question_serializer.rb

class QuestionSerializer < ActiveModel::Serializer
  attributes :id,
    :content,
    :type,
    :answers_count,
    :answer_size

  def answers_count
    return self.send(object.type) if %w[binary_swipe prioritise_top3 select_many date_picker].include?(object.type)

    return uniq_answers if %w[freeform_text audio picture].include?(object.type)

    filtered_answers.group(:content).count
  end

  def answer_size
    filtered_answers.count
  end

  def prioritise_top3
    answers = filtered_answers.map { |answer| answer.content[0] }
    answers.uniq.map { |answer| { "#{answer}": answers.count(answer) } }.reduce({}, :merge)
  end

  def select_many
    answers = filtered_answers.map(&:content).flatten
    answers.uniq.map { |answer| { "#{answer}": answers.count(answer) } }.reduce({}, :merge)
  end

  def date_picker
    answers = filtered_answers.map(&:content).flatten
    answers.uniq.map { |answer| { "#{answer.to_date}": answers.count(answer) } }.reduce({}, :merge)
  end

  def binary_swipe
    answers = filtered_answers.map(&:content).flatten
    answers.uniq.map { |answer| {
      "#{answer}": {
        "positive": answers.flatten.count(answer),
        "negative": answer_size - answers.flatten.count(answer)
      } }
    }.reduce({}, :merge)
  end

  def filtered_answers
    story_id = instance_options[:story_id]

    object.answers.where(story_id: story_id)
  end

  def uniq_answers
    filtered_answers.map{ |answer| { content: answer.content } }
  end
end