skill-assessment-app/app/models/candidate.rb

class Candidate < ApplicationRecord
  belongs_to :quiz
  has_many :questions, -> { order("sort") }, through: :quiz
  has_many :answers
  belongs_to :recruiter, class_name: "User"

  before_validation(:generate_test_hash, on: :create)

  validates_presence_of :recruiter_id
  validates_presence_of :name
  validates_presence_of :experience
  validates :email, uniqueness: true, presence: true, email_format: true
  validates :test_hash, uniqueness: true, presence: true

  def submitted_answers
    answers.where(submitted: true)
  end

  def answered_questions
    answers.where.not(answer: nil)
           .where("answers.answer not like '%later:%'")
  end

  def fetch_question qid
    CandidateQuiz.new(id).fetch_question(qid).first
  end

  def my_quiz
    @candidate_quiz ||= CandidateQuiz.new(id).build_my_quiz
  end

  def my_status
    @candidate_status ||= QuizStatus.new(self)
  end

  def status
    "#{my_status.progress}%"
  end

  def complete!
    if update_attributes(completed: true)
      CandidateMailer.submitted(self).deliver_now
      RecruiterMailer.candidate_submitted(self).deliver_now
      ReviewerMailer.candidate_submission(self).deliver_now
      return true
    end
    false
  end

  private

    def generate_test_hash
      loop do
        self[:test_hash] = SecureRandom.urlsafe_base64(8)

        break unless Candidate.exists?(test_hash: self[:test_hash])
      end
    end
end