Adding a nest folders collection

Modules/Media/Support/Collection/NestedFoldersCollection.php

+<?php
+
+namespace Modules\Media\Support\Collection;
+
+use Illuminate\Database\Eloquent\Collection;
+use Illuminate\Support\Collection as BaseCollection;
+
+class NestedFoldersCollection extends Collection
+{
+    private $total;
+    private $parentColumn;
+    private $removeItemsWithMissingAncestor = true;
+    private $indentChars = '&nbsp;&nbsp;&nbsp;&nbsp;';
+
+    public function __construct($items = [])
+    {
+        parent::__construct($items);
+        $this->parentColumn = 'folder_id';
+        $this->total = count($items);
+    }
+
+    /**
+     * Nest items.
+     * @return mixed NestableCollection
+     */
+    public function nest()
+    {
+        $parentColumn = $this->parentColumn;
+        if ( ! $parentColumn) {
+            return $this;
+        }
+        // Set id as keys.
+        $this->items = $this->getDictionary();
+        $keysToDelete = [];
+        // Add empty collection to each items.
+        $collection = $this->each(function ($item) {
+            if ( ! $item->items) {
+                $item->items = app(BaseCollection::class);
+            }
+        });
+        // Remove items with missing ancestor.
+        if ($this->removeItemsWithMissingAncestor) {
+            $collection = $this->reject(function ($item) use ($parentColumn) {
+                if ($item->$parentColumn) {
+                    $missingAncestor = $this->anAncestorIsMissing($item);
+                    return $missingAncestor;
+                }
+            });
+        }
+        // Add items to children collection.
+        foreach ($collection->items as $key => $item) {
+            if ($item->$parentColumn && isset($collection[$item->$parentColumn])) {
+                $collection[$item->$parentColumn]->items->push($item);
+                $keysToDelete[] = $item->id;
+            }
+        }
+        // Delete moved items.
+        $this->items = array_values(array_except($collection->items, $keysToDelete));
+        return $this;
+    }
+
+    /**
+     * Recursive function that flatten a nested Collection
+     * with characters (default is four spaces).
+     * @param string $column
+     * @param BaseCollection|null $collection
+     * @param int $level
+     * @param array &$flattened
+     * @param string|null $indentChars
+     * @param string|boolen|null $parent_string
+     * @return array
+     */
+    public function listsFlattened(
+        $column = 'title', BaseCollection $collection = null, $level = 0, array &$flattened = [], $indentChars = null,
+        $parent_string = null
+    ) {
+        $collection = $collection ?: $this;
+        $indentChars = $indentChars ?: $this->indentChars;
+        foreach ($collection as $item) {
+            if ($parent_string) {
+                $item_string = ($parent_string === true) ? $item->$column : $parent_string . $indentChars . $item->$column;
+            } else {
+                $item_string = str_repeat($indentChars, $level) . $item->$column;
+            }
+            $flattened[$item->id] = $item_string;
+            if ($item->items) {
+                $this->listsFlattened($column, $item->items, $level + 1, $flattened, $indentChars,
+                    ($parent_string) ? $item_string : null);
+            }
+        }
+        return $flattened;
+    }
+
+    /**
+     * Returns a fully qualified version of listsFlattened.
+     * @param BaseCollection|null $collection
+     * @param string $column
+     * @param int $level
+     * @param array &$flattened
+     * @param string $indentChars
+     * @return array
+     */
+    public function listsFlattenedQualified(
+        $column = 'title', BaseCollection $collection = null, $level = 0, array &$flattened = [], $indentChars = null
+    ) {
+        return $this->listsFlattened($column, $collection, $level, $flattened, $indentChars, true);
+    }
+
+    /**
+     * Change the default indent characters when flattening lists.
+     * @param string $indentChars
+     * @return $this
+     */
+    public function setIndent(string $indentChars)
+    {
+        $this->indentChars = $indentChars;
+        return $this;
+    }
+
+    /**
+     * Force keeping items that have a missing ancestor.
+     * @return NestableCollection
+     */
+    public function noCleaning()
+    {
+        $this->removeItemsWithMissingAncestor = false;
+        return $this;
+    }
+
+    /**
+     * Check if an ancestor is missing.
+     * @param $item
+     * @return bool
+     */
+    public function anAncestorIsMissing($item)
+    {
+        $parentColumn = $this->parentColumn;
+        if ( ! $item->$parentColumn) {
+            return false;
+        }
+        if ( ! $this->has($item->$parentColumn)) {
+            return true;
+        }
+        $parent = $this[$item->$parentColumn];
+        return $this->anAncestorIsMissing($parent);
+    }
+
+    /**
+     * Get total items in nested collection.
+     * @return int
+     */
+    public function total()
+    {
+        return $this->total;
+    }
+
+    /**
+     * Get total items for laravel 4 compatibility.
+     * @return int
+     */
+    public function getTotal()
+    {
+        return $this->total();
+    }
+}