lib/eac_ruby_utils/fs/extname.rb


# frozen_string_literal: true

module EacRubyUtils
  module Fs
    class << self
      # A [File.extname] which find multiple extensions (Ex.: .tar.gz).
      def extname(path, limit = -1)
        recursive_extension(::File.basename(path), limit)
      end

      # Shortcut to +extname(2)+.
      def extname2(path)
        extname(path, 2)
      end

      private

      def recursive_extension(basename, limit)
        return '' if limit.zero?

        m = /\A(.+)(\.[a-z][a-z0-9]*)\z/i.match(basename)
        if m
          "#{recursive_extension(m[1], limit - 1)}#{m[2]}"
        else
          ''
        end
      end
    end
  end
end