue_arrange_subqueue_form',
    );
  }
  return $forms;
}

/**
 * Implements hook_theme().
 */
function nodequeue_theme() {
  return array(
    'nodequeue_arrange_subqueue_form_table' => array(
      'render element' => 'form',
    ),
    'nodequeue_subqueue_empty_text' => array(
      'variables' => array(),
    ),
    'nodequeue_subqueue_full_text' => array(
      'variables' => array(),
    ),
    'nodequeue_subqueue_count_text' => array(
      'variables' => array('count' => 0),
    ),
  );
}

/**
 * Implements hook_element_info().
 */
function nodequeue_element_info() {
  $type = array();

  $type['position'] = array(
    '#input'         => TRUE,
    '#delta'         => 10,
    '#default_value' => 0,
    '#process'       => array('process_position', 'ajax_process_form'),
  );

  return $type;
}

/**
 * Expand position elements into selects. Works like the weight element, except
 * only positive values are allowed.
 */
function process_position($element) {
  for ($n = 1; $n <= $element['#delta']; $n++) {
    $positions[$n] = $n;
  }

  $element['#options']      = $positions;
  $element['#options']['r'] = t('Remove');
  $element['#type']         = 'select';

  // add default properties for the select element
  $element += element_info('select');

  return $element;
}

/**
 * If no default value is set for position select boxes, use 1.
 */
function position_value(&$form) {
  if (isset($form['#default_value'])) {
    $form['#value'] = $form['#default_value'];
  }
  else {
    $form['#value'] = 1;
  }
}

/**
 * Implements hook_views_api().
 */
function nodequeue_views_api() {
  return array(
    'api' => 2,
    'path' => drupal_get_path('module', 'nodequeue') . '/includes/views',
  );
}

// --------------------------------------------------------------------------
// Nodequeue Apache Solr Search Integration

/**
 * Implements hook_form_FORM_ID_alter().
 */
function nodequeue_form_apachesolr_search_bias_form_alter(&$form, &$form_state, $form_id) {
  // Setup for the form building.
  $weights = drupal_map_assoc(array('21.0', '13.0', '8.0', '5.0', '3.0', '2.0', '1.0', '0.8', '0.5', '0.3', '0.2', '0.1'));
  $weights['0'] = t('Normal');
  $queues = nodequeue_load_subqueues_by_queue(array_keys(nodequeue_get_all_qids()));

  // Build the form.
  $form['biasing']['nodequeue_boost'] = array(
    '#type' => 'fieldset',
    '#title' => t('Nodequeue Biasing'),
    '#weight' => -5,
    '#collapsible' => TRUE,
    '#collapsed' => TRUE,
  );
  $form['biasing']['nodequeue_boost']['nodequeue_apachesolr_boost'] = array(
    '#type' => 'item',
    '#description' => t("Specify to bias the search result when a node is in a queue. Any value except <em>Normal</em> will increase the socre for the given queue in the search results"),
  );
  foreach ($queues as $sqid => $queue) {
    $boost = variable_get("nodequeue_apachesolr_boost_$sqid", 0);
    // Add in setting for each queue.
    $form['biasing']['nodequeue_boost']['nodequeue_apachesolr_boost']["nodequeue_apachesolr_boost_$sqid"] = array(
      '#type' => 'select',
      '#title' => t('Weight for %title nodequeue', array('%title' => $queue->title)),
      '#options' => $weights,
      '#default_value' => $boost,
    );
  }
}

/**
 * Implements hook_apachesolr_index_document_ENTITY_TYPE().
 */
function nodequeue_apachesolr_index_document_node($document, $node, $env_id) {
  if (empty($document)) {
    return;
  }

  $queues = nodequeue_load_queues(array_keys(nodequeue_get_all_qids()));
  $subqueues = nodequeue_get_subqueues_by_node($queues, $node);

  nodequeue_set_subqueue_positions($subqueues, $node->nid);
  if (is_array($subqueues)) {
    foreach ($subqueues as $sqid => $subqueue) {
      if (!empty($subqueue->position)) {
        $key = _nodequeue_solr_qid_key();
        $document->setMultiValue($key, $sqid);
      }
    }
  }
}

/**
 * Returns the apachesolr index key for group id.
 */
function _nodequeue_solr_qid_key() {
  $qid_key = array(
    'index_type' => 'sint',
    'multiple' => TRUE,
    'name' => "nodequeue",
  );

  return apachesolr_index_key($qid_key);
}

/**
 * Implements hook_apachesolr_query_alter().
 */
function nodequeue_apachesolr_query_alter(DrupalSolrQueryInterface $query) {
  $queues = nodequeue_load_subqueues_by_queue(array_keys(nodequeue_get_all_qids()));
  $added = FALSE;
  foreach ($queues as $sqid => $queue) {
    $boost = variable_get("nodequeue_apachesolr_boost_$sqid", 0);
    if (!empty($boost)) {
      $query->params['bq'][] = _nodequeue_solr_qid_key() . ":$sqid^$boost";
      if (!$added) {
        // Only want to add the facet.field once. no need to repeat it.
        $query->params['facet.field'][] = _nodequeue_solr_qid_key();
        $added = TRUE;
      }
    }
  }
}

// --------------------------------------------------------------------------
// Nodequeue manipulation API.

/**
 * @defgroup nodequeue_api
 * @{
 * Access to the internals of nodequeues are handled primarily through these
 * API functions. They allow easy loading of queues for manipulation.
 */

/**
 * The nodequeue queue class; the constructor makes it so we don't have to
 * always check to see if our variables are empty or not.
 */
class nodequeue_queue {
  var $name = '';
  var $title = '';
  var $size = 0;
  var $link = '';
  var $link_remove = '';
  var $roles = array();
  var $types = array();
  var $show_in_links = TRUE;
  var $show_in_tab = TRUE;
  var $show_in_ui = TRUE;
  var $reference = 0;
  var $i18n = 0;

  var $subqueue_title = '';
  var $reverse = 0;
  var $insert_at_front = 0;

  // runtime
  var $subqueues = array();
  var $subqueue = NULL;

  var $current = NULL;

  function nodequeue_queue($type) {
    $this->owner = $type;
  }
}

/**
 * Fetch a list of available queues for a given location. These queues
 * will be fully loaded and ready to go.
 */
function nodequeue_load_queues_by_type($type, $location = NULL, $account = NULL, $bypass_cache = FALSE) {
  $qids = nodequeue_get_qids($type, $account, $bypass_cache);
  if ($location) {
    nodequeue_filter_qids($qids, $location);
  }
  return nodequeue_load_queues(array_keys($qids), $bypass_cache);
}

/**
 * Filter a list of qids returned by nodequeue_get_qids to a location.
 *
 * @param $qids
 *   An array of $qids from @see nodequeue_get_qids()
 * @param $location
 *   One of:
 *   - 'links': Only check for queues that have node links.
 *   - 'tab': Only check for queues that appear on the node tab.
 *   - 'ui': Only check for queues that appear in the UI.
 */
function nodequeue_filter_qids(&$qids, $location) {
  $var = "show_in_$location";
  foreach ($qids as $qid => $info) {
    if (empty($info->$var)) {
      unset($qids[$qid]);
    }
  }
}

/**
 * Get an array of qids applicable to this node type.
 *
 * @param $type
 *   The node type.
 * @param $account
 *   The account to test against. Defaults to the currently logged in user.
 *
 * @return $qids
 *   An array in the format: @code { array($qid => array('qid' => $qid, 'show_in_tab' '
 *   => true/false, 'show_in_links' => true/false }
 *
 * @param $bypass_cache
 *  Boolean value indicating whether to bypass the cache or not.
 */
function nodequeue_get_qids($type, $account = NULL, $bypass_cache = FALSE) {
  if (!isset($account)) {
    global $user;
    $account = $user;
  }

  $cache = &drupal_static(__FUNCTION__, array());
  if ($bypass_cache || !isset($cache[$type])) {
    $roles_join = $roles_where = '';
    $roles = array();

    // superuser always has access.
    if (!user_access('manipulate all queues', $account)) {
      $roles_join = "INNER JOIN {nodequeue_roles} nr ON nr.qid = nq.qid ";
      $roles = array_keys((array) $account->roles) + array(DRUPAL_AUTHENTICATED_RID);

      $roles_where .= "AND nr.rid IN (:roles)";
    }

    $sql = 'SELECT nq.qid, nq.show_in_tab, nq.show_in_links, nq.show_in_ui, nq.i18n ' .
      'FROM {nodequeue_queue} nq ' .
      'INNER JOIN {nodequeue_types} nt ON nt.qid = nq.qid ' . $roles_join .
      "WHERE nt.type = :type " . $roles_where;
    $result = db_query($sql, array(':type' => $type, ':roles' => $roles));

    $qids = array();
    foreach ($result as $qid) {
      $qids[$qid->qid] = $qid;
    }
    $cache[$type] = $qids;
  }
  return $cache[$type];
}

/**
 * Get an array of qids using the pager query. This administrative list
 * does no permission checking, so should only be available to users who
 * have passed the 'administer queues' check.
 *
 * @param $page_size
 *   The page size to use. If this is 0 or NULL, all queues will be returned.
 *   Defaults to 0.
 * @param $pager_element
 *   In the rare event this should use another pager element, set this..
 * @param $bypass_cache
 *   Boolean value indicating whether to bypass the cache or not.
 *
 * @return $qids
 *   An array in the format: @code { array($qid => $qid) }
 */
function nodequeue_get_all_qids($page_size = 0, $pager_element = 0, $bypass_cache = FALSE) {
  $cache = &drupal_static(__FUNCTION__, array());
  if ($bypass_cache || empty($cache[$page_size])) {
    $query = db_select('nodequeue_queue', 'nq')
      ->fields('nq', array('qid'));

    if (!empty($page_size)) {
      $query->extend('PagerDefault')
        ->extend('TableSort')
        ->limit($page_size)
        ->element($pager_element);
    }

    $qids = $query->execute()->fetchAllKeyed(0, 0);

    $cache[$page_size] = $qids;
  }
  return $cache[$page_size];
}

/**
 * Load an array of $qids.
 *
 * This exists to provide a way of loading a bunch of queues with
 * the fewest queries. Loading 5 queues results in only 4 queries,
 * not 20. This also caches queues so that they don't get loaded
 * repeatedly.
 *
 * @param $qids
 *   An array of queue IDs to load.
 *
 * @param $bypass_cache
 *   Boolean value indicating whether to bypass the cache or not.
 */
function nodequeue_load_queues($qids = array(), $bypass_cache = FALSE) {
  $cache = &drupal_static(__FUNCTION__, array());
  $to_load = $loaded = array();

  foreach ($qids as $qid) {
    if ($bypass_cache || !isset($cache[$qid])) {
      $to_load[] = $qid;
    }
  }

  if (!empty($to_load)) {
    $result = db_query("SELECT q.*, (SELECT count(*) FROM {nodequeue_subqueue} s WHERE q.qid = s.qid) AS subqueues FROM {nodequeue_queue} q WHERE q.qid IN (:to_load)", array(':to_load' => $to_load));

    foreach ($result as $queue) {
      $loaded[$queue->qid] = $queue;
      // ensure valid defaults:
      $loaded[$queue->qid]->types = array();
      $loaded[$queue->qid]->roles = array();
      $loaded[$queue->qid]->count = 0;
    }

    $result = db_query("SELECT qid, rid FROM {nodequeue_roles} WHERE qid IN (:to_load)", array(':to_load' => $to_load));
    foreach ($result as $obj) {
      $loaded[$obj->qid]->roles[] = $obj->rid;
    }

    $result = db_query("SELECT qid, type FROM {nodequeue_types} WHERE qid IN (:to_load)", array(':to_load' => $to_load));
    foreach ($result as $obj) {
      $loaded[$obj->qid]->types[] = $obj->type;
    }

    $context = 'load_queues';
    drupal_alter('nodequeue', $loaded, $context);
  }

  if ($bypass_cache) {
    return $loaded;
  }
  else {
    if (!empty($loaded)) {
      $cache += $loaded;
    }
    $queues = array();
    foreach ($qids as $qid) {
      if (isset($cache[$qid])) {
        $queues[$qid] = $cache[$qid];
      }
    }
    return $queues;
  }
}

/**
 * Load a nodequeue.
 *
 * @param $qid
 *   The qid of the queue to load.
 */
function nodequeue_load($qid) {
  $queues = nodequeue_load_queues(array($qid));
  return !empty($queues) ? array_shift($queues) : array();
}

/**
 * This function exists so that %subqueue will work in hook_menu.
 */
function subqueue_load($sqid) {
  if (!$sqid) {
    return NULL;
  }
  $queues = nodequeue_load_subqueues(array($sqid));
  return !empty($queues) ? array_shift($queues) : array();
}

/**
 * Load a list of subqueues.
 *
 * This exists to provide a way of loading a bunch of queues with
 * the fewest queries. Loading 5 queues results in only 4 queries,
 * not 20. This also caches queues so that they don't get loaded
 * repeatedly.
 *
 * @param array $sqids
 *   An array of subqueue IDs to load.
 * @param bool $bypass_cache
 *   Boolean value indicating whether to bypass the cache or not.
 *
 * @return array
 *   An array of subqueues.
 */
function nodequeue_load_subqueues($sqids, $bypass_cache = FALSE) {
  $cache = &drupal_static(__FUNCTION__, array());
  $to_load = array();
  $subqueues = array();

  foreach ($sqids as $sqid) {
    if ($bypass_cache || !isset($cache[$sqid])) {
      $to_load[] = $sqid;
    }
  }

  if (!empty($to_load)) {
    $result = db_query("SELECT s.*, (SELECT count(*) FROM {nodequeue_nodes} n WHERE n.sqid = s.sqid) AS count FROM {nodequeue_subqueue} s WHERE s.sqid IN (:to_load)", array(':to_load' => $to_load));
    foreach ($result as $obj) {
      // Sometimes we want to get to subqueues by reference, sometimes by sqid.
      // sqid is always unique, but reference is sometimes more readily available.
      $cache[$obj->sqid] = $obj;
    }
  }

  foreach ($sqids as $sqid) {
    if (isset($cache[$sqid])) {
      $subqueues[$sqid] = $cache[$sqid];
    }
  }
  return $subqueues;
}

/**
 * Load a single subqueue.
 *
 * @param $sqid
 *   The subqueue ID to load.
 * @param $bypass_cache
 *   Boolean value indicating whether to bypass the cache or not.
 */
function nodequeue_load_subqueue($sqid, $bypass_cache = FALSE) {
  $subqueues = nodequeue_load_subqueues(array($sqid), $bypass_cache);
  if ($subqueues) {
    return array_shift($subqueues);
  }

}

/**
 * Load the entire set of subqueues for a queue.
 *
 * This will load the entire set of subqueues for a given queue (and can
 * respect the pager, if desired). It does NOT cache the subqueues like
 * nodequeue_load_subqueues does, so beware of this mixed caching.
 *
 * @param $qids
 *   A $qid or array of $qids
 * @param $page_size
 *   If non-zero, use the pager_query and limit the page-size to the parameter.
 */
function nodequeue_load_subqueues_by_queue($qids, $page_size = 0) {
  if (is_numeric($qids)) {
    $qids = array($qids);
  }

  if (empty($qids)) {
    return array();
  }

  $query = "SELECT s.*, (SELECT count(*) FROM {nodequeue_nodes} n WHERE n.sqid = s.sqid) AS count FROM {nodequeue_subqueue} s WHERE s.qid IN (:qids)";
  $result = db_query($query, array(':qids' => $qids));

  $subqueues = array();

  foreach ($result as $subqueue) {
    $subqueues[$subqueue->sqid] = $subqueue;
  }

  return $subqueues;
}

/**
 * Load a set of subqueues by reference.
 *
 * This can be used to load a set of subqueues by reference; it will primarily
 * be used by plugins that are managing subqueues.
 *
 * @param $references
 *   A keyed array of references to load. The key is the $qid and each value
 *   is another array of references.
 */
function nodequeue_load_subqueues_by_reference($references, $bypass_cache = FALSE) {
  $cache = &drupal_static(__FUNCTION__, array());
  $subqueues = array();
  if ($bypass_cache) {
    $cache = array();
  }

  if (!empty($references)) {
    $query = db_select('nodequeue_subqueue', 's')
      ->groupBy('s.sqid')
      ->fields('s');
    $query->leftJoin('nodequeue_nodes', 'n', 'n.sqid = s.sqid');
    $query->addExpression('COUNT(n.position)', 'count');

    $where = db_or();
    foreach ($references as $qid => $reference) {
      $where->condition(db_and()->condition('s.qid', $qid)->condition('s.reference', $reference));
    }
    $query->condition($where);
    $result = $query->execute();

    foreach ($result as $subqueue) {
      $cache[$subqueue->qid][$subqueue->reference] = $subqueues[$subqueue->sqid] = $subqueue;
    }
  }

  return $subqueues;
}

/**
 * Return a queue by its machine name. This is obviously not ideal due to the
 * extra queries, but probably preferable to changing current API calls.
 *
 * @param $name
 *   The queue machine name
 *
 * @return
 *   The queue definition, or an empty array if no queue was found with the
 *   given machine name.
 */
function nodequeue_load_queue_by_name($name) {
  $map = nodequeue_get_qid_map();
  if (isset($map[$name])) {
    $queues = nodequeue_load_queues(array($map[$name]));
    if ($queues) {
      return current($queues);
    }
  }

  return array();
}

/**
 * Return a map of queue name to qid values to aid in various lookups.
 *
 * @return array
 *   A array of qids, keyed by machine name.
 */
function nodequeue_get_qid_map() {
  $map = &drupal_static(__FUNCTION__, array());
  if (!$map) {
    $result = db_query("SELECT qid, name FROM {nodequeue_queue}");
    while ($get = $result->fetchObject()) {
      $map[$get->name] = $get->qid;
    }
  }
  return $map;
}

/**
 * Save a nodequeue. This does not save subqueues; those must be added separately.
 */
function nodequeue_save(&$queue) {
  $nodequeue_queue_fields = array(
    'name' => $queue->name,
    'title' => $queue->title,
    'subqueue_title' => $queue->subqueue_title,
    'size' => $queue->size,
    'link' => $queue->link,
    'link_remove' => $queue->link_remove,
    'owner' => $queue->owner,
    'show_in_links' => ($queue->show_in_links) ? 1 : 0,
    'show_in_tab' => $queue->show_in_tab,
    'show_in_ui' => $queue->show_in_ui,
    'i18n' => $queue->i18n,
    'reverse' => $queue->reverse,
    'insert_at_front' => $queue->insert_at_front,
    'reference' => $queue->reference,
  );

  if (!isset($queue->qid)) {
    $queue->qid = db_insert('nodequeue_queue')
      ->fields($nodequeue_queue_fields)
      ->execute();

    if (module_exists('views')) {
      views_invalidate_cache();
    }
  }
  else {
    db_update('nodequeue_queue')
      ->fields($nodequeue_queue_fields)
      ->condition('qid', $queue->qid)
      ->execute();

    db_delete('nodequeue_roles')
      ->condition('qid', $queue->qid)
      ->execute();

    db_delete('nodequeue_types')
      ->condition('qid', $queue->qid)
      ->execute();
  }

  if (is_array($queue->roles)) {
    foreach ($queue->roles as $rid) {
      db_insert('nodequeue_roles')
        ->fields(array(
          'qid' => $queue->qid,
          'rid' => $rid,
        ))
        ->execute();
    }
  }

  if (is_array($queue->types)) {
    foreach ($queue->types as $type) {
      db_insert('nodequeue_types')
        ->fields(array(
          'qid' => $queue->qid,
          'type' => $type,
        ))
        ->execute();
    }
  }

  // set our global that tells us whether or not we need to activate hook_link
  if (db_query("SELECT COUNT(*) FROM {nodequeue_queue} WHERE link <> ''")->fetchField()) {
    variable_set('nodequeue_links', TRUE);
  }
  else {
    variable_set('nodequeue_links', FALSE);
  }

  if (isset($queue->add_subqueue) && is_array($queue->add_subqueue)) {
    foreach ($queue->add_subqueue as $reference => $title) {
      // If reference is unset it should be set to the qid; this is generally
      // used for a single subqueue; setting the reference to the qid makes
      // it easy to find that one subqueue.
      if ($reference == 0) {
        $reference = $queue->qid;
      }
      nodequeue_add_subqueue($queue, $title, $reference);
    }
  }
  return $queue->qid;
}

/**
 * Delete a nodequeue.
 */
function nodequeue_delete($qid) {
  db_delete('nodequeue_roles')
    ->condition('qid', $qid)
    ->execute();

  db_delete('nodequeue_types')
    ->condition('qid', $qid)
    ->execute();

  db_delete('nodequeue_queue')
    ->condition('qid', $qid)
    ->execute();

  db_delete('nodequeue_nodes')
    ->condition('qid', $qid)
    ->execute();

  db_delete('nodequeue_subqueue')
    ->condition('qid', $qid)
    ->execute();

  // Invoke a hook to notify other modules that a nodequeue has been deleted.
  module_invoke_all('nodequeue_delete', $qid);
}

/**
 * Add a new subqueue to a queue.
 *
 * @param $queue
 *   The queue object that is the parent of this subqueue.
 * @param $title
 *   The title of the subqueue.
 * @param $reference
 *   A reference that uniquely identifies this subqueue. If NULL it will
 *   be assigned the sqid.
 */
function nodequeue_add_subqueue(&$queue, $title, $reference = NULL) {
  if (empty($reference)) {
    $insert_reference = "";
  }
  else {
    $insert_reference = $reference;
  }

  $subqueue = new stdClass();
  $subqueue->reference = $reference;
  $subqueue->qid = $queue->qid;
  $subqueue->title = $title;


  $subqueue->sqid = db_insert('nodequeue_subqueue')
    ->fields(array(
      'qid' => $queue->qid,
      'reference' => $insert_reference,
      'title' => $title,
    ))
    ->execute();

  // If somehow the $reference is null, here we set it to the sqid.
  // We have to do it here, because before the insert we don't know what the sqid will be.
  if (empty($reference)) {
    db_update('nodequeue_subqueue')
      ->fields(array('reference' => $subqueue->sqid))
      ->condition('sqid', $subqueue->sqid)
      ->execute();
  }

  return $subqueue;
}

/**
 * Change the title of a subqueue.
 *
 * Note that only the title of a subqueue is changeable; it can change to
 * reflect updates in taxonomy term names, for example.
 */
function nodequeue_subqueue_update_title($sqid, $title) {
  db_update('nodequeue_subqueue')
    ->fields(array('title' => $title))
    ->condition('sqid', $sqid)
    ->execute();
}

/**
 * Remove a subqueue.
 */
function nodequeue_remove_subqueue($sqid) {
  nodequeue_queue_clear($sqid);
  db_delete('nodequeue_subqueue')
    ->condition('sqid', $sqid)
    ->execute();
}

// --------------------------------------------------------------------------
// Queue position control

/**
 * Add a node to a queue.
 *
 * @param $queue_name
 *   A machine-readable name of the queue.
 * @param $nid
 *   The node ID. Defaults to NULL.
 */
function nodequeue_queue_add($queue_name, $nid = NULL) {
  if (!empty($nid)) {
    $queue = nodequeue_load_queue_by_name($queue_name);
    $subqueues = nodequeue_load_subqueues_by_queue($queue->qid);
    foreach ($subqueues as $subqueue) {
      nodequeue_subqueue_add($queue, $subqueue, $nid);
    }
  }
}

/**
 * Add a node to a subqueue.
 *
 * @param $queue
 *   The parent queue of the subqueue. This is required so that we can
 *   pop nodes out if the queue breaks size limits.
 * @param $subqueue
 *   The subqueue to add the node to.
 * @param $nid
 *   The node ID. Defaults to NULL.
 */
function nodequeue_subqueue_add($queue, &$subqueue, $nid = NULL) {
  if (!empty($nid)) {
    $transaction = db_transaction();
    try {
      if ($queue->insert_at_front) {
        db_update('nodequeue_nodes')
          ->expression('position', 'position + 1')
          ->condition('sqid', $subqueue->sqid)
          ->execute();
        $position = 1;
      }
      else {
        $position = db_query("SELECT COALESCE((SELECT MAX(position) + 1 FROM {nodequeue_nodes} WHERE sqid = :sqid), 1)", array(':sqid' => $subqueue->sqid))->fetchField();
      }
      db_insert('nodequeue_nodes')
        ->fields(array(
            'sqid' => $subqueue->sqid,
            'qid' => $queue->qid,
            'nid' => $nid,
            'position' => $position,
            'timestamp' => REQUEST_TIME,
          ))
        ->execute();
    }
    catch (Exception $e) {
      $transaction->rollback();
      watchdog_exception('nodequeue', $e);
      throw $e;
    }

    $subqueue->count = db_query("SELECT COUNT(nid) FROM {nodequeue_nodes} WHERE sqid = :sqid", array(':sqid' => $subqueue->sqid))->fetchField();
    // If adding this would make the queue too big, pop the front node
    // (or nodes) out.
    if (!empty($queue->size)) {
      // 0 means infinity so never do this if FALSE.
      nodequeue_check_subqueue_size($queue, $subqueue, $queue->size);
    }
    if (module_exists('apachesolr')) {
      apachesolr_mark_entity('node', $nid);
    }
    // Invoke the hook to notify other modules of the node addition.
    module_invoke_all('nodequeue_add', $subqueue->sqid, $nid);
  }
}

/**
 * Remove a node from the queue. If a node is in the queue more than once,
 * only the first (closest to 0 position, or the front of the queue) will
 * be removed.
 *
 * @param $sqid
 *   The subqueue to remove nodes from.
 * @param $nid
 *   The node to remove.
 */
function nodequeue_subqueue_remove_node($sqid, $nid) {
  if ($pos = nodequeue_get_subqueue_position($sqid, $nid)) {
    nodequeue_subqueue_remove($sqid, $pos);
    if (module_exists('apachesolr')) {
      apachesolr_mark_entity('node', $nid);
    }
  }
}

/**
 * Remove a node or node(s) from a nodequeue by position.
 *
 * If you know the nid but but not the position, use
 * @see nodequeue_subqueue_remove_node() instead.
 *
 * @param $sqid
 *   The subqueue to remove nodes from.
 * @param $start
 *   The first position (starting from 1) to remove.
 * @param $end
 *   The last position to remove. If NULL or equal to $start,
 *   only one node will be removed. Thus if $start is 1 and $end is 2,
 *   the first and second items will be removed from the queue.
 *
 */
function nodequeue_subqueue_remove($sqid, $start, $end = NULL) {
  if (!isset($end)) {
    $end = $start;
  }

  // Retrieve the nodes that are being removed.
  $result = db_query("SELECT nid FROM {nodequeue_nodes} WHERE sqid = :sqid AND position >= :start AND position <= :end",
    array(
      ':sqid' => $sqid,
      ':start' => $start,
      ':end' => $end,
    )
  );

  $diff = $end - $start + 1;
  db_delete('nodequeue_nodes')
    ->condition('sqid', $sqid)
    ->condition('position', $start, '>=')
    ->condition('position', $end, '<=')
    ->execute();

  db_update('nodequeue_nodes')
    ->expression('position', 'position - ' . $diff)
    ->condition('sqid', $sqid)
    ->condition('position', $end, '>')
    ->execute();

  // Invoke the hook to let other modules know that the nodes were removed.
  foreach ($result as $node) {
    module_invoke_all('nodequeue_remove', $sqid, $node->nid);
  }
}

/**
 * Empty a subqueue.
 *
 * @param $sqid
 *   The sqid to empty.
 */
function nodequeue_queue_clear($sqid) {
  db_delete('nodequeue_nodes')
    ->condition('sqid', $sqid)
    ->execute();
}

/**
 * Guarantee that a subqueue has not gotten too big. It's important to call
 * this after an operation that might have reduced a queue's maximum size.
 * It stores the count to save a query if this is to be followed by an add
 * operation.
 *
 * @param $queue
 *   The queue object.
 * @param $reference
 *   The subqueue to check.
 *
 */
function nodequeue_check_subqueue_size($queue, &$subqueue, $size = NULL) {
  if (!isset($size)) {
    $size = $queue->size;
  }

  if ($queue->size && $subqueue->count > $size) {
    if ($queue->insert_at_front) {
      nodequeue_subqueue_remove($subqueue->sqid, $size + 1, $subqueue->count);
    }
    else {
      nodequeue_subqueue_remove($subqueue->sqid, 1, $subqueue->count - $size);
    }
    $subqueue->count = $size;
  }
}

/**
 * Guarantee that all subqueues are within the size constraints set
 * by $queue->size.
 */
function nodequeue_check_subqueue_sizes($queue) {
  // Don't check if size is 0, as that means infinite size.
  if (!$queue->size) {
    return;
  }

  $subqueues = nodequeue_load_subqueues_by_queue($queue->qid);
  foreach ($subqueues as $subqueue) {
    nodequeue_check_subqueue_size($queue, $subqueue);
  }
}

/**
 * Swap two positions within a subqueue.
 */
function nodequeue_queue_swap($subqueue, $pos1, $pos2) {
  // Grab the nid off one of the positions so we can more easily swap.
  $nid = db_query("SELECT nid FROM {nodequeue_nodes} WHERE sqid = :sqid AND position = :position",
    array(':sqid' => $subqueue->sqid, ':position' => $pos1))
    ->fetchField();

  if (!$nid) {
    return;
  }

  db_update('nodequeue_nodes')
    ->fields(array('position' => $pos1))
    ->condition('position', $pos2)
    ->condition('sqid', $subqueue->sqid)
    ->execute();

  db_update('nodequeue_nodes')
    ->fields(array('position' => $pos2))
    ->condition('nid', $nid)
    ->condition('sqid', $subqueue->sqid)
    ->execute();

  // notify other modules of the swap
  module_invoke_all('nodequeue_swap', $subqueue->sqid, $nid);

}

/**
 * Move a position within a subqueue up by one.
 */
function nodequeue_queue_up($subqueue, $position) {
  if ($position < 2 || $position > $subqueue->count) {
    return;
  }
  nodequeue_queue_swap($subqueue, $position - 1, $position);
}

/**
 * Move a position within a subqueue down by one.
 */
function nodequeue_queue_down($subqueue, $position) {
  if ($position < 1 || $position >= $subqueue->count) {
    return;
  }
  nodequeue_queue_swap($subqueue, $position + 1, $position);
}

/**
 * Move an item to the front of the queue.
 */
function nodequeue_queue_front($subqueue, $position) {
  if ($position < 2 || $position > $subqueue->count) {
    return;
  }
  $result = db_query("SELECT * FROM {nodequeue_nodes} WHERE sqid= :sqid AND position = :position", array(
    ':sqid' => $subqueue->sqid,
    ':position' => $position,
  ));
  $entry = $result->fetchObject();

  db_delete('nodequeue_nodes')
    ->condition('sqid', $subqueue->sqid)
    ->condition('position', $position)
    ->execute();

  db_update('nodequeue_nodes')
    ->expression('position', 'position + 1')
    ->condition('sqid', $subqueue->sqid)
    ->condition('position', $position, '<')
    ->execute();

  db_insert('nodequeue_nodes')
    ->fields(array(
      'qid' => $entry->qid,
      'sqid' => $subqueue->sqid,
      'nid' => $entry->nid,
      'position' => 1,
      'timestamp' => $entry->timestamp,
    ))
    ->execute();
}

/**
 * Move an item to the back of the queue.
 */
function nodequeue_queue_back($subqueue, $position) {
  if ($position < 1 || $position >= $subqueue->count) {
    return;
  }

  $result = db_query("SELECT * FROM {nodequeue_nodes} WHERE sqid= :sqid AND position = :position", array(
    ':sqid' => $subqueue->sqid,
    ':position' => $position,
  ));
  $entry = $result->fetchObject();

  db_delete('nodequeue_nodes')
    ->condition('sqid', $subqueue->sqid)
    ->condition('position', $position)
    ->execute();

  db_update('nodequeue_nodes')
    ->expression('position', 'position - 1')
    ->condition('sqid', $subqueue->sqid)
    ->condition('position', $position, '<')
    ->execute();

  db_insert('nodequeue_nodes')
    ->fields(array(
      'qid' => $entry->qid,
      'sqid' => $subqueue->sqid,
      'nid' => $entry->nid,
      'position' => $subqueue->count,
      'timestamp' => $entry->timestamp,
    ))
    ->execute();
}

/**
 * Get the position of a node in a subqueue, or 0 if not found.
 */
function nodequeue_get_subqueue_position($sqid, $nid) {
  // We use MIN to make sure we always get the closes to the front of the
  // queue in case the queue has nodes in it multiple times.
  $pos = db_query("SELECT MIN(position) FROM {nodequeue_nodes} WHERE sqid = :sqid AND nid = :nid", array(':sqid' => $sqid, ':nid' => $nid))->fetchField();
  return $pos;
}

/**
 * Get the position of a node in several subqueues.
 */
function nodequeue_set_subqueue_positions(&$subqueues, $nid) {
  if (empty($subqueues)) {
    return;
  }

  $query = db_select('nodequeue_nodes', 'n')
    ->fields('n', array('sqid'))
    ->condition('sqid', array_keys($subqueues), 'IN')
    ->condition('nid', $nid)
    ->groupBy('sqid');
  $query->addExpression('MIN(position)', 'position');
  $result = $query->execute();

  foreach ($result as $obj) {
    $subqueues[$obj->sqid]->position = $obj->position;
  }
}

/**
 * Get a list of valid subqueues for a node, along with the position of the node.
 *
 * @param $queues
 *   An array of fully loaded queue objects.
 * @param $node
 *   A fully loaded node object.
 *
 */
function nodequeue_get_subqueues_by_node($queues, $node) {
  // Determine which subqueues are valid for each queue.
  $references = array();
  $last_nid = &drupal_static(__FUNCTION__, 0);
  foreach ($queues as $queue) {
    if ($result = nodequeue_api_subqueues($queue, $node)) {
      $references[$queue->qid] = is_array($result) ? $result : array($result);
    }
  }

  if (empty($references)) {
    return array();
  }
  // only allow the static cache to be used if the nid is the same as the last
  $subqueues = nodequeue_load_subqueues_by_reference($references, ($last_nid != $node->nid));
  $last_nid = $node->nid;

  return $subqueues;
}

/**
 * Get a textual representation of a nodequeue's queue size.
 */
function nodequeue_subqueue_size_text($max, $count, $long = TRUE) {
  if (empty($count)) {
    $message = theme('nodequeue_subqueue_empty_text');
  }
  elseif ($count == $max) {
    $message = theme('nodequeue_subqueue_full_text');
  }
  else {
    if ($long) {
      $message = theme('nodequeue_subqueue_count_text', array('count' => $count));
    }
    else {
      $message = $count;
    }
  }
  return $message;
}

/**
 * Substitute the subqueue title into some other string.
 *
 * This function does NOT check_plain the title! The output MUST be checked
 * after this is complete.
 */
function nodequeue_title_substitute($text, $queue, $subqueue) {
  if (empty($text)) {
    return $subqueue->title;
  }
  $text = str_replace('%subqueue', $subqueue->title, $text);
  return $text;
}

/**
 * Shuffle a queue.
 *
 * @param $subqueue
 *   The subqueue to shuffle. May be a sqid or the loaded object.
 */
function nodequeue_subqueue_shuffle($subqueue) {
  // Load the queue
  if (!is_object($subqueue)) {
    $subqueue = nodequeue_load_subqueue($subqueue);
  }

  if (empty($subqueue)) {
    return;
  }

  $count = $subqueue->count;
  // Swap each item with another randomly picked one.
  foreach (range(1, $count) as $i) {
    nodequeue_queue_swap($subqueue, $i, rand(1, $count));
  }
}

/**
 * @} End of defgroup "nodequeue_api"
 */

// --------------------------------------------------------------------------
// Hooks to implement the default nodequeue type.

/**
 * Implements hook_nodequeue_info().
 */
function nodequeue_nodequeue_info() {
  return array('nodequeue' => array(
    'title' => t('Simple queue'),
    'description' => t('Simple queues have just one subqueue. Nodes put into a queue are added to the back of the queue; when a node is added to a full queue, the node in the front of the queue will be popped out to make room.'),
    ));
}

/**
 * Implements hook_nodequeue_form_submit().
 */
function nodequeue_nodequeue_form_submit(&$queue, $form_state) {
  // This will add a single subqueue to our new queue.
  if (!isset($queue->qid) && !isset($queue->add_subqueue)) {
    // A 0 will set the reference to the sqid of the queue.
    $queue->add_subqueue = array(0 => $queue->title);
  }
  //If the qid is set at this point, we're saving an existing queue.
  if (isset($queue->qid)) {
    //We don't check to see if the title has been updated since the $queue object already matches $form_state['values'].
    db_update('nodequeue_subqueue')
      ->fields(array('title' => $form_state['values']['title']))
      ->condition('qid', $queue->qid)
      ->execute();
  }
}

// --------------------------------------------------------------------------
// External queue fetching

/**
 * In general it's preferable to use Views for this functionality.
 */
function nodequeue_node_titles($sqid, $title = '', $backward = TRUE, $from = 0, $count = 0, $published_only = TRUE) {
  $orderby = ($backward ? "DESC" : "ASC");
  $query = db_select('node', 'n')
    ->fields('n', array('nid', 'title'))
    ->condition('nn.sqid', $sqid)
    ->orderBy('nn.position', $orderby)
    ->addTag('node_access');
  $query->leftJoin('nodequeue_nodes', 'nn', 'n.nid = nn.nid');

  if ($published_only) {
    $query->condition('n.status', 1);
  }

  if ($count) {
    $result = $query->range($from, $count)->execute();
  }
  else {
    $result = $query->execute();
  }
  return node_title_list($result, $title);
}

/**
 * Returns an array of nodequeue links for a node.
 */
function nodequeue_node_links($node) {
  $links = array();
  if (variable_get('nodequeue_links', FALSE) &&
      user_access('manipulate queues')) {
    $queues = nodequeue_load_queues_by_type($node->type, 'links');
    $subqueues = nodequeue_get_subqueues_by_node($queues, $node);
    if (empty($subqueues)) {
      return;
    }

    // resort the subqueues to retain consistent ordering:

    ksort($subqueues);
    // Due to caching, we can accidentally get positions leftover
    // from previous iterations on teaser list pages, so we must
    // remove any existing positions here.
    foreach ($subqueues as $id => $subqueue) {
      unset($subqueues[$id]->position);
    }

    if (!module_exists('translation')) {
      nodequeue_set_subqueue_positions($subqueues, $node->nid);
    }

    foreach ($subqueues as $subqueue) {
      $queue = $queues[$subqueue->qid];
      $id = nodequeue_get_content_id($queue, $node);
      if (module_exists('translation')) {
        $subqueue = array($subqueue->sqid => $subqueue);
        nodequeue_set_subqueue_positions($subqueue, $id);
        $subqueue = array_shift($subqueue);
      }
      $query_string = nodequeue_get_query_string($id, TRUE);
      $class = 'nodequeue-ajax-toggle nodequeue-toggle-q-' . $queue->qid . ' nodequeue-toggle-sq-' . $subqueue->sqid . ' nodequeue-toggle-ref-' . $subqueue->reference;
      if (!isset($subqueue->position)) {
        $links[$class] = array(
          'title' => nodequeue_title_substitute($queue->link, $queue, $subqueue),
          'href' => "nodequeue/$queue->qid/add-node/$subqueue->sqid/$id",
          'attributes' => array('class' => array($class . ' toggle-add')),
          'query' => $query_string,
          'purl' => array('disabled' => TRUE),
        );
      }
      elseif ($queue->link_remove) {
        $links[$class] = array(
          'title' => nodequeue_title_substitute($queue->link_remove, $queue, $subqueue),
          'href' => "nodequeue/$queue->qid/remove-node/$subqueue->sqid/$id",
          'attributes' => array('class' => array($class . ' toggle-remove')),
          'query' => $query_string,
          'purl' => array('disabled' => TRUE),
        );
      }
    }
    drupal_add_js(drupal_get_path('module', 'nodequeue') . '/nodequeue.js');
    drupal_add_css(drupal_get_path('module', 'nodequeue') . '/nodequeue.css');
  }
  return $links;
}

/**
 * Get node_view output from a nodequeue.
 *
 * @param integer $sqid
 *   Subqueue ID
 * @param boolean $backward
 *   If TRUE (default), display the node with the highest queue position first.
 * @param $view_mode
 *   View mode, e.g. 'full', 'teaser'... For backward compatibility, non-string
 *   arguments will be converted to boolean, TRUE implies 'teaser' and FALSE
 *   implies 'full'.
 * @param boolean $links
 *   Deprecated.
 * @param integer $from
 *   Display offset from highest (if $backward is FALSE, lowest) queue position.
 * @param integer $count
 *   Maximum number of nodes to display.
 *
 * @return array
 *   An array as expected by drupal_render().
 */
function nodequeue_view_nodes($sqid, $backward = TRUE, $view_mode = 'teaser', $links = TRUE, $from = 0, $count = 0) {
  // This is for backward compatibility with 'D6 style' argument, which used
  // to be $teaser = TRUE (and previously wasn't converted as necessary in D7
  // version):
  if (!is_string($view_mode)) {
    $view_mode = $view_mode ? 'teaser' : 'full';
   }

  $nodes = nodequeue_load_nodes($sqid, $backward, $from, $count);
  $output = node_view_multiple($nodes, $view_mode);

  // Keep backward compatibility with the previous version of this function, which
  // returned an array of individually built nodes.
  // @todo reevaluate this.
  unset($output['nodes']['#sorted']);
  return array_values($output['nodes']);
}

/**
 * Load an array of node objects belonging to a particular nodequeue.
 *
 * @param integer $sqid
 *   Subqueue ID
 * @param boolean $backward
 *   If TRUE (default), display the node with the highest queue position first.
 * @param integer $from
 *   Display offset from highest (if $backward is FALSE, lowest) queue position.
 * @param integer $count
 *   Maximum number of nodes to display.
 * @param bool $published_only
 *   If TRUE (default), only load published nodes.
 *
 * @return array
 *   An array of node objects (indexed sequentially, not by nid).
 */
function nodequeue_load_nodes($sqid, $backward = FALSE, $from = 0, $count = 5, $published_only = TRUE) {
  $orderby = ($backward ? "DESC" : "ASC");
  $query = db_select('node', 'n')
    ->fields('n', array('nid'))
    ->condition('nn.sqid', $sqid)
    ->orderBy('nn.position', $orderby)
    ->addTag('node_access');
  $query->join('nodequeue_nodes', 'nn', 'n.nid = nn.nid');

  if ($published_only) {
    $query->condition('n.status', 1);
  }

  if ($count) {
    $result = $query->range($from, $count)->execute()->fetchCol();
  }
  else {
    $result = $query->execute()->fetchCol();
  }

  // Return numerically indexed array for backward compatibility.
  // @todo reevaluate this.
  return array_values(node_load_multiple($result));
}

/**
 * Load the first node of a queue.
 */
function nodequeue_load_front($sqid) {
  $nodequeue_nodes = nodequeue_load_nodes($sqid, FALSE, 0, 1);
  return array_shift($nodequeue_nodes);
}

/**
 * Load the last node of a queue.
 */
function nodequeue_load_back($sqid, $teaser = TRUE, $links = TRUE) {
  $nodequeue_nodes = nodequeue_load_nodes($sqid, TRUE, 0, 1);
  return array_shift($nodequeue_nodes);
}

/**
 * View a random node from a queue.
 */
function nodequeue_view_random_node($sqid, $teaser = TRUE, $links = TRUE) {
  $query = db_select('node', 'n')
    ->fields('n', array('nid'));
  $query->join('nodequeue_nodes', 'nn', 'n.nid = nn.nid');
  $count = $query->addTag('node_access')
     ->condition('nn.sqid', $sqid)
     ->condition('n.status', 1)
     ->countQuery()
     ->execute()
     ->fetchField();

  return nodequeue_view_nodes($sqid, FALSE, $teaser, $links, rand(0, $count - 1), 1);
}

/**
 * Load a random node object from a queue.
 */
function nodequeue_load_random_node($sqid) {
  $query = db_select('node', 'n')
    ->fields('n', array('nid'));
  $query->join('nodequeue_nodes', 'nn', 'n.nid = nn.nid');
  $count = $query->addTag('node_access')
     ->condition('nn.sqid', $sqid)
     ->condition('n.status', 1)
     ->countQuery()
     ->execute()
     ->fetchField();

  $nodequeue_nodes = nodequeue_load_nodes($sqid, TRUE, rand(0, $count - 1), 1);
  return array_shift($nodequeue_nodes);
}

/**
 * Get the position of a node in a subqueue, or FALSE if not found.
 */
function nodequeue_subqueue_position($sqid, $nid) {
  return db_query("SELECT position FROM {nodequeue_nodes} WHERE sqid = :sqid AND nid = :nid", array(':sqid' => $sqid, ':nid' => $nid))->fetchField();
}

/**
 * Get the position of a node in a queue; this queue MUST have only one
 * subqueue or the results of this function will be unpredictable.
 */
function nodequeue_queue_position($qid, $nid) {
  $sqid = db_select('nodequeue_subqueue', 'ns')
    ->fields('ns', array('sqid'))
    ->condition('qid', $qid)
    ->range(0, 1)
    ->execute()
    ->fetchField();

  return nodequeue_subqueue_position($sqid, $nid);
}

// --------------------------------------------------------------------------
// API for modules implementing subqueues.

/**
 * Send the nodequeue edit form to the owning module for modification.
 *
 * @param $queue
 *   The queue being edited.
 * @param &$form
 *   The form. This may be modified.
 */
function nodequeue_api_queue_form($queue, &$form) {
  $function = $queue->owner . "_nodequeue_form";
  if (function_exists($function)) {
    $function($queue, $form);
  }
}

/**
 * Validate the nodequeue edit form.
 *
 * @param $queue
 *   The queue being edited.
 * @param $form_state
 *   The form values that were submitted.
 * @param &$form
 *   The actual form object. This may be modified.
 */
function nodequeue_api_queue_form_validate($queue, &$form_state, &$form) {
  $function = $queue->owner . "_nodequeue_form_validate";
  if (function_exists($function)) {
    $function($queue, $form_state, $form);
  }
}

/**
 * Send the nodequeue edit form to the owning module upon submit.
 *
 * @param &$queue
 *   The queue being edited. This may be modified prior to being
 *   saved.
 * @param $form_state
 *   The form values that were submitted.
 */
function nodequeue_api_queue_form_submit(&$queue, &$form_state) {
  $function = $queue->owner . "_nodequeue_form_submit";
  if (function_exists($function)) {
    $function($queue, $form_state);
  }
}

/**
 * Send the nodequeue edit form to the owning module after the queue
 * has been saved.
 *
 * @param &$queue
 *   The queue being edited. This may be modified prior to being
 *   saved.
 * @param $form_state
 *   The form values that were submitted.
 */
function nodequeue_api_queue_form_submit_finish($queue, &$form_state) {
  $function = $queue->owner . "_nodequeue_form_submit_finish";
  if (function_exists($function)) {
    $function($queue, $form_state);
  }
}

/**
 * Fetch a list of subqueues that are valid for this node from
 * the owning module.
 *
 * @param $queue
 *   The queue being edited.
 * @param $node
 *   The loaded node object being checked.
 *
 * @return
 *   An array of subqueues. This will be keyed by $sqid.
 */
function nodequeue_api_subqueues(&$queue, $node) {
  $function = $queue->owner . "_nodequeue_subqueues";
  // This will return an array of references.
  if (function_exists($function)) {
    return $function($queue, $node);
  }
  else {
    return $queue->qid;
  }
}

/**
 * Fetch a list of nodes available to a given subqueue
 * for autocomplete.
 *
 * @param $queue
 *   The queue that owns the subqueue
 * @param $subqueue
 *   The subqueue
 * @param $string
 *   The string being matched.
 *
 * @return
 *   An keyed array $nid => $title
 */
function nodequeue_api_autocomplete($queue, $subqueue, $string) {
  $matches = array();
  if (empty($string)) {
    return $matches;
  }

  $query = db_select('node', 'n')
    ->addTag('node_access')
    ->fields('n', array('nid', 'tnid', 'title'))
    ->range(0, variable_get('nodequeue_autocomplete_limit', 10));

  if (!empty($queue->types)) {
    $query->condition('n.type', $queue->types, 'IN');
  }

  global $user;
  if (!user_access('administer nodes', $user)) {
    $query->condition(db_or()->condition('n.status', 1)->condition('n.uid', $user->uid));
  }

  // Run a match to see if they're specifying by nid.
  $preg_matches = array();
  $match = preg_match('/\[nid: (\d+)\]/', $string, $preg_matches);
  if (!$match) {
    $match = preg_match('/^nid: (\d+)/', $string, $preg_matches);
  }

  if ($match) {
    // If it found a nid via specification, reduce our resultset to just that nid.
    $query->condition('n.nid', $preg_matches[1]);
  }
  else {
    // Build the constant parts of the query.
    $query->where('LOWER(n.title) LIKE LOWER(:string)', array(':string' => '%' . db_like($string) . '%'));
  }

  // Call to the API.
  $function = $queue->owner . "_nodequeue_autocomplete";
  if (function_exists($function)) {
    return $function($queue, $subqueue, $string, $query);
  }
  else {
    $query->addTag('i18n_select');
    $result = $query->execute();

    foreach ($result as $node) {
      $id = nodequeue_get_content_id($queue, $node);
      $matches[$node->nid] = check_plain($node->title) . " [nid: $id]";
    }
  }

  return $matches;
}

/**
 * Collect info about all of the possible nodequeue types from owning
 * modules.
 */
function nodequeue_api_info() {
  return module_invoke_all('nodequeue_info');
}

function nodequeue_api_queue_access($queue, $account = NULL) {
  if (!$account) {
    global $user;
    $account = $user;
  }

  if ($queue->owner != 'nodequeue') { // Avoids an infinite loop.
    $function = $queue->owner . '_queue_access';
    if (function_exists($function)) {
      $access = $function($queue, $account);
    }
  }

  if (!isset($access)) {
    $access = TRUE;
  }
  return $access;
}

/**
 * Allows the owning module of a subqueue to restrict access to viewing and
 * manipulating the queue.
 */
function nodequeue_api_subqueue_access($subqueue, $account = NULL, $queue = NULL) {
  if (!$account) {
    global $user;
    $account = $user;
  }

  if (!$queue) {
    $queue = nodequeue_load($subqueue->qid);
  }

  $function = $queue->owner . '_subqueue_access';
  if (function_exists($function)) {
    $access = $function($subqueue, $account, $queue);
  }

  if (!isset($access)) {
    $access = TRUE;
  }

  return $access;
}

/**
 * Generate a query string to use on nodequeue's private links.
 *
 * @param $seed
 *   The seed to use when generating a token. If NULL no token will
 *   be generated.
 * @param $destination
 *   The destination to use. If FALSE one won't be used; if TRUE
 *   one will be generated from drupal_get_destination().
 * @param $query
 *   An array of additional items to add to the query.
 *
 * @return
 *   The query string suitable for use in the l() function.
 */
function nodequeue_get_query_string($seed, $destination = FALSE, $query = array()) {
  $dest = drupal_get_destination();
  foreach ($dest as $key => $value) {
    $query[$key] = $value;
  }

  if (isset($seed)) {
    $token = explode('=', nodequeue_get_token($seed));
    $query[$token[0]] = $token[1];
  }

  return $query;

  return implode('&', $query);
}

/**
 * Get a private token used to protect nodequeue's links from spoofing.
 */
function nodequeue_get_token($nid) {
  return 'token=' . drupal_get_token($nid);
}

/**
 * Check to see if the token generated from seed matches.
 */
function nodequeue_check_token($seed) {
  return drupal_get_token($seed) == $_GET['token'];
}

/* --- UTILITY -------------------------------------------------------------- */

/**
 * Helper function - since hook_menu now takes a function instead of a boolean,
 * this function is used to compute the user's access.
 *
 * @return boolean
 */
function _nodequeue_access_admin_or_manipulate() {
  return user_access('administer nodequeue') || user_access('manipulate queues') || user_access('manipulate all queues');
}

/**
 * Used by menu system to determine access to the node and the queue in question.
 *
 * No, this isn't some odd hook_access implementation.
 *
 * @param unknown_type $node
 * @param unknown_type $queue
 * @return unknown
 */
function nodequeue_node_and_queue_access($node, $queue, $subqueue = NULL) {
  return nodequeue_nodequeue_access($node->type) && nodequeue_queue_access($queue, $subqueue);
}

/**
 * Return TRUE if $user can queue(s) for this node.
 *
 * @param $type
 *   The node type.
 * @param $location
 *   Optional argument. May be one of:
 *   - 'links': Only check for queues that have node links.
 *   - 'tab': Only check for queues that appear on the node tab.
 *   - 'ui': Only check for queues that appear in the UI.
 */
function nodequeue_nodequeue_access($type, $location = NULL, $account = NULL) {
  if (isset($type->type)) {
    $type = $type->type;
  }
  $qids = nodequeue_get_qids($type, $account);
  if ($location) {
    nodequeue_filter_qids($qids, $location);
  }

  return !empty($qids);
}

/**
 * Return TRUE If the specified account has access to manipulate this queue.
 */
function nodequeue_queue_access($queue, $subqueue = NULL, $account = NULL) {
  if (!$account) {
    global $user;
    $account = $user;
  }

  // Automatically true if all queues.
  if (user_access('manipulate all queues', $account)) {
    return TRUE;
  }

  // Automatically false if they can't manipulate queues at all.
  if (!user_access('manipulate queues', $account) || empty($queue->roles)) {
    return FALSE;
  }

  if ($subqueue) {
    return nodequeue_api_subqueue_access($subqueue, $account);
  }

  if (!nodequeue_api_queue_access($queue, $account)) {
    return FALSE;
  }

  $roles = array_keys((array) $account->roles) + array(DRUPAL_AUTHENTICATED_RID);
  return (bool) array_intersect($roles, $queue->roles);
}

function nodequeue_node_tab_access($node) {
  if (!variable_get('nodequeue_use_tab', 1) || !user_access('manipulate queues')) {
    // For performance reasons: If the menu tab is disabled or the user can't
    // manipulate queues, there is no reason to run the rest of these queries.
    return FALSE;
  }
  $queues = nodequeue_load_queues_by_type($node->type, 'tab');
  $subqueues = nodequeue_get_subqueues_by_node($queues, $node);
  if (empty($subqueues)) {
    return FALSE;
  }
  foreach ($subqueues as $subqueue) {
    if (nodequeue_api_subqueue_access($subqueue)) {
      return TRUE;
    }
  }
  return FALSE;
}

/**
 * Print the JSON output for our AJAX calls.
 */
function nodequeue_js_output($label, $href, $count = NULL, $sqid = NULL) {
  $return = new stdClass();
  $return->status = 1;
  $return->label = check_plain($label);
  $return->href = $href;
  if (isset($count)) {
    $return->count = $count;
  }
  if (isset($sqid)) {
    $return->sqid = $sqid;
  }

  drupal_json_output($return);
  exit;
}

/**
 * Return content id based on i18n settings
 */
function nodequeue_get_content_id($queue, $node) {
  return ($queue->i18n && !empty($node->tnid)) ? $node->tnid : $node->nid;
}

/**
 * Determine if the machine name is in use.
 */
function nodequeue_machine_name_exists($machine_name) {
  $queue_exists = db_query_range('SELECT 1 FROM {nodequeue_queue} WHERE name = :name', 0, 1, array(':name' => $machine_name))->fetchField();

  return $queue_exists;
}

/* --- THEME ---------------------------------------------------------------- */

/**
 * Theme the subqueue overview as a sortable list.
 *
 * @ingroup themeable
 */
function theme_nodequeue_arrange_subqueue_form_table($variables) {
  $form = $variables['form'];

  $output = '';

  // Get css to hide some of the help text if javascript is disabled.
  drupal_add_css(drupal_get_path('module', 'nodequeue') . '/nodequeue.css');

  $table_id = 'nodequeue-dragdrop-' . $form['#subqueue']['sqid'];
  $table_classes = array(
    'nodequeue-dragdrop',
    'nodequeue-dragdrop-qid-' . $form['#subqueue']['qid'],
    'nodequeue-dragdrop-sqid-' . $form['#subqueue']['sqid'],
    'nodequeue-dragdrop-reference-' . $form['#subqueue']['reference'],
  );
  drupal_add_tabledrag($table_id, 'order', 'sibling', 'node-position');
  drupal_add_js(drupal_get_path('module', 'nodequeue') . '/nodequeue_dragdrop.js');

  $reverse[str_replace('-', '_', $table_id)] = (bool) $form['#queue']['reverse'];
  drupal_add_js(
    array(
      'nodequeue' => array(
        'reverse' => $reverse,
      )
    ),
    array(
      'type' => 'setting',
      'scope' => JS_DEFAULT,
    )
  );

  // Render form as table rows.
  $rows = array();
  $counter = 1;
  foreach (element_children($form) as $key) {
    if (isset($form[$key]['title'])) {
      $row = array();

      $row[] = drupal_render($form[$key]['title']);
      $row[] = drupal_render($form[$key]['author']);
      $row[] = drupal_render($form[$key]['date']);
      $row[] = drupal_render($form[$key]['position']);
      $row[] = (!empty($form[$key]['edit'])) ? drupal_render($form[$key]['edit']) : '&nbsp;';
      $row[] = drupal_render($form[$key]['remove']);
      $row[] = array(
        'data' => $counter,
        'class' => array('position')
      );

      $rows[] = array(
        'data'  => $row,
        'class' => array('draggable'),
      );
    }

    $counter++;
  }
  if (empty($rows)) {
    $rows[] = array(array('data' => t('No nodes in this queue.'), 'colspan' => 7));
  }

  // Render the main nodequeue table.
  $header = array(t('Title'), t('Author'), t('Post Date'), t('Position'), array('data' => t('Operations'), 'colspan' => 2), t('Position'));
  $output .= theme('table', array('header' => $header, 'rows' => $rows, 'attributes' => array('id' => $table_id, 'class' => $table_classes)));

  return $output;
}

/**
 * Return a "queue is empty" message.
 *
 * @ingroup themeable
 */
function theme_nodequeue_subqueue_empty_text() {
  return t('Queue empty');
}

/**
 * Return a "queue is full" message.
 *
 * @ingroup themeable
 */
function theme_nodequeue_subqueue_full_text() {
  return t('Queue full');
}

/**
 * Return a count of elements in the queue.
 *
 * @ingroup themeable
 */
function theme_nodequeue_subqueue_count_text($variables) {
  return t('@count in queue', array('@count' => $variables['count']));
}
