class ResponseRate
  def initialize(subcategory:, school:, academic_year:)
    @subcategory = subcategory
    @school = school
    @academic_year = academic_year
  end

  def student
    rate(survey_item_count: student_survey_item_count, response_count: student_response_count,
         total_possible_responses: total_possible_student_responses)
  end

  def teacher
    response_rate = rate(survey_item_count: teacher_survey_item_count, response_count: teacher_response_count,
                         total_possible_responses: total_possible_teacher_responses)
    cap_at_100(response_rate)
  end

  private

  def cap_at_100(response_rate)
    response_rate > 100 ? 100 : response_rate
  end

  def rate(survey_item_count:, response_count:, total_possible_responses:)
    return 0 unless survey_item_count.positive?

    average_responses_per_survey_item = response_count / survey_item_count

    return 0 unless total_possible_responses.positive?

    (average_responses_per_survey_item / total_possible_responses * 100).round
  end

  def total_possible_student_responses
    @total_possible_student_responses ||= total_possible_responses do |responses|
      responses.total_students
    end
  end

  def total_possible_teacher_responses
    @total_possible_teacher_responses ||= total_possible_responses do |responses|
      responses.total_teachers
    end
  end

  def total_possible_responses
    total_responses = Respondent.where(school: @school, academic_year: @academic_year).first
    return 0 unless total_responses.present?

    yield total_responses
  end

  def student_response_count
    @student_response_count ||= SurveyItemResponse.student_responses_for_measures(@subcategory.measures, @school,
                                                                                  @academic_year).count.to_f
  end

  def teacher_response_count
    @teacher_response_count ||= SurveyItemResponse.teacher_responses_for_measures(@subcategory.measures, @school,
                                                                                  @academic_year).count.to_f
  end

  def student_survey_item_count
    @student_survey_item_count ||= @subcategory.measures.map do |measure|
      measure.student_survey_items.count
    end.sum.to_f
  end

  def teacher_survey_item_count
    @teacher_survey_item_count ||= @subcategory.measures.map do |measure|
      measure.teacher_survey_items.count
    end.sum.to_f
  end
end