sugi/ya_kansuji

# frozen_string_literal: true

# Simple kansuji formatter
module YaKansuji
  module Formatter
    module Simple
      module_function

      def call(num, _options = {})
        return '零' if num.zero?

        ret = ''
        (UNIT_EXP4.reverse + ['']).each_with_index do |unit4, ridx4|
          i4 = (num / 10_000**(UNIT_EXP4.size - ridx4)).to_i % 10_000
          next if i4.zero?

          if i4 == 1
            ret += "一#{unit4}"
            next
          end
          (UNIT_EXP3.reverse + ['']).each_with_index do |unit3, ridx3|
            i3 = (i4 / 10**(UNIT_EXP3.size - ridx3)).to_i % 10
            next if i3.zero?

            if i3 == 1 && unit3 != ''
              ret += unit3
            else
              ret += i3.to_s.tr('123456789', '一二三四五六七八九') + unit3
            end
          end
          ret += unit4
        end
        ret
      end
      YaKansuji.register_formatter :simple, self
    end
  end
end