Closes area17#600: Improve tree reorder algorithm for nested modules

The idea here was to reduce the number of times the script needs to interact with the database. With this new code, there should be fewer `save()`, `saveAsRoot()`, and `self::find()` calls happening. The trade-off is that there is now an `all()` call, which could cause issues if there is truly a massive amount of items (thousands). But for most use-cases, this new algorithm should behave better than the old one when there is a middling number of items (hundreds).
MamlukiSn · Jul 6, 2020 · c00bf01 · c00bf01
1 parent 12acbd6
commit c00bf01
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diff --git a/docs/.sections/crud-modules.md b/docs/.sections/crud-modules.md
@@ -708,43 +708,48 @@ use Kalnoy\Nestedset\NodeTrait;
 class Page extends Model {
     use HasPosition, NodeTrait;
     ...
-    public static function saveTreeFromIds($nodesArray)
+    public static function saveTreeFromIds($nodeTree)
     {
-        $parentNodes = self::find(Arr::pluck($nodesArray, 'id'));
-
-        if (is_array($nodesArray)) {
-            $position = 1;
-            foreach ($nodesArray as $nodeArray) {
-                $node = $parentNodes->where('id', $nodeArray['id'])->first();
-                $node->position = $position++;
-                $node->saveAsRoot();
-            }
-        }
+        $nodeModels = self::all();
+        $nodeArrays = self::flattenTree($nodeTree);
 
-        $parentNodes = self::find(Arr::pluck($nodesArray, 'id'));
+        foreach ($nodeArrays as $nodeArray) {
+            $nodeModel = $nodeModels->where('id', $nodeArray['id'])->first();
 
-        self::rebuildTree($nodesArray, $parentNodes);
+            if ($nodeArray['parent_id'] === null) {
+                if (!$nodeModel->isRoot() || $nodeModel->position !== $nodeArray['position']) {
+                    $nodeModel->position = $nodeArray['position'];
+                    $nodeModel->saveAsRoot();
+                }
+            } else {
+                if ($nodeModel->position !== $nodeArray['position'] || $nodeModel->parent_id !== $nodeArray['parent_id']) {
+                    $nodeModel->position = $nodeArray['position'];
+                    $nodeModel->parent_id = $nodeArray['parent_id'];
+                    $nodeModel->save();
+                }
+            }
+        }
     }
 
-    public static function rebuildTree($nodesArray, $parentNodes)
+    public static function flattenTree(array $nodeTree, int $parentId = null)
     {
-        if (is_array($nodesArray)) {
-            foreach ($nodesArray as $nodeArray) {
-                $parent = $parentNodes->where('id', $nodeArray['id'])->first();
-                if (isset($nodeArray['children']) && is_array($nodeArray['children'])) {
-                    $position = 1;
-                    $nodes = self::find(Arr::pluck($nodeArray['children'], 'id'));
-                    foreach ($nodeArray['children'] as $child) {
-                        //append the children to their (old/new)parents
-                        $descendant = $nodes->where('id', $child['id'])->first();
-                        $descendant->position = $position++;
-                        $descendant->parent_id = $parent->id;
-                        $descendant->save();
-                        self::rebuildTree($nodeArray['children'], $nodes);
-                    }
-                }
+        $nodeArrays = [];
+        $position = 0;
+
+        foreach ($nodeTree as $node) {
+            $nodeArrays[] = [
+                'id' => $node['id'],
+                'position' => $position++,
+                'parent_id' => $parentId,
+            ];
+
+            if (count($node['children']) > 0) {
+                $childArrays = self::flattenTree($node['children'], $node['id']);
+                $nodeArrays = array_merge($nodeArrays, $childArrays);
             }
         }
+
+        return $nodeArrays;
     }
 }
 ```

diff --git a/tests/stubs/modules/categories/Category.php b/tests/stubs/modules/categories/Category.php
@@ -30,49 +30,47 @@ class Category extends Model
     // add checkbox fields names here (published toggle is itself a checkbox)
     public $checkboxes = ['published'];
 
-    public static function saveTreeFromIds($nodesArray)
+    public static function saveTreeFromIds($nodeTree)
     {
-        $parentNodes = self::find(array_pluck($nodesArray, 'id'));
+        $nodeModels = self::all();
+        $nodeArrays = self::flattenTree($nodeTree);
 
-        if (is_array($nodesArray)) {
-            $position = 1;
-            foreach ($nodesArray as $nodeArray) {
-                $node = $parentNodes->where('id', $nodeArray['id'])->first();
-                $node->position = $position++;
-                $node->saveAsRoot();
+        foreach ($nodeArrays as $nodeArray) {
+            $nodeModel = $nodeModels->where('id', $nodeArray['id'])->first();
+
+            if ($nodeArray['parent_id'] === null) {
+                if (!$nodeModel->isRoot() || $nodeModel->position !== $nodeArray['position']) {
+                    $nodeModel->position = $nodeArray['position'];
+                    $nodeModel->saveAsRoot();
+                }
+            } else {
+                if ($nodeModel->position !== $nodeArray['position'] || $nodeModel->parent_id !== $nodeArray['parent_id']) {
+                    $nodeModel->position = $nodeArray['position'];
+                    $nodeModel->parent_id = $nodeArray['parent_id'];
+                    $nodeModel->save();
+                }
             }
         }
-
-        $parentNodes = self::find(array_pluck($nodesArray, 'id'));
-
-        self::rebuildTree($nodesArray, $parentNodes);
     }
 
-    public static function rebuildTree($nodesArray, $parentNodes)
+    public static function flattenTree(array $nodeTree, int $parentId = null)
     {
-        if (is_array($nodesArray)) {
-            foreach ($nodesArray as $nodeArray) {
-                $parent = $parentNodes->where('id', $nodeArray['id'])->first();
-                if (
-                    isset($nodeArray['children']) &&
-                    is_array($nodeArray['children'])
-                ) {
-                    $position = 1;
-                    $nodes = self::find(
-                        array_pluck($nodeArray['children'], 'id')
-                    );
-                    foreach ($nodeArray['children'] as $child) {
-                        //append the children to their (old/new)parents
-                        $descendant = $nodes
-                            ->where('id', $child['id'])
-                            ->first();
-                        $descendant->position = $position++;
-                        $descendant->parent_id = $parent->id;
-                        $descendant->save();
-                        self::rebuildTree($nodeArray['children'], $nodes);
-                    }
-                }
+        $nodeArrays = [];
+        $position = 0;
+
+        foreach ($nodeTree as $node) {
+            $nodeArrays[] = [
+                'id' => $node['id'],
+                'position' => $position++,
+                'parent_id' => $parentId,
+            ];
+
+            if (count($node['children']) > 0) {
+                $childArrays = self::flattenTree($node['children'], $node['id']);
+                $nodeArrays = array_merge($nodeArrays, $childArrays);
             }
         }
+
+        return $nodeArrays;
     }
 }