# frozen_string_literal: true

class Scheduler::FeedCleanupScheduler
  include Sidekiq::Worker
  include Redisable

  sidekiq_options unique: :until_executed, retry: 0

  def perform
    clean_home_feeds!
    clean_list_feeds!
  end

  private

  def clean_home_feeds!
    clean_feeds!(inactive_account_ids, :home)
  end

  def clean_list_feeds!
    clean_feeds!(inactive_list_ids, :list)
  end

  def clean_feeds!(ids, type)
    reblogged_id_sets = {}

    redis.with do |conn|
      conn.pipelined do
        ids.each do |feed_id|
          conn.del(feed_manager.key(type, feed_id))
          reblog_key = feed_manager.key(type, feed_id, 'reblogs')
          # We collect a future for this: we don't block while getting
          # it, but we can iterate over it later.
          reblogged_id_sets[feed_id] = conn.zrange(reblog_key, 0, -1)
          conn.del(reblog_key)
        end
      end

      # Remove all of the reblog tracking keys we just removed the
      # references to.
      conn.pipelined do
        reblogged_id_sets.each do |feed_id, future|
          future.value.each do |reblogged_id|
            reblog_set_key = feed_manager.key(type, feed_id, "reblogs:#{reblogged_id}")
            conn.del(reblog_set_key)
          end
        end
      end
    end
  end

  def inactive_account_ids
    @inactive_account_ids ||= User.confirmed.inactive.pluck(:account_id)
  end

  def inactive_list_ids
    List.where(account_id: inactive_account_ids).pluck(:id)
  end

  def feed_manager
    FeedManager.instance
  end
end