feat: Add support for persistent copilot threads and messages (#11489)

The agents can see the previous conversations with the copilot if needed
with this change. We would have to cleanup the data after a while. For
now, that is not considered.

This PR adds:
- A new model for copilot_threads (intentionally named thread instead of
conversation to avoid confusion), copilot_messages
- Add the controller to fetch previous threads and messages.

enterprise/app/controllers/api/v1/accounts/captain/copilot_messages_controller.rb

@@ -0,0 +1,25 @@
+class Api::V1::Accounts::Captain::CopilotMessagesController < Api::V1::Accounts::BaseController
+  before_action :current_account
+  before_action -> { check_authorization(Captain::Assistant) }
+  before_action :set_copilot_thread
+
+  def index
+    @copilot_messages = @copilot_thread
+                        .copilot_messages
+                        .order(created_at: :asc)
+                        .page(permitted_params[:page] || 1)
+                        .per(1000)
+  end
+
+  private
+
+  def set_copilot_thread
+    @copilot_thread = Current.account.copilot_threads.find_by!(
+      uuid: params[:copilot_thread_id], user_id: Current.user.id
+    )
+  end
+
+  def permitted_params
+    params.permit(:page)
+  end
+end

enterprise/app/controllers/api/v1/accounts/captain/copilot_threads_controller.rb

@@ -0,0 +1,19 @@
+class Api::V1::Accounts::Captain::CopilotThreadsController < Api::V1::Accounts::BaseController
+  before_action :current_account
+  before_action -> { check_authorization(Captain::Assistant) }
+
+  def index
+    @copilot_threads = Current.account.copilot_threads
+                              .where(user_id: Current.user.id)
+                              .includes(:user)
+                              .order(created_at: :desc)
+                              .page(permitted_params[:page] || 1)
+                              .per(5)
+  end
+
+  private
+
+  def permitted_params
+    params.permit(:page)
+  end
+end

enterprise/app/models/copilot_message.rb

@@ -0,0 +1,27 @@
+# == Schema Information
+#
+# Table name: copilot_messages
+#
+#  id                :bigint           not null, primary key
+#  message           :jsonb            not null
+#  message_type      :string           not null
+#  created_at        :datetime         not null
+#  updated_at        :datetime         not null
+#  account_id        :bigint           not null
+#  copilot_thread_id :bigint           not null
+#  user_id           :bigint           not null
+#
+# Indexes
+#
+#  index_copilot_messages_on_account_id         (account_id)
+#  index_copilot_messages_on_copilot_thread_id  (copilot_thread_id)
+#  index_copilot_messages_on_user_id            (user_id)
+#
+class CopilotMessage < ApplicationRecord
+  belongs_to :copilot_thread
+  belongs_to :user
+  belongs_to :account
+
+  validates :message_type, presence: true, inclusion: { in: %w[user assistant assistant_thinking] }
+  validates :message, presence: true
+end

enterprise/app/models/copilot_thread.rb

@@ -0,0 +1,26 @@
+# == Schema Information
+#
+# Table name: copilot_threads
+#
+#  id         :bigint           not null, primary key
+#  title      :string           not null
+#  uuid       :uuid             not null
+#  created_at :datetime         not null
+#  updated_at :datetime         not null
+#  account_id :bigint           not null
+#  user_id    :bigint           not null
+#
+# Indexes
+#
+#  index_copilot_threads_on_account_id  (account_id)
+#  index_copilot_threads_on_user_id     (user_id)
+#  index_copilot_threads_on_uuid        (uuid) UNIQUE
+#
+class CopilotThread < ApplicationRecord
+  belongs_to :user
+  belongs_to :account
+  has_many :copilot_messages, dependent: :destroy
+
+  validates :title, presence: true
+  validates :uuid, presence: true, uniqueness: true
+end

enterprise/app/models/enterprise/concerns/account.rb

@@ -9,5 +9,7 @@ module Enterprise::Concerns::Account
     has_many :captain_assistants, dependent: :destroy_async, class_name: 'Captain::Assistant'
     has_many :captain_assistant_responses, dependent: :destroy_async, class_name: 'Captain::AssistantResponse'
     has_many :captain_documents, dependent: :destroy_async, class_name: 'Captain::Document'
+
+    has_many :copilot_threads, dependent: :destroy_async
   end
 end

enterprise/app/models/enterprise/concerns/user.rb

@@ -5,6 +5,8 @@ module Enterprise::Concerns::User
     before_validation :ensure_installation_pricing_plan_quantity, on: :create
 
     has_many :captain_responses, class_name: 'Captain::AssistantResponse', dependent: :nullify, as: :documentable
+    has_many :copilot_threads, dependent: :destroy_async
+    has_many :copilot_messages, dependent: :destroy_async
   end
 
   def ensure_installation_pricing_plan_quantity

enterprise/app/views/api/v1/accounts/captain/copilot_messages/index.json.jbuilder

@@ -0,0 +1,8 @@
+json.payload do
+  json.array! @copilot_messages do |message|
+    json.id message.id
+    json.message message.message
+    json.message_type message.message_type
+    json.created_at message.created_at.to_i
+  end
+end

enterprise/app/views/api/v1/accounts/captain/copilot_threads/index.json.jbuilder

@@ -0,0 +1,12 @@
+json.payload do
+  json.array! @copilot_threads do |thread|
+    json.id thread.id
+    json.title thread.title
+    json.uuid thread.uuid
+    json.created_at thread.created_at.to_i
+    json.user do
+      json.id thread.user.id
+      json.name thread.user.name
+    end
+  end
+end