#50: implemented tree rebuilding feature

Author: lazychaser

CHANGELOG.markdown

@@ -16,6 +16,7 @@
     `has('parent')` instead
 *   Default order is no longer applied for `siblings()`, `descendants()`,
     `prevNodes`, `nextNodes`
+*   #50: implemented tree rebuilding feature
 
 ### 3.1.1
 

README.markdown

@@ -184,6 +184,34 @@ $node = Category::create([
 
 `$node->children` now contains a list of created child nodes.
 
+#### Rebuilding a tree from array
+
+You can easily rebuild a tree. This is useful for mass-changing the structure of
+the tree.
+
+```php
+Category::rebuildTree($data, $delete);
+```
+
+`$data` is an array of nodes:
+
+```php
+$data = [
+    [ 'id' => 1, 'name' => 'foo', 'children' => [ ... ] ],
+    [ 'name' => 'bar' ],
+];
+```
+
+There is an id specified for node with the name of `foo` which means that existing
+node will be filled and saved. If node is not exists `ModelNotFoundException` is
+thrown. Also, this node has `children` specified which is also an array of nodes;
+they will be processed in the same manner and saved as children of node `foo`.
+
+Node `bar` has no primary key specified, so it will be created.
+
+`$delete` shows whether to delete nodes that are already exists but not present
+in `$data`. By default, nodes aren't deleted.
+
 ### Retrieving nodes
 
 *In some cases we will use an `$id` variable which is an id of the target node.*
@@ -504,7 +532,7 @@ MenuItem::scoped([ 'menu_id' => 5 ])->fixTree();
 ```
 
 When requesting nodes using model instance, scopes applied automatically based 
-on data of that model. See examples:
+on the attributes of that model. See examples:
 
 ```php
 $node = MenuItem::findOrFail($id);

src/Collection.php

@@ -46,11 +46,11 @@ public function linkNodes()
      *
      * If `$root` is provided, the tree will contain only descendants of that node.
      *
-     * @param int|Model|null $root
+     * @param mixed $root
      *
      * @return Collection
      */
-    public function toTree($root = null)
+    public function toTree($root = false)
     {
         if ($this->isEmpty()) {
             return new static;
@@ -77,13 +77,13 @@ public function toTree($root = null)
      *
      * @return int
      */
-    protected function getRootNodeId($root = null)
+    protected function getRootNodeId($root)
     {
         if (NestedSet::isNode($root)) {
             return $root->getKey();
         }
 
-        if ($root !== null) {
+        if ($root !== false) {
             return $root;
         }
 

src/NodeTrait.php

@@ -90,7 +90,7 @@ public static function bootNodeTrait()
      *
      * @return $this
      */
-    protected function setAction($action)
+    protected function setNodeAction($action)
     {
         $this->pending = func_get_args();
 
@@ -136,6 +136,14 @@ public static function usesSoftDelete()
         return $softDelete;
     }
 
+    /**
+     * @return bool
+     */
+    protected function actionRaw()
+    {
+        return true;
+    }
+
     /**
      * Make a root node.
      */
@@ -342,7 +350,7 @@ public function ancestors()
      */
     public function makeRoot()
     {
-        return $this->setAction('root');
+        return $this->setNodeAction('root');
     }
 
     /**
@@ -420,7 +428,7 @@ public function appendOrPrependTo(self $parent, $prepend = false)
 
         $this->setParent($parent)->dirtyBounds();
 
-        return $this->setAction('appendOrPrepend', $parent, $prepend);
+        return $this->setNodeAction('appendOrPrepend', $parent, $prepend);
     }
 
     /**
@@ -463,7 +471,7 @@ public function beforeOrAfterNode(self $node, $after = false)
 
         $this->dirtyBounds();
 
-        return $this->setAction('beforeOrAfter', $node, $after);
+        return $this->setNodeAction('beforeOrAfter', $node, $after);
     }
 
     /**
@@ -495,6 +503,20 @@ public function insertBeforeNode(self $node)
         return true;
     }
 
+    /**
+     * @param $lft
+     * @param $rgt
+     * @param $parentId
+     *
+     * @return $this
+     */
+    public function rawNode($lft, $rgt, $parentId)
+    {
+        $this->setLft($lft)->setRgt($rgt)->setParentId($parentId);
+
+        return $this->setNodeAction('raw');
+    }
+
     /**
      * Move node up given amount of positions.
      *

src/QueryBuilder.php

@@ -7,6 +7,7 @@
 use Illuminate\Database\Eloquent\ModelNotFoundException;
 use Illuminate\Database\Query\Builder as Query;
 use Illuminate\Database\Query\Builder as BaseQueryBuilder;
+use Illuminate\Support\Arr;
 use LogicException;
 use Illuminate\Database\Query\Expression;
 
@@ -726,9 +727,9 @@ public function isBroken()
     /**
      * Fixes the tree based on parentage info.
      *
-     * Requires at least one root node. This will not update nodes with invalid parent.
+     * Nodes with invalid parent are saved as roots.
      *
-     * @return int The number of fixed nodes.
+     * @return int The number of fixed nodes
      */
     public function fixTree()
     {
@@ -739,54 +740,64 @@ public function fixTree()
             $this->model->getRgtName(),
         ];
 
-        $nodes = $this->model
-                      ->newNestedSetQuery()
-                      ->defaultOrder()
-                      ->get($columns)
-                      ->groupBy($this->model->getParentIdName());
+        $dictionary = $this->defaultOrder()
+                           ->get($columns)
+                           ->groupBy($this->model->getParentIdName())
+                           ->all();
 
+        return self::fixNodes($dictionary);
+    }
+
+    /**
+     * @param array $dictionary
+     *
+     * @return int
+     */
+    protected static function fixNodes(array &$dictionary)
+    {
         $fixed = 0;
 
-        $cut = self::reorderNodes($nodes, $fixed);
+        $cut = self::reorderNodes($dictionary, $fixed);
 
-        // Saved nodes that have invalid parent as roots
-        while ( ! $nodes->isEmpty()) {
-            $parentId = $nodes->keys()->first();
+        // Save nodes that have invalid parent as roots
+        while ( ! empty($dictionary)) {
+            $dictionary[null] = reset($dictionary);
 
-            foreach ($nodes[$parentId] as $model) {
-                $model->setParentId(null);
-            }
+            unset($dictionary[key($dictionary)]);
 
-            $cut = self::reorderNodes($nodes, $fixed, $parentId, $cut);
+            $cut = self::reorderNodes($dictionary, $fixed, null, $cut);
         }
 
         return $fixed;
     }
 
     /**
-     * @param Collection $models
+     * @param array $dictionary
      * @param int $fixed
      * @param $parentId
      * @param int $cut
      *
      * @return int
      */
-    protected static function reorderNodes(Collection $models, &$fixed,
+    protected static function reorderNodes(array &$dictionary, &$fixed,
                                            $parentId = null, $cut = 1
     ) {
-        if ( ! isset($models[$parentId])) {
+        if ( ! isset($dictionary[$parentId])) {
             return $cut;
         }
 
-        /** @var Model|self $model */
-        foreach ($models[$parentId] as $model) {
-            $model->setLft($cut);
+        /** @var Model|NodeTrait $model */
+        foreach ($dictionary[$parentId] as $model) {
+            $lft = $cut;
 
-            $cut = self::reorderNodes($models, $fixed, $model->getKey(), $cut + 1);
+            $cut = self::reorderNodes($dictionary,
+                                      $fixed,
+                                      $model->getKey(),
+                                      $cut + 1);
 
-            $model->setRgt($cut);
+            $rgt = $cut;
 
-            if ($model->isDirty()) {
+            if ($model->rawNode($lft, $rgt, $parentId)->isDirty()) {
                 $model->save();
 
                 $fixed++;
@@ -795,13 +806,89 @@ protected static function reorderNodes(Collection $models, &$fixed,
             ++$cut;
         }
 
-        unset($models[$parentId]);
+        unset($dictionary[$parentId]);
 
         return $cut;
     }
 
     /**
-     * @param null $table
+     * Rebuild the tree based on raw data.
+     *
+     * If item data does not contain primary key, new node will be created.
+     *
+     * @param array $data
+     * @param bool $delete Whether to delete nodes that exists but not in the data
+     *                     array
+     *
+     * @return int
+     */
+    public function rebuildTree(array $data, $delete = false)
+    {
+        $existing = $this->get()->getDictionary();
+        $dictionary = [];
+
+        $this->buildRebuildDictionary($dictionary, $data, $existing);
+
+        if ( ! empty($existing)) {
+            if ($delete) {
+                $this->model
+                    ->newScopedQuery()
+                    ->whereIn($this->model->getKeyName(), array_keys($existing))
+                    ->forceDelete();
+            } else {
+                foreach ($existing as $model) {
+                    $dictionary[$model->getParentId()][] = $model;
+                }
+            }
+        }
+
+        return $this->fixNodes($dictionary);
+    }
+
+    /**
+     * @param array $dictionary
+     * @param array $data
+     * @param array $existing
+     * @param mixed $parentId
+     */
+    protected function buildRebuildDictionary(array &$dictionary,
+                                              array $data,
+                                              array &$existing,
+                                                    $parentId = null
+    ) {
+        $keyName = $this->model->getKeyName();
+
+        foreach ($data as $itemData) {
+            if ( ! isset($itemData[$keyName])) {
+                $model = $this->model->newInstance();
+
+                // We will save it as raw node since tree will be fixed
+                $model->rawNode(0, 0, $parentId);
+            } else {
+                if ( ! isset($existing[$key = $itemData[$keyName]])) {
+                    throw new ModelNotFoundException;
+                }
+
+                $model = $existing[$key];
+
+                unset($existing[$key]);
+            }
+
+            $model->fill($itemData)->save();
+
+            $dictionary[$parentId][] = $model;
+
+            if ( ! isset($itemData['children'])) continue;
+
+            $this->buildRebuildDictionary($dictionary,
+                                          $itemData['children'],
+                                          $existing,
+                                          $model->getKey());
+        }
+    }
+
+    /**
+     * @param string|null $table
      *
      * @return $this
      */