require "study_engine/config"
require "study_engine/study_id"

module StudyEngine
  class Assessment < ActiveRecord::Base
    cattr_accessor(:timeout_interval) { 10.minutes }

    default_scope -> { includes(:persisted_results) }

    def timestamp_attributes_for_create
      super + [:assessment_updated_at]
    end

    def self.by_event event
      where(event: event)
    end

    def self.by_study_id study_id
      return none unless study_id
      where(study_id: study_id)
    end

    def self.by_site site
      where("study_id RLIKE '...-#{site}-....'")
    end

    has_many :persisted_results, class_name: "Result", dependent: :destroy

    before_create :assign_group_index

    belongs_to :coordinator, class_name: "User"

    def coordinator_email
      coordinator.try(:email)
    end

    def restarted_assessment
      Assessment.by_study_id(study_id).where(event: event).where.not(id: id).last
    end

    def stream_id
      StudyID.new("STR-#{study_id.site}-#{1000 + id}") unless new_record?
    end

    def notes?
      notes.present?
    end

    serialize :study_id, StudyID

    def results
      @results ||= begin
        bank_ids = StudyEngine.bank_finder.call(self)
        return persisted_results if persisted_results.length == bank_ids.length
        bank_ids.map do |bank_id|
          persisted_results.find_or_initialize_by(bank_id: bank_id)
        end
      end
    end

    def current_result
      results.find { |result| !result.finished? }
    end

    def percent_complete
      (results.select(&:finished?).count / results.count.to_f * 100).round
    end

    delegate :current_question, to: :current_result

    def save_answer answer
      current_result.save_answer answer
      save!
      touch :assessment_updated_at
    end

    def complete?
      current_result.nil?
    end

    def incomplete?
      !complete?
    end

    def results_summary
      "#{results.select(&:finished?).count}/#{results.count}"
    end

    def full_history
      persisted_results.flat_map(&:answers).map(&:question_id)
    end

    def by_url?
      method_applied == "By URL"
    end

    def by_mail?
      method_applied == "By mail"
    end

    def group_index_name
      return "" if group_index.nil?
      event_groups[group_index]
    end

    private

    def assign_group_index
      return unless event_groups.any?
      self.group_index = restarted_assessment.try(:group_index) || self.class.by_event(event).count % event_groups.length
    end

    def event_groups
      StudyEngine.groups[event] || []
    end
  end
end