class Roundrobin

# File lib/roundrobin.rb, line 7
def initialize(redis_conn = nil)
  @redis = redis_conn.nil? ? Redis.new : Redis.new(url: redis_conn)
end

# File lib/roundrobin.rb, line 11
def next(candidates)
  return nil unless candidates.is_a?(Array) and candidates.length > 0
  identifier = get_hash(candidates)
  iterator = @redis.get(identifier)
  if iterator.nil?
    iterator   = -1 
  else
    iterator = iterator.to_i
  end
  iterator += 1
  iterator = 0 if iterator >= candidates.length
  @redis.set(identifier, iterator)
  candidates[iterator]
end

# File lib/roundrobin.rb, line 27
def get_hash(candidates)
  Digest::SHA1.hexdigest candidates.to_s
end