module Jets::Cfn::Builders::ParentBuilder::Stagger

def add_stagger(resource)
  batch_size = stagger_batch_size # shorter convenience variable
  return if !stagger_enabled || batch_size.nil? || batch_size == 0
  # initialize all here to keep logic together
  @previous_stacks ||= []
  @added_count ||= 0
  if @previous_stacks.size >= batch_size
    at_boundary = @added_count % batch_size == 0
    if at_boundary
      @left = @added_count - batch_size
      @right = @left + batch_size - 1
    end
    previous_stack_batch = @previous_stacks[@left..@right]
    resource.add_stagger_depends_on(previous_stack_batch)
  end
  @added_count += 1
  @previous_stacks << resource
end

def stagger_batch_size
  Jets.config.deploy.stagger.batch_size
end

def stagger_enabled
  Jets.config.deploy.stagger.enabled
end