add upcoming job notifier

app/jobs/telegram_notify_upcoming_job.rb

+class TelegramNotifyUpcomingJob < ApplicationJob
+  queue_as :default
+
+  def perform(**args)
+    Session.scheduled.includes(:stage, :assignments).where(stage: { name: ["Stage 1", "Stage 2", "Standby"] }).where(starts_at: Time.now..(Time.now + args[:interval])).order(:starts_at).each do |session|
+      assignees = session.assignments.map(&:user)
+      if assignees.length.positive?
+        notify_names = assignees.map { |a| a.telegram_username ? "@#{a.telegram_username}" : a.name }
+
+        message = notify_names.join(' ') + ": Your scheduled session <i>#{session.title}</i> starts at <b>#{session.starts_at.strftime("%H:%M")}</b> on <b>#{session.stage.name}</b>"
+        TelegramGroupChatNotificationJob.perform_later(target: "-316096320", text: message, parse_mode: 'HTML')
+        # TelegramGroupChatNotificationJob.perform_now(target: "2192297", text: message, parse_mode: 'HTML')
+      else
+        message = "<b>⚠️ No assignees</b> for session <i>#{session.title}</i> starting at <b>#{session.starts_at.strftime("%H:%M")}</b> on <b>#{session.stage.name}</b>"
+        TelegramGroupChatNotificationJob.perform_later(target: "-316096320", text: message, parse_mode: 'HTML')
+        # TelegramGroupChatNotificationJob.perform_now(target: "2192297", text: message, parse_mode: 'HTML')
+      end
+    end
+  end
+end

config/cronotab.rb

@@ -15,3 +15,4 @@
 #
 
 Crono.perform(FetchConferenceDataJob, 'rp2024').every 5.minutes
+Crono.perform(TelegramNotifyUpcomingJob, interval: 15.minutes).every 15.minutes

test/jobs/telegram_notify_upcoming_job_test.rb

+require "test_helper"
+
+class TelegramNotifyUpcomingJobTest < ActiveJob::TestCase
+  # test "the truth" do
+  #   assert true
+  # end
+end