question.rb

class Question < ActiveRecord::Base
  belongs_to :question_group
  has_many :all_options, :dependent => :destroy, :class_name => 'Option'
  has_many :options, :conditions => {:active => true}
  has_many :correct_options, :conditions => {:correct => true, :active => true}, :class_name => 'Option'
  has_many :askings
  has_many :notes, :as => :notable, :dependent => :destroy

  scope :active, where(:active => true)
  scope :inactive, where(:active => false)

  validates_presence_of :body, :question_group_id
  acts_as_textiled :body, :justification
  accepts_nested_attributes_for :all_options, :reject_if => proc { |attributes| attributes['title'].blank? }

  has_attached_file :media,
                    :storage          => CONFIG.storage,
                    :path             => CONFIG.path,
                    :url              => CONFIG.url

  def self.create_from_blob(blob=nil)
    raise ArgumentError if blob.blank?
    body = blob.scan(/^\?{1}.+$/).map{|s| s.gsub(/^\?/, '').strip}.join("\n\n")
    justification = blob.scan(/^={1}.+$/).map{|s| s.gsub(/^\=/, '').strip}.join("\n\n")
    question = create(:body => body, :justification => justification)
    option_blobs = blob.scan(/^[+-]{1}.+$/)

    option_blobs.each do |blob|
      question.options.create_from_blob(blob)
    end
    question
  end

  def update_option_positions(positions)
    options.active.each do |option|
      option.update_attribute(:position, positions.index(option.id.to_s) + 1)
    end
  end

    def self.update_correctly_answered_proportions!
      Question.find_each do |question|
        question.correctly_answered_proportion(true)
      end
    end

    def correctly_answered_proportion(force=false)
      db_value = read_attribute(:correctly_answered_proportion)
      if db_value.blank? || force
        new_value = correctly_answered_proportion!
        write_attribute(:correctly_answered_proportion, new_value)
        #self.correctly_answered_proportion = new_value
        save!
        new_value
      else
        db_value
      end
    end

    def correctly_answered_proportion!
      askings_count = askings.count
      correct_askings_count = askings.select{|a| correct_option_ids.include? a.answer_id}.size
      correct_askings_count.to_f / askings_count.to_f unless askings_count.zero?
    end

  #def calc_correctly_answered_proportion
    #askings_count = askings.count
    #correct_askings_count = askings.select{|a| correct_option_ids.include? a.answer_id}.size
    #prop = correct_askings_count.to_f / askings_count.to_f unless askings_count.zero?
    #puts prop
    #self.correctly_answered_proportion = prop
    #save(:validate => false)
    #prop
  #end
end