course.rb

class Course < ActiveRecord::Base
  validates_presence_of :name, :description, :price, :start_at, :stop_at, :location, :maximum_students, :short_description, :audience_id

  belongs_to :audience
  has_many :sections
  has_many :questions, :order => "created_at asc"
  has_many :follow_ups
  has_many :registrations, :through => :sections
  accepts_nested_attributes_for :questions, :reject_if => :all_blank
  accepts_nested_attributes_for :follow_ups, :reject_if => :all_blank

  acts_as_list

  def self.by_position
    order("courses.position asc")
  end

  def self.unscheduled
    where("courses.id not in (select sections.course_id from sections where sections.ends_on >= ?)", Date.today)
  end

  def self.only_public
    where(:public => true)
  end

  def questions_with_blank
    questions + [questions.new]
  end

  def follow_ups_with_blank
    follow_ups + [follow_ups.new]
  end

  def active?
    active_section.present?
  end

  def active_section
    sections.active[0]
  end

  def active_date_range
    active_section.try(:date_range)
  end

  def to_param
    "#{id}-#{name.parameterize}"
  end
end