new feature: source/destination links between categories. Will we keep this

feature? Code is complicated and very few people will understand how it
works...

modification: #images.storage_category_id replaced by
#image_category.is_storage

improvement: many code refactoring to improve readibility

improvement: virtual category creation code was moved to a dedicated
function in order to be called from admin/cat_list.php and
admin/cat_modify.php (create a new destination category)


git-svn-id: http://piwigo.org/svn/trunk@1064 68402e56-0260-453c-a942-63ccdbb3a9ee

10 files changed, 1057 insertions, 269 deletions

diff --git a/admin/cat_list.php b/admin/cat_list.php
index 3acbbad5e..0c350ea00 100644
--- a/admin/cat_list.php
+++ b/admin/cat_list.php
@@ -83,92 +83,18 @@ if (isset($_GET['delete']) and is_numeric($_GET['delete']))
 // request to add a virtual category
 else if (isset($_POST['submitAdd']))
 {
-  // is the given category name only containing blank spaces ?
-  if (preg_match('/^\s*$/', $_POST['virtual_name']))
+  $output_create = create_virtual_category(
+    $_POST['virtual_name'],
+    @$_GET['parent_id']
+    );
+
+  if (isset($output_create['error']))
   {
-    array_push($page['errors'], $lang['cat_error_name']);
+    array_push($page['errors'], $output_create['error']);
   }
-	
-  if (!count($page['errors']))
+  else
   {
-    $parent_id = !empty($_GET['parent_id'])?$_GET['parent_id']:'NULL';
-    
-    if ($parent_id != 'NULL')
-    {
-      $query = '
-SELECT id,uppercats,global_rank,visible,status
-  FROM '.CATEGORIES_TABLE.'
-  WHERE id = '.$parent_id.'
-;';
-      $row = mysql_fetch_array(pwg_query($query));
-      $parent = array('id' => $row['id'],
-                      'uppercats' => $row['uppercats'],
-                      'visible' => $row['visible'],
-                      'status' => $row['status'],
-                      'global_rank' => $row['global_rank']);
-    }
-
-    // what will be the inserted id ?
-    $query = '
-SELECT IF(MAX(id)+1 IS NULL, 1, MAX(id)+1)
-  FROM '.CATEGORIES_TABLE.'
-;';
-    list($next_id) = mysql_fetch_array(pwg_query($query));
-    
-    $insert = array();
-    $insert{'id'} = $next_id++;
-    $insert{'name'} = $_POST['virtual_name'];
-    $insert{'rank'} = $_POST['rank'];
-    $insert{'commentable'} = $conf['newcat_default_commentable'];
-
-    // a virtual category can't be uploadable
-    $insert{'uploadable'} = 'false';
-    
-    if (isset($parent))
-    {
-      $insert{'id_uppercat'} = $parent{'id'};
-      $insert{'uppercats'}   = $parent{'uppercats'}.','.$insert{'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';
-      }
-      else
-      {
-        $insert{'visible'} = $conf['newcat_default_visible'];
-      }
-      // 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';
-      }
-      else
-      {
-        $insert{'status'} = $conf['newcat_default_status'];
-      }
-    }
-    else
-    {
-      $insert{'visible'} = $conf['newcat_default_visible'];
-      $insert{'status'} = $conf['newcat_default_status'];
-      $insert{'uppercats'} = $insert{'id'};
-      $insert{'global_rank'} = $insert{'rank'};
-    }
-
-    $inserts = array($insert);
-    
-    // we have then to add the virtual category
-    $dbfields = array('id','site_id','name','id_uppercat','rank',
-                      'commentable','uploadable','visible','status',
-                      'uppercats','global_rank');
-    mass_inserts(CATEGORIES_TABLE, $dbfields, $inserts);
-
-    array_push($page['infos'], $lang['cat_virtual_added']);
+    array_push($page['infos'], $output_create['info']);
   }
 }
 else if (isset($_POST['submitOrder']))
@@ -211,9 +137,12 @@ if (isset($_GET['parent_id']))
   $navigation.= $conf['level_separator'];
 
   $current_category = get_cat_info($_GET['parent_id']);
-  $navigation.= get_cat_display_name($current_category['name'],
-                                     $base_url.'&parent_id=',
-                                     false);
+  
+  $navigation.= get_cat_display_name(
+    $current_category['name'],
+    $base_url.'&parent_id=',
+    false
+    );
 }
 // +-----------------------------------------------------------------------+
 // |                       template initialization                         |
@@ -226,18 +155,8 @@ if (isset($_GET['parent_id']))
   $form_action.= '&parent_id='.$_GET['parent_id'];
 }
 
-if (count($categories) > 0)
-{
-  $next_rank = max(array_keys($categories)) + 1;
-}
-else
-{
-  $next_rank = 1;
-}
-
 $template->assign_vars(array(
   'CATEGORIES_NAV'=>$navigation,
-  'NEXT_RANK'=>$next_rank,
   'F_ACTION'=>$form_action,
   
   'L_ADD_VIRTUAL'=>$lang['cat_add'],
diff --git a/admin/cat_modify.php b/admin/cat_modify.php
index 309425c91..e06e1a8cb 100644
--- a/admin/cat_modify.php
+++ b/admin/cat_modify.php
@@ -88,6 +88,122 @@ UPDATE '.CATEGORIES_TABLE.'
 ;';
   pwg_query($query);
 }
+else if (isset($_POST['submitAdd']))
+{
+  $output_create = create_virtual_category(
+    $_POST['virtual_name'],
+    (0 == $_POST['parent'] ? null : $_POST['parent'])
+    );
+  
+  if (isset($output_create['error']))
+  {
+    array_push($page['errors'], $output_create['error']);
+  }
+  else
+  {
+    // Virtual category creation succeeded
+    //
+    // Add the information in the information list
+    array_push($page['infos'], $output_create['info']);
+    
+    // Link the new category to the current category
+    $query = '
+INSERT
+  INTO '.CATEGORIES_LINK_TABLE.'
+  (source, destination)
+  VALUES
+  ('.$_GET['cat_id'].', '.$output_create['id'].')
+;';
+    pwg_query($query);
+
+    check_links(array($output_create['id']));
+    update_category(array($output_create['id']));
+  }
+}
+else if (isset($_POST['destination_trueify'])
+         and isset($_POST['destination_false'])
+         and count($_POST['destination_false']))
+{
+  $datas = array();
+  
+  foreach ($_POST['destination_false'] as $category_id)
+  {
+    array_push(
+      $datas,
+      array(
+        'source'      => $_GET['cat_id'],
+        'destination' => $category_id,
+        )
+      );
+  }
+  
+  mass_inserts(
+    CATEGORIES_LINK_TABLE,
+    array('source', 'destination'),
+    $datas
+    );
+
+  check_links($_POST['destination_false']);
+  update_category(
+    $_POST['destination_false'],
+    true                          // recursive update
+    );
+}
+else if (isset($_POST['destination_falsify'])
+         and isset($_POST['destination_true'])
+         and count($_POST['destination_true']))
+{
+  foreach ($_POST['destination_true'] as $destination)
+  {
+    delete_sources($destination, array($_GET['cat_id']));
+  }
+
+  update_category(
+    $_POST['destination_true'],
+    true                          // recursive update
+    );
+}
+else if (isset($_POST['source_trueify'])
+         and isset($_POST['source_false'])
+         and count($_POST['source_false']))
+{
+  $datas = array();
+  
+  foreach ($_POST['source_false'] as $category_id)
+  {
+    array_push(
+      $datas,
+      array(
+        'source'      => $category_id,
+        'destination' => $_GET['cat_id'],
+        )
+      );
+  }
+  
+  mass_inserts(
+    CATEGORIES_LINK_TABLE,
+    array('source', 'destination'),
+    $datas
+    );
+
+  check_links(array($_GET['cat_id']));
+  update_category(
+    array($_GET['cat_id']),
+    true                          // recursive update
+    );
+}
+else if (isset($_POST['source_falsify'])
+         and isset($_POST['source_true'])
+         and count($_POST['source_true']))
+{
+  delete_sources($_GET['cat_id'], $_POST['source_true']);
+  
+  update_category(
+    array($_GET['cat_id']),
+    true                          // recursive update
+    );
+}
+
 
 $query = '
 SELECT *
@@ -316,6 +432,71 @@ if (!$category['is_virtual'] and !url_is_remote($category['cat_dir']) )
   $template->assign_block_vars('upload' ,array());
 }
 
+$blockname = 'category_option_parent';
+
+$template->assign_block_vars(
+  $blockname,
+  array(
+    'VALUE'=> 0,
+    'OPTION' => '------------'
+    )
+  );
+
+$query = '
+SELECT id,name,uppercats,global_rank
+  FROM '.CATEGORIES_TABLE.'
+;';
+
+display_select_cat_wrapper(
+  $query,
+  array(),
+  $blockname
+  );
+
+// destination categories
+$query = '
+SELECT DISTINCT id, name, uppercats, global_rank
+  FROM '.CATEGORIES_TABLE.'
+    INNER JOIN '.CATEGORIES_LINK_TABLE.' ON destination = id
+  WHERE source = '.$_GET['cat_id'].'
+;';
+display_select_cat_wrapper($query, array(), 'destination_option_true');
+
+// non destination categories
+$destinations = array_merge(
+  array($_GET['cat_id']),
+  array_from_query($query, 'id')
+  );
+
+$query = '
+SELECT DISTINCT id, name, uppercats, global_rank
+  FROM '.CATEGORIES_TABLE.'
+  WHERE id NOT IN ('.implode(',', $destinations).')
+;';
+display_select_cat_wrapper($query, array(), 'destination_option_false');
+
+// source categories
+$query = '
+SELECT DISTINCT id, name, uppercats, global_rank
+  FROM '.CATEGORIES_TABLE.'
+    INNER JOIN '.CATEGORIES_LINK_TABLE.' ON source = id
+  WHERE destination = '.$_GET['cat_id'].'
+;';
+display_select_cat_wrapper($query, array(), 'source_option_true');
+
+// non source categories
+$sources = array_merge(
+  array($_GET['cat_id']),
+  array_from_query($query, 'id')
+  );
+
+$query = '
+SELECT DISTINCT id, name, uppercats, global_rank
+  FROM '.CATEGORIES_TABLE.'
+  WHERE id NOT IN ('.implode(',', $sources).')
+;';
+display_select_cat_wrapper($query, array(), 'source_option_false');
+
 //----------------------------------------------------------- sending html code
 $template->assign_var_from_handle('ADMIN_CONTENT', 'categories');
 ?>
diff --git a/admin/include/functions.php b/admin/include/functions.php
index 9c385092e..a1c13cd05 100644
--- a/admin/include/functions.php
+++ b/admin/include/functions.php
@@ -1,3 +1,4 @@
+
 <?php
 // +-----------------------------------------------------------------------+
 // | PhpWebGallery - a PHP based picture gallery                           |
@@ -152,16 +153,22 @@ function delete_categories($ids)
 
   // destruction of all the related elements
   $query = '
-SELECT id
-  FROM '.IMAGES_TABLE.'
-  WHERE storage_category_id IN (
-'.wordwrap(implode(', ', $ids), 80, "\n").')
+SELECT image_id
+  FROM '.IMAGE_CATEGORY_TABLE.'
+  WHERE is_storage = \'true\'
+    AND category_id IN ('.
+    wordwrap(
+      implode(', ', $ids),
+      80,
+      "\n"
+      ).
+    ')
 ;';
   $result = pwg_query($query);
   $element_ids = array();
   while ($row = mysql_fetch_array($result))
   {
-    array_push($element_ids, $row['id']);
+    array_push($element_ids, $row['image_id']);
   }
   delete_elements($element_ids);
 
@@ -180,6 +187,7 @@ DELETE FROM '.USER_ACCESS_TABLE.'
 '.wordwrap(implode(', ', $ids), 80, "\n").')
 ;';
   pwg_query($query);
+  
   $query = '
 DELETE FROM '.GROUP_ACCESS_TABLE.'
   WHERE cat_id IN (
@@ -187,6 +195,37 @@ DELETE FROM '.GROUP_ACCESS_TABLE.'
 ;';
   pwg_query($query);
 
+  // source/destination links deletion
+  $query = '
+SELECT destination, source
+  FROM '.CATEGORIES_LINK_TABLE.'
+  WHERE source IN ('.implode(',', $ids).')
+    OR destination IN ('.implode(',', $ids).')
+;';
+  $result = pwg_query($query);
+
+  $sources_of = array();
+  
+  while ($row = mysql_fetch_array($result))
+  {
+    if (!isset($sources_of[ $row['destination'] ]))
+    {
+      $sources_of[ $row['destination'] ] = array();
+    }
+
+    array_push(
+      $sources_of[ $row['destination'] ],
+      $row['source']
+      );
+  }
+
+  foreach ($sources_of as $destination => $sources)
+  {
+    delete_sources($destination, $sources);
+  }
+
+  update_category();
+
   // destruction of the category
   $query = '
 DELETE FROM '.CATEGORIES_TABLE.'
@@ -395,30 +434,48 @@ SELECT id
 SELECT category_id,
        COUNT(image_id) AS nb_images,
        MAX(date_available) AS date_last
-  FROM '.IMAGES_TABLE.' INNER JOIN '.IMAGE_CATEGORY_TABLE.' ON id = image_id
+  FROM '.IMAGES_TABLE.'
+    INNER JOIN '.IMAGE_CATEGORY_TABLE.' ON id = image_id
   WHERE category_id IN ('.wordwrap(implode(', ', $cat_ids), 80, "\n").')
   GROUP BY category_id
 ;';
   $result = pwg_query($query);
   $datas = array();
   $query_ids = array();
-  while ( $row = mysql_fetch_array( $result ) )
+  while ($row = mysql_fetch_array($result))
   {
     array_push($query_ids, $row['category_id']);
-    array_push($datas, array('id' => $row['category_id'],
-                             'date_last' => $row['date_last'],
-                             'nb_images' => $row['nb_images']));
+    
+    array_push(
+      $datas,
+      array(
+        'id'        => $row['category_id'],
+        'date_last' => $row['date_last'],
+        'nb_images' => $row['nb_images']
+        )
+      );
   }
   // if all links between a category and elements have disappeared, no line
   // is returned but the update must be done !
   foreach (array_diff($cat_ids, $query_ids) as $id)
   {
-    array_push($datas, array('id' => $id, 'nb_images' => 0));
+    array_push(
+      $datas,
+      array(
+        'id'        => $id,
+        'nb_images' => 0,
+        )
+      );
   }
 
-  $fields = array('primary' => array('id'),
-                  'update'  => array('date_last', 'nb_images'));
-  mass_updates(CATEGORIES_TABLE, $fields, $datas);
+  mass_updates(
+    CATEGORIES_TABLE,
+    array(
+      'primary' => array('id'),
+      'update'  => array('date_last', 'nb_images')
+      ),
+    $datas
+    );
 
   // representative pictures
   if (count($cat_ids) > 0)
@@ -1291,19 +1348,42 @@ SELECT id, id_uppercat
  */
 function update_path()
 {
+  $images_of = array();
+  
   $query = '
-SELECT DISTINCT(storage_category_id)
-  FROM '.IMAGES_TABLE.'
+SELECT category_id, image_id
+  FROM '.IMAGE_CATEGORY_TABLE.'
+  WHERE is_storage = \'true\'
 ;';
-  $cat_ids = array_from_query($query, 'storage_category_id');
-  $fulldirs = get_fulldirs($cat_ids);
+  $result = pwg_query($query);
+  while ($row = mysql_fetch_array($result))
+  {
+    if (!isset($images_of[ $row['category_id'] ]))
+    {
+      $images_of[ $row['category_id'] ] = array();
+    }
 
-  foreach ($cat_ids as $cat_id)
+    array_push(
+      $images_of[ $row['category_id'] ],
+      $row['image_id']
+      );
+  }
+  
+  $fulldirs = get_fulldirs(
+    array_keys($images_of)
+    );
+
+  foreach ($images_of as $cat_id => $image_ids)
   {
     $query = '
 UPDATE '.IMAGES_TABLE.'
   SET path = CONCAT(\''.$fulldirs[$cat_id].'\',\'/\',file)
-  WHERE storage_category_id = '.$cat_id.'
+  WHERE id IN ('.
+      wordwrap(
+        implode(', ', $image_ids),
+        80,
+        "\n").
+      ')
 ;';
     pwg_query($query);
   }
@@ -1522,4 +1602,474 @@ DELETE FROM '.$table.'
       )
     );
 }
+
+/**
+ * Returns all destinations of a list of source categories. This function
+ * solves transitivity.
+ *
+ * @param mixed array of category ids, empty for all categories
+ */
+function get_destinations($categories = 'all')
+{
+  $query = '
+SELECT source, destination
+  FROM '.CATEGORIES_LINK_TABLE.'
+';
+  $result = pwg_query($query);
+
+  $destinations_of = array();
+  
+  while ($row = mysql_fetch_array($result))
+  {
+    if (!isset($destinations_of[ $row['source'] ]))
+    {
+      $destinations_of[ $row['source'] ] = array();
+    }
+
+    array_push(
+      $destinations_of[ $row['source'] ],
+      $row['destination']
+      );
+  }
+
+  // transitivity resolution: if " => " means "source of", if A=>B=>C
+  // implies A=>B and A=>C. So A has 2 destinations: B and C.
+  do
+  {
+    // let's suppose we only need a single turn
+    $need_new_turn = false;
+    
+    foreach ($destinations_of as $source => $destinations)
+    {
+      foreach ($destinations as $destination)
+      {
+        // does the current destination has destinations itself?
+        if (isset($destinations_of[$destination]))
+        {
+          // are there destinations of current destination not already among
+          // destinations of the current source? (advise: take a piece of
+          // paper and draw a schema). The source itself must not be counted
+          // as a destination, thus avoiding cyclic links.
+          $missing_destinations = array_diff(
+            $destinations_of[$destination],
+            $destinations,
+            array($source) // no cyclic link
+            );
+          
+          if (count($missing_destinations) > 0)
+          {
+            $destinations_of[$source] = array_unique(
+              array_merge(
+                $destinations,
+                $missing_destinations
+                )
+              );
+
+            // a category has a least one new destination, we have to check
+            // one more time that it doesn't generate more destinations
+            $need_new_turn = true;
+          }
+        }
+      }
+    }
+  } while ($need_new_turn);
+
+  if (is_array($categories))
+  {
+    $filtered_destinations_of = array();
+
+    // Even if there is no destinations for the requested categories, we
+    // return empty arrays
+    foreach ($categories as $category)
+    {
+      $filtered_destinations_of[$category] = array();
+    }
+    
+    foreach ($destinations_of as $source => $destinations)
+    {
+      if (in_array($source, $categories))
+      {
+        $filtered_destinations_of[$source] = $destinations;
+      }
+    }
+
+    return $filtered_destinations_of;
+  }
+  else
+  {
+    return $destinations_of;
+  }
+}
+
+/**
+ * Returns all sources of a list of destination categories. This function
+ * solves transitivity.
+ *
+ * @param mixed array of category ids, empty for all categories
+ */
+function get_sources($categories = 'all')
+{
+  $destinations_of = get_destinations();
+
+  $sources_of = array();
+  
+  foreach ($destinations_of as $source => $destinations)
+  {
+    foreach ($destinations as $destination)
+    {
+      if (!isset($sources_of[$destination]))
+      {
+        $sources_of[$destination] = array();
+      }
+
+      array_push($sources_of[$destination], $source);
+    }
+  }
+  
+  // eventually, filter
+  if (is_array($categories))
+  {
+    $filtered_sources_of = array();
+
+    // Even if there is no sources for the requested categories, we return
+    // empty arrays
+    foreach ($categories as $category)
+    {
+      $filtered_sources_of[$category] = array();
+    }
+    
+    foreach ($sources_of as $destination => $sources)
+    {
+      if (in_array($destination, $categories))
+      {
+        $filtered_sources_of[$destination] = $sources;
+      }
+    }
+
+    return $filtered_sources_of;
+  }
+  else
+  {
+    return $sources_of;
+  }
+}
+
+/**
+ * Checks categories links are respected for a given list of destinations.
+ *
+ * Checking categories links means that each destination must be associated
+ * to the images of its sources.
+ *
+ * @param mixed source category ids
+ */
+function check_links($destinations = 'all')
+{
+  $sources_of = get_sources($destinations);
+
+  if (empty($sources_of))
+  {
+    return true;
+  }
+
+  // we need to search images of all sources and destinations
+  $images_of = array();
+
+  foreach ($sources_of as $destination => $sources)
+  {
+    $images_of[$destination] = array();
+
+    foreach ($sources as $source)
+    {
+      $images_of[$source] = array();
+    }
+  }
+  
+  $query = '
+SELECT image_id, category_id
+  FROM '.IMAGE_CATEGORY_TABLE.'
+  WHERE category_id IN ('.
+    implode(',', array_keys($images_of)).
+    ')
+;';
+  $result = pwg_query($query);
+
+  while ($row = mysql_fetch_array($result))
+  {
+    array_push(
+      $images_of[ $row['category_id'] ],
+      $row['image_id']
+      );
+  }
+
+  $inserts = array();
+  
+  foreach ($sources_of as $destination => $sources)
+  {
+    // merge all images from the sources of this destination
+    $sources_images = array();
+    
+    foreach ($sources as $source)
+    {
+      $sources_images = array_merge(
+        $sources_images,
+        $images_of[$source]
+        );
+    }
+
+    $sources_images = array_unique($sources_images);
+
+    // are there images among the sources that are not linked to the
+    // destination?
+    $missing_images = array_diff(
+      $sources_images,
+      $images_of[$destination]
+      );
+
+    // if we find missing images (missing links in reality), we prepare the
+    // final mass_inserts
+    if (count($missing_images) > 0)
+    {
+      foreach ($missing_images as $missing_image)
+      {
+        array_push(
+          $inserts,
+          array(
+            'category_id' => $destination,
+            'image_id'    => $missing_image,
+            )
+          );
+      }
+    }
+  }
+
+  if (count($inserts) > 0)
+  {
+    mass_inserts(
+      IMAGE_CATEGORY_TABLE,
+      array_keys($inserts[0]),
+      $inserts
+      );
+  }
+}
+
+/**
+ * Based on categories links, delete image_category links on destinations.
+ *
+ * The rule is the following: if an image belong to the category and to the
+ * source, we suppose it comes from the source. If the source/destination
+ * link is broken, we delete the image/category link if the only origin of
+ * the link was the broken categories link.
+ *
+ * Example: "=>" means "source of". Between brackets the associated images.
+ *
+ * A (1,2,9) => \
+ *               |=> C (1,2,3,4,5,9) => D (1,2,3,4,5,6,9)
+ * B (3,4,9) => /
+ *
+ * In category C, we suppose (1,2) come from A, (3,4) from B, 9 from A or B
+ * and 5 was manually added. In category D, 6 was added manually.
+ *
+ * If we break A=>C, C and D loose (1,2) but not 9 because it can come from
+ * B. If we break C=>D, D loose (3,4,5,9) but not 6 because it was
+ * associated manually to 9.
+ *
+ * Warning: only virtual links can be removed, physical links are protected.
+ * 
+ * @param int destination
+ * @param array sources
+ */
+function delete_sources($destination, $sources)
+{
+  // if no sources to unlink, we stop with OK status
+  if (count($sources) == 0)
+  {
+    return true;
+  }
+
+  $query = '
+DELETE
+  FROM '.CATEGORIES_LINK_TABLE.'
+  WHERE destination = '.$destination.'
+    AND source IN ('.implode(',', $sources).')
+;';
+  pwg_query($query);
+  
+  // The strategy is the following:
+  //
+  // * first we brutally delete the image/category associations on
+  // destinations categories for all images belonging to sources.
+  //
+  // * then we check_links on destinations to rebuild missing image/category
+  // associations.
+
+  // what are the images associated to the sources to unlink
+  $query = '
+SELECT image_id
+  FROM '.IMAGE_CATEGORY_TABLE.'
+  WHERE category_id IN ('.
+    implode(',', $sources).
+    ')
+;';
+  $sources_images = array_unique(
+    array_from_query($query, 'image_id')
+    );
+
+  if (count($sources_images) == 0)
+  {
+    return true;
+  }
+
+  // retrieve all direct and indirect destinations of the current
+  // destination
+  $destinations_of = get_destinations(array($destination));
+
+  $destinations = array_merge(
+    array($destination),
+    $destinations_of[$destination]
+    );
+  
+  // unlink sources images from destinations
+  $query = '
+DELETE
+  FROM '.IMAGE_CATEGORY_TABLE.'
+  WHERE category_id IN ('.implode(',', $destinations).')
+    AND image_id IN ('.implode(',', $sources_images).')
+    AND is_storage = \'false\'
+;';
+  pwg_query($query);
+
+  // if the representative thumbnail of destinations was a picture from
+  // $sources_images, we request a new random representant
+  $query = '
+SELECT id, representative_picture_id
+  FROM '.CATEGORIES_TABLE.'
+  WHERE id IN ('.implode(',', $destinations).')
+;';
+  $result = pwg_query($query);
+
+  $request_random = array();
+  
+  while ($row = mysql_fetch_array($result))
+  {
+    if (isset($row['representative_picture_id']))
+    {
+      if (in_array($row['representative_picture_id'], $sources_images))
+      {
+        array_push($request_random, $row['id']);
+      }
+    }
+  }
+
+  set_random_representant($request_random);
+
+  // eventually, we check_links to rebuild missing associations
+  check_links($destinations);
+
+  return true;
+}
+
+/**
+ * create a virtual category
+ *
+ * @param string category name
+ * @param int parent category id
+ * @return array with ('info' and 'id') or ('error') key
+ */
+function create_virtual_category($category_name, $parent_id=null)
+{
+  global $conf;
+  
+  // is the given category name only containing blank spaces ?
+  if (preg_match('/^\s*$/', $category_name))
+  {
+    return array('error' => l10n('cat_error_name'));
+  }
+	
+  $parent_id = !empty($parent_id) ? $parent_id : 'NULL';
+
+  $query = '
+SELECT MAX(rank)
+  FROM '.CATEGORIES_TABLE.'
+  WHERE id_uppercat '.(is_numeric($parent_id) ? '= '.$parent_id : 'IS NULL').'
+;';
+  list($current_rank) = mysql_fetch_array(pwg_query($query));
+  
+  $insert = array(
+    'name' => $category_name,
+    'rank' => ++$current_rank,
+    'commentable' => $conf['newcat_default_commentable'],
+    'uploadable' => 'false',
+    );
+    
+  if ($parent_id != 'NULL')
+  {
+    $query = '
+SELECT id, uppercats, global_rank, visible, status
+  FROM '.CATEGORIES_TABLE.'
+  WHERE id = '.$parent_id.'
+;';
+    $parent = mysql_fetch_array(pwg_query($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';
+    }
+    else
+    {
+      $insert{'visible'} = $conf['newcat_default_visible'];
+    }
+    
+    // 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';
+    }
+    else
+    {
+      $insert{'status'} = $conf['newcat_default_status'];
+    }
+  }
+  else
+  {
+    $insert{'visible'} = $conf['newcat_default_visible'];
+    $insert{'status'} = $conf['newcat_default_status'];
+    $insert{'global_rank'} = $insert{'rank'};
+  }
+
+  // we have then to add the virtual category
+  mass_inserts(
+    CATEGORIES_TABLE,
+    array(
+      'site_id', 'name', 'id_uppercat', 'rank', 'commentable',
+      'uploadable', 'visible', 'status', 'global_rank',
+      ),
+    array($insert)
+    );
+
+  $inserted_id = mysql_insert_id();
+
+  $query = '
+UPDATE
+  '.CATEGORIES_TABLE.'
+  SET uppercats = \''.
+    (isset($parent) ? $parent{'uppercats'}.',' : '').
+    $inserted_id.
+    '\'
+  WHERE id = '.$inserted_id.'
+;';
+  pwg_query($query);
+  
+  return array(
+    'info' => l10n('cat_virtual_added'),
+    'id'   => $inserted_id,
+    );
+}
 ?>
diff --git a/admin/include/functions_metadata.php b/admin/include/functions_metadata.php
index 23dca79a9..337019b2e 100644
--- a/admin/include/functions_metadata.php
+++ b/admin/include/functions_metadata.php
@@ -224,7 +224,9 @@ SELECT id
   $query = '
 SELECT id, path
   FROM '.IMAGES_TABLE.'
-  WHERE storage_category_id IN ('.implode(',', $cat_ids).')';
+    INNER JOIN '.IMAGE_CATEGORY_TABLE.' ON image_id = id
+  WHERE is_storage = \'true\'
+    AND category_id IN ('.implode(',', $cat_ids).')';
   if ($only_new)
   {
     $query.= '
diff --git a/admin/maintenance.php b/admin/maintenance.php
index 067f1ff82..5653ed4cd 100644
--- a/admin/maintenance.php
+++ b/admin/maintenance.php
@@ -41,6 +41,7 @@ switch ($action)
 {
   case 'categories' :
   {
+    check_links();
     update_uppercats();
     update_category('all');
     ordering();
diff --git a/admin/picture_modify.php b/admin/picture_modify.php
index 097857ec5..a4d5d8ac5 100644
--- a/admin/picture_modify.php
+++ b/admin/picture_modify.php
@@ -171,11 +171,13 @@ if (isset($_POST['dismiss'])
 $query = '
 SELECT *
   FROM '.IMAGES_TABLE.'
+    INNER JOIN '.IMAGE_CATEGORY_TABLE.' ON image_id = id
   WHERE id = '.$_GET['image_id'].'
+    AND is_storage = \'true\'
 ;';
 $row = mysql_fetch_array(pwg_query($query));
 
-$storage_category_id = $row['storage_category_id'];
+$storage_category_id = $row['category_id'];
 
 // Navigation path
 
@@ -341,7 +343,7 @@ SELECT id,name,uppercats,global_rank
   FROM '.CATEGORIES_TABLE.'
     INNER JOIN '.IMAGE_CATEGORY_TABLE.' ON id = category_id
   WHERE image_id = '.$_GET['image_id'].'
-    AND id != '.$storage_category_id.'
+    AND is_storage = \'false\'
 ;';
 display_select_cat_wrapper($query, array(), 'associated_option');
 
diff --git a/admin/rating.php b/admin/rating.php
index 6be2dd8ca..38f58f3ff 100644
--- a/admin/rating.php
+++ b/admin/rating.php
@@ -168,16 +168,26 @@ for ($i=0; $i<count($available_order_by); $i++)
     );
 }
 
-$query = 'SELECT i.id, i.path, i.file, i.tn_ext, i.average_rate, i.storage_category_id,
-          MAX(r.date) as recently_rated, COUNT(r.rate) as nb_rates,
-          SUM(r.rate) as sum_rates, ROUND(STD(r.rate),2) as std_rates
-FROM '.RATE_TABLE.' AS r LEFT JOIN '.IMAGES_TABLE.' AS i
-ON r.element_id=i.id
-WHERE 1=1 ' . $display_filter . '
-GROUP BY r.element_id
-ORDER BY ' . $available_order_by[$order_by_index][1] .'
-LIMIT '.$start.','.$elements_per_page .
-';';
+$query = '
+SELECT i.id,
+       i.path,
+       i.file,
+       i.tn_ext,
+       i.average_rate,
+       MAX(r.date)          AS recently_rated,
+       COUNT(r.rate)        AS nb_rates,
+       SUM(r.rate)          AS sum_rates,
+       ROUND(STD(r.rate),2) AS std_rates,
+       ic.category_id       AS storage_category_id
+  FROM '.RATE_TABLE.' AS r
+    LEFT JOIN '.IMAGES_TABLE.' AS i ON r.element_id = i.id
+    INNER JOIN '.IMAGE_CATEGORY_TABLE.' AS ic ON ic.image_id = i.id
+  WHERE 1 = 1 ' . $display_filter . '
+    AND ic.is_storage = \'true\'
+  GROUP BY r.element_id
+  ORDER BY ' . $available_order_by[$order_by_index][1] .'
+  LIMIT '.$start.','.$elements_per_page.'
+;';
 
 $images = array();
 $result = pwg_query($query);
@@ -188,13 +198,13 @@ while ($row = mysql_fetch_array($result))
 
 foreach ($images as $image)
 {
-  $thumbnail_src = get_thumbnail_src(
-    $image['path'], $image['tn_ext']
-    );
+  $thumbnail_src = get_thumbnail_src($image['path'], $image['tn_ext']);
 
-  $image_url = PHPWG_ROOT_PATH.'picture.php?'.
-                'cat=' . $image['storage_category_id'].
-                '&amp;image_id=' . $image['id'];
+  $image_url =
+    PHPWG_ROOT_PATH.'picture.php?'.
+    'cat=' . $image['storage_category_id'].
+    '&amp;image_id=' . $image['id']
+    ;
 
   $query = 'SELECT *
 FROM '.RATE_TABLE.' AS r
diff --git a/admin/site_reader_local.php b/admin/site_reader_local.php
index fc31aaec8..23161d2e2 100644
--- a/admin/site_reader_local.php
+++ b/admin/site_reader_local.php
@@ -44,11 +44,20 @@ function LocalSiteReader($url)
 function open()
 {
   global $errors;
+  
   if (!is_dir($this->site_url))
   {
-    array_push($errors, array('path' => $this->site_url, 'type' => 'PWG-ERROR-NO-FS'));
+    array_push(
+      $errors,
+      array(
+        'path' => $this->site_url,
+        'type' => 'PWG-ERROR-NO-FS'
+        )
+      );
+    
     return false;
   }
+  
   return true;
 }
 
@@ -135,8 +144,11 @@ function get_elements($path)
 function get_update_attributes()
 {
   global $conf;
-  $update_fields = array( 'has_high', 'representative_ext',
-      'filesize', 'width', 'height' );
+  
+  $update_fields = array(
+    'has_high', 'representative_ext', 'filesize', 'width', 'height'
+    );
+  
   if ($conf['use_exif'])
   {
     $update_fields =
@@ -154,6 +166,7 @@ function get_update_attributes()
         array_keys($conf['use_iptc_mapping'])
         );
   }
+  
   return $update_fields;
 }
 
@@ -169,9 +182,13 @@ function get_element_update_attributes($file)
   $data = array();
 
   $filename = basename($file);
-  $data['has_high'] = $this->get_has_high( dirname($file), $filename );
-  $data['representative_ext'] = $this->get_representative_ext( dirname($file),
-                                        get_filename_wo_extension($filename) );
+  
+  $data['has_high'] = $this->get_has_high(dirname($file), $filename);
+  
+  $data['representative_ext'] = $this->get_representative_ext(
+    dirname($file),
+    get_filename_wo_extension($filename)
+    );
 
   $data['filesize'] = floor(filesize($file)/1024);
   if ($image_size = @getimagesize($file))
@@ -204,6 +221,7 @@ function get_element_update_attributes($file)
       }
     }
   }
+  
   return $data;
 }
 
@@ -212,8 +230,7 @@ function get_element_update_attributes($file)
 function get_representative_ext($path, $filename_wo_ext)
 {
   global $conf;
-  $base_test = $path.'/pwg_representative/';
-  $base_test.= $filename_wo_ext.'.';
+  $base_test = $path.'/pwg_representative/'.$filename_wo_ext.'.';
   foreach ($conf['picture_ext'] as $ext)
   {
     $test = $base_test.$ext;
@@ -228,8 +245,10 @@ function get_representative_ext($path, $filename_wo_ext)
 function get_tn_ext($path, $filename_wo_ext)
 {
   global $conf;
-  $base_test = $path.'/thumbnail/';
-  $base_test.= $conf['prefix_thumbnail'].$filename_wo_ext.'.';
+  
+  $base_test =
+    $path.'/thumbnail/'.$conf['prefix_thumbnail'].$filename_wo_ext.'.';
+  
   foreach ($conf['picture_ext'] as $ext)
   {
     $test = $base_test.$ext;
@@ -238,6 +257,7 @@ function get_tn_ext($path, $filename_wo_ext)
       return $ext;
     }
   }
+  
   return null;
 }
 
@@ -247,6 +267,7 @@ function get_has_high($path, $filename)
   {
     return 'true';
   }
+  
   return null;
 }
 
diff --git a/admin/site_reader_remote.php b/admin/site_reader_remote.php
index 3bcd367d3..1810b955b 100644
--- a/admin/site_reader_remote.php
+++ b/admin/site_reader_remote.php
@@ -39,8 +39,12 @@ var $update_attributes;
 function RemoteSiteReader($url)
 {
   $this->site_url = $url;
-  $this->insert_attributes = array('tn_ext', 'representative_ext', 'has_high');
-  $this->update_attributes = array( 'representative_ext', 'has_high', 'filesize', 'width', 'height' );
+  $this->insert_attributes = array(
+    'tn_ext', 'representative_ext', 'has_high'
+    );
+  $this->update_attributes = array(
+    'representative_ext', 'has_high', 'filesize', 'width', 'height'
+    );
 }
 
 /**
@@ -51,6 +55,7 @@ function RemoteSiteReader($url)
 function open()
 {
   global $errors;
+  
   $listing_file = $this->site_url.'/listing.xml';
   if (@fopen($listing_file, 'r'))
   {
@@ -58,20 +63,38 @@ function open()
     $this->site_files = array();
     $xml_content = getXmlCode($listing_file);
     $info_xml_element = getChild($xml_content, 'informations');
-    if ( getAttribute($info_xml_element , 'phpwg_version') != PHPWG_VERSION )
+    if (getAttribute($info_xml_element , 'phpwg_version') != PHPWG_VERSION)
     {
-      array_push($errors, array('path' => $listing_file, 'type' => 'PWG-ERROR-VERSION'));
+      array_push(
+        $errors,
+        array(
+          'path' => $listing_file,
+          'type' => 'PWG-ERROR-VERSION'
+          )
+        );
+      
       return false;
     }
-    $meta_attributes = explode ( ',',
-        getAttribute($info_xml_element , 'metadata') );
-    $this->update_attributes = array_merge( $this->update_attributes, $meta_attributes );
+
+    $this->update_attributes = array_merge(
+      $this->update_attributes,
+      explode(',', getAttribute($info_xml_element, 'metadata'))
+      );
+    
     $this->build_structure($xml_content, '', 0);
+    
     return true;
   }
   else
   {
-    array_push($errors, array('path' => $listing_file, 'type' => 'PWG-ERROR-NOLISTING'));
+    array_push(
+      $errors,
+      array(
+        'path' => $listing_file,
+        'type' => 'PWG-ERROR-NOLISTING'
+        )
+      );
+
     return false;
   }
 }
@@ -83,8 +106,8 @@ function get_full_directories($basedir)
   foreach ( array_keys($this->site_dirs) as $dir)
   {
     $full_dir = $this->site_url . $dir;
-    if ( $full_dir!=$basedir
-      and strpos($full_dir, $basedir)===0
+    if ($full_dir != $basedir
+        and strpos($full_dir, $basedir) === 0
       )
     {
       array_push($dirs, $full_dir);
@@ -105,12 +128,14 @@ function get_elements($path)
   foreach ( $this->site_dirs as $dir=>$files)
   {
     $full_dir = $this->site_url . $dir;
-    if ( strpos($full_dir, $path)===0 )
+    if (strpos($full_dir, $path) === 0)
     {
-      foreach ( $files as $file)
+      foreach ($files as $file)
       {
-        $data = $this->get_element_attributes($file,
-                                              $this->insert_attributes);
+        $data = $this->get_element_attributes(
+          $file,
+          $this->insert_attributes
+          );
         $elements[$file] = $data;
       }
     }
@@ -129,8 +154,10 @@ function get_update_attributes()
 // returns a hash of attributes (metadata+filesize+width,...) for file
 function get_element_update_attributes($file)
 {
-    return $this->get_element_attributes($file,
-                                         $this->update_attributes);
+  return $this->get_element_attributes(
+    $file,
+    $this->update_attributes
+    );
 }
 
 //-------------------------------------------------- private functions --------
@@ -143,7 +170,7 @@ function get_element_update_attributes($file)
 function get_element_attributes($file, $attributes)
 {
   $xml_element = $this->site_files[$file];
-  if ( ! isset($xml_element) )
+  if (!isset($xml_element))
   {
     return null;
   }
@@ -177,12 +204,15 @@ function build_structure($xml_content, $basedir, $level)
 
   if ($basedir != '')
   {
-    $xml_elements = getChildren( getChild($xml_content, 'root'), 'element' );
+    $xml_elements = getChildren(
+      getChild($xml_content, 'root'),
+      'element'
+      );
     foreach ($xml_elements as $xml_element)
     {
       $path = getAttribute($xml_element, 'path');
       $this->site_files[$path] = $xml_element;
-      array_push( $this->site_dirs[$basedir], $path);
+      array_push($this->site_dirs[$basedir], $path);
     }
   }
 }
diff --git a/admin/site_update.php b/admin/site_update.php
index 04f395190..8c5ecf54c 100644
--- a/admin/site_update.php
+++ b/admin/site_update.php
@@ -27,22 +27,25 @@
 
 if (!defined('PHPWG_ROOT_PATH'))
 {
-  die ('Hacking attempt!');
+  die('Hacking attempt!');
 }
 include_once( PHPWG_ROOT_PATH.'admin/include/isadmin.inc.php');
 
-if (! is_numeric($_GET['site']) )
+if (!is_numeric($_GET['site']))
 {
   die ('site param missing or invalid');
 }
 $site_id = $_GET['site'];
-$query='SELECT galleries_url FROM '.SITES_TABLE.'
-WHERE id='.$site_id.'
+
+$query='
+SELECT galleries_url
+  FROM '.SITES_TABLE.'
+  WHERE id = '.$site_id.'
 ;';
-list($site_url)=mysql_fetch_row(pwg_query($query));
-if (! isset($site_url) )
+list($site_url) = mysql_fetch_row(pwg_query($query));
+if (!isset($site_url))
 {
-  die ("site $site_id does not exist");
+  die('site '.$site_id.' does not exist');
 }
 $site_is_remote = url_is_remote($site_url);
 
@@ -50,24 +53,33 @@ list($dbnow) = mysql_fetch_row(pwg_query('SELECT NOW();'));
 define('CURRENT_DATE', $dbnow);
 
 $error_labels = array(
-  'PWG-UPDATE-1' => array( l10n('update_wrong_dirname_short'),
-                           l10n('update_wrong_dirname_info') ),
-  'PWG-UPDATE-2' => array( l10n('update_missing_tn_short'),
-                           l10n('update_missing_tn_info')
-                           . implode(',', $conf['picture_ext']) ),
-  'PWG-ERROR-NO-FS' => array( l10n('update_missing_file_or_dir'),
-                             l10n('update_missing_file_or_dir_info')),
-  'PWG-ERROR-VERSION' => array( l10n('update_err_pwg_version_differs'),
-                             l10n('update_err_pwg_version_differs_info')),
-  'PWG-ERROR-NOLISTING' => array( l10n('update_err_remote_listing_not_found'),
-                             l10n('update_err_remote_listing_not_found_info'))
-                      );
+  'PWG-UPDATE-1' => array(
+    l10n('update_wrong_dirname_short'),
+    l10n('update_wrong_dirname_info')
+    ),
+  'PWG-UPDATE-2' => array(
+    l10n('update_missing_tn_short'),
+    l10n('update_missing_tn_info').implode(',', $conf['picture_ext'])
+    ),
+  'PWG-ERROR-NO-FS' => array(
+    l10n('update_missing_file_or_dir'),
+    l10n('update_missing_file_or_dir_info')
+    ),
+  'PWG-ERROR-VERSION' => array(
+    l10n('update_err_pwg_version_differs'),
+    l10n('update_err_pwg_version_differs_info')
+    ),
+  'PWG-ERROR-NOLISTING' => array(
+    l10n('update_err_remote_listing_not_found'),
+    l10n('update_err_remote_listing_not_found_info')
+    )
+  );
 $errors = array();
 $infos = array();
 
 if ($site_is_remote)
 {
-  include_once( PHPWG_ROOT_PATH.'admin/site_reader_remote.php');
+  include_once(PHPWG_ROOT_PATH.'admin/site_reader_remote.php');
   $site_reader = new RemoteSiteReader($site_url);
 }
 else
@@ -76,7 +88,7 @@ else
   $site_reader = new LocalSiteReader($site_url);
 }
 
-$general_failure=true;
+$general_failure = true;
 if (isset($_POST['submit']))
 {
   if ($site_reader->open())
@@ -213,23 +225,18 @@ SELECT IF(MAX(id)+1 IS NULL, 1, MAX(id)+1) AS next_id
     $dir = basename($fulldir);
     if (preg_match('/^[a-zA-Z0-9-_.]+$/', $dir))
     {
-      $insert = array();
-
-      $insert{'id'} = $next_id++;
-      $insert{'dir'} = $dir;
-      $insert{'name'} = str_replace('_', ' ', $dir);
-      $insert{'site_id'} = $site_id;
-      $insert{'commentable'} = $conf['newcat_default_commentable'];
-      if (! $site_is_remote)
-      {
-        $insert{'uploadable'} = $conf['newcat_default_uploadable'];
-      }
-      else
-      {
-        $insert{'uploadable'} = 'false';
-      }
-      $insert{'status'} = $conf{'newcat_default_status'};
-      $insert{'visible'} = $conf{'newcat_default_visible'};
+      $insert = array(
+        'id'          => $next_id++,
+        'dir'         => $dir,
+        'name'        => str_replace('_', ' ', $dir),
+        'site_id'     => $site_id,
+        'commentable' => $conf['newcat_default_commentable'],
+        'uploadable'  => $site_is_remote
+          ? false
+          : $conf['newcat_default_uploadable'],
+        'status'      => $conf{'newcat_default_status'},
+        'visible'     => $conf{'newcat_default_visible'},
+        );
 
       if (isset($db_fulldirs[dirname($fulldir)]))
       {
@@ -258,8 +265,13 @@ SELECT IF(MAX(id)+1 IS NULL, 1, MAX(id)+1) AS next_id
       }
 
       array_push($inserts, $insert);
-      array_push($infos, array('path' => $fulldir,
-                               'info' => l10n('update_research_added')));
+      array_push(
+        $infos,
+        array(
+          'path' => $fulldir,
+          'info' => l10n('update_research_added')
+          )
+        );
 
       // add the new category to $db_categories and $db_fulldirs array
       $db_categories[$insert{'id'}] =
@@ -275,7 +287,13 @@ SELECT IF(MAX(id)+1 IS NULL, 1, MAX(id)+1) AS next_id
     }
     else
     {
-      array_push($errors, array('path' => $fulldir, 'type' => 'PWG-UPDATE-1'));
+      array_push(
+        $errors,
+        array(
+          'path' => $fulldir,
+          'type' => 'PWG-UPDATE-1'
+          )
+        );
     }
   }
 
@@ -338,8 +356,15 @@ if (isset($_POST['submit']) and $_POST['sync'] == 'files'
     $query = '
 SELECT id, path
   FROM '.IMAGES_TABLE.'
-  WHERE storage_category_id IN (
-'.wordwrap(implode(', ', $cat_ids), 80, "\n").')
+    INNER JOIN '.IMAGE_CATEGORY_TABLE.' ON image_id = id
+  WHERE is_storage = \'true\'
+    AND category_id IN ('.
+      wordwrap(
+        implode(', ', $cat_ids),
+        80,
+        "\n"
+        ).
+      ')
 ;';
     $result = pwg_query($query);
     while ($row = mysql_fetch_array($result))
@@ -361,8 +386,10 @@ SELECT file,storage_category_id
     {
       array_push(
         $db_unvalidated,
-        array_search($row['storage_category_id'],
-                     $db_fulldirs).'/'.$row['file']
+        array_search(
+          $row['storage_category_id'],
+          $db_fulldirs)
+        .'/'.$row['file']
         );
     }
   }
@@ -391,7 +418,14 @@ SELECT IF(MAX(id)+1 IS NULL, 1, MAX(id)+1) AS next_element_id
     $filename = basename($path);
     if (!preg_match('/^[a-zA-Z0-9-_.]+$/', $filename))
     {
-      array_push($errors, array('path' => $path, 'type' => 'PWG-UPDATE-1'));
+      array_push(
+        $errors,
+        array(
+          'path' => $path,
+          'type' => 'PWG-UPDATE-1'
+          )
+        );
+      
       continue;
     }
 
@@ -401,67 +435,90 @@ SELECT IF(MAX(id)+1 IS NULL, 1, MAX(id)+1) AS next_element_id
     if (in_array(get_extension($filename), $conf['picture_ext']))
     {
       // if we found a thumnbnail corresponding to our picture...
-      if ( isset($fs[$path]['tn_ext']) )
+      if (isset($fs[$path]['tn_ext']))
       {
-        $insert{'id'} = $next_element_id++;
-        $insert{'file'} = $filename;
-        $insert{'storage_category_id'} = $db_fulldirs[$dirname];
-        $insert{'date_available'} = CURRENT_DATE;
-        $insert{'tn_ext'} = $fs[$path]['tn_ext'];
-        if ( isset($fs[$path]['has_high']) )
-        {
-          $insert{'has_high'} = $fs[$path]['has_high'];
-        }
-        else
-        {
-          $insert{'has_high'} = null;
-        }
-        $insert{'path'} = $path;
-
-        array_push($inserts, $insert);
-        array_push($insert_links,
-                   array('image_id' => $insert{'id'},
-                         'category_id' => $insert{'storage_category_id'}));
-        array_push($infos, array('path' => $insert{'path'},
-                                 'info' => l10n('update_research_added')));
+        $insert = array(
+          'id'             => $next_element_id++,
+          'file'           => $filename,
+          'date_available' => CURRENT_DATE,
+          'tn_ext'         => $fs[$path]['tn_ext'],
+          'has_high'       => isset($fs[$path]['has_high'])
+            ? $fs[$path]['has_high']
+            : null,
+          'path'           => $path,
+          );
+        
+        array_push(
+          $inserts,
+          $insert
+          );
+        
+        array_push(
+          $insert_links,
+          array(
+            'image_id'    => $insert{'id'},
+            'category_id' => $db_fulldirs[$dirname],
+            'is_storage'  => 'true',
+            )
+          );
+        array_push(
+          $infos,
+          array(
+            'path' => $insert{'path'},
+            'info' => l10n('update_research_added')
+            )
+          );
       }
       else
       {
-        array_push($errors, array('path' => $path, 'type' => 'PWG-UPDATE-2'));
+        array_push(
+          $errors,
+          array(
+            'path' => $path,
+            'type' => 'PWG-UPDATE-2'
+            )
+          );
       }
     }
     else
     {
-      $insert{'id'} = $next_element_id++;
-      $insert{'file'} = $filename;
-      $insert{'storage_category_id'} = $db_fulldirs[$dirname];
-      $insert{'date_available'} = CURRENT_DATE;
-      $insert{'has_high'} = $fs[$path]['has_high'];
-      if ( isset($fs[$path]['has_high']) )
-      {
-        $insert{'has_high'} = $fs[$path]['has_high'];
-      }
-      else
-      {
-        $insert{'has_high'} = null;
-      }
-      $insert{'path'} = $path;
+      $insert = array(
+        'id'             => $next_element_id++,
+        'file'           => $filename,
+        'date_available' => CURRENT_DATE,
+        'path'           => $path,
+        'has_high'       => isset($fs[$path]['has_high'])
+          ? $fs[$path]['has_high']
+          : null,
+        'tn_ext'         => isset($fs[$path]['tn_ext'])
+          ? $fs[$path]['tn_ext']
+          : null,
+        'representative_ext' => isset($fs[$path]['representative_ext'])
+          ? $fs[$path]['representative_ext']
+          : null,
+        );
 
-      if ( isset($fs[$path]['tn_ext']) )
-      {
-        $insert{'tn_ext'} = $fs[$path]['tn_ext'];
-      }
-      if (isset($fs[$path]['representative_ext']))
-      {
-        $insert{'representative_ext'} = $fs[$path]['representative_ext'];
-      }
+      array_push(
+        $inserts,
+        $insert
+        );
 
-      array_push($inserts, $insert);
-      array_push($insert_links,
-                 array('image_id' => $insert{'id'},
-                       'category_id' => $insert{'storage_category_id'}));
-      array_push($infos, array('path' => $insert{'path'},
-                               'info' => l10n('update_research_added')));
+      array_push(
+        $insert_links,
+        array(
+          'image_id'    => $insert{'id'},
+          'category_id' => $db_fulldirs[$dirname],
+          'is_storage'  => 'true',
+          )
+        );
+
+      array_push(
+        $infos,
+        array(
+          'path' => $insert{'path'},
+          'info' => l10n('update_research_added')
+          )
+        );
     }
   }
 
@@ -470,15 +527,23 @@ SELECT IF(MAX(id)+1 IS NULL, 1, MAX(id)+1) AS next_element_id
     if (!$simulate)
     {
       // inserts all new elements
-      $dbfields = array(
-        'id','file','storage_category_id','date_available','tn_ext'
-        ,'representative_ext', 'has_high', 'path'
+      mass_inserts(
+        IMAGES_TABLE,
+        array(
+          'id', 'file', 'date_available', 'tn_ext', 'representative_ext',
+          'has_high', 'path',
+          ),
+        $inserts
         );
-      mass_inserts(IMAGES_TABLE, $dbfields, $inserts);
 
-      // insert all links between new elements and their storage category
-      $dbfields = array('image_id','category_id');
-      mass_inserts(IMAGE_CATEGORY_TABLE, $dbfields, $insert_links);
+      // inserts all links between new elements and their storage category
+      mass_inserts(
+        IMAGE_CATEGORY_TABLE,
+        array(
+          'image_id','category_id', 'is_storage',
+          ),
+        $insert_links
+        );
     }
     $counts['new_elements'] = count($inserts);
   }
@@ -532,7 +597,9 @@ SELECT id,file,storage_category_id,infos
       $query = '
 SELECT id
   FROM '.IMAGES_TABLE.'
-  WHERE storage_category_id = \''.$row['storage_category_id'].'\'
+    INNER JOIN '.IMAGE_CATEGORY_TABLE.' ON image_id = id
+  WHERE is_storage = \'true\'
+    AND category_id = '.$row['storage_category_id'].'
     AND file = \''.$row['file'].'\'
 ;';
       list($data['id']) = mysql_fetch_array(pwg_query($query));
@@ -580,6 +647,11 @@ if (isset($_POST['submit'])
   if (!$simulate)
   {
     $start = get_moment();
+    check_links('all');
+    echo '<!-- check_links(all) : ';
+    echo get_elapsed_time($start,get_moment());
+    echo ' -->'."\n";
+    $start = get_moment();
     update_category('all');
     echo '<!-- update_category(all) : ';
     echo get_elapsed_time($start,get_moment());