mastodon/app/services/clear_domain_media_service.rb

# frozen_string_literal: true

class ClearDomainMediaService < BaseService
  attr_reader :domain_block

  def call(domain_block)
    @domain_block = domain_block
    clear_media! if domain_block.reject_media?
  end

  private

  def invalidate_association_caches!(status_ids)
    # Normally, associated models of a status are immutable (except for accounts)
    # so they are aggressively cached. After updating the media attachments to no
    # longer point to a local file, we need to clear the cache to make those
    # changes appear in the API and UI
    Rails.cache.delete_multi(status_ids.map { |id| "statuses/#{id}" })
  end

  def clear_media!
    clear_account_images!
    clear_account_attachments!
    clear_emojos!
  end

  def clear_account_images!
    blocked_domain_accounts.reorder(nil).find_each do |account|
      account.avatar.destroy if account.avatar&.exists?
      account.header.destroy if account.header&.exists?
      account.save
    end
  end

  def clear_account_attachments!
    media_from_blocked_domain.reorder(nil).find_in_batches do |attachments|
      affected_status_ids = []

      attachments.each do |attachment|
        affected_status_ids << attachment.status_id if attachment.status_id.present?

        attachment.file.destroy if attachment.file&.exists?
        attachment.type = :unknown
        attachment.save
      end

      invalidate_association_caches!(affected_status_ids) unless affected_status_ids.empty?
    end
  end

  def clear_emojos!
    emojis_from_blocked_domains.destroy_all
  end

  def blocked_domain
    domain_block.domain
  end

  def blocked_domain_accounts
    Account.by_domain_and_subdomains(blocked_domain)
  end

  def media_from_blocked_domain
    MediaAttachment.joins(:account).merge(blocked_domain_accounts).reorder(nil)
  end

  def emojis_from_blocked_domains
    CustomEmoji.by_domain_and_subdomains(blocked_domain)
  end
end