fix -- support for custom relationships that extends base BelongsTo, …

…BelongsToMany, HasMany relationships

src/Domain/Relation/RelationHandlerResolver.php

@@ -4,6 +4,7 @@
 
 use DomainException;
 use Illuminate\Support\Collection;
+use Illuminate\Support\Facades\App;
 use PhoenixLib\NovaNestedTreeAttachMany\Domain\Relation\Handlers\RelationHandler;
 
 class RelationHandlerResolver implements RelationHandlerFactory
@@ -16,9 +17,14 @@ public function __construct(){
 
     public function make( $relation ): RelationHandler
     {
-        if($this->handlers->has( $relation ))
+        $handler = $this->handlers->first(function (RelationHandler $handler) use ($relation){
+            $handlerRelation = $handler->relation();
+            return $relation instanceof $handlerRelation;
+        });
+
+        if($handler)
         {
-            return $this->handlers->get( $relation );
+            return $handler;
         }
 
         throw new DomainException(sprintf('RelationHandler for relation: %s is not registered', $relation));

src/Http/Controllers/NestedTreeController.php

@@ -19,9 +19,7 @@ public function attached(NovaRequest $request, $resource, $resourceId, $relation
     {
         $model = $request->findResourceOrFail()->model();
 
-        $relation = get_class($model->{$relationship}());
-
-        $handler = $this->factory->make($relation);
+        $handler = $this->factory->make($model->{$relationship}());
 
         return $handler->retrieve($model, $relationship, $idKey);
     }

src/NestedTreeAttachManyField.php

@@ -41,9 +41,7 @@ public function __construct($name, $attribute = null, $resource = null)
 
                     $factory = App::make(RelationHandlerFactory::class);
 
-                    $relation = get_class($model->{$attribute}());
-
-                    $handler = $factory->make($relation);
+                    $handler = $factory->make($model->{$attribute}());
 
                     $handler->attach($model, $attribute, json_decode($request->{$attribute}, true));