Add text with last update to seats usage data

- The information will be displayed in the Billings page
- Introduced a method in the worker class to get the last_enqueue_time
from the job
- Marked messages for translation and updated gitlab.pot file

ee/app/helpers/billing_plans_helper.rb

@@ -71,6 +71,13 @@ module BillingPlansHelper
     namespace == current_user.namespace
   end
 
+  def seats_data_last_update_info
+    last_enqueue_time = UpdateMaxSeatsUsedForGitlabComSubscriptionsWorker.last_enqueue_time&.utc
+    return _("Seats usage data as of %{last_enqueue_time}" % { last_enqueue_time: last_enqueue_time }) if last_enqueue_time
+
+    _('Seats usage data is updated every day at 12:00pm UTC')
+  end
+
   private
 
   def plan_purchase_url(group, plan)

ee/app/views/shared/billings/_billing_plans.html.haml

@@ -12,3 +12,5 @@
 - if namespace.actual_plan&.paid?
   .center
     &= s_('BillingPlans|If you would like to downgrade your plan please contact %{support_link_start}Customer Support%{support_link_end}.').html_safe % { support_link_start: support_link_start, support_link_end: support_link_end }
+
+  %p= seats_data_last_update_info

ee/app/workers/update_max_seats_used_for_gitlab_com_subscriptions_worker.rb

@@ -39,6 +39,10 @@ class UpdateMaxSeatsUsedForGitlabComSubscriptionsWorker # rubocop:disable Scalab
     end
   end
 
+  def self.last_enqueue_time
+    Sidekiq::Cron::Job.find('update_max_seats_used_for_gitlab_com_subscriptions_worker')&.last_enqueue_time
+  end
+
   private
 
   def track_error(subscription)

ee/changelogs/unreleased/al-233444-show-last-enqueue-time-billing-page.yml

+---
+title: Show when the last update to seats usage data was in the Billing page
+merge_request: 42763
+author:
+type: added

ee/spec/helpers/billing_plans_helper_spec.rb

@@ -125,4 +125,26 @@ RSpec.describe BillingPlansHelper do
       end
     end
   end
+
+  describe '#seats_data_last_update_info' do
+    before do
+      allow(UpdateMaxSeatsUsedForGitlabComSubscriptionsWorker).to receive(:last_enqueue_time).and_return(enqueue_time)
+    end
+
+    context 'when last_enqueue_time from the worker is known' do
+      let(:enqueue_time) { Time.current }
+
+      it 'shows the last enqueue time' do
+        expect(helper.seats_data_last_update_info).to match("as of #{enqueue_time}")
+      end
+    end
+
+    context 'when last_enqueue_time from the worker is unknown' do
+      let(:enqueue_time) { nil }
+
+      it 'shows default message' do
+        expect(helper.seats_data_last_update_info).to match('is updated every day at 12:00pm UTC')
+      end
+    end
+  end
 end

ee/spec/workers/update_max_seats_used_for_gitlab_com_subscriptions_worker_spec.rb

@@ -120,4 +120,16 @@ RSpec.describe UpdateMaxSeatsUsedForGitlabComSubscriptionsWorker do
       end
     end
   end
+
+  describe '.last_enqueue_time' do
+    it 'returns last_enqueue_time from the cron job instance' do
+      time = Time.current
+      job = double(Sidekiq::Cron::Job, last_enqueue_time: time)
+      allow(Sidekiq::Cron::Job).to receive(:find)
+        .with('update_max_seats_used_for_gitlab_com_subscriptions_worker')
+        .and_return(job)
+
+      expect(described_class.last_enqueue_time).to eq(time)
+    end
+  end
 end

locale/gitlab.pot

@@ -22439,6 +22439,12 @@ msgstr ""
 msgid "Seat Link is disabled, and cannot be configured through this form."
 msgstr ""
 
+msgid "Seats usage data as of %{last_enqueue_time}"
+msgstr ""
+
+msgid "Seats usage data is updated every day at 12:00pm UTC"
+msgstr ""
+
 msgid "Secondary"
 msgstr ""