ika_bot/ika.rb

 require 'discordrb'
 require_relative './session'
 require_relative './lesson'

 token = File.read("./token")

 bot = Discordrb::Bot.new(token:)

 current_session = nil
 current_lesson = Lesson.new

 bot.message do |event|
   if event.message.content == "!init"
     next event.respond("There's already a session running") unless current_session.nil?

     next current_session = Session.new(event, event.message.author)
   elsif event.message.content == "!lesson"
     next event.respond("There's already a lesson running") if current_lesson.running?
     event.respond("Starting a lesson now!")
     next current_lesson.start!(event.channel)
   elsif event.message.content == "!stoplesson"
     next event.respond("There's no lesson running") unless current_lesson.running?
     event.respond("Ending the current lesson!")
     next current_lesson.stop!
   end

   current_session&.respond_to event
 end

 bot.run