catstodon/app/lib/activitypub/activity/announce.rb

# frozen_string_literal: true

class ActivityPub::Activity::Announce < ActivityPub::Activity
  def perform
    return reject_payload! if delete_arrived_first?(@json['id']) || !related_to_local_activity?

    RedisLock.acquire(lock_options) do |lock|
      if lock.acquired?
        original_status = status_from_object

        return reject_payload! if original_status.nil? || !announceable?(original_status)

        @status = Status.find_by(account: @account, reblog: original_status)

        return @status unless @status.nil?

        @status = Status.create!(
          account: @account,
          reblog: original_status,
          uri: @json['id'],
          created_at: @json['published'],
          override_timestamps: @options[:override_timestamps],
          visibility: visibility_from_audience
        )

        distribute(@status)
      else
        raise Mastodon::RaceConditionError
      end
    end

    @status
  end

  private

  def visibility_from_audience
    if equals_or_includes?(@json['to'], ActivityPub::TagManager::COLLECTIONS[:public])
      :public
    elsif equals_or_includes?(@json['cc'], ActivityPub::TagManager::COLLECTIONS[:public])
      :unlisted
    elsif equals_or_includes?(@json['to'], @account.followers_url)
      :private
    else
      :direct
    end
  end

  def announceable?(status)
    status.account_id == @account.id || status.distributable?
  end

  def related_to_local_activity?
    followed_by_local_accounts? || requested_through_relay? || reblog_of_local_status?
  end

  def requested_through_relay?
    super || Relay.find_by(inbox_url: @account.inbox_url)&.enabled?
  end

  def reblog_of_local_status?
    status_from_uri(object_uri)&.account&.local?
  end

  def lock_options
    { redis: Redis.current, key: "announce:#{@object['id']}" }
  end
end