expirable_set.rb

# frozen_string_literal: true

require "concurrent"

module Sidekiq
  module Throttled
    class ExpirableSet
      attr_reader :default_ttl

      def initialize(default_ttl:)
        @default_ttl = default_ttl.to_i
        @elements    = Concurrent::Map.new
      end

      def add(element, ttl: default_ttl)
        @elements[element] = now + ttl.to_i
      end

      def to_a
        now.then do |horizon|
          @elements.each_pair.filter_map do |element, sunset|
            element if horizon <= sunset
          end
        end
      end

      private

      def now
        ::Process.clock_gettime(::Process::CLOCK_MONOTONIC)
      end
    end
  end
end