class Cdao::LibrarySubject < Cdao::Base
  acts_as_list column: :rank, scope: %i[library_id subject_parent_id]

  belongs_to :library, optional: false
  delegate :name, :rank, to: :library, prefix: true

  belongs_to :subject, optional: false

  validates :library_id, uniqueness: { scope: %i[subject_id] }

  after_save do
    update_column :subject_parent_id, subject.parent_id # rubocop:disable Rails/SkipsModelValidations
  end

  def self.import
    Subject.find_each do |subject|
      subject.library_subjects.where(library_id: subject.library_id).first_or_create
    end
  end

  def self.import_rank_from_subjects
    Subject.find_each do |subject|
      subject.library_subjects.each do |subject_library|
        subject_library.update(rank: subject.rank)
      end
    end
  end
end