require 'fileutils'
require 'pathname'
require 'rubygems/package'
require 'zlib'

module ZipTarGz

  def self.pack_zip(zip_file, base_dir, entries)
    require 'zip'
    Zip::File.open(zip_file, Zip::File::CREATE) do |zip|
      list_files(base_dir, entries).each do |file|
        path = File.join(base_dir, file)

        zip.get_output_stream(file) do |zip_file|
          open(path, 'rb') do |file|
            copy(file, zip_file)
          end
        end
      end
    end
  end

  def self.pack_tar_gz(tar_gz_file, base_dir, entries)
    write_tar_gz(tar_gz_file) do |tar|
      list_files(base_dir, entries).each do |file|
        path = File.join(base_dir, file)
        stat = File.stat(path)

        tar.add_file_simple(file, stat.mode, stat.size) do |tar_file|
          open(path, 'rb') do |file|
            copy(file, tar_file)
          end
        end
      end
    end
  end

  def self.unpack_tar_gz(tar_gz_file, base_dir)
    read_tar_gz(tar_gz_file) do |entry|
      path = File.join(base_dir, entry.full_name)

      FileUtils.rm_rf(path)

      FileUtils.mkdir_p(File.dirname(path))

      if entry.file?
        open(path, 'wb', entry.header.mode) do |out|
          copy(entry, out)
        end
      end
    end
  end

  private

  def self.copy(src, dst)
    dst.write(src.read(16384)) until src.eof?
  end

  def self.list_files(base_dir, entries)
    files = []
    entries.each do |entry|
      path = File.join(base_dir, entry)
      if File.directory?(path)
        Dir.glob(File.join(path, '**/*'), File::FNM_DOTMATCH) do |f|
          files << Pathname.new(f).relative_path_from(Pathname.new(base_dir)).to_s if File.file?(f)
        end
      else
        files << entry
      end
    end
    files
  end

  def self.write_tar_gz(tar_gz_file)
    Zlib::GzipWriter.open(tar_gz_file) do |gz|
      Gem::Package::TarWriter.new(gz) do |tar|
        yield tar
      end
    end
  end

  def self.read_tar_gz(tar_gz_file)
    Zlib::GzipReader.open(tar_gz_file) do |gz|
      Gem::Package::TarReader.new(gz).each do |entry|
        yield entry
      end
    end
  end
end