chore: Automate conversation display_id generation with db triggers (#1412)

Automate conversation display_id generation with db triggers

Co-authored-by: Saurabh Mehta <saurabh1.mehta@airtel.com>
Co-authored-by: Sojan Jose <sojan@pepalo.com>

app/models/account.rb

@@ -91,4 +91,8 @@ class Account < ApplicationRecord
   def notify_creation
     Rails.configuration.dispatcher.dispatch(ACCOUNT_CREATED, Time.zone.now, account: self)
   end
+
+  trigger.after(:insert).for_each(:row) do
+    "execute format('create sequence IF NOT EXISTS conv_dpid_seq_%s', NEW.id);"
+  end
 end

app/models/conversation.rb

@@ -7,12 +7,12 @@
 #  agent_last_seen_at    :datetime
 #  contact_last_seen_at  :datetime
 #  identifier            :string
-#  last_activity_at      :datetime         not null
+#  last_activity_at      :datetime
 #  locked                :boolean          default(FALSE)
 #  status                :integer          default("open"), not null
 #  uuid                  :uuid             not null
-#  created_at            :datetime         not null
-#  updated_at            :datetime         not null
+#  created_at            :datetime
+#  updated_at            :datetime
 #  account_id            :integer          not null
 #  assignee_id           :integer
 #  contact_id            :bigint
@@ -52,12 +52,13 @@ class Conversation < ApplicationRecord
   has_many :messages, dependent: :destroy, autosave: true
 
   before_create :set_bot_conversation
-  before_create :set_display_id, unless: :display_id?
+
   # wanted to change this to after_update commit. But it ended up creating a loop
   # reinvestigate in future and identity the implications
   after_update :notify_status_change, :create_activity
   after_create_commit :notify_conversation_creation, :queue_conversation_auto_resolution_job
   after_save :run_round_robin
+  after_commit :set_display_id, unless: :display_id?
 
   delegate :auto_resolve_duration, to: :account
 
@@ -154,10 +155,7 @@ class Conversation < ApplicationRecord
   end
 
   def set_display_id
-    self.display_id = loop do
-      next_display_id = account.conversations.maximum('display_id').to_i + 1
-      break next_display_id unless account.conversations.exists?(display_id: next_display_id)
-    end
+    reload
   end
 
   def create_activity
@@ -289,4 +287,9 @@ class Conversation < ApplicationRecord
   def mute_period
     6.hours
   end
+
+  # creating db triggers
+  trigger.before(:insert).for_each(:row) do
+    "NEW.display_id := nextval('conv_dpid_seq_' || NEW.account_id);"
+  end
 end