module Helpers
  module Validations
    private

    def assert_valid_url url
      assert_match URI::regexp(%w(http https)), url, "\"#{url}\" isn't a valid URL"
    end

    def assert_validated_presence object, attribute, success_val = "not blank", expected_msg = :blank
      assert_validated object, attribute,
        :success_val  => success_val,
        :failing_val  => nil,
        :expected_msg => expected_msg
    end

    def assert_validated_url object, attribute, expected_msg = :invalid_url
      assert_validated object, attribute,
        :failing_val  => "1234",
        :success_val  => "http://www.google.ca",
        :expected_msg => expected_msg
    end

    def assert_validated object, attribute, options = {}

      failing_val  = options.fetch(:failing_val)
      success_val  = options.fetch(:success_val)
      expected_msg = options.fetch(:expected_msg)

      attribute = attribute.to_sym

      get_expected_msg = lambda { |msg|
        case expected_msg
        when Symbol
          object.errors.generate_message(attribute, expected_msg)
        when Proc
          msg.call(object, attribute)
        when String
          #noop
        else
          raise ArgumentError, "Invalid expected_msg #{msg}"
        end
      }

      expected_msg = get_expected_msg.call(expected_msg)

      write_attribute(object, attribute, failing_val)

      assert object.invalid?
      assert_includes object.errors[attribute], expected_msg

      write_attribute(object, attribute, success_val)

      object.valid?

      refute_includes object.errors[attribute], expected_msg
    end

    def read_attribute object, attribute
      object.send(:"#{attribute}")
    end

    def write_attribute object, attribute, val
      object.send(:"#{attribute}=", val)
    end
  end
end