module DataMaker
  module China
     module PhoneNumber
      extend ModuleUtilities

      def self.mobile
        number = PhoneNumberGenerator.new("mobile")
        number.generate
      end

      def self.landline
        number = PhoneNumberGenerator.new(LANDLINE_FORMAT)
        number.generate
      end

      def self.phone_number
      end

      class PhoneNumberGenerator
        def initialize(format)
          self.format = format
        end

        def mobile_prefix
          prefix = DataMaker::China::PhoneNumber::MOBILE_PHONE_PREFIXES.sample
          raise StandardError, "You're file is empty!" if prefix.length == 0
          prefix
        end

        def landline_prefix
          prefix = DataMaker::China::PhoneNumber::LANDLINE_PHONE_PREFIXES.sample
          raise StandardError, "You're file is empty!" if prefix.length == 0
          prefix
        end

        def generate_masks(mask_length = 1)
          raise ArgumentError, "Pass a number greater than 1" if mask_length < 1
          "#" * mask_length
        end

        def generate
          if format == "mobile"
            phone_prefix = mobile_prefix
            phone_number_max_length = 11
            prefix_length = phone_prefix.length
            mask_length = phone_number_max_length - prefix_length
          end

          if format == "landline"
            phone_prefix = landline_prefix
            phone_number_max_length = eleven_digit_rule?(phone_prefix) ? 11 : 10
            prefix_length = phone_prefix.length
            mask_length = phone_number_max_length - prefix_length
          end

          masks = generate_masks(mask_length)

          number = [
            phone_prefix,
            masks
          ].join

          DataMaker.numerify(number)
        end

        protected

        attr_accessor :format

        def eleven_digit_rule?(prefix)
          [
            10,
            311,
            371,
            376,
            377,
            379,
            411,
            431,
            432,
            451,
            531,
            532,
            551,
            571,
            591,
            731,
            754,
            755,
            757,
            760,
            769,
            791,
            851,
            871
          ].include?(prefix)
        end
      end
    end
  end
end