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, :responder
  attr_accessor :current_lesson_step_index, :current_lesson_step_job_id

  def initialize(lesson_plan=DEFAULT_LESSON_PLAN, scheduler: Rufus::Scheduler.new, responder: nil)
    @lesson_plan = lesson_plan
    @running = false
    @scheduler = scheduler
    @responder = responder
    @current_lesson_step_index = 0
    @current_lesson_step_job_id = nil
  end

  def respond(response)
    responder.call response
  end

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

  def start!
    self.current_lesson_step_index = 0
    run_current_lesson_step
    @running = true
  end

  def current_lesson_step
    lesson_plan[current_lesson_step_index]
  end

  def next_lesson_step
    lesson_plan[current_lesson_step_index + 1]
  end

  def run_current_lesson_step
    scheduler.unschedule(current_lesson_step_job_id) if current_lesson_step_job_id

    if current_lesson_step.nil?
      end_lesson
      return
    end

    duration, comment = current_lesson_step
    respond "#{duration} minutes to #{comment}"

    self.current_lesson_step_job_id = scheduler.in "#{duration}s" do
      if current_lesson_step_index == lesson_plan.length - 1
        end_lesson
      else
        respond "Time's up! Type `next` to move to the next part of the lesson"
      end
      self.current_lesson_step_job_id = nil
    end
  end

  def end_lesson
    respond "Lesson over!"
    @running = false
    self.current_lesson_step_job_id = nil
  end

  def running?
    running
  end

  ACTIONS = %w[next previous pause help]

  def can_handle_message?(message)
    return false unless running?

    ACTIONS.include? message.content.downcase
  end

  def handle_message(message)
    return false unless can_handle_message?(message)

    send("handle_#{message.content.downcase}", message)
  end

  def handle_next(_)
    self.current_lesson_step_index += 1
    run_current_lesson_step
  end

  def handle_previous(message)
    respond "Prev!"
  end

  def handle_pause(message)
    respond "Stop!"
  end

  def handle_help(message)
    respond "HALP!"
  end
end