Restructure omni services and add Chatwoot research snapshot

research/chatwoot/app/models/mention.rb

@@ -0,0 +1,58 @@
+# == Schema Information
+#
+# Table name: mentions
+#
+#  id              :bigint           not null, primary key
+#  mentioned_at    :datetime         not null
+#  created_at      :datetime         not null
+#  updated_at      :datetime         not null
+#  account_id      :bigint           not null
+#  conversation_id :bigint           not null
+#  user_id         :bigint           not null
+#
+# Indexes
+#
+#  index_mentions_on_account_id                   (account_id)
+#  index_mentions_on_conversation_id              (conversation_id)
+#  index_mentions_on_user_id                      (user_id)
+#  index_mentions_on_user_id_and_conversation_id  (user_id,conversation_id) UNIQUE
+#
+class Mention < ApplicationRecord
+  include SortHandler
+
+  before_validation :ensure_account_id
+  validates :mentioned_at, presence: true
+  validates :account_id, presence: true
+  validates :conversation_id, presence: true
+  validates :user_id, presence: true
+  validates :user, uniqueness: { scope: :conversation }
+
+  belongs_to :account
+  belongs_to :conversation
+  belongs_to :user
+
+  after_commit :notify_mentioned_user
+
+  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}) AS grouped_conversations
+      ON grouped_conversations.conversation_id = mentions.conversation_id"
+    ).sort_on_last_user_message_at
+  end
+
+  private
+
+  def ensure_account_id
+    self.account_id = conversation&.account_id
+  end
+
+  def notify_mentioned_user
+    Rails.configuration.dispatcher.dispatch(CONVERSATION_MENTIONED, Time.zone.now, user: user, conversation: conversation)
+  end
+end