Feat: custom sort (#4864)

app/models/concerns/sort_handler.rb

@@ -0,0 +1,25 @@
+module SortHandler
+  extend ActiveSupport::Concern
+
+  included do
+    def self.latest
+      order(last_activity_at: :desc)
+    end
+
+    def self.sort_on_created_at
+      order(created_at: :asc)
+    end
+
+    def self.last_messaged_conversations
+      Message.except(:order).select('DISTINCT ON (conversation_id) *').order('conversation_id, created_at DESC')
+    end
+
+    def self.sort_on_last_user_message_at
+      where(
+        'grouped_conversations.message_type = 0'
+      ).order(
+        'grouped_conversations.created_at ASC'
+      )
+    end
+  end
+end

app/models/conversation.rb

@@ -50,6 +50,7 @@ class Conversation < ApplicationRecord
   include RoundRobinHandler
   include ActivityMessageHandler
   include UrlHelper
+  include SortHandler
 
   validates :account_id, presence: true
   validates :inbox_id, presence: true
@@ -60,7 +61,6 @@ class Conversation < ApplicationRecord
 
   enum status: { open: 0, resolved: 1, pending: 2, snoozed: 3 }
 
-  scope :latest, -> { order(last_activity_at: :desc) }
   scope :unassigned, -> { where(assignee_id: nil) }
   scope :assigned, -> { where.not(assignee_id: nil) }
   scope :assigned_to, ->(agent) { where(assignee_id: agent.id) }
@@ -70,6 +70,13 @@ class Conversation < ApplicationRecord
     open.where('last_activity_at < ? ', Time.now.utc - auto_resolve_duration.days)
   }
 
+  scope :last_user_message_at, lambda {
+    joins(
+      "INNER JOIN (#{last_messaged_conversations.to_sql}) grouped_conversations
+      ON grouped_conversations.conversation_id = conversations.id"
+    ).sort_on_last_user_message_at
+  }
+
   belongs_to :account
   belongs_to :inbox
   belongs_to :assignee, class_name: 'User', optional: true

app/models/mention.rb

@@ -23,6 +23,8 @@
 #  fk_rails_...  (user_id => users.id) ON DELETE => cascade
 #
 class Mention < ApplicationRecord
+  include SortHandler
+
   before_validation :ensure_account_id
   validates :mentioned_at, presence: true
   validates :account_id, presence: true
@@ -38,6 +40,17 @@ class Mention < ApplicationRecord
 
   scope :latest, -> { order(mentioned_at: :desc) }
 
+  def self.last_user_message_at
+    # INNER query finds the last message created in the conversation group
+    # The outer query JOINS with the latest created message conversations
+    # Then select only latest incoming message from the conversations which doesn't have last message as outgoing
+    # Order by message created_at
+    Mention.joins(
+      "INNER JOIN (#{last_messaged_conversations.to_sql}) grouped_conversations
+      ON grouped_conversations.conversation_id = mentions.conversation_id"
+    ).sort_on_last_user_message_at
+  end
+
   private
 
   def ensure_account_id