class KPM::Utils

def path_with_skipped_top_level_dir(path)
  Pathname(path).each_filename.to_a[1..-1].join(File::SEPARATOR)
end

def unpack_tgz(tar_gz_archive, destination, skip_top_dir=false)
  top_dir = nil
  Gem::Package::TarReader.new(Zlib::GzipReader.open(tar_gz_archive)) do |tar|
    dest = nil
    tar.each do |entry|
      if entry.full_name == TAR_LONGLINK
        dest = File.join destination, skip_top_dir ? path_with_skipped_top_level_dir(entry.read.strip) : entry.read.strip
        next
      end
      dest ||= File.join destination, skip_top_dir ? path_with_skipped_top_level_dir(entry.full_name) : entry.full_name
      if entry.directory?
        File.delete dest if File.file? dest
        FileUtils.mkdir_p dest, :mode => entry.header.mode, :verbose => false
      elsif entry.file?
        FileUtils.rm_rf dest if File.directory? dest
        FileUtils.mkdir_p File.dirname(dest), :verbose => false
        File.open dest, "wb" do |f|
          f.print entry.read
        end
        FileUtils.chmod entry.header.mode, dest, :verbose => false
        current_dir = File.dirname(dest)
        # In case there are two top dirs, keep the last one by convention
        top_dir = current_dir if (top_dir.nil? || top_dir.size >= current_dir.size)
      elsif entry.header.typeflag == '2' # Symlink
        File.symlink entry.header.linkname, dest
      end
      dest = nil
    end
  end
  top_dir
end