module FirstAfterCreatedAt

# File lib/first_after_created_at.rb, line 2
def first_after_created_at(time)
  time = Time.parse(time.to_s)
  best = nil
  first = select(:id, :created_at).first
  return unless first
  min_id = first.id
  max_id = select(:id, :created_at).last.id

  loop do
    mid_id = (min_id + max_id) / 2
    mid_obj =
      select(:id, :created_at).where("#{quoted_table_name}.#{connection.quote_column_name('id')} >= ?", mid_id).order(:id).first

    best = get_best(mid_obj, time, best)
    break if min_id == max_id

    if mid_obj.created_at < time
      # handle even / odd
      min_id = mid_id < max_id ? mid_id + 1 : mid_id
    else
      max_id = mid_id > min_id ? mid_id - 1 : mid_id
    end
  end

  find(best.id) if best
end

# File lib/first_after_created_at.rb, line 29
def get_best(obj, time, best)
  return best if obj.created_at < time
  return obj if best.nil?
  obj.id < best.id ? obj : best
end