InvitationSet

invitation_set.rb

class InvitationSet
  attr_reader :organization

  def initialize(organization)
    @organization = organization
  end

  def invite(email)
    invite_code = Token.generate(6).upcase
    key.zadd(Time.now.to_i, invite_code)
    # deliver(email, invite_code)
    invite_code
  end

  def invited?(invite_code)
    purge_old
    key.zscore(invite_code.upcase).to_i > 0
  end

  def purge_old(days = 7, start_time = Time.now - (days * 86_400))
    key.zremrangebyscore 0, start_time.to_i
  end

  def key
    organization.key[:invites]
  end
end

Could also TTL on #invite so an unused set is harvested after a time, but probably overkill at first.