<?php
// +-----------------------------------------------------------------------+
// | Piwigo - a PHP based photo gallery                                    |
// +-----------------------------------------------------------------------+
// | Copyright(C) 2008-2016 Piwigo Team                  http://piwigo.org |
// | Copyright(C) 2003-2008 PhpWebGallery Team    http://phpwebgallery.net |
// | Copyright(C) 2002-2003 Pierrick LE GALL   http://le-gall.net/pierrick |
// +-----------------------------------------------------------------------+
// | This program is free software; you can redistribute it and/or modify  |
// | it under the terms of the GNU General Public License as published by  |
// | the Free Software Foundation                                          |
// |                                                                       |
// | This program is distributed in the hope that it will be useful, but   |
// | WITHOUT ANY WARRANTY; without even the implied warranty of            |
// | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU      |
// | General Public License for more details.                              |
// |                                                                       |
// | You should have received a copy of the GNU General Public License     |
// | along with this program; if not, write to the Free Software           |
// | Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, |
// | USA.                                                                  |
// +-----------------------------------------------------------------------+

/**
 * @package functions\admin\___
 */

include_once(PHPWG_ROOT_PATH.'admin/include/functions_metadata.php');


/**
 * Deletes a site and call delete_categories for each primary category of the site
 *
 * @param int $id
 */
function delete_site($id)
{
  // destruction of the categories of the site
  $query = '
SELECT id
  FROM '.CATEGORIES_TABLE.'
  WHERE site_id = '.$id.'
;';
  $category_ids = query2array($query, null, 'id');
  delete_categories($category_ids);

  // destruction of the site
  $query = '
DELETE FROM '.SITES_TABLE.'
  WHERE id = '.$id.'
;';
  pwg_query($query);
}

/**
 * Recursively deletes one or more categories.
 * It also deletes :
 *    - all the elements physically linked to the category (with delete_elements)
 *    - all the links between elements and this category
 *    - all the restrictions linked to the category
 *
 * @param int[] $ids
 * @param string $photo_deletion_mode
 *    - no_delete : delete no photo, may create orphans
 *    - delete_orphans : delete photos that are no longer linked to any category
 *    - force_delete : delete photos even if they are linked to another category
 */
function delete_categories($ids, $photo_deletion_mode='no_delete')
{
  if (count($ids) == 0)
  {
    return;
  }

  // add sub-category ids to the given ids : if a category is deleted, all
  // sub-categories must be so
  $ids = get_subcat_ids($ids);

  // destruction of all photos physically linked to the category
  $query = '
SELECT id
  FROM '.IMAGES_TABLE.'
  WHERE storage_category_id IN (
'.wordwrap(implode(', ', $ids), 80, "\n").')
;';
  $element_ids = query2array($query, null, 'id');
  delete_elements($element_ids);

  // now, should we delete photos that are virtually linked to the category?
  if ('delete_orphans' == $photo_deletion_mode or 'force_delete' == $photo_deletion_mode)
  {
    $query = '
SELECT
    DISTINCT(image_id)
  FROM '.IMAGE_CATEGORY_TABLE.'
  WHERE category_id IN ('.implode(',', $ids).')
;';
    $image_ids_linked = query2array($query, null, 'image_id');

    if (count($image_ids_linked) > 0)
    {
      if ('delete_orphans' == $photo_deletion_mode)
      {
        $query = '
SELECT
    DISTINCT(image_id)
  FROM '.IMAGE_CATEGORY_TABLE.'
  WHERE image_id IN ('.implode(',', $image_ids_linked).')
    AND category_id NOT IN ('.implode(',', $ids).')
;';
        $image_ids_not_orphans = query2array($query, null, 'image_id');
        $image_ids_to_delete = array_diff($image_ids_linked, $image_ids_not_orphans);
      }

      if ('force_delete' == $photo_deletion_mode)
      {
        $image_ids_to_delete = $image_ids_linked;
      }

      delete_elements($image_ids_to_delete, true);
    }
  }

  // destruction of the links between images and this category
  $query = '
DELETE FROM '.IMAGE_CATEGORY_TABLE.'
  WHERE category_id IN (
'.wordwrap(implode(', ', $ids), 80, "\n").')
;';
  pwg_query($query);

  // destruction of the access linked to the category
  $query = '
DELETE FROM '.USER_ACCESS_TABLE.'
  WHERE cat_id IN (
'.wordwrap(implode(', ', $ids), 80, "\n").')
;';
  pwg_query($query);

  $query = '
DELETE FROM '.GROUP_ACCESS_TABLE.'
  WHERE cat_id IN (
'.wordwrap(implode(', ', $ids), 80, "\n").')
;';
  pwg_query($query);

  // destruction of the category
  $query = '
DELETE FROM '.CATEGORIES_TABLE.'
  WHERE id IN (
'.wordwrap(implode(', ', $ids), 80, "\n").')
;';
  pwg_query($query);

  $query='
DELETE FROM '.OLD_PERMALINKS_TABLE.'
  WHERE cat_id IN ('.implode(',',$ids).')';
  pwg_query($query);

  $query='
DELETE FROM '.USER_CACHE_CATEGORIES_TABLE.'
  WHERE cat_id IN ('.implode(',',$ids).')';
  pwg_query($query);

  trigger_notify('delete_categories', $ids);
}

/**
 * Deletes all files (on disk) related to given image ids.
 *
 * @param int[] $ids
 * @return 0|int[] image ids where files were successfully deleted
 */
function delete_element_files($ids)
{
  global $conf;
  if (count($ids) == 0)
  {
    return 0;
  }

  $new_ids = array();
  $formats_of = array();

  $query = '
SELECT
    image_id,
    ext
  FROM '.IMAGE_FORMAT_TABLE.'
  WHERE image_id IN ('.implode(',', $ids).')
;';
  $result = pwg_query($query);
  while ($row = pwg_db_fetch_assoc($result))
  {
    if (!isset($formats_of[ $row['image_id'] ]))
    {
      $formats_of[ $row['image_id'] ] = array();
    }

    $formats_of[ $row['image_id'] ][] = $row['ext'];
  }

  $query = '
SELECT
    id,
    path,
    representative_ext
  FROM '.IMAGES_TABLE.'
  WHERE id IN ('.implode(',', $ids).')
;';
  $result = pwg_query($query);
  while ($row = pwg_db_fetch_assoc($result))
  {
    if (url_is_remote($row['path']))
    {
      continue;
    }

    $files = array();
    $files[] = get_element_path($row);

    if (!empty($row['representative_ext']))
    {
      $files[] = original_to_representative( $files[0], $row['representative_ext']);
    }

    if (isset($formats_of[ $row['id'] ]))
    {
      foreach ($formats_of[ $row['id'] ] as $format_ext)
      {
        $files[] = original_to_format($files[0], $format_ext);
      }
    }

    $ok = true;
    if (!isset($conf['never_delete_originals']))
    {
      foreach ($files as $path)
      {
        if (is_file($path) and !unlink($path))
        {
          $ok = false;
          trigger_error('"'.$path.'" cannot be removed', E_USER_WARNING);
          break;
        }
      }
    }

    if ($ok)
    {
      delete_element_derivatives($row);
      $new_ids[] = $row['id'];
    }
    else
    {
      break;
    }
  }
  return $new_ids;
}

/**
 * Deletes elements from database.
 * It also deletes :
 *    - all the comments related to elements
 *    - all the links between categories/tags and elements
 *    - all the favorites/rates associated to elements
 *    - removes elements from caddie
 *
 * @param int[] $ids
 * @param bool $physical_deletion
 * @return int number of deleted elements
 */
function delete_elements($ids, $physical_deletion=false)
{
  if (count($ids) == 0)
  {
    return 0;
  }
  trigger_notify('begin_delete_elements', $ids);

  if ($physical_deletion)
  {
    $ids = delete_element_files($ids);
    if (count($ids)==0)
    {
      return 0;
    }
  }

  $ids_str = wordwrap(implode(', ', $ids), 80, "\n");

  // destruction of the comments on the image
  $query = '
DELETE FROM '.COMMENTS_TABLE.'
  WHERE image_id IN ('. $ids_str .')
;';
  pwg_query($query);

  // destruction of the links between images and categories
  $query = '
DELETE FROM '.IMAGE_CATEGORY_TABLE.'
  WHERE image_id IN ('. $ids_str .')
;';
  pwg_query($query);

  // destruction of the formats
  $query = '
DELETE FROM '.IMAGE_FORMAT_TABLE.'
  WHERE image_id IN ('. $ids_str .')
;';
  pwg_query($query);

  // destruction of the links between images and tags
  $query = '
DELETE FROM '.IMAGE_TAG_TABLE.'
  WHERE image_id IN ('. $ids_str .')
;';
  pwg_query($query);

  // destruction of the favorites associated with the picture
  $query = '
DELETE FROM '.FAVORITES_TABLE.'
  WHERE image_id IN ('. $ids_str .')
;';
  pwg_query($query);

  // destruction of the rates associated to this element
  $query = '
DELETE FROM '.RATE_TABLE.'
  WHERE element_id IN ('. $ids_str .')
;';
  pwg_query($query);

  // destruction of the caddie associated to this element
  $query = '
DELETE FROM '.CADDIE_TABLE.'
  WHERE element_id IN ('. $ids_str .')
;';
  pwg_query($query);

  // destruction of the image
  $query = '
DELETE FROM '.IMAGES_TABLE.'
  WHERE id IN ('. $ids_str .')
;';
  pwg_query($query);

  // are the photo used as category representant?
  $query = '
SELECT
    id
  FROM '.CATEGORIES_TABLE.'
  WHERE representative_picture_id IN ('. $ids_str .')
;';
  $category_ids = query2array($query, null, 'id');
  if (count($category_ids) > 0)
  {
    update_category($category_ids);
  }

  trigger_notify('delete_elements', $ids);
  return count($ids);
}

/**
 * Deletes an user.
 * It also deletes all related data (accesses, favorites, permissions, etc.)
 * @todo : accept array input
 *
 * @param int $user_id
 */
function delete_user($user_id)
{
  global $conf;
  $tables = array(
    // destruction of the access linked to the user
    USER_ACCESS_TABLE,
    // destruction of data notification by mail for this user
    USER_MAIL_NOTIFICATION_TABLE,
    // destruction of data RSS notification for this user
    USER_FEED_TABLE,
    // deletion of calculated permissions linked to the user
    USER_CACHE_TABLE,
    // deletion of computed cache data linked to the user
    USER_CACHE_CATEGORIES_TABLE,
    // destruction of the group links for this user
    USER_GROUP_TABLE,
    // destruction of the favorites associated with the user
    FAVORITES_TABLE,
    // destruction of the caddie associated with the user
    CADDIE_TABLE,
    // deletion of piwigo specific informations
    USER_INFOS_TABLE,
    USER_AUTH_KEYS_TABLE
    );

  foreach ($tables as $table)
  {
    $query = '
DELETE FROM '.$table.'
  WHERE user_id = '.$user_id.'
;';
    pwg_query($query);
  }

  // purge of sessions
  delete_user_sessions($user_id);

  // destruction of the user
  $query = '
DELETE FROM '.USERS_TABLE.'
  WHERE '.$conf['user_fields']['id'].' = '.$user_id.'
;';
  pwg_query($query);

  trigger_notify('delete_user', $user_id);
}

/**
 * Deletes all tags linked to no photo
 */
function delete_orphan_tags()
{
  $orphan_tags = get_orphan_tags();

  if (count($orphan_tags) > 0)
  {
    $orphan_tag_ids = array();
    foreach ($orphan_tags as $tag)
    {
      $orphan_tag_ids[] = $tag['id'];
    }

    delete_tags($orphan_tag_ids);
  }
}

/**
 * Get all tags (id + name) linked to no photo
 */
function get_orphan_tags()
{
  $query = '
SELECT
    id,
    name
  FROM '.TAGS_TABLE.'
    LEFT JOIN '.IMAGE_TAG_TABLE.' ON id = tag_id
  WHERE tag_id IS NULL
    AND lastmodified < SUBDATE(NOW(), INTERVAL 1 DAY)
;';
  return query2array($query);
}

/**
 * Verifies that the representative picture really exists in the db and
 * picks up a random representative if possible and based on config.
 *
 * @param 'all'|int|int[] $ids
 */
function update_category($ids = 'all')
{
  global $conf;

  if ($ids=='all')
  {
    $where_cats = '1=1';
  }
  elseif ( !is_array($ids) )
  {
    $where_cats = '%s='.$ids;
  }
  else
  {
    if (count($ids) == 0)
    {
      return false;
    }
    $where_cats = '%s IN('.wordwrap(implode(', ', $ids), 120, "\n").')';
  }

  // find all categories where the setted representative is not possible :
  // the picture does not exist
  $query = '
SELECT DISTINCT c.id
  FROM '.CATEGORIES_TABLE.' AS c LEFT JOIN '.IMAGES_TABLE.' AS i
    ON c.representative_picture_id = i.id
  WHERE representative_picture_id IS NOT NULL
    AND '.sprintf($where_cats, 'c.id').'
    AND i.id IS NULL
;';
  $wrong_representant = query2array($query, null, 'id');

  if (count($wrong_representant) > 0)
  {
    $query = '
UPDATE '.CATEGORIES_TABLE.'
  SET representative_picture_id = NULL
  WHERE id IN ('.wordwrap(implode(', ', $wrong_representant), 120, "\n").')
;';
    pwg_query($query);
  }

  if (!$conf['allow_random_representative'])
  {
    // If the random representant is not allowed, we need to find
    // categories with elements and with no representant. Those categories
    // must be added to the list of categories to set to a random
    // representant.
    $query = '
SELECT DISTINCT id
  FROM '.CATEGORIES_TABLE.' INNER JOIN '.IMAGE_CATEGORY_TABLE.'
    ON id = category_id
  WHERE representative_picture_id IS NULL
    AND '.sprintf($where_cats, 'category_id').'
;';
    $to_rand = query2array($query, null, 'id');
    if (count($to_rand) > 0)
    {
      set_random_representant($to_rand);
    }
  }
}

/**
 * Checks and repairs IMAGE_CATEGORY_TABLE integrity.
 * Removes all entries from the table which correspond to a deleted image.
 */
function images_integrity()
{
  $query = '
SELECT
    image_id
  FROM '.IMAGE_CATEGORY_TABLE.'
    LEFT JOIN '.IMAGES_TABLE.' ON id = image_id
  WHERE id IS NULL
;';
  $result = pwg_query($query);
  $orphan_image_ids = query2array($query, null, 'image_id');

  if (count($orphan_image_ids) > 0)
  {
    $query = '
DELETE
  FROM '.IMAGE_CATEGORY_TABLE.'
  WHERE image_id IN ('.implode(',', $orphan_image_ids).')
;';
    pwg_query($query);
  }
}

/**
 * Returns an array containing sub-directories which are potentially
 * a category.
 * Directories named ".svn", "thumbnail", "pwg_high" or "pwg_representative"
 * are omitted.
 *
 * @param string $basedir (eg: ./galleries)
 * @return string[]
 */
function get_fs_directories($path, $recursive = true)
{
  global $conf;

  $dirs = array();
  $path = rtrim($path, '/');

  $exclude_folders = array_merge(
    $conf['sync_exclude_folders'],
    array(
      '.', '..', '.svn',
      'thumbnail', 'pwg_high',
      'pwg_representative',
      'pwg_format',
      )
    );
  $exclude_folders = array_flip($exclude_folders);

  if (is_dir($path))
  {
    if ($contents = opendir($path))
    {
      while (($node = readdir($contents)) !== false)
      {
        if (is_dir($path.'/'.$node) and !isset($exclude_folders[$node]))
        {
          $dirs[] = $path.'/'.$node;
          if ($recursive)
          {
            $dirs = array_merge($dirs, get_fs_directories($path.'/'.$node));
          }
        }
      }
      closedir($contents);
    }
  }

  return $dirs;
}

/**
 * Orders categories (update categories.rank and global_rank database fields)
 * so that rank field are consecutive integers starting at 1 for each child.
 */
function update_global_rank()
{
  $query = '
SELECT id, id_uppercat, uppercats, rank, global_rank
  FROM '.CATEGORIES_TABLE.'
  ORDER BY id_uppercat,rank,name';

  global $cat_map; // used in preg_replace callback
  $cat_map = array();

  $current_rank = 0;
  $current_uppercat = '';

  $result = pwg_query($query);
  while ($row = pwg_db_fetch_assoc($result))
  {
    if ($row['id_uppercat'] != $current_uppercat)
    {
      $current_rank = 0;
      $current_uppercat = $row['id_uppercat'];
    }
    ++$current_rank;
    $cat =
      array(
        'rank' =>        $current_rank,
        'rank_changed' =>$current_rank!=$row['rank'],
        'global_rank' => $row['global_rank'],
        'uppercats' =>   $row['uppercats'],
        );
    $cat_map[ $row['id'] ] = $cat;
  }

  $datas = array();

  $cat_map_callback = create_function('$m', 'global $cat_map; return $cat_map[$m[1]]["rank"];');

  foreach( $cat_map as $id=>$cat )
  {
    $new_global_rank = preg_replace_callback(
      '/(\d+)/',
      $cat_map_callback,
      str_replace(',', '.', $cat['uppercats'] )
      );

    if ($cat['rank_changed'] or $new_global_rank !== $cat['global_rank'])
    {
      $datas[] = array(
          'id' => $id,
          'rank' => $cat['rank'],
          'global_rank' => $new_global_rank,
        );
    }
  }

  unset($cat_map);

  mass_updates(
    CATEGORIES_TABLE,
    array(
      'primary' => array('id'),
      'update'  => array('rank', 'global_rank')
      ),
    $datas
    );
  return count($datas);
}

/**
 * Change the **visible** property on a set of categories.
 *
 * @param int[] $categories
 * @param boolean|string $value
 * @param boolean $unlock_child optional   default false
 */
function set_cat_visible($categories, $value, $unlock_child = false)
{
  if ( ($value = filter_var($value, FILTER_VALIDATE_BOOLEAN, FILTER_NULL_ON_FAILURE)) === null )
  {
    trigger_error("set_cat_visible invalid param $value", E_USER_WARNING);
    return false;
  }

  // unlocking a category => all its parent categories become unlocked
  if ($value)
  {
    $cats = get_uppercat_ids($categories);
    if ($unlock_child) {
      $cats = array_merge($cats, get_subcat_ids($categories));
    }
    $query = '
UPDATE '.CATEGORIES_TABLE.'
  SET visible = \'true\'
  WHERE id IN ('.implode(',', $cats).')';
    pwg_query($query);
  }
  // locking a category   => all its child categories become locked
  else
  {
    $subcats = get_subcat_ids($categories);
    $query = '
UPDATE '.CATEGORIES_TABLE.'
  SET visible = \'false\'
  WHERE id IN ('.implode(',', $subcats).')';
    pwg_query($query);
  }
}

/**
 * Change the **status** property on a set of categories : private or public.
 *
 * @param int[] $categories
 * @param string $value
 */
function set_cat_status($categories, $value)
{
  if (!in_array($value, array('public', 'private')))
  {
    trigger_error("set_cat_status invalid param $value", E_USER_WARNING);
    return false;
  }

  // make public a category => all its parent categories become public
  if ($value == 'public')
  {
    $uppercats = get_uppercat_ids($categories);
    $query = '
UPDATE '.CATEGORIES_TABLE.'
  SET status = \'public\'
  WHERE id IN ('.implode(',', $uppercats).')
;';
    pwg_query($query);
  }

  // make a category private => all its child categories become private
  if ($value == 'private')
  {
    $subcats = get_subcat_ids($categories);

    $query = '
UPDATE '.CATEGORIES_TABLE.'
  SET status = \'private\'
  WHERE id IN ('.implode(',', $subcats).')';
    pwg_query($query);

    // We have to keep permissions consistant: a sub-album can't be
    // permitted to a user or group if its parent album is not permitted to
    // the same user or group. Let's remove all permissions on sub-albums if
    // it is not consistant. Let's take the following example:
    //
    // A1        permitted to U1,G1
    // A1/A2     permitted to U1,U2,G1,G2
    // A1/A2/A3  permitted to U3,G1
    // A1/A2/A4  permitted to U2
    // A1/A5     permitted to U4
    // A6        permitted to U4
    // A6/A7     permitted to G1
    //
    // (we consider that it can be possible to start with inconsistant
    // permission, given that public albums can have hidden permissions,
    // revealed once the album returns to private status)
    //
    // The admin selects A2,A3,A4,A5,A6,A7 to become private (all but A1,
    // which is private, which can be true if we're moving A2 into A1). The
    // result must be:
    //
    // A2 permission removed to U2,G2
    // A3 permission removed to U3
    // A4 permission removed to U2
    // A5 permission removed to U2
    // A6 permission removed to U4
    // A7 no permission removed
    //
    // 1) we must extract "top albums": A2, A5 and A6
    // 2) for each top album, decide which album is the reference for permissions
    // 3) remove all inconsistant permissions from sub-albums of each top-album

    // step 1, search top albums
    $top_categories = array();
    $parent_ids = array();

    $query = '
SELECT
    id,
    name,
    id_uppercat,
    uppercats,
    global_rank
  FROM '.CATEGORIES_TABLE.'
  WHERE id IN ('.implode(',', $categories).')
;';
    $all_categories = query2array($query);
    usort($all_categories, 'global_rank_compare');

    foreach ($all_categories as $cat)
    {
      $is_top = true;

      if (!empty($cat['id_uppercat']))
      {
        foreach (explode(',', $cat['uppercats']) as $id_uppercat)
        {
          if (isset($top_categories[$id_uppercat]))
          {
            $is_top = false;
            break;
          }
        }
      }

      if ($is_top)
      {
        $top_categories[$cat['id']] = $cat;

        if (!empty($cat['id_uppercat']))
        {
          $parent_ids[] = $cat['id_uppercat'];
        }
      }
    }

    // step 2, search the reference album for permissions
    //
    // to find the reference of each top album, we will need the parent albums
    $parent_cats = array();

    if (count($parent_ids) > 0)
    {
      $query = '
SELECT
    id,
    status
  FROM '.CATEGORIES_TABLE.'
  WHERE id IN ('.implode(',', $parent_ids).')
;';
      $parent_cats= query2array($query, 'id');
    }

    $tables = array(
      USER_ACCESS_TABLE => 'user_id',
      GROUP_ACCESS_TABLE => 'group_id'
      );

    foreach ($top_categories as $top_category)
    {
      // what is the "reference" for list of permissions? The parent album
      // if it is private, else the album itself
      $ref_cat_id = $top_category['id'];

      if (!empty($top_category['id_uppercat'])
          and isset($parent_cats[ $top_category['id_uppercat'] ])
          and 'private' == $parent_cats[ $top_category['id_uppercat'] ]['status'])
      {
        $ref_cat_id = $top_category['id_uppercat'];
      }

      $subcats = get_subcat_ids(array($top_category['id']));

      foreach ($tables as $table => $field)
      {
        // what are the permissions user/group of the reference album
        $query = '
SELECT '.$field.'
  FROM '.$table.'
  WHERE cat_id = '.$ref_cat_id.'
;';
        $ref_access = query2array($query, null, $field);

        if (count($ref_access) == 0)
        {
          $ref_access[] = -1;
        }

        // step 3, remove the inconsistant permissions from sub-albums
        $query = '
DELETE
  FROM '.$table.'
  WHERE '.$field.' NOT IN ('.implode(',', $ref_access).')
    AND cat_id IN ('.implode(',', $subcats).')
;';
        pwg_query($query);
      }
    }
  }
}

/**
 * Returns all uppercats category ids of the given category ids.
 *
 * @param int[] $cat_ids
 * @return int[]
 */
function get_uppercat_ids($cat_ids)
{
  if (!is_array($cat_ids) or count($cat_ids) < 1)
  {
    return array();
  }

  $uppercats = array();

  $query = '
SELECT uppercats
  FROM '.CATEGORIES_TABLE.'
  WHERE id IN ('.implode(',', $cat_ids).')
;';
  $result = pwg_query($query);
  while ($row = pwg_db_fetch_assoc($result))
  {
    $uppercats = array_merge($uppercats,
                             explode(',', $row['uppercats']));
  }
  $uppercats = array_unique($uppercats);

  return $uppercats;
}

/**
 */
function get_category_representant_properties($image_id)
{
  $query = '
SELECT id,representative_ext,path
  FROM '.IMAGES_TABLE.'
  WHERE id = '.$image_id.'
;';
  $row = pwg_db_fetch_assoc(pwg_query($query));
  $src = DerivativeImage::thumb_url($row);
  $url = get_root_url().'admin.php?page=photo-'.$image_id;

  return array(
    'src' => $src,
    'url' => $url
    );
}

/**
 * Set a new random representant to the categories.
 *
 * @param int[] $categories
 */
function set_random_representant($categories)
{
  $datas = array();
  foreach ($categories as $category_id)
  {
    $query = '
SELECT image_id
  FROM '.IMAGE_CATEGORY_TABLE.'
  WHERE category_id = '.$category_id.'
  ORDER BY '.DB_RANDOM_FUNCTION.'()
  LIMIT 1
;';
    list($representative) = pwg_db_fetch_row(pwg_query($query));

    $datas[] = array(
      'id' => $category_id,
      'representative_picture_id' => $representative,
      );
  }

  mass_updates(
    CATEGORIES_TABLE,
    array(
      'primary' => array('id'),
      'update' => array('representative_picture_id')
      ),
    $datas
    );
}

/**
 * Returns the fulldir for each given category id.
 *
 * @param int[] intcat_ids
 * @return string[]
 */
function get_fulldirs($cat_ids)
{
  if (count($cat_ids) == 0)
  {
    return array();
  }

  // caching directories of existing categories
  global $cat_dirs; // used in preg_replace callback
  $query = '
SELECT id, dir
  FROM '.CATEGORIES_TABLE.'
  WHERE dir IS NOT NULL
;';
  $cat_dirs = query2array($query, 'id', 'dir');

  // caching galleries_url
  $query = '
SELECT id, galleries_url
  FROM '.SITES_TABLE.'
;';
  $galleries_url = query2array($query, 'id', 'galleries_url');

  // categories : id, site_id, uppercats
  $query = '
SELECT id, uppercats, site_id
  FROM '.CATEGORIES_TABLE.'
  WHERE dir IS NOT NULL
    AND id IN (
'.wordwrap(implode(', ', $cat_ids), 80, "\n").')
;';
  $categories = query2array($query);

  // filling $cat_fulldirs
  $cat_dirs_callback = create_function('$m', 'global $cat_dirs; return $cat_dirs[$m[1]];');

  $cat_fulldirs = array();
  foreach ($categories as $category)
  {
    $uppercats = str_replace(',', '/', $category['uppercats']);
    $cat_fulldirs[$category['id']] = $galleries_url[$category['site_id']];
    $cat_fulldirs[$category['id']].= preg_replace_callback(
      '/(\d+)/',
      $cat_dirs_callback,
      $uppercats
      );
  }

  unset($cat_dirs);

  return $cat_fulldirs;
}

/**
 * Returns an array with all file system files according to $conf['file_ext']
 *
 * @param string $path
 * @param bool $recursive
 * @return array
 */
function get_fs($path, $recursive = true)
{
  global $conf;

  // because isset is faster than in_array...
  if (!isset($conf['flip_picture_ext']))
  {
    $conf['flip_picture_ext'] = array_flip($conf['picture_ext']);
  }
  if (!isset($conf['flip_file_ext']))
  {
    $conf['flip_file_ext'] = array_flip($conf['file_ext']);
  }

  $fs['elements'] = array();
  $fs['thumbnails'] = array();
  $fs['representatives'] = array();
  $subdirs = array();

  if (is_dir($path))
  {
    if ($contents = opendir($path))
    {
      while (($node = readdir($contents)) !== false)
      {
        if ($node == '.' or $node == '..') continue;

        if (is_file($path.'/'.$node))
        {
          $extension = get_extension($node);

          if (isset($conf['flip_picture_ext'][$extension]))
          {
            if (basename($path) == 'thumbnail')
            {
              $fs['thumbnails'][] = $path.'/'.$node;
            }
            elseif (basename($path) == 'pwg_representative')
            {
              $fs['representatives'][] = $path.'/'.$node;
            }
            else
            {
              $fs['elements'][] = $path.'/'.$node;
            }
          }
          elseif (isset($conf['flip_file_ext'][$extension]))
          {
            $fs['elements'][] = $path.'/'.$node;
          }
        }
        elseif (is_dir($path.'/'.$node) and $node != 'pwg_high' and $recursive)
        {
          $subdirs[] = $node;
        }
      }
    }
    closedir($contents);

    foreach ($subdirs as $subdir)
    {
      $tmp_fs = get_fs($path.'/'.$subdir);

      $fs['elements']        = array_merge($fs['elements'],
                                           $tmp_fs['elements']);

      $fs['thumbnails']      = array_merge($fs['thumbnails'],
                                           $tmp_fs['thumbnails']);

      $fs['representatives'] = array_merge($fs['representatives'],
                                           $tmp_fs['representatives']);
    }
  }
  return $fs;
}

/**
 * Synchronize base users list and related users list.
 *
 * Compares and synchronizes base users table (USERS_TABLE) with its child
 * tables (USER_INFOS_TABLE, USER_ACCESS, USER_CACHE, USER_GROUP) : each
 * base user must be present in child tables, users in child tables not
 * present in base table must be deleted.
 */
function sync_users()
{
  global $conf;

  $query = '
SELECT '.$conf['user_fields']['id'].' AS id
  FROM '.USERS_TABLE.'
;';
  $base_users = query2array($query, null, 'id');

  $query = '
SELECT user_id
  FROM '.USER_INFOS_TABLE.'
;';
  $infos_users = query2array($query, null, 'user_id');

  // users present in $base_users and not in $infos_users must be added
  $to_create = array_diff($base_users, $infos_users);

  if (count($to_create) > 0)
  {
    create_user_infos($to_create);
  }

  // users present in user related tables must be present in the base user
  // table
  $tables = array(
    USER_MAIL_NOTIFICATION_TABLE,
    USER_FEED_TABLE,
    USER_INFOS_TABLE,
    USER_ACCESS_TABLE,
    USER_CACHE_TABLE,
    USER_CACHE_CATEGORIES_TABLE,
    USER_GROUP_TABLE
    );

  foreach ($tables as $table)
  {
    $query = '
SELECT DISTINCT user_id
  FROM '.$table.'
;';
    $to_delete = array_diff(
      query2array($query, null, 'user_id'),
      $base_users
      );

    if (count($to_delete) > 0)
    {
      $query = '
DELETE
  FROM '.$table.'
  WHERE user_id in ('.implode(',', $to_delete).')
;';
      pwg_query($query);
    }
  }
}

/**
 * Updates categories.uppercats field based on categories.id + categories.id_uppercat
 */
function update_uppercats()
{
  $query = '
SELECT id, id_uppercat, uppercats
  FROM '.CATEGORIES_TABLE.'
;';
  $cat_map = query2array($query, 'id');

  $datas = array();
  foreach ($cat_map as $id => $cat)
  {
    $upper_list = array();

    $uppercat = $id;
    while ($uppercat)
    {
      $upper_list[] = $uppercat;
      $uppercat = $cat_map[$uppercat]['id_uppercat'];
    }

    $new_uppercats = implode(',', array_reverse($upper_list));
    if ($new_uppercats != $cat['uppercats'])
    {
      $datas[] = array(
        'id' => $id,
        'uppercats' => $new_uppercats
        );
    }
  }
  $fields = array('primary' => array('id'), 'update' => array('uppercats'));
  mass_updates(CATEGORIES_TABLE, $fields, $datas);
}

/**
 * Update images.path field base on images.file and storage categories fulldirs.
 */
function update_path()
{
  $query = '
SELECT DISTINCT(storage_category_id)
  FROM '.IMAGES_TABLE.'
  WHERE storage_category_id IS NOT NULL
;';
  $cat_ids = query2array($query, null, 'storage_category_id');
  $fulldirs = get_fulldirs($cat_ids);

  foreach ($cat_ids as $cat_id)
  {
    $query = '
UPDATE '.IMAGES_TABLE.'
  SET path = '.pwg_db_concat(array("'".$fulldirs[$cat_id]."/'",'file')).'
  WHERE storage_category_id = '.$cat_id.'
;';
    pwg_query($query);
  }
}

/**
 * Change the parent category of the given categories. The categories are
 * supposed virtual.
 *
 * @param int[] $category_ids
 * @param int $new_parent (-1 for root)
 */
function move_categories($category_ids, $new_parent = -1)
{
  global $page;

  if (count($category_ids) == 0)
  {
    return;
  }

  $new_parent = $new_parent < 1 ? 'NULL' : $new_parent;

  $categories = array();

  $query = '
SELECT id, id_uppercat, status, uppercats
  FROM '.CATEGORIES_TABLE.'
  WHERE id IN ('.implode(',', $category_ids).')
;';
  $result = pwg_query($query);
  while ($row = pwg_db_fetch_assoc($result))
  {
    $categories[$row['id']] =
      array(
        'parent' => empty($row['id_uppercat']) ? 'NULL' : $row['id_uppercat'],
        'status' => $row['status'],
        'uppercats' => $row['uppercats']
        );
  }

  // is the movement possible? The movement is impossible if you try to move
  // a category in a sub-category or itself
  if ('NULL' != $new_parent)
  {
    $query = '
SELECT uppercats
  FROM '.CATEGORIES_TABLE.'
  WHERE id = '.$new_parent.'
;';
    list($new_parent_uppercats) = pwg_db_fetch_row(pwg_query($query));

    foreach ($categories as $category)
    {
      // technically, you can't move a category with uppercats 12,125,13,14
      // into a new parent category with uppercats 12,125,13,14,24
      if (preg_match('/^'.$category['uppercats'].'(,|$)/', $new_parent_uppercats))
      {
        $page['errors'][] = l10n('You cannot move an album in its own sub album');
        return;
      }
    }
  }

  $tables = array(
    USER_ACCESS_TABLE => 'user_id',
    GROUP_ACCESS_TABLE => 'group_id'
    );

  $query = '
UPDATE '.CATEGORIES_TABLE.'
  SET id_uppercat = '.$new_parent.'
  WHERE id IN ('.implode(',', $category_ids).')
;';
  pwg_query($query);

  update_uppercats();
  update_global_rank();

  // status and related permissions management
  if ('NULL' == $new_parent)
  {
    $parent_status = 'public';
  }
  else
  {
    $query = '
SELECT status
  FROM '.CATEGORIES_TABLE.'
  WHERE id = '.$new_parent.'
;';
    list($parent_status) = pwg_db_fetch_row(pwg_query($query));
  }

  if ('private' == $parent_status)
  {
    set_cat_status(array_keys($categories), 'private');
  }

  $page['infos'][] = l10n_dec(
    '%d album moved', '%d albums moved',
    count($categories)
    );
}

/**
 * Create a virtual category.
 *
 * @param string $category_name
 * @param int $parent_id
 * @param array $options
 *    - boolean commentable
 *    - boolean visible
 *    - string status
 *    - string comment
 *    - boolean inherit
 * @return array ('info', 'id') or ('error')
 */
function create_virtual_category($category_name, $parent_id=null, $options=array())
{
  global $conf, $user;

  // is the given category name only containing blank spaces ?
  if (preg_match('/^\s*$/', $category_name))
  {
    return array('error' => l10n('The name of an album must not be empty'));
  }

  $rank = 0;
  if ('last' == $conf['newcat_default_position'])
  {
    //what is the current higher rank for this parent?
    $query = '
SELECT MAX(rank) AS max_rank
  FROM '. CATEGORIES_TABLE .'
  WHERE id_uppercat '.(empty($parent_id) ? 'IS NULL' : '= '.$parent_id).' 
;';
    $row = pwg_db_fetch_assoc(pwg_query($query));

    if (is_numeric($row['max_rank']))
    {
      $rank = $row['max_rank'] + 1;
    }
  }

  $insert = array(
    'name' => $category_name,
    'rank' => $rank,
    'global_rank' => 0,
    );

  // is the album commentable?
  if (isset($options['commentable']) and is_bool($options['commentable']))
  {
    $insert['commentable'] = $options['commentable'];
  }
  else
  {
    $insert['commentable'] = $conf['newcat_default_commentable'];
  }
  $insert['commentable'] = boolean_to_string($insert['commentable']);

  // is the album temporarily locked? (only visible by administrators,
  // whatever permissions) (may be overwritten if parent album is not
  // visible)
  if (isset($options['visible']) and is_bool($options['visible']))
  {
    $insert['visible'] = $options['visible'];
  }
  else
  {
    $insert['visible'] = $conf['newcat_default_visible'];
  }
  $insert['visible'] = boolean_to_string($insert['visible']);

  // is the album private? (may be overwritten if parent album is private)
  if (isset($options['status']) and 'private' == $options['status'])
  {
    $insert['status'] = 'private';
  }
  else
  {
    $insert['status'] = $conf['newcat_default_status'];
  }

  // any description for this album?
  if (isset($options['comment']))
  {
    $insert['comment'] = $conf['allow_html_descriptions'] ? $options['comment'] : strip_tags($options['comment']);
  }

  if (!empty($parent_id) and is_numeric($parent_id))
  {
    $query = '
SELECT id, uppercats, global_rank, visible, status
  FROM '.CATEGORIES_TABLE.'
  WHERE id = '.$parent_id.'
;';
    $parent = pwg_db_fetch_assoc(pwg_query($query));

    $insert['id_uppercat'] = $parent['id'];
    $insert['global_rank'] = $parent['global_rank'].'.'.$insert['rank'];

    // at creation, must a category be visible or not ? Warning : if the
    // parent category is invisible, the category is automatically create
    // invisible. (invisible = locked)
    if ('false' == $parent['visible'])
    {
      $insert['visible'] = 'false';
    }

    // at creation, must a category be public or private ? Warning : if the
    // parent category is private, the category is automatically create
    // private.
    if ('private' == $parent['status'])
    {
      $insert['status'] = 'private';
    }

    $uppercats_prefix = $parent['uppercats'].',';
  }
  else
  {
    $uppercats_prefix = '';
  }

  // we have then to add the virtual category
  single_insert(CATEGORIES_TABLE, $insert);
  $inserted_id = pwg_db_insert_id(CATEGORIES_TABLE);

  single_update(
    CATEGORIES_TABLE,
    array('uppercats' => $uppercats_prefix.$inserted_id),
    array('id' => $inserted_id)
    );

  update_global_rank();

  if ('private' == $insert['status'] and !empty($insert['id_uppercat']) and ((isset($options['inherit']) and $options['inherit']) or $conf['inheritance_by_default']) )
  {
    $query = '
      SELECT group_id
      FROM '.GROUP_ACCESS_TABLE.'
      WHERE cat_id = '.$insert['id_uppercat'].'
    ;';
    $granted_grps =  query2array($query, null, 'group_id');
    $inserts = array();
    foreach ($granted_grps as $granted_grp)
    {
      $inserts[] = array(
        'group_id' => $granted_grp,
        'cat_id' => $inserted_id
        );
    }
    mass_inserts(GROUP_ACCESS_TABLE, array('group_id','cat_id'), $inserts);

    $query = '
      SELECT user_id
      FROM '.USER_ACCESS_TABLE.'
      WHERE cat_id = '.$insert['id_uppercat'].'
    ;';
    $granted_users =  query2array($query, null, 'user_id');
    add_permission_on_category($inserted_id, array_unique(array_merge(get_admins(), array($user['id']), $granted_users)));
  }
  elseif ('private' == $insert['status'])
  {
    add_permission_on_category($inserted_id, array_unique(array_merge(get_admins(), array($user['id']))));
  }

  return array(
    'info' => l10n('Virtual album added'),
    'id'   => $inserted_id,
    );
}

/**
 * Set tags to an image.
 * Warning: given tags are all tags associated to the image, not additionnal tags.
 *
 * @param int[] $tags
 * @param int $image_id
 */
function set_tags($tags, $image_id)
{
  set_tags_of( array($image_id=>$tags) );
}

/**
 * Add new tags to a set of images.
 *
 * @param int[] $tags
 * @param int[] $images
 */
function add_tags($tags, $images)
{
  if (count($tags) == 0 or count($images) == 0)
  {
    return;
  }

  $taglist_before = get_image_tag_ids($images);

  // we can't insert twice the same {image_id,tag_id} so we must first
  // delete lines we'll insert later
  $query = '
DELETE
  FROM '.IMAGE_TAG_TABLE.'
  WHERE image_id IN ('.implode(',', $images).')
    AND tag_id IN ('.implode(',', $tags).')
;';
  pwg_query($query);

  $inserts = array();
  foreach ($images as $image_id)
  {
    foreach ( array_unique($tags) as $tag_id)
    {
      $inserts[] = array(
          'image_id' => $image_id,
          'tag_id' => $tag_id,
        );
    }
  }
  mass_inserts(
    IMAGE_TAG_TABLE,
    array_keys($inserts[0]),
    $inserts
    );

  $taglist_after = get_image_tag_ids($images);
  $images_to_update = compare_image_tag_lists($taglist_before, $taglist_after);
  update_images_lastmodified($images_to_update);

  invalidate_user_cache_nb_tags();
}

/**
 * Delete tags and tags associations.
 *
 * @param int[] $tag_ids
 */
function delete_tags($tag_ids)
{
  if (is_numeric($tag_ids))
  {
    $tag_ids = array($tag_ids);
  }

  if (!is_array($tag_ids))
  {
    return false;
  }

  // we need the list of impacted images, to update their lastmodified
  $query = '
SELECT
    image_id
  FROM '.IMAGE_TAG_TABLE.'
  WHERE tag_id IN ('.implode(',', $tag_ids).')
;';
  $image_ids = query2array($query, null, 'image_id');

  $query = '
DELETE
  FROM '.IMAGE_TAG_TABLE.'
  WHERE tag_id IN ('.implode(',', $tag_ids).')
;';
  pwg_query($query);

  $query = '
DELETE
  FROM '.TAGS_TABLE.'
  WHERE id IN ('.implode(',', $tag_ids).')
;';
  pwg_query($query);

  update_images_lastmodified($image_ids);
  invalidate_user_cache_nb_tags();
}

/**
 * Returns a tag id from its name. If nothing found, create a new tag.
 *
 * @param string $tag_name
 * @return int
 */
function tag_id_from_tag_name($tag_name)
{
  global $page;

  $tag_name = trim($tag_name);
  if (isset($page['tag_id_from_tag_name_cache'][$tag_name]))
  {
    return $page['tag_id_from_tag_name_cache'][$tag_name];
  }

  // search existing by exact name
  $query = '
SELECT id
  FROM '.TAGS_TABLE.'
  WHERE name = \''.$tag_name.'\'
;';
  if (count($existing_tags = query2array($query, null, 'id')) == 0)
  {
    $url_name = trigger_change('render_tag_url', $tag_name);
    // search existing by url name
    $query = '
SELECT id
  FROM '.TAGS_TABLE.'
  WHERE url_name = \''.$url_name.'\'
;';
    if (count($existing_tags = query2array($query, null, 'id')) == 0)
    {
      // search by extended description (plugin sub name)
      $sub_name_where = trigger_change('get_tag_name_like_where', array(), $tag_name);
      if (count($sub_name_where))
      {
        $query = '
SELECT id
  FROM '.TAGS_TABLE.'
  WHERE '.implode(' OR ', $sub_name_where).'
;';
        $existing_tags = query2array($query, null, 'id');
      }
      
      if (count($existing_tags) == 0)
      {// finally create the tag
        mass_inserts(
          TAGS_TABLE,
          array('name', 'url_name'),
          array(
            array(
              'name' => $tag_name,
              'url_name' => $url_name,
              )
            )
          );

        $page['tag_id_from_tag_name_cache'][$tag_name] = pwg_db_insert_id(TAGS_TABLE);

        invalidate_user_cache_nb_tags();

        return $page['tag_id_from_tag_name_cache'][$tag_name];
      }
    }
  }

  $page['tag_id_from_tag_name_cache'][$tag_name] = $existing_tags[0];
  return $page['tag_id_from_tag_name_cache'][$tag_name];
}

/**
 * Set tags of images. Overwrites all existing associations.
 *
 * @param array $tags_of - keys are image ids, values are array of tag ids
 */
function set_tags_of($tags_of)
{
  if (count($tags_of) > 0)
  {
    $taglist_before = get_image_tag_ids(array_keys($tags_of));
    global $logger; $logger->debug('taglist_before', $taglist_before);

    $query = '
DELETE
  FROM '.IMAGE_TAG_TABLE.'
  WHERE image_id IN ('.implode(',', array_keys($tags_of)).')
;';
    pwg_query($query);

    $inserts = array();

    foreach ($tags_of as $image_id => $tag_ids)
    {
      foreach (array_unique($tag_ids) as $tag_id)
      {
        $inserts[] = array(
            'image_id' => $image_id,
            'tag_id' => $tag_id,
          );
      }
    }

    if (count($inserts))
    {
      mass_inserts(
        IMAGE_TAG_TABLE,
        array_keys($inserts[0]),
        $inserts
        );
    }

    $taglist_after = get_image_tag_ids(array_keys($tags_of));
    global $logger; $logger->debug('taglist_after', $taglist_after);
    $images_to_update = compare_image_tag_lists($taglist_before, $taglist_after);
    global $logger; $logger->debug('$images_to_update', $images_to_update);

    update_images_lastmodified($images_to_update);
    invalidate_user_cache_nb_tags();
  }
}

/**
 * Get list of tag ids for each image. Returns an empty list if the image has
 * no tags.
 *
 * @since 2.9
 * @param array $image_ids
 * @return associative array, image_id => list of tag ids
 */
function get_image_tag_ids($image_ids)
{
  if (!is_array($image_ids) and is_int($image_ids))
  {
    $images_ids = array($image_ids);
  }
  
  if (count($image_ids) == 0)
  {
    return array();
  }

  $query = '
SELECT
    image_id,
    tag_id
  FROM '.IMAGE_TAG_TABLE.'
  WHERE image_id IN ('.implode(',', $image_ids).')
;';

  $tags_of = array_fill_keys($image_ids, array());
  $image_tags = query2array($query);
  foreach ($image_tags as $image_tag)
  {
    $tags_of[ $image_tag['image_id'] ][] = $image_tag['tag_id'];
  }
  
  return $tags_of;
}

/**
 * Compare the list of tags, for each image. Returns image_ids where tag list has changed.
 *
 * @since 2.9
 * @param array $taglist_before - for each image_id (key), list of tag ids
 * @param array $taglist_after - for each image_id (key), list of tag ids
 * @return array - image_ids where the list has changed
 */
function compare_image_tag_lists($taglist_before, $taglist_after)
{
  $images_to_update = array();

  foreach ($taglist_after as $image_id => $list_after)
  {
    sort($list_after);

    $list_before = isset($taglist_before[$image_id]) ? $taglist_before[$image_id] : array();
    sort($list_before);
    
    if ($list_after != $list_before)
    {
      $images_to_update[] = $image_id;
    }
  }

  return $images_to_update;
}

/**
 * Associate a list of images to a list of categories.
 * The function will not duplicate links and will preserve ranks.
 *
 * @param int[] $images
 * @param int[] $categories
 */
function associate_images_to_categories($images, $categories)
{
  if (count($images) == 0
      or count($categories) == 0)
  {
    return false;
  }

  // get existing associations
  $query = '
SELECT
    image_id,
    category_id
  FROM '.IMAGE_CATEGORY_TABLE.'
  WHERE image_id IN ('.implode(',', $images).')
    AND category_id IN ('.implode(',', $categories).')
;';
  $result = pwg_query($query);

  $existing = array();
  while ($row = pwg_db_fetch_assoc($result))
  {
    $existing[ $row['category_id'] ][] = $row['image_id'];
  }

  // get max rank of each categories
  $query = '
SELECT
    category_id,
    MAX(rank) AS max_rank
  FROM '.IMAGE_CATEGORY_TABLE.'
  WHERE rank IS NOT NULL
    AND category_id IN ('.implode(',', $categories).')
  GROUP BY category_id
;';

  $current_rank_of = query2array(
    $query,
    'category_id',
    'max_rank'
    );

  // associate only not already associated images
  $inserts = array();
  foreach ($categories as $category_id)
  {
    if (!isset($current_rank_of[$category_id]))
    {
      $current_rank_of[$category_id] = 0;
    }
    if (!isset($existing[$category_id]))
    {
      $existing[$category_id] = array();
    }

    foreach ($images as $image_id)
    {
      if (!in_array($image_id, $existing[$category_id]))
      {
        $rank = ++$current_rank_of[$category_id];

        $inserts[] = array(
          'image_id' => $image_id,
          'category_id' => $category_id,
          'rank' => $rank,
          );
      }
    }
  }

  if (count($inserts))
  {
    mass_inserts(
      IMAGE_CATEGORY_TABLE,
      array_keys($inserts[0]),
      $inserts
      );

    update_category($categories);
  }
}

/**
 * Dissociate images from all old categories except their storage category and
 * associate to new categories.
 * This function will preserve ranks.
 *
 * @param int[] $images
 * @param int[] $categories
 */
function move_images_to_categories($images, $categories)
{
  if (count($images) == 0)
  {
    return false;
  }

  // let's first break links with all old albums but their "storage album"
  $query = '
DELETE '.IMAGE_CATEGORY_TABLE.'.*
  FROM '.IMAGE_CATEGORY_TABLE.'
    JOIN '.IMAGES_TABLE.' ON image_id=id
  WHERE id IN ('.implode(',', $images).')
';

  if (is_array($categories) and count($categories) > 0)
  {
    $query.= '
    AND category_id NOT IN ('.implode(',', $categories).')
';
  }

  $query.= '
    AND (storage_category_id IS NULL OR storage_category_id != category_id)
;';
  pwg_query($query);

  if (is_array($categories) and count($categories) > 0)
  {
    associate_images_to_categories($images, $categories);
  }
}

/**
 * Associate images associated to a list of source categories to a list of
 * destination categories.
 *
 * @param int[] $sources
 * @param int[] $destinations
 */
function associate_categories_to_categories($sources, $destinations)
{
  if (count($sources) == 0)
  {
    return false;
  }

  $query = '
SELECT image_id
  FROM '.IMAGE_CATEGORY_TABLE.'
  WHERE category_id IN ('.implode(',', $sources).')
;';
  $images = query2array($query, null, 'image_id');

  associate_images_to_categories($images, $destinations);
}

/**
 * Refer main Piwigo URLs (currently PHPWG_DOMAIN domain)
 *
 * @return string[]
 */
function pwg_URL()
{
  $urls = array(
    'HOME'       => PHPWG_URL,
    'WIKI'       => PHPWG_URL.'/doc',
    'DEMO'       => PHPWG_URL.'/demo',
    'FORUM'      => PHPWG_URL.'/forum',
    'BUGS'       => PHPWG_URL.'/bugs',
    'EXTENSIONS' => PHPWG_URL.'/ext',
    );
  return $urls;
}

/**
 * Invalidates cached data (permissions and category counts) for all users.
 */
function invalidate_user_cache($full = true)
{
  if ($full)
  {
    $query = '
TRUNCATE TABLE '.USER_CACHE_CATEGORIES_TABLE.';';
    pwg_query($query);
    $query = '
TRUNCATE TABLE '.USER_CACHE_TABLE.';';
    pwg_query($query);
  }
  else
  {
    $query = '
UPDATE '.USER_CACHE_TABLE.'
  SET need_update = \'true\';';
    pwg_query($query);
  }
  trigger_notify('invalidate_user_cache', $full);
}

/**
 * Invalidates cached tags counter for all users.
 */
function invalidate_user_cache_nb_tags()
{
  global $user;
  unset($user['nb_available_tags']);

  $query = '
UPDATE '.USER_CACHE_TABLE.'
  SET nb_available_tags = NULL';
  pwg_query($query);
}

/**
 * Adds the caracter set to a create table sql query.
 * All CREATE TABLE queries must call this function
 *
 * @param string $query
 * @return string
 */
function create_table_add_character_set($query)
{
  defined('DB_CHARSET') or fatal_error('create_table_add_character_set DB_CHARSET undefined');
  if ('DB_CHARSET'!='')
  {
    if ( version_compare(pwg_get_db_version(), '4.1.0', '<') )
    {
      return $query;
    }
    $charset_collate = " DEFAULT CHARACTER SET ".DB_CHARSET;
    if (DB_COLLATE!='')
    {
      $charset_collate .= " COLLATE ".DB_COLLATE;
    }
    if ( is_array($query) )
    {
      foreach( $query as $id=>$q)
      {
        $q=trim($q);
        $q=trim($q, ';');
        if (preg_match('/^CREATE\s+TABLE/i',$q))
        {
          $q.=$charset_collate;
        }
        $q .= ';';
        $query[$id] = $q;
      }
    }
    else
    {
      $query=trim($query);
      $query=trim($query, ';');
      if (preg_match('/^CREATE\s+TABLE/i',$query))
      {
        $query.=$charset_collate;
      }
      $query .= ';';
    }
  }
  return $query;
}

/**
 * Returns access levels as array used on template with html_options functions.
 *
 * @param int $MinLevelAccess
 * @param int $MaxLevelAccess
 * @return array
 */
function get_user_access_level_html_options($MinLevelAccess = ACCESS_FREE, $MaxLevelAccess = ACCESS_CLOSED)
{
  $tpl_options = array();
  for ($level = $MinLevelAccess; $level <= $MaxLevelAccess; $level++)
  {
    $tpl_options[$level] = l10n(sprintf('ACCESS_%d', $level));
  }
  return $tpl_options;
}

/**
 * returns a list of templates currently available in template-extension.
 * Each .tpl file is extracted from template-extension.
 *
 * @param string $start (internal use)
 * @return string[]
 */
function get_extents($start='')
{
  if ($start == '') { $start = './template-extension'; }
  $dir = opendir($start);
  $extents = array();

  while (($file = readdir($dir)) !== false)
  {
    if ( $file == '.' or $file == '..' or $file == '.svn') continue;
    $path = $start . '/' . $file;
    if (is_dir($path))
    {
      $extents = array_merge($extents, get_extents($path));
    }
    elseif ( !is_link($path) and file_exists($path)
            and get_extension($path) == 'tpl' )
    {
      $extents[] = substr($path, 21);
    }
  }
  return $extents;
}

/**
 * Create a new tag.
 *
 * @param string $tag_name
 * @return array ('id', info') or ('error')
 */
function create_tag($tag_name)
{
  // does the tag already exists?
  $query = '
SELECT id
  FROM '.TAGS_TABLE.'
  WHERE name = \''.$tag_name.'\'
;';
  $existing_tags = query2array($query, null, 'id');

  if (count($existing_tags) == 0)
  {
    single_insert(
      TAGS_TABLE,
      array(
        'name' => $tag_name,
        'url_name' => trigger_change('render_tag_url', $tag_name),
        )
      );

    $inserted_id = pwg_db_insert_id(TAGS_TABLE);

    return array(
      'info' => l10n('Tag "%s" was added', stripslashes($tag_name)),
      'id' => $inserted_id,
      );
  }
  else
  {
    return array(
      'error' => l10n('Tag "%s" already exists', stripslashes($tag_name))
      );
  }
}

/**
 * Is the category accessible to the (Admin) user ?
 * Note : if the user is not authorized to see this category, category jump
 * will be replaced by admin cat_modify page
 *
 * @param int $category_id
 * @return bool
 */
function cat_admin_access($category_id)
{
  global $user;

  // $filter['visible_categories'] and $filter['visible_images']
  // are not used because it's not necessary (filter <> restriction)
  if (in_array($category_id, explode(',', $user['forbidden_categories'])))
  {
    return false;
  }
  return true;
}

/**
 * Retrieve data from external URL.
 *
 * @param string $src
 * @param string|Ressource $dest - can be a file ressource or string
 * @param array $get_data - data added to request url
 * @param array $post_data - data transmitted with POST
 * @param string $user_agent
 * @param int $step (internal use)
 * @return bool
 */
function fetchRemote($src, &$dest, $get_data=array(), $post_data=array(), $user_agent='Piwigo', $step=0)
{
  global $conf;

  // Try to retrieve data from local file?
  if (!url_is_remote($src))
  {
    $content = @file_get_contents($src);
    if ($content !== false)
    {
      is_resource($dest) ? @fwrite($dest, $content) : $dest = $content;
      return true;
    }
    else
    {
      return false;
    }
  }

  // After 3 redirections, return false
  if ($step > 3) return false;

  // Initialization
  $method  = empty($post_data) ? 'GET' : 'POST';
  $request = empty($post_data) ? '' : http_build_query($post_data, '', '&');
  if (!empty($get_data))
  {
    $src .= strpos($src, '?') === false ? '?' : '&';
    $src .= http_build_query($get_data, '', '&');
  }

  // Initialize $dest
  is_resource($dest) or $dest = '';

  // Try curl to read remote file
  // TODO : remove all these @
  if (function_exists('curl_init') && function_exists('curl_exec'))
  {
    $ch = @curl_init();

    if (isset($conf['use_proxy']) && $conf['use_proxy'])
    {
      @curl_setopt($ch, CURLOPT_HTTPPROXYTUNNEL, 0);
      @curl_setopt($ch, CURLOPT_PROXY, $conf['proxy_server']);
      if (isset($conf['proxy_auth']) && !empty($conf['proxy_auth']))
      {
        @curl_setopt($ch, CURLOPT_PROXYUSERPWD, $conf['proxy_auth']);
      }
    }

    @curl_setopt($ch, CURLOPT_URL, $src);
    @curl_setopt($ch, CURLOPT_HEADER, 1);
    @curl_setopt($ch, CURLOPT_USERAGENT, $user_agent);
    @curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    if ($method == 'POST')
    {
      @curl_setopt($ch, CURLOPT_POST, 1);
      @curl_setopt($ch, CURLOPT_POSTFIELDS, $request);
    }
    $content = @curl_exec($ch);
    $header_length = @curl_getinfo($ch, CURLINFO_HEADER_SIZE);
    $status = @curl_getinfo($ch, CURLINFO_HTTP_CODE);
    @curl_close($ch);
    if ($content !== false and $status >= 200 and $status < 400)
    {
      if (preg_match('/Location:\s+?(.+)/', substr($content, 0, $header_length), $m))
      {
        return fetchRemote($m[1], $dest, array(), array(), $user_agent, $step+1);
      }
      $content = substr($content, $header_length);
      is_resource($dest) ? @fwrite($dest, $content) : $dest = $content;
      return true;
    }
  }

  // Try file_get_contents to read remote file
  if (ini_get('allow_url_fopen'))
  {
    $opts = array(
      'http' => array(
        'method' => $method,
        'user_agent' => $user_agent,
      )
    );
    if ($method == 'POST')
    {
      $opts['http']['content'] = $request;
    }
    $context = @stream_context_create($opts);
    $content = @file_get_contents($src, false, $context);
    if ($content !== false)
    {
      is_resource($dest) ? @fwrite($dest, $content) : $dest = $content;
      return true;
    }
  }

  // Try fsockopen to read remote file
  $src = parse_url($src);
  $host = $src['host'];
  $path = isset($src['path']) ? $src['path'] : '/';
  $path .= isset($src['query']) ? '?'.$src['query'] : '';

  if (($s = @fsockopen($host,80,$errno,$errstr,5)) === false)
  {
    return false;
  }

  $http_request  = $method." ".$path." HTTP/1.0\r\n";
  $http_request .= "Host: ".$host."\r\n";
  if ($method == 'POST')
  {
    $http_request .= "Content-Type: application/x-www-form-urlencoded;\r\n";
    $http_request .= "Content-Length: ".strlen($request)."\r\n";
  }
  $http_request .= "User-Agent: ".$user_agent."\r\n";
  $http_request .= "Accept: */*\r\n";
  $http_request .= "\r\n";
  $http_request .= $request;

  fwrite($s, $http_request);

  $i = 0;
  $in_content = false;
  while (!feof($s))
  {
    $line = fgets($s);

    if (rtrim($line,"\r\n") == '' && !$in_content)
    {
      $in_content = true;
      $i++;
      continue;
    }
    if ($i == 0)
    {
      if (!preg_match('/HTTP\/(\\d\\.\\d)\\s*(\\d+)\\s*(.*)/',rtrim($line,"\r\n"), $m))
      {
        fclose($s);
        return false;
      }
      $status = (integer) $m[2];
      if ($status < 200 || $status >= 400)
      {
        fclose($s);
        return false;
      }
    }
    if (!$in_content)
    {
      if (preg_match('/Location:\s+?(.+)$/',rtrim($line,"\r\n"),$m))
      {
        fclose($s);
        return fetchRemote(trim($m[1]),$dest,array(),array(),$user_agent,$step+1);
      }
      $i++;
      continue;
    }
    is_resource($dest) ? @fwrite($dest, $line) : $dest .= $line;
    $i++;
  }
  fclose($s);
  return true;
}

/**
 * Returns the groupname corresponding to the given group identifier if exists.
 *
 * @param int $group_id
 * @return string|false
 */
function get_groupname($group_id)
{
  $query = '
SELECT name
  FROM '.GROUPS_TABLE.'
  WHERE id = '.intval($group_id).'
;';
  $result = pwg_query($query);
  if (pwg_db_num_rows($result) > 0)
  {
    list($groupname) = pwg_db_fetch_row($result);
  }
  else
  {
    return false;
  }

  return $groupname;
}

/**
 * Returns the username corresponding to the given user identifier if exists.
 *
 * @param int $user_id
 * @return string|false
 */
function get_username($user_id)
{
  global $conf;

  $query = '
SELECT '.$conf['user_fields']['username'].'
  FROM '.USERS_TABLE.'
  WHERE '.$conf['user_fields']['id'].' = '.intval($user_id).'
;';
  $result = pwg_query($query);
  if (pwg_db_num_rows($result) > 0)
  {
    list($username) = pwg_db_fetch_row($result);
  }
  else
  {
    return false;
  }

  return stripslashes($username);
}

/**
 * Get url on piwigo.org for newsletter subscription
 *
 * @param string $language (unused)
 * @return string
 */
function get_newsletter_subscribe_base_url($language='en_UK')
{
  return PHPWG_URL.'/announcement/subscribe/';
}

/**
 * Return admin menu id for accordion.
 *
 * @param string $menu_page
 * @return int
 */
function get_active_menu($menu_page)
{
  global $page;

  if (isset($page['active_menu']))
  {
    return $page['active_menu'];
  }

  switch ($menu_page)
  {
    case 'photo':
    case 'photos_add':
    case 'rating':
    case 'tags':
    case 'batch_manager':
      return 0;

    case 'album':
    case 'cat_list':
    case 'cat_move':
    case 'cat_options':
    case 'permalinks':
      return 1;

    case 'user_list':
    case 'user_perm':
    case 'group_list':
    case 'group_perm':
    case 'notification_by_mail':
      return 2;

    case 'plugins':
    case 'plugin':
      return 3;

    case 'site_manager':
    case 'site_update':
    case 'stats':
    case 'history':
    case 'maintenance':
    case 'comments':
    case 'updates':
      return 4;

    case 'configuration':
    case 'derivatives':
    case 'extend_for_templates':
    case 'menubar':
    case 'themes':
    case 'theme':
    case 'languages':
      return 5;

    default:
      return 0;
  }
}

/**
 * Get tags list from SQL query (ids are surrounded by ~~, for get_tag_ids()).
 *
 * @param string $query
 * @param boolean $only_user_language - if true, only local name is returned for
 *    multilingual tags (if ExtendedDescription plugin is active)
 * @return array[] ('id', 'name')
 */
function get_taglist($query, $only_user_language=true)
{
  $result = pwg_query($query);

  $taglist = array();
  $altlist = array();
  while ($row = pwg_db_fetch_assoc($result))
  {
    $raw_name = $row['name'];
    $name = trigger_change('render_tag_name', $raw_name, $row);

    $taglist[] =  array(
        'name' => $name,
        'id' => '~~'.$row['id'].'~~',
      );

    if (!$only_user_language)
    {
      $alt_names = trigger_change('get_tag_alt_names', array(), $raw_name);

      foreach( array_diff( array_unique($alt_names), array($name) ) as $alt)
      {
        $altlist[] =  array(
            'name' => $alt,
            'id' => '~~'.$row['id'].'~~',
          );
      }
    }
  }

  usort($taglist, 'tag_alpha_compare');
  if (count($altlist))
  {
    usort($altlist, 'tag_alpha_compare');
    $taglist = array_merge($taglist, $altlist);
  }

  return $taglist;
}

/**
 * Get tags ids from a list of raw tags (existing tags or new tags).
 *
 * In $raw_tags we receive something like array('~~6~~', '~~59~~', 'New
 * tag', 'Another new tag') The ~~34~~ means that it is an existing
 * tag. We added the surrounding ~~ to permit creation of tags like "10"
 * or "1234" (numeric characters only)
 *
 * @param string|string[] $raw_tags - array or comma separated string
 * @param boolean $allow_create
 * @return int[]
 */
function get_tag_ids($raw_tags, $allow_create=true)
{
  $tag_ids = array();
  if (!is_array($raw_tags))
  {
    $raw_tags = explode(',',$raw_tags);
  }

  foreach ($raw_tags as $raw_tag)
  {
    if (preg_match('/^~~(\d+)~~$/', $raw_tag, $matches))
    {
      $tag_ids[] = $matches[1];
    }
    elseif ($allow_create)
    {
      // we have to create a new tag
      $tag_ids[] = tag_id_from_tag_name($raw_tag);
    }
  }

  return $tag_ids;
}

/**
 * Returns the argument_ids array with new sequenced keys based on related
 * names. Sequence is not case sensitive.
 * Warning: By definition, this function breaks original keys.
 *
 * @param int[] $elements_ids
 * @param string[] $name - names of elements, indexed by ids
 * @return int[]
 */
function order_by_name($element_ids, $name)
{
  $ordered_element_ids = array();
  foreach ($element_ids as $k_id => $element_id)
  {
    $key = strtolower($name[$element_id]) .'-'. $name[$element_id] .'-'. $k_id;
    $ordered_element_ids[$key] = $element_id;
  }
  ksort($ordered_element_ids);
  return $ordered_element_ids;
}

/**
 * Grant access to a list of categories for a list of users.
 *
 * @param int[] $category_ids
 * @param int[] $user_ids
 */
function add_permission_on_category($category_ids, $user_ids)
{
  if (!is_array($category_ids))
  {
    $category_ids = array($category_ids);
  }
  if (!is_array($user_ids))
  {
    $user_ids = array($user_ids);
  }

  // check for emptiness
  if (count($category_ids) == 0 or count($user_ids) == 0)
  {
    return;
  }

  // make sure categories are private and select uppercats or subcats
  $cat_ids = get_uppercat_ids($category_ids);
  if (isset($_POST['apply_on_sub']))
  {
    $cat_ids = array_merge($cat_ids, get_subcat_ids($category_ids));
  }

  $query = '
SELECT id
  FROM '.CATEGORIES_TABLE.'
  WHERE id IN ('.implode(',', $cat_ids).')
    AND status = \'private\'
;';
  $private_cats = query2array($query, null, 'id');

  if (count($private_cats) == 0)
  {
    return;
  }

  $inserts = array();
  foreach ($private_cats as $cat_id)
  {
    foreach ($user_ids as $user_id)
    {
      $inserts[] = array(
        'user_id' => $user_id,
        'cat_id' => $cat_id
        );
    }
  }

  mass_inserts(
    USER_ACCESS_TABLE,
    array('user_id','cat_id'),
    $inserts,
    array('ignore'=>true)
    );
}

/**
 * Returns the list of admin users.
 *
 * @param boolean $include_webmaster
 * @return int[]
 */
function get_admins($include_webmaster=true)
{
  $status_list = array('admin');

  if ($include_webmaster)
  {
    $status_list[] = 'webmaster';
  }

  $query = '
SELECT
    user_id
  FROM '.USER_INFOS_TABLE.'
  WHERE status in (\''.implode("','", $status_list).'\')
;';

  return query2array($query, null, 'user_id');
}

/**
 * Delete all derivative files for one or several types
 *
 * @param 'all'|int[] $types
 */
function clear_derivative_cache($types='all')
{
  if ($types === 'all')
  {
    $types = ImageStdParams::get_all_types();
    $types[] = IMG_CUSTOM;
  }
  elseif (!is_array($types))
  {
    $types = array($types);
  }

  for ($i=0; $i<count($types); $i++)
  {
    $type = $types[$i];
    if ($type == IMG_CUSTOM)
    {
      $type = derivative_to_url($type).'[a-zA-Z0-9]+';
    }
    elseif (in_array($type, ImageStdParams::get_all_types()))
    {
      $type = derivative_to_url($type);
    }
    else
    {//assume a custom type
      $type = derivative_to_url(IMG_CUSTOM).'_'.$type;
    }
    $types[$i] = $type;
  }

  $pattern='#.*-';
  if (count($types)>1)
  {
    $pattern .= '(' . implode('|',$types) . ')';
  }
  else
  {
    $pattern .= $types[0];
  }
  $pattern.='\.[a-zA-Z0-9]{3,4}$#';

  if ($contents = @opendir(PHPWG_ROOT_PATH.PWG_DERIVATIVE_DIR))
  {
    while (($node = readdir($contents)) !== false)
    {
      if ($node != '.'
          and $node != '..'
          and is_dir(PHPWG_ROOT_PATH.PWG_DERIVATIVE_DIR.$node))
      {
        clear_derivative_cache_rec(PHPWG_ROOT_PATH.PWG_DERIVATIVE_DIR.$node, $pattern);
      }
    }
    closedir($contents);
  }
}

/**
 * Used by clear_derivative_cache()
 * @ignore
 */
function clear_derivative_cache_rec($path, $pattern)
{
  $rmdir = true;
  $rm_index = false;

  if ($contents = opendir($path))
  {
    while (($node = readdir($contents)) !== false)
    {
      if ($node == '.' or $node == '..')
        continue;
      if (is_dir($path.'/'.$node))
      {
        $rmdir &= clear_derivative_cache_rec($path.'/'.$node, $pattern);
      }
      else
      {
        if (preg_match($pattern, $node))
        {
          unlink($path.'/'.$node);
        }
        elseif ($node=='index.htm')
        {
          $rm_index = true;
        }
        else
        {
          $rmdir = false;
        }
      }
    }
    closedir($contents);

    if ($rmdir)
    {
      if ($rm_index)
      {
        unlink($path.'/index.htm');
      }
      clearstatcache();
      @rmdir($path);
    }
    return $rmdir;
  }
}

/**
 * Deletes derivatives of a particular element
 *
 * @param array $infos ('path'[, 'representative_ext'])
 * @param 'all'|int $type
 */
function delete_element_derivatives($infos, $type='all')
{
  $path = $infos['path'];
  if (!empty($infos['representative_ext']))
  {
    $path = original_to_representative( $path, $infos['representative_ext']);
  }
  if (substr_compare($path, '../', 0, 3)==0)
  {
    $path = substr($path, 3);
  }
  $dot = strrpos($path, '.');
  if ($type=='all')
  {
    $pattern = '-*';
  }
  else
  {
    $pattern = '-'.derivative_to_url($type).'*';
  }
  $path = substr_replace($path, $pattern, $dot, 0);
  if ( ($glob=glob(PHPWG_ROOT_PATH.PWG_DERIVATIVE_DIR.$path)) !== false)
  {
    foreach( $glob as $file)
    {
      @unlink($file);
    }
  }
}

/**
 * Returns an array containing sub-directories, excluding ".svn"
 *
 * @param string $directory
 * @return string[]
 */
function get_dirs($directory)
{
  $sub_dirs = array();
  if ($opendir = opendir($directory))
  {
    while ($file = readdir($opendir))
    {
      if ($file != '.'
          and $file != '..'
          and is_dir($directory.'/'.$file)
          and $file != '.svn')
      {
        $sub_dirs[] = $file;
      }
    }
    closedir($opendir);
  }
  return $sub_dirs;
}

/**
 * Recursively delete a directory.
 *
 * @param string $path
 * @param string $trash_path, try to move the directory to this path if it cannot be delete
 */
function deltree($path, $trash_path=null)
{
  if (is_dir($path))
  {
    $fh = opendir($path);
    while ($file = readdir($fh))
    {
      if ($file != '.' and $file != '..')
      {
        $pathfile = $path . '/' . $file;
        if (is_dir($pathfile))
        {
          deltree($pathfile, $trash_path);
        }
        else
        {
          @unlink($pathfile);
        }
      }
    }
    closedir($fh);

    if (@rmdir($path))
    {
      return true;
    }
    elseif (!empty($trash_path))
    {
      if (!is_dir($trash_path))
      {
        @mkgetdir($trash_path, MKGETDIR_RECURSIVE|MKGETDIR_DIE_ON_ERROR|MKGETDIR_PROTECT_HTACCESS);
      }
      while ($r = $trash_path . '/' . md5(uniqid(rand(), true)))
      {
        if (!is_dir($r))
        {
          @rename($path, $r);
          break;
        }
      }
    }
    else
    {
      return false;
    }
  }
}

/**
 * Returns keys to identify the state of main tables. A key consists of the
 * last modification timestamp and the total of items (separated by a _).
 * Additionally returns the hash of root path.
 * Used to invalidate LocalStorage cache on admin pages.
 *
 * @param string|string[] list of keys to retrieve (categories,groups,images,tags,users)
 * @return string[]
 */
function get_admin_client_cache_keys($requested=array())
{
  $tables = array(
    'categories' => CATEGORIES_TABLE,
    'groups' => GROUPS_TABLE,
    'images' => IMAGES_TABLE,
    'tags' => TAGS_TABLE,
    'users' => USER_INFOS_TABLE
    );

  if (!is_array($requested))
  {
    $requested = array($requested);
  }
  if (empty($requested))
  {
    $requested = array_keys($tables);
  }
  else
  {
    $requested = array_intersect($requested, array_keys($tables));
  }

  $keys = array(
    '_hash' => md5(get_absolute_root_url()),
    );

  foreach ($requested as $item)
  {
    $query = '
SELECT CONCAT(
    UNIX_TIMESTAMP(MAX(lastmodified)),
    "_",
    COUNT(*)
  )
  FROM '. $tables[$item] .'
;';
    list($keys[$item]) = pwg_db_fetch_row(pwg_query($query));
  }

  return $keys;
}

/**
 * Return the list of image ids associated to no album
 *
 * @return int[] $image_ids
 */
function get_orphans()
{
  $query = '
SELECT
    id
  FROM '.IMAGES_TABLE.'
    LEFT JOIN '.IMAGE_CATEGORY_TABLE.' ON id = image_id
  WHERE category_id is null
;';
  
  return query2array($query, null, 'id');
}

/**
 * save the rank depending on given images order
 *
 * The list of ordered images id is supposed to be in the same parent
 * category
 *
 * @param int category_id
 * @param int[] images
 * @return void
 */
function save_images_order($category_id, $images)
{
  $current_rank = 0;
  $datas = array();
  foreach ($images as $id)
  {
    $datas[] = array(
      'category_id' => $category_id,
      'image_id' => $id,
      'rank' => ++$current_rank,
      );
  }
  $fields = array(
    'primary' => array('image_id', 'category_id'),
    'update' => array('rank')
    );
  mass_updates(IMAGE_CATEGORY_TABLE, $fields, $datas);
}

/**
 * Force update on images.lastmodified column. Useful when modifying the tag
 * list.
 *
 * @since 2.9
 * @param array $image_ids
 */
function update_images_lastmodified($image_ids)
{
  if (!is_array($image_ids) and is_int($image_ids))
  {
    $images_ids = array($image_ids);
  }
  
  if (count($image_ids) == 0)
  {
    return;
  }

  $query = '
UPDATE '.IMAGES_TABLE.'
  SET lastmodified = NOW()
  WHERE id IN ('.implode(',', $image_ids).')
;';
  pwg_query($query);
}

/**
 * Get a more human friendly representation of big numbers. Like 17.8k instead of 17832
 *
 * @since 2.9
 * @param float $numbers
 */
function number_format_human_readable($numbers)
{
  $readable = array("",  "k", "M");
  $index = 0;

  while ($numbers >= 1000)
  {
    $numbers /= 1000;
    $index++;

    if ($index > count($readable) - 1)
    {
      $index--;
      break;
    }
  }

  return number_format($numbers, 1).$readable[$index];
}
