class Paper < ActiveRecord::Base
  # Validation
  validates_presence_of :title, :contact_email, :abstract
  # We don't want two papers with the same title now, do we?
  validates_uniqueness_of :title
  # Checking if the email address is valid one
  validates_format_of :contact_email, :with => /\A([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})\Z/i
  validate :abstract_cannot_contain_latex

  # TODO: We need to add another field for password confirmation
  # and use validates_confirmation_of

  # We indicate that topics associated to the paper can be fetched
  # through the paper_topics join table
  #has_many :paper_topics
  #has_many :topics, :through => :paper_topics
  has_many_and_belongs_to_many :topics
  protected
  def abstract_cannot_contain_latex
    # TODO: Make the validation non-naive and use i18n on the error message
    errors.add(:abstract, "The abstract cannot contain LaTeX expressions, please escape them appropriately") if %w{\\ ~ $ _}.any? {|w| abstract.include? w}
  end
end