require "rufus-scheduler"

DEFAULT_LESSON_PLAN = [
  [15, "login and catch up on the week"],
  [45, "review chapter vocab and grammar"],
  [15, "answer Seth Clydesdale Genki review questions"],
  [15, "ask closing questions and have Japanese conversation"],
]

class Lesson
  attr_reader :lesson_plan, :channel, :running, :scheduler
  attr_accessor :responder

  def initialize(lesson_plan=DEFAULT_LESSON_PLAN, scheduler: Rufus::Scheduler.new, responder: nil)
    @lesson_plan = lesson_plan
    @running = false
    @scheduler = scheduler
    @responder = responder
  end

  def stop!
    @scheduler.shutdown
    @running = false
  end

  def start!
    lesson_plan.each_with_index do |(time, message), index|
      offset = lesson_plan.map(&:first)[0..index - 1].sum(0)
      offset = 0 if index == 0
      scheduler.in "#{offset}m" do
        responder.call "#{time} minutes to #{message}"
      end
    end

    end_offset = lesson_plan.map(&:first).sum(0)
    scheduler.in "#{end_offset}m" do
      responder.call "Lesson over!"
      @running = false
    end

    @running = true
  end

  def running?
    running
  end

  def handle_message(_)
    # TODO: make it possible to advance the lesson or whatever
  end
end