module Sidekiq::Paginator

def page(key, pageidx=1, page_size=25)
  current_page = pageidx.to_i < 1 ? 1 : pageidx.to_i
  pageidx = current_page - 1
  total_size = 0
  items = []
  starting = pageidx * page_size
  ending = starting + page_size - 1
  Sidekiq.redis do |conn|
    type = conn.type(key)
    case type
    when 'zset'
      total_size = conn.zcard(key)
      items = conn.zrange(key, starting, ending, :with_scores => true)
    when 'list'
      total_size = conn.llen(key)
      items = conn.lrange(key, starting, ending)
    when 'none'
      return [1, 0, []]
    else
      raise "can't page a #{type}"
    end
  end
  [current_page, total_size, items]
end