Contents

# frozen_string_literal: true

module ConvenientService
  module Examples
    module Standard
      class Factorial
        module Services
          class Calculate
            include ConvenientService::Standard::Config

            attr_reader :number, :timeout_seconds

            def initialize(number:, timeout_seconds: 10)
              @number = number
              @timeout_seconds = timeout_seconds
            end

            def result
              return failure(number: "is `nil`") if number.nil?
              return failure(number: "is NOT an integer") unless number.instance_of?(::Integer)
              return failure(number: "is lower than `0`") if number < 0

              return error("Timeout (`#{timeout_seconds}` seconds) is exceeded for `#{number}`") if factorial.timeout?

              success(factorial: factorial.value)
            end

            private

            def factorial
              @factorial ||= Utils::Timeout.with_timeout(timeout_seconds) { calculate_factorial }
            end

            ##
            # @internal
            #   NOTE: What is a Factorial?
            #   - https://en.wikipedia.org/wiki/Factorial
            #
            def calculate_factorial
              return 1 if [0, 1].include?(number)

              1.upto(number).reduce(1) { |prev_value, next_value| prev_value * next_value }
            end
          end
        end
      end
    end
  end
end

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
convenient_service-0.13.0	lib/convenient_service/examples/standard/factorial/services/calculate.rb