capture topic and synapse updates, store the old values

app/models/event.rb

@@ -2,7 +2,8 @@
 class Event < ApplicationRecord
   KINDS = %w(user_present_on_map conversation_started_on_map 
                topic_added_to_map topic_moved_on_map topic_removed_from_map
-               synapse_added_to_map synapse_removed_from_map).freeze
+               synapse_added_to_map synapse_removed_from_map
+               topic_updated synapse_updated).freeze
 
   belongs_to :eventable, polymorphic: true
   belongs_to :map

app/models/events/synapse_updated.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+class Events::SynapseUpdated < Event
+  # after_create :notify_users!
+
+  def self.publish!(synapse, user, meta)
+    create!(kind: 'synapse_updated',
+            eventable: synapse,
+            user: user,
+            meta: meta)
+  end
+end

app/models/events/topic_updated.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+class Events::TopicUpdated < Event
+  # after_create :notify_users!
+
+  def self.publish!(topic, user, meta)
+    create!(kind: 'topic_updated',
+            eventable: topic,
+            user: user,
+            meta: meta)
+  end
+end

app/models/synapse.rb

@@ -22,6 +22,8 @@ class Synapse < ApplicationRecord
     where(topic1_id: topic_id).or(where(topic2_id: topic_id))
   }
 
+  after_update :after_updated
+
   delegate :name, to: :user, prefix: true
 
   def user_image
@@ -39,4 +41,14 @@ class Synapse < ApplicationRecord
   def as_json(_options = {})
     super(methods: [:user_name, :user_image, :collaborator_ids])
   end
+
+  def after_updated
+    attrs = ['desc', 'category', 'permission', 'defer_to_map_id']
+    if attrs.any? {|k| changed_attributes.key?(k)}
+      new = self.attributes.select {|k,v| attrs.include?(k) } 
+      old = changed_attributes.select {|k,v| attrs.include?(k) } 
+      meta = new.merge(old) # we are prioritizing the old values, keeping them 
+      Events::SynapseUpdated.publish!(self, user, meta)
+    end
+  end
 end

app/models/topic.rb

@@ -16,6 +16,7 @@ class Topic < ApplicationRecord
   belongs_to :metacode
 
   before_create :create_metamap?
+  after_update :after_updated
 
   validates :permission, presence: true
   validates :permission, inclusion: { in: Perm::ISSIONS.map(&:to_s) }
@@ -135,4 +136,14 @@ class Topic < ApplicationRecord
     self.link = Rails.application.routes.url_helpers
                      .map_url(host: ENV['MAILER_DEFAULT_URL'], id: @map.id)
   end
+
+  def after_updated
+    attrs = ['name', 'desc', 'link', 'metacode_id', 'permission', 'defer_to_map_id']
+    if attrs.any? {|k| changed_attributes.key?(k)}
+      new = self.attributes.select {|k,v| attrs.include?(k) } 
+      old = changed_attributes.select {|k,v| attrs.include?(k) } 
+      meta = new.merge(old) # we are prioritizing the old values, keeping them 
+      Events::TopicUpdated.publish!(self, user, meta)
+    end
+  end
 end