regenerate slug if needed

app/models/communication/website/author.rb

@@ -59,4 +59,9 @@ class Communication::Website::Author < ApplicationRecord
     )
   end
 
+  protected
+
+  def slug_unavailable?(slug)
+    self.class.unscoped.where(communication_website_id: self.communication_website_id, slug: slug).where.not(id: self.id).exists?
+  end
 end

app/models/communication/website/category.rb

@@ -101,4 +101,7 @@ class Communication::Website::Category < ApplicationRecord
     end
   end
 
+  def slug_unavailable?(slug)
+    self.class.unscoped.where(communication_website_id: self.communication_website_id, slug: slug).where.not(id: self.id).exists?
+  end
 end

app/models/communication/website/page.rb

@@ -65,7 +65,7 @@ class Communication::Website::Page < ApplicationRecord
   validates :title, presence: true
   validates :slug, uniqueness: { scope: :communication_website_id }
 
-  before_validation :regenerate_slug, :make_path
+  before_validation :make_path
   after_save :update_children_paths if :saved_change_to_path?
 
   scope :ordered, -> { order(:position) }
@@ -93,13 +93,8 @@ class Communication::Website::Page < ApplicationRecord
 
   protected
 
-  def regenerate_slug
-    current_slug = self.slug
-    n = 0
-    while self.class.unscoped.where(communication_website_id: communication_website_id, slug: self.slug).where.not(id: id).exists?
-      n += 1
-      self.slug = [current_slug, n].join('-')
-    end
+  def slug_unavailable?(slug)
+    self.class.unscoped.where(communication_website_id: self.communication_website_id, slug: slug).where.not(id: self.id).exists?
   end
 
   def make_path

app/models/communication/website/post.rb

@@ -70,4 +70,10 @@ class Communication::Website::Post < ApplicationRecord
   def to_s
     "#{title}"
   end
+
+  protected
+
+  def slug_unavailable?(slug)
+    self.class.unscoped.where(communication_website_id: self.communication_website_id, slug: slug).where.not(id: self.id).exists?
+  end
 end

app/models/concerns/with_slug.rb

@@ -6,5 +6,22 @@ module WithSlug
               uniqueness: { scope: :university_id }
     validates :slug,
               format: { with: /\A[a-z0-9\-]+\z/, message: I18n.t('slug_error') }
+
+    before_validation :regenerate_slug
+
+    def regenerate_slug
+      current_slug = self.slug
+      n = 0
+      while slug_unavailable?(self.slug)
+        n += 1
+        self.slug = [current_slug, n].join('-')
+      end
+    end
+
+    protected
+
+    def slug_unavailable?(slug)
+      self.class.unscoped.where(university_id: self.university_id, slug: slug).where.not(id: self.id).exists?
+    end
   end
 end