require 'devise_zxcvbn/email_tokeniser'

module Devise
  module Models
    module Zxcvbnable
      extend ActiveSupport::Concern

      delegate :min_password_score, to: "self.class"
      delegate :zxcvbn_tester, to: "self.class"

      included do
        validate :not_weak_password, if: :password_required?
      end

      def password_score
        @pass_score = self.class.password_score(self)
      end

      private

      def not_weak_password
        if password_score.score < min_password_score
          errors.add :password, :weak_password, i18n_variables
        end
      end

      def i18n_variables
        {
          feedback: zxcvbn_feedback,
          crack_time_display: time_to_crack,
          score: @pass_score.score,
          min_password_score: min_password_score
        }
      end

      def zxcvbn_feedback
        feedback = @pass_score.feedback.values.flatten.reject(&:empty?)
        return 'Add another word or two. Uncommon words are better.' if feedback.empty?

        feedback.join('. ').gsub(/\.\s*\./, '.')
      end

      def time_to_crack
        @pass_score.crack_times_display['offline_fast_hashing_1e10_per_second']
      end

      module ClassMethods
        Devise::Models.config(self, :min_password_score)
        Devise::Models.config(self, :zxcvbn_tester)

        def password_score(user, arg_email=nil)
          password = user.respond_to?(:password) ? user.password : user

          zxcvbn_weak_words = []

          if arg_email
            zxcvbn_weak_words += [arg_email, *DeviseZxcvbn::EmailTokeniser.split(arg_email)]
          end

          # User method results are saved locally to prevent repeat calls that might be expensive
          if user.respond_to? :email
            local_email = user.email
            zxcvbn_weak_words += [local_email, *DeviseZxcvbn::EmailTokeniser.split(local_email)]
          end

          if user.respond_to? :weak_words
            local_weak_words = user.weak_words
            raise "weak_words must return an Array" unless (local_weak_words.is_a? Array)
            zxcvbn_weak_words += local_weak_words
          end

          zxcvbn_tester.test(password, zxcvbn_weak_words)
        end
      end
    end
  end
end