Chore: Refactor round robin logic (#1015)

Co-authored-by: Pranav Raj S <pranav@thoughtwoot.com>

app/models/conversation.rb

@@ -188,7 +188,7 @@ class Conversation < ApplicationRecord
     return unless conversation_status_changed_to_open?
     return unless should_round_robin?
 
-    inbox.next_available_agent.then { |new_assignee| update_assignee(new_assignee) }
+    ::RoundRobin::AssignmentService.new(conversation: self).perform
   end
 
   def create_status_change_message(user_name)

app/models/inbox.rb

@@ -64,11 +64,6 @@ class Inbox < ApplicationRecord
     channel.class.name.to_s == 'Channel::WebWidget'
   end
 
-  def next_available_agent
-    user_id = Redis::Alfred.rpoplpush(round_robin_key, round_robin_key)
-    account.users.find_by(id: user_id)
-  end
-
   def webhook_data
     {
       id: id,
@@ -79,10 +74,6 @@ class Inbox < ApplicationRecord
   private
 
   def delete_round_robin_agents
-    Redis::Alfred.delete(round_robin_key)
-  end
-
-  def round_robin_key
-    format(Constants::RedisKeys::ROUND_ROBIN_AGENTS, inbox_id: id)
+    ::RoundRobin::ManageService.new(inbox: self).clear_queue
   end
 end

app/models/inbox_member.rb

@@ -26,14 +26,10 @@ class InboxMember < ApplicationRecord
   private
 
   def add_agent_to_round_robin
-    Redis::Alfred.lpush(round_robin_key, user_id)
+    ::RoundRobin::ManageService.new(inbox: inbox).add_agent_to_queue(user_id)
   end
 
   def remove_agent_from_round_robin
-    Redis::Alfred.lrem(round_robin_key, user_id)
-  end
-
-  def round_robin_key
-    format(Constants::RedisKeys::ROUND_ROBIN_AGENTS, inbox_id: inbox_id)
+    ::RoundRobin::ManageService.new(inbox: inbox).remove_agent_from_queue(user_id)
   end
 end

app/models/message.rb

@@ -153,7 +153,6 @@ class Message < ApplicationRecord
   end
 
   def notify_via_mail
-    conversation_mail_key = Redis::Alfred::CONVERSATION_MAILER_KEY % conversation.id
     if Redis::Alfred.get(conversation_mail_key).nil? && conversation.contact.email? && outgoing?
       # set a redis key for the conversation so that we don't need to send email for every
       # new message that comes in and we dont enque the delayed sidekiq job for every message
@@ -165,6 +164,10 @@ class Message < ApplicationRecord
     end
   end
 
+  def conversation_mail_key
+    format(::Redis::Alfred::CONVERSATION_MAILER_KEY, conversation_id: conversation.id)
+  end
+
   def validate_attachments_limit(_attachment)
     errors.add(attachments: 'exceeded maximum allowed') if attachments.size >= NUMBER_OF_PERMITTED_ATTACHMENTS
   end

app/services/round_robin/assignment_service.rb

@@ -0,0 +1,24 @@
+class RoundRobin::AssignmentService
+  pattr_initialize [:conversation]
+
+  def perform
+    # online agents will get priority
+    new_assignee = round_robin_manage_service.available_agent(priority_list: online_agents)
+    conversation.update(assignee: new_assignee) if new_assignee
+  end
+
+  private
+
+  def online_agents
+    online_agents = OnlineStatusTracker.get_available_users(conversation.account_id)
+    online_agents.select { |_key, value| value.eql?('online') }.keys if online_agents.present?
+  end
+
+  def round_robin_manage_service
+    @round_robin_manage_service ||= RoundRobin::ManageService.new(inbox: conversation.inbox)
+  end
+
+  def round_robin_key
+    format(::Redis::Alfred::ROUND_ROBIN_AGENTS, inbox_id: conversation.inbox_id)
+  end
+end

app/services/round_robin/manage_service.rb

@@ -0,0 +1,56 @@
+class RoundRobin::ManageService
+  pattr_initialize [:inbox!]
+
+  # called on inbox delete
+  def clear_queue
+    ::Redis::Alfred.delete(round_robin_key)
+  end
+
+  # called on inbox member create
+  def add_agent_to_queue(user_id)
+    ::Redis::Alfred.lpush(round_robin_key, user_id)
+  end
+
+  # called on inbox member delete
+  def remove_agent_from_queue(user_id)
+    ::Redis::Alfred.lrem(round_robin_key, user_id)
+  end
+
+  def available_agent(priority_list: [])
+    reset_queue unless validate_queue?
+    user_id = get_agent_via_priority_list(priority_list)
+    # incase priority list was empty or inbox members weren't present
+    user_id ||= ::Redis::Alfred.rpoplpush(round_robin_key, round_robin_key)
+    inbox.inbox_members.find_by(user_id: user_id)&.user if user_id.present?
+  end
+
+  def reset_queue
+    clear_queue
+    add_agent_to_queue(inbox.inbox_members.map(&:user_id))
+  end
+
+  private
+
+  def get_agent_via_priority_list(priority_list)
+    return if priority_list.blank?
+
+    user_id = queue.intersection(priority_list.map(&:to_s)).pop
+    if user_id.present?
+      remove_agent_from_queue(user_id)
+      add_agent_to_queue(user_id)
+    end
+    user_id
+  end
+
+  def validate_queue?
+    return true if inbox.inbox_members.map(&:user_id).sort == queue.sort.map(&:to_i)
+  end
+
+  def queue
+    ::Redis::Alfred.lrange(round_robin_key)
+  end
+
+  def round_robin_key
+    format(::Redis::Alfred::ROUND_ROBIN_AGENTS, inbox_id: inbox.id)
+  end
+end

app/workers/conversation_reply_email_worker.rb

@@ -9,7 +9,12 @@ class ConversationReplyEmailWorker
     ConversationReplyMailer.reply_with_summary(@conversation, queued_time).deliver_later
 
     # delete the redis set from the first new message on the conversation
-    conversation_mail_key = Redis::Alfred::CONVERSATION_MAILER_KEY % @conversation.id
     Redis::Alfred.delete(conversation_mail_key)
   end
+
+  private
+
+  def conversation_mail_key
+    format(::Redis::Alfred::CONVERSATION_MAILER_KEY, conversation_id: @conversation.id)
+  end
 end