attr_writer :empty_ok

def self.included host_class
  host_class.extend CarrierWave::CardMount
end

event :select_file_revision, after: :select_action do
  attachment.retrieve_from_store!(attachment.identifier)
end

# we need a card id for the path so we have to update db_content when we have
# an id
event :correct_identifier, :finalize, on: :create, when: proc { |c| !c.web? } do
  update_column(:db_content, attachment.db_content)
  expire
end

event :save_original_filename, :prepare_to_store, on: :save, when: :file_ready_to_save? do
  return unless @current_action

  @current_action.update! comment: original_filename
end

event :validate_file_exist, :validate, on: :create do
  return if empty_ok?

  if will_be_stored_as == :web
    errors.add "url is missing" if content.blank?
  elsif !attachment.file.present?
    errors.add attachment_name, "is missing"
  end
end

event :write_identifier, after: :save_original_filename, when: proc { |c| !c.web? } do
  self.content = attachment.db_content
end

def file_ready_to_save?
  attachment.file.present? &&
    !preliminary_upload? &&
    !save_preliminary_upload? &&
    attachment_is_changing?
end

# needed for flexmail attachments.  hacky.
def item_names _args={}
  [name]
end

def original_filename
  return content.split("/").last if web?

  attachment.original_filename
end

def unfilled?
  !attachment.present? && !save_preliminary_upload? && !subcards? && blank_content?
end

def attachment_changed?
  send "#{attachment_name}_changed?"
end

def attachment_is_changing?
  send "#{attachment_name}_is_changing?"
end

def attachment_before_act
  send "#{attachment_name}_before_act"
end

def create_versions? _new_file
  true
end

def empty_ok?
  @empty_ok
end

def assign_set_specific_attributes
  # reset content if we really have something to upload
  self.content = nil if set_specific[attachment_name].present?
  super
end

def delete_files_for_action action
  with_selected_action_id(action.id) do
    attachment.file.delete
    attachment.versions.each_value do |version|
      version.file.delete
    end
  end
end

def revision action, before_action=false
  return unless (result = super)

  result[:empty_ok] = true
  result
end

def attachment_format ext
  rescuing_extension_issues do
    return unless ext.present? && original_extension

    confirm_original_extension(ext) || detect_extension(ext)
  end
end

def rescuing_extension_issues
  yield
rescue StandardError => e
  Rails.logger.info "attachment_format issue: #{e.message}"
  nil
end

def detect_extension ext
  return unless (mime_types = MIME::Types[attachment.content_type])

  recognized_extension?(mime_types, ext) ? ext : mime_types[0].extensions[0]
end

def recognized_extension? mime_types, ext
  mime_types.find { |mt| mt.extensions.member? ext }
end

def confirm_original_extension ext
  return unless ["file", original_extension].member? ext

  original_extension
end

def original_extension
  @original_extension ||= attachment&.extension&.sub(/^\./, "")
end