Improve user experience on drag and drop

js/Plugin/jstree/hm.jstree.js

@@ -37,11 +37,6 @@
             treeContainer.jstree({
               core: {
                 'check_callback' : function (operation, node, node_parent, node_position, more) {
-                  // prevent any node with multiple parents from moving.
-                  if (operation === 'move_node') {
-                    return node.id.indexOf('_') === -1;
-                  }
-
                   return true;
                 },
                 data: {
@@ -57,6 +52,20 @@
                 themes: themes,
                 "multiple": false,
               },
+              'dnd' : {
+                "is_draggable" : function(node) {
+                  let can_drag = node[0].data.draggable;
+                  if (can_drag) {
+                    return true;
+                  }
+                  else {
+                    let drupalMessages = new Drupal.Message();
+                    drupalMessages.clear();
+                    drupalMessages.add(Drupal.t("Can't drag this item. It may because it has multiple parents."), {type: 'warning'});
+                    return false;
+                  }
+                }
+              },
               search: {
                 show_only_matches: true,
                 "search_callback": function(str, node) {

src/Controller/HmMenuController.php

@@ -175,28 +175,18 @@ class HmMenuController extends ControllerBase {
     $parent = $request->get('parent');
     $updated_links = $request->get('keys');
     $all_siblings = [];
-    $links_uuid = [];
 
     if (is_array($updated_links) && !empty($updated_links)) {
       if (empty($parent)) {
         // Root is the parent.
         $parent = '';
+        // All children menu links (depth = 1).
         $parent_links = $children = $this->loadMenuLinkObjs($mid, $parent, 1);
       }
       else {
-        $parent = $this->entityTypeManager->getStorage('menu_link_content')->load($parent);
-        if (!empty($parent)) {
-          $parent = $parent->getPluginId();
-        }
-        else {
-          $parent = '';
-        }
-        // All children menu links (depth = 1).
         $parent_links = $this->loadMenuLinkObjs($mid, $parent, 1);
       }
-      // In order to make room for menu links inserted,
-      // we need to move all children links forward,
-      // and work out the weight for links inserted.
+
       if (empty($parent_links)) {
           // The parent menu doesn't exist.
           return new JsonResponse(['result' => 'fail']);
@@ -213,30 +203,18 @@ class HmMenuController extends ControllerBase {
 
         foreach ($children as $child) {
           $link = $child->link;
-          $uuid = $link->getDerivativeId();
-          $link_id = $this->entityRepository->loadEntityByUuid('menu_link_content', $uuid)->id();
-          $links_uuid[$link_id] = $link->getPluginId();
-
+          $link_id = $link->getPluginId();
           $all_siblings[$link_id] = $link->getWeight();
         }
       }
 
+      // In order to make room for menu links inserted,
+      // we need to move all children links forward,
+      // and work out the weight for links inserted.
       $new_hierarchy = $this->hmPluginTypeManager->updateHierarchy($target_position, $all_siblings, $updated_links, $old_position);
-      foreach ($updated_links as $id) {
-        if (!isset($links_uuid[$id])) {
-          $entity = $this->entityTypeManager->getStorage('menu_link_content')->load($id);
-          if (!empty($entity)) {
-            $links_uuid[$id] = $entity->getPluginId();
-          }
-          else {
-            // The updated menu link doesn't exist.
-            return new JsonResponse(['result' => 'fail']);
-          }
-        }
-      }
       // Update all links need to update.
       foreach ($new_hierarchy as $link_id => $link_weight) {
-        $this->menuLinkManager->updateDefinition($links_uuid[$link_id], ['weight' => $link_weight, 'parent' => $parent]);
+        $this->menuLinkManager->updateDefinition($link_id, ['weight' => $link_weight, 'parent' => $parent]);
       }
 
       $result = [
@@ -345,10 +323,7 @@ class HmMenuController extends ControllerBase {
       /** @var \Drupal\Core\Menu\MenuLinkInterface $link */
       $link = $element->link;
       if ($link) {
-        // The id consistes of plugin ID and link ID.
-        $uuid = $link->getDerivativeId();
-        $menu_entity = $this->entityRepository->loadEntityByUuid('menu_link_content', $uuid);
-        $id = $menu_entity->id();
+        $id = $link->getPluginId();
         $this->overviewTree[$id]['id'] = $id;
         $this->overviewTree[$id]['status'] = $link->isEnabled();
         if (!$link->isEnabled()) {
@@ -366,14 +341,7 @@ class HmMenuController extends ControllerBase {
           $this->overviewTree[$id]['title'] = $link->getTitle();
         }
 
-        $parent_uuid = explode(':', $link->getParent());
-        if (isset($parent_uuid[1])) {
-          $parent_id = $this->entityRepository->loadEntityByUuid($parent_uuid[0], $parent_uuid[1])->id();
-        }
-        else {
-          $parent_id = '';
-        }
-
+        $parent_id = $link->getParent();
         $this->overviewTree[$id]['parent'] = $parent_id;
         $this->overviewTree[$id]['weight'] = $link->getWeight();
         // Build the edit url.

src/Controller/HmTaxonomyController.php

@@ -112,10 +112,12 @@ class HmTaxonomyController extends ControllerBase {
               $term_parent_index = $parents[$term->id()] = 0;
             }
             $term_id = $term->id() . '_' . $term_parent_index;
+            $draggable = false;
           }
           else {
             $term_id = $term->id();
             $term_parent_index = 0;
+            $draggable = true;
           }
 
           $term_array[] = $this->hmPluginTypeManager->buildHierarchyItem(
@@ -124,7 +126,8 @@ class HmTaxonomyController extends ControllerBase {
             $term->parents[$term_parent_index],
             $url,
             $term->isPublished(),
-            $term->getWeight()
+            $term->getWeight(),
+            $draggable
           );
         }
       }

src/Plugin/HmDisplayPlugin/HmDisplayJstree.php

@@ -118,6 +118,7 @@ class HmDisplayJstree extends HmDisplayPluginBase implements HmDisplayPluginInte
       ];
       $jstree_node['data'] = [
         'weight' => $tree_node['weight'],
+        'draggable' => $tree_node['draggable']
       ];
       unset($jstree_node['edit_url']);
       // Add this node into the data array.

src/PluginTypeManager.php

@@ -57,7 +57,7 @@ class PluginTypeManager {
    * @return array
    *   The hierarchy item array.
    */
-  public function buildHierarchyItem($id, $label, $parent, $edit_url, $status = TRUE, $weight = 0) {
+  public function buildHierarchyItem($id, $label, $parent, $edit_url, $status = TRUE, $weight = 0, $draggable = TRUE) {
     return 
     [
       'id' => $id,
@@ -65,7 +65,8 @@ class PluginTypeManager {
       'parent' => $parent,
       'edit_url' => $edit_url,
       'status' => $status,
-      'weight' => $weight
+      'weight' => $weight,
+      'draggable' => $draggable
     ];
   }
   
@@ -136,7 +137,8 @@ class PluginTypeManager {
       }
       else {
         $target_item = array_slice($all_siblings, $target_position, 1);
-        $weight = $target_item[0];
+        $target_weight = reset($target_item);
+        $weight = $target_weight;
         $total_insert = count($updated_items);
         // Figure out if the target element should move forward.
         if ($num_new || ($old_position > $target_position)) {
@@ -154,11 +156,11 @@ class PluginTypeManager {
         if ($target_position - $num_new >= $total / 2) {
           if ($move_forward) {
             $moving_siblings = array_slice($all_siblings, $target_position, NULL, TRUE);
-            $weight = $target_item[0];
+            $weight = $target_weight;
           }
           else {
             $moving_siblings = array_slice($all_siblings, $target_position + 1, NULL, TRUE);
-            $weight = $target_item[0] + 1;
+            $weight = $target_weight + 1;
           }
           $after = true;
           $expected_weight = $weight + $total_insert;
@@ -167,11 +169,11 @@ class PluginTypeManager {
         else {
           if ($move_forward) {
             $moving_siblings = array_slice($all_siblings, 0, $target_position, TRUE);
-            $weight = $target_item[0] - 1;
+            $weight = $target_weight - 1;
           }
           else {
             $moving_siblings = array_slice($all_siblings, 0, $target_position + 1, TRUE);
-            $weight = $target_item[0];
+            $weight = $target_weight;
           }
           $after = false;
           $expected_weight = $weight - count($moving_siblings) - $total_insert + 1;