toggle behavior on skus for default product sku, photos for default category photo and default product photo

src/Model/Behavior/SecondToggleBehavior.php

@@ -0,0 +1,37 @@
+<?php
+
+namespace CakeProducts\Model\Behavior;
+
+use ArrayObject;
+use Cake\Datasource\EntityInterface;
+use Cake\Event\EventInterface;
+use Cake\ORM\Behavior;
+use LogicException;
+use Tools\Model\Behavior\ToggleBehavior;
+
+/**
+ * ToggleBehavior
+ *
+ * An implementation of a unique field toggle per table or scope.
+ * This will ensure that on a set of records only one can be a "primary" one, setting the others to false then.
+ * On delete it will give the primary status to another record if applicable.
+ *
+ * @author Mark Scherer
+ * @license MIT
+ */
+class SecondToggleBehavior extends ToggleBehavior {
+
+    /**
+     * Default config
+     *
+     * @var array<string, mixed>
+     */
+    protected array $_defaultConfig = [
+        'field' => 'primary',
+        'on' => 'afterSave', // afterSave (without transactions) or beforeSave (with transactions)
+        'scopeFields' => [],
+        'scope' => [],
+        'findOrder' => null, // null = autodetect modified/created, false to disable
+        'implementedMethods' => [], // to prevent conflict with public toggleField method
+    ];
+}

src/Model/Table/ProductPhotosTable.php

@@ -58,7 +58,22 @@ class ProductPhotosTable extends Table
         );
 
         $this->addBehavior('Timestamp');
-
+        $this->addBehavior('Tools.Toggle', [
+            'field' => 'primary_photo',
+            'scopeFields' => ['product_id'],
+            'scope' => [
+                'deleted IS' => null,
+                'product_id IS NOT' => null,
+            ],
+        ]);
+        $this->addBehavior('CakeProducts.SecondToggle', [
+            'field' => 'primary_category_photo',
+            'scopeFields' => ['product_category_id'],
+            'scope' => [
+                'deleted IS' => null,
+                'product_category_id IS NOT' => null,
+            ],
+        ]);
         $this->belongsTo('Products', [
             'foreignKey' => 'product_id',
             'joinType' => 'LEFT',

src/Model/Table/ProductSkusTable.php

@@ -59,6 +59,13 @@ class ProductSkusTable extends Table
         );
 
         $this->addBehavior('Timestamp');
+        $this->addBehavior('Tools.Toggle', [
+            'field' => 'default_sku',
+            'scopeFields' => ['product_id'],
+            'scope' => [
+                'deleted IS' => null,
+            ],
+        ]);
 
         $this->belongsTo('Products', [
             'className' => 'CakeProducts.Products',