[ADD] Nested Menu (unlimited levels).

Author: Seiger

docs/pages/use-in-blade.md

@@ -120,6 +120,53 @@ Output in the Blade template
 @endif
 ```
 
+### Multi-level menu (tree)
+
+If you need a nested menu (unlimited levels), get all menu items in one query and then convert the collection to a tree.
+
+Data preparation in BaseController.php
+```php
+use Seiger\sLang\Models\sLangContent;
+
+...
+
+public function globalElements()
+{
+    $this->data['mainMenu'] = sLangContent::withTVs(['menu_main'])
+        ->where('hidemenu', 0)
+        ->whereTv('menu_main', 1)
+        ->orderBy('parent_id')
+        ->orderBy('menuindex')
+        ->active()
+        ->get()
+        ->toTreeParent(0); // return only parent=0 nodes, with nested children
+}
+```
+
+Recursive output in Blade (example with partial)
+
+`views/partials/menu-tree.blade.php`
+```php
+<ul>
+    @foreach($items as $item)
+        <li class="{% raw %}{{$item->id == evo()->documentObject['id'] ? 'active' : ''}}{% endraw %}">
+            <a href="{% raw %}{{$item->full_link}}{% endraw %}">{% raw %}{{$item->menutitle}}{% endraw %}</a>
+
+            @if($item->children && $item->children->isNotEmpty())
+                @include('partials.menu-tree', ['items' => $item->children])
+            @endif
+        </li>
+    @endforeach
+</ul>
+```
+
+Call it from your layout/template:
+```php
+@if($mainMenu && $mainMenu->isNotEmpty())
+    @include('partials.menu-tree', ['items' => $mainMenu])
+@endif
+```
+
 ## TV variables
 
 The `withTVs()` scope makes it easy to retrieve TV parameters associated with a resource. For example, the **tv_image** parameter.

src/Models/sLangContent.php

@@ -4,6 +4,7 @@
 use Illuminate\Database\Eloquent;
 use Illuminate\Database\Eloquent\Builder;
 use Illuminate\Support\Facades\DB;
+use Seiger\sLang\Support\TreeCollection;
 
 class sLangContent extends Eloquent\Model
 {
@@ -87,7 +88,7 @@ public function scopeActive($query)
     /**
      * Performs a search on the query based on the search term.
      *
-     * @return \Illuminate\Database\Query\Builder|null The modified query builder instance or null if no search term is provided
+     * @return \Illuminate\Support\HigherOrderWhenProxy|sLangContent The modified query builder instance or null if no search term is provided
      */
     public function scopeSearch()
     {
@@ -270,6 +271,10 @@ protected function applyContentSelects(Builder $query): Builder
         }
 
         return $query->addSelect(
+            'site_content.parent as parent_id',
+            'site_content.menuindex as menuindex',
+            'site_content.hidemenu as hidemenu',
+            'site_content.isfolder as isfolder',
             'site_content.pagetitle as pagetitle_orig',
             'site_content.longtitle as longtitle_orig',
             'site_content.description as description_orig',
@@ -403,4 +408,15 @@ protected static function booted(): void
             $builder->where($model->getTable() . '.lang', '=', $locale);
         });
     }
-}
+
+    /**
+     * Create a new Eloquent Collection instance.
+     *
+     * @param array $models
+     * @return \Illuminate\Database\Eloquent\Collection
+     */
+    public function newCollection(array $models = [])
+    {
+        return new TreeCollection($models);
+    }
+}

src/Support/TreeCollection.php

@@ -0,0 +1,49 @@
+<?php namespace Seiger\sLang\Support;
+
+use Illuminate\Database\Eloquent\Collection as EloquentCollection;
+use Illuminate\Database\Eloquent\Model;
+
+class TreeCollection extends EloquentCollection
+{
+    public const CHILDREN_RELATION_NAME = 'children';
+
+    public function toTree(): static
+    {
+        return $this->toTreeParent(null);
+    }
+
+    public function toTreeParent($parent = null): static
+    {
+        /** @var array<int|string, Model> $byId */
+        $byId = [];
+        $tops = [];
+
+        foreach ($this->items as $item) {
+            if ($item instanceof Model) {
+                $item->setRelation(static::CHILDREN_RELATION_NAME, new static());
+                $byId[$item->getKey()] = $item;
+            }
+        }
+
+        foreach ($this->items as $item) {
+            if (!$item instanceof Model) {
+                continue;
+            }
+
+            $parentId = $item->getAttribute('parent_id');
+
+            if ($parentId !== null && array_key_exists($parentId, $byId)) {
+                /** @var Model $parentItem */
+                $parentItem = $byId[$parentId];
+                $parentItem->getRelation(static::CHILDREN_RELATION_NAME)->push($item);
+                continue;
+            }
+
+            if ($parent === null || (string)$parentId === (string)$parent) {
+                $tops[] = $item;
+            }
+        }
+
+        return new static($tops);
+    }
+}