class ActiveSupport::NumberHelper::NumberToHumanConverter

def calculate_exponent(units)
  exponent = number != 0 ? Math.log10(number.abs).floor : 0
  unit_exponents(units).find { |e| exponent >= e } || 0
end

def convert # :nodoc:
  @number = Float(number)
  # for backwards compatibility with those that didn't add strip_insignificant_zeros to their locale files
  unless options.key?(:strip_insignificant_zeros)
    options[:strip_insignificant_zeros] = true
  end
  units = opts[:units]
  exponent = calculate_exponent(units)
  @number = number / (10 ** exponent)
  until (rounded_number = NumberToRoundedConverter.convert(number, options)) != NumberToRoundedConverter.convert(1000, options)
    @number = number / 1000.0
    exponent += 3
  end
  unit = determine_unit(units, exponent)
  format.gsub('%n'.freeze, rounded_number).gsub('%u'.freeze, unit).strip
end

def determine_unit(units, exponent)
  exp = DECIMAL_UNITS[exponent]
  case units
  when Hash
    units[exp] || ''
  when String, Symbol
    I18n.translate("#{units}.#{exp}", :locale => options[:locale], :count => number.to_i)
  else
    translate_in_locale("human.decimal_units.units.#{exp}", count: number.to_i)
  end
end

def format
  options[:format] || translate_in_locale('human.decimal_units.format')
end

def unit_exponents(units)
  case units
  when Hash
    units
  when String, Symbol
    I18n.translate(units.to_s, :locale => options[:locale], :raise => true)
  when nil
    translate_in_locale("human.decimal_units.units", raise: true)
  else
    raise ArgumentError, ":units must be a Hash or String translation scope."
  end.keys.map { |e_name| INVERTED_DECIMAL_UNITS[e_name] }.sort_by(&:-@)
end