fix1: consider the parent has changed IF the left key is not set. This is valueable for calculating edges for a node that has a parentID set, but the edges are not yet calculated

fix2: allow calculations of surrounding nodes only if the current node already has edges calculated

Author: Flaviu Chelaru

src/Behavior.php

@@ -196,48 +196,16 @@ public function processUpdate(ModelInterface $model): void
         ]);
 
         // parent has changed (unset parent or set a new parent)
-        if ($model->readAttribute(self::$parentKey) == $currentModel->readAttribute(self::$parentKey)) {
+        // or current left is not set
+        if (
+            $model->readAttribute(self::$leftKey) > 0
+            && $model->readAttribute(self::$parentKey) == $currentModel->readAttribute(self::$parentKey)
+        ) {
             return;
         }
 
-        // upgrade children of current node in the tree
-        $query = 'UPDATE `' . $model->getSource() . '` SET ' .
-            '`' . self::$depthDbColumn . '` = `' . self::$depthDbColumn . '` - 1, ' .
-            '`' . self::$rightDbColumn . '` = `' . self::$rightDbColumn . '` - 1, ' .
-            '`' . self::$leftDbColumn . '` = `' . self::$leftDbColumn . '` - 1 ' .
-            'WHERE `' . self::$leftDbColumn . '` > :left AND `' . self::$rightDbColumn . '` < :right ' .
-            'AND `' . self::$primaryDbColumn . '` != :id';
-        $model->getWriteConnection()->query($query, [
-            'right' => $currentModel->readAttribute(self::$rightKey),
-            'left' => $currentModel->readAttribute(self::$leftKey),
-            'id' => $model->readAttribute(self::$primaryKey),
-        ]);
-
-        // update parent for immediate sub-nodes of current category
-        $query = 'UPDATE `' . $model->getSource() . '` SET' .
-            ' `' . self::$parentDbColumn . '` = :parent ' .
-            'WHERE `' . self::$parentDbColumn . '` = :id';
-        $model->getWriteConnection()->query($query, [
-            'id' => $currentModel->readAttribute(self::$primaryKey),
-            'parent' => $currentModel->readAttribute(self::$parentKey)
-        ]);
-
-        // update nodes on the right of the tree
-        $query = 'UPDATE `' . $model->getSource() . '` SET ' .
-            '`' . self::$rightDbColumn . '` = `' . self::$rightDbColumn . '` - 2 ' .
-            'WHERE `' . self::$rightDbColumn . '` > :right AND `' . self::$primaryDbColumn . '` != :id';
-        $model->getWriteConnection()->query($query, [
-            'right' => $currentModel->readAttribute(self::$rightKey),
-            'id' => $model->readAttribute(self::$primaryKey),
-        ]);
-
-        $query = 'UPDATE `' . $model->getSource() . '` SET ' .
-            '`' . self::$leftDbColumn . '` = `' . self::$leftDbColumn . '` - 2 ' .
-            'WHERE `' . self::$leftDbColumn . '` > :right AND `' . self::$primaryDbColumn . '` != :id';
-        $model->getWriteConnection()->query($query, [
-            'right' => $currentModel->readAttribute(self::$rightKey),
-            'id' => $model->readAttribute(self::$primaryKey),
-        ]);
+        // upgrade children of current node in the tree, but only if we currently have a tree set
+        $this->preUpdateHook($model, $currentModel);
 
         $maxRight = $model::maximum(['column' => self::$rightKey]);
         // unset the parent - make the node a root
@@ -254,12 +222,16 @@ public function processUpdate(ModelInterface $model): void
 
         $right = $parentModel->readAttribute(self::$rightKey);
         $depth = $parentModel->readAttribute(self::$depthKey);
-        if ($parentModel->readAttribute(self::$rightKey) > $currentModel->readAttribute(self::$rightKey)
-            && $parentModel->readAttribute(self::$rightKey) > $currentModel->readAttribute(self::$leftKey)) {
+        if (
+            $parentModel->readAttribute(self::$rightKey) > $currentModel->readAttribute(self::$rightKey)
+            && $parentModel->readAttribute(self::$rightKey) > $currentModel->readAttribute(self::$leftKey)
+        ) {
             $right = $parentModel->readAttribute(self::$rightKey) - 2;
             $depth = $parentModel->readAttribute(self::$depthKey) + 1;
-        } elseif ($parentModel->readAttribute(self::$rightKey) < $currentModel->readAttribute(self::$rightKey)
-            && $parentModel->readAttribute(self::$rightKey) > $currentModel->readAttribute(self::$leftKey)) {
+        } elseif (
+            $parentModel->readAttribute(self::$rightKey) < $currentModel->readAttribute(self::$rightKey)
+            && $parentModel->readAttribute(self::$rightKey) > $currentModel->readAttribute(self::$leftKey)
+        ) {
             $right = $parentModel->readAttribute(self::$rightKey) - 1;
             $depth = $parentModel->readAttribute(self::$depthKey);
         }
@@ -285,4 +257,53 @@ public function processUpdate(ModelInterface $model): void
             self::$parentKey => $parentModel->readAttribute(self::$primaryKey),
         ]);
     }
+
+    /**
+     * @param ModelInterface $model
+     * @param $currentModel
+     */
+    private function preUpdateHook(ModelInterface $model, ModelInterface $currentModel): void
+    {
+        if (!$currentModel->readAttribute(self::$rightKey) > 0) {
+            return;
+        }
+
+        $query = 'UPDATE `' . $model->getSource() . '` SET ' .
+            '`' . self::$depthDbColumn . '` = `' . self::$depthDbColumn . '` - 1, ' .
+            '`' . self::$rightDbColumn . '` = `' . self::$rightDbColumn . '` - 1, ' .
+            '`' . self::$leftDbColumn . '` = `' . self::$leftDbColumn . '` - 1 ' .
+            'WHERE `' . self::$leftDbColumn . '` > :left AND `' . self::$rightDbColumn . '` < :right ' .
+            'AND `' . self::$primaryDbColumn . '` != :id';
+        $model->getWriteConnection()->query($query, [
+            'right' => $currentModel->readAttribute(self::$rightKey),
+            'left' => $currentModel->readAttribute(self::$leftKey),
+            'id' => $model->readAttribute(self::$primaryKey),
+        ]);
+
+        // update parent for immediate sub-nodes of current category
+        $query = 'UPDATE `' . $model->getSource() . '` SET' .
+            ' `' . self::$parentDbColumn . '` = :parent ' .
+            'WHERE `' . self::$parentDbColumn . '` = :id';
+        $model->getWriteConnection()->query($query, [
+            'id' => $currentModel->readAttribute(self::$primaryKey),
+            'parent' => $currentModel->readAttribute(self::$parentKey)
+        ]);
+
+        // update nodes on the right of the tree
+        $query = 'UPDATE `' . $model->getSource() . '` SET ' .
+            '`' . self::$rightDbColumn . '` = `' . self::$rightDbColumn . '` - 2 ' .
+            'WHERE `' . self::$rightDbColumn . '` > :right AND `' . self::$primaryDbColumn . '` != :id';
+        $model->getWriteConnection()->query($query, [
+            'right' => $currentModel->readAttribute(self::$rightKey),
+            'id' => $model->readAttribute(self::$primaryKey),
+        ]);
+
+        $query = 'UPDATE `' . $model->getSource() . '` SET ' .
+            '`' . self::$leftDbColumn . '` = `' . self::$leftDbColumn . '` - 2 ' .
+            'WHERE `' . self::$leftDbColumn . '` > :right AND `' . self::$primaryDbColumn . '` != :id';
+        $model->getWriteConnection()->query($query, [
+            'right' => $currentModel->readAttribute(self::$rightKey),
+            'id' => $model->readAttribute(self::$primaryKey),
+        ]);
+    }
 }