Run callbacks on state change

README.md

@@ -149,6 +149,24 @@ Instances with accepted Friendship.
 @dee.friends # => [@mac]
 ```
 
+### Callbacks
+
+To use callbacks you can add methods described below, to your Friendable model.
+
+```ruby
+def on_friendship_created(friendship)
+  ...
+end
+
+def on_friendship_accepted(friendship)
+  ...
+end
+
+def on_friendship_blocked(friendship)
+  ...
+end
+```
+
 ## Roadmap
 
 Thanks for all the contributors. Pull requests are encouraged for the following

lib/has_friendship/friendable.rb

@@ -88,6 +88,10 @@ def friends_with?(friend)
         HasFriendship::Friendship.find_relation(self, friend, status: 2).any?
       end
 
+      def on_friendship_created(*args); end
+      def on_friendship_accepted(*args); end
+      def on_friendship_blocked(*args); end
+
       private
 
       def has_blocked(friend)

lib/has_friendship/friendship.rb

@@ -1,16 +1,27 @@
 module HasFriendship
   class Friendship < ActiveRecord::Base
 
+    after_create do
+      friend.on_friendship_created(self)
+    end
+
     enum status: { pending: 0, requested: 1, accepted: 2, blocked: 3 } do
       event :accept do
         transition [:pending, :requested] => :accepted
+
+        after do
+          friendable.on_friendship_accepted(self)
+        end
       end
 
       event :block do
         before do
           self.blocker_id = self.friendable.id
         end
 
+        after do
+          friendable.on_friendship_blocked(self)
+        end
         transition all - [:blocked] => :blocked
       end
     end

spec/has_friendship/friendable_spec.rb

@@ -272,5 +272,30 @@
         end
       end
     end
+
+    describe '#on_friendship_accepted' do
+      context 'when friendship is accepted' do
+        it 'should be called' do
+          user.friend_request(friend)
+          friendship = find_friendship_record(user, friend)
+
+          expect(friendship.friendable).to receive(:on_friendship_accepted)
+          friendship.accept!
+        end
+      end
+    end
+
+    describe '#on_friendship_blocked' do
+      context 'when friendship is blocked' do
+        it 'should be called' do
+          user.friend_request(friend)
+          friendship = find_friendship_record(user, friend)
+
+          expect(friendship.friendable).to receive(:on_friendship_blocked)
+          friendship.block!
+        end
+      end
+    end
+
   end
 end