module Devise
  module Models
    module EmailValidatable
      def self.included(base)
        base.extend ClassMethods

        base.class_eval do
          validates_presence_of   :email, if: :email_required?
          validates_uniqueness_of :email, allow_blank: true, if: :email_changed?
          validates_format_of     :email, with: email_regexp, allow_blank: true, if: :email_changed?
        end
      end

      def email_required?
        true
      end

      module ClassMethods
        Devise::Models.config(self, :email_regexp)
      end
    end

    module MultiEmailValidatable
      def self.required_fields(klass)
        []
      end

      # All validations used by this module.
      VALIDATIONS = [:validates_presence_of, :validates_uniqueness_of, :validates_format_of,
                     :validates_confirmation_of, :validates_length_of].freeze

      def self.included(base)
        base.extend ClassMethods
        assert_validations_api!(base)

        base.class_eval do
          validates_presence_of     :email, if: :email_required?

          validates_presence_of     :password, if: :password_required?
          validates_confirmation_of :password, if: :password_required?
          validates_length_of       :password, within: password_length, allow_blank: true

          after_validation :propagate_email_errors
          email_class.send :include, EmailValidatable
        end

        base.devise_modules << :validatable
      end

      def self.assert_validations_api!(base) #:nodoc:
        unavailable_validations = VALIDATIONS.select { |v| !base.respond_to?(v) }

        unless unavailable_validations.empty?
          raise "Could not use :validatable module since #{base} does not respond " <<
                    "to the following methods: #{unavailable_validations.to_sentence}."
        end
      end

      protected

      # Same as Devise::Models::Validatable#password_required?
      def password_required?
        !persisted? || !password.nil? || !password_confirmation.nil?
      end

      # Same as Devise::Models::Validatable#email_required?
      def email_required?
        true
      end

      private

      def propagate_email_errors
        email_error_key = self.class::EMAILS_ASSOCIATION
        if respond_to?("#{self.class::EMAILS_ASSOCIATION}_attributes=")
          email_error_key = "#{email_error_key}.email".to_sym
        end

        return if (email_errors = errors.delete(email_error_key)).nil?

        email_errors.each do |error|
          errors.add(:email, error)
        end
      end

      module ClassMethods
        Devise::Models.config(self, :password_length)
      end
    end
  end
end