Closure Table in redis

insert.rb

def insert(item, parent, comment)
  cid = @redis.incr 'comments_counter'

  parent_path = @redis.zrangebyscore("asc:#{item}:#{parent}", "0", "+inf", with_scores: true) if parent
  parent_path ||= []
  @redis.multi do |multi|
    multi.set "comments:#{cid}", {
      data: comment,
      item: item,
      date: Time.now,
      status: 'saved',
      edited: false
    }.to_json

    multi.rpush "comments_for_item:#{item}", cid

    if parent
      asc_key = "asc:#{item}:#{cid}"
      parent_path.each do |p|
        multi.zadd asc_key, p[1].to_i+1, p[0]
        multi.zadd "desc:#{item}:#{p[0]}", p[1].to_i+1, cid
      end
      multi.zadd asc_key, 1, parent
      multi.zadd "desc:#{item}:#{parent}", 1, cid
    end
  end
  cid
end