class ConferenceCoAuthor
  include Mongoid::Document

  LANGUAGE_TYPES = [ "English", "Chinese" ]

  field :name_id, type: BSON::ObjectId # this is author
  field :co_author, localize: true
  field :email

  belongs_to :conference_co_author_relations
  has_and_belongs_to_many :writing_conferences

  VALID_EMAIL_REGEX = /\A[\w+\-.]+@[a-z\d\-.]+\.[a-z]+\z/
  validates :email, format: { with: VALID_EMAIL_REGEX },
            allow_blank: true,
            uniqueness: { case_sensitive: false }

  validates :co_author, presence: true
  before_save { |coauthor| coauthor.email = email.downcase if not coauthor.email.nil?}
end