Add getCategory, getCompany, isBelong methods to Item model.

app/Models/Item.php

@@ -31,6 +31,40 @@ class Item extends Model
         return $this->belongsToMany(Cart::class, 'carts_items', 'item_id', 'cart_id');
     }
 
+    public function getCategory(): Category
+    {
+        $category = Category::where('id', $this->category_id)->first();
+
+        return $category;
+    }
+
+    public function getCompany()
+    {
+        $category = $this->getCategory();
+
+        if($category == null)
+            return null;
+
+        $company = Company::where('id', $category->company_id)->first();
+
+        return $company;
+    }
+
+    public function isBelong(Company $company): bool
+    {
+        $category = $this->getCategory();
+
+        if($category == null)
+            return false;
+
+        $its_company = $this->getCompany();
+
+        if($its_company == null or $company == null)
+            return false;
+
+        return $its_company->id == $company->id;
+    }
+
     public static function validate_with_name(string $name)
     {
         $name = $name ?? '';