class Bundler::Installer

def generate_standalone(groups)
  standalone_path = Bundler.settings[:path]
  bundler_path = File.join(standalone_path, "bundler")
  FileUtils.mkdir_p(bundler_path)
  paths = []
  if groups.empty?
    specs = @definition.requested_specs
  else
    specs = @definition.specs_for groups.map { |g| g.to_sym }
  end
  specs.each do |spec|
    next if spec.name == "bundler"
    next if spec.require_paths.nil? # builtin gems
    spec.require_paths.each do |path|
      full_path = File.join(spec.full_gem_path, path)
      gem_path = Pathname.new(full_path).relative_path_from(Bundler.root.join(bundler_path))
      paths << gem_path.to_s.sub("#{Bundler.ruby_version.engine}/#{RbConfig::CONFIG['ruby_version']}", '#{ruby_engine}/#{ruby_version}')
    end
  end
  File.open File.join(bundler_path, "setup.rb"), "w" do |file|
    file.puts "require 'rbconfig'"
    file.puts "# ruby 1.8.7 doesn't define RUBY_ENGINE"
    file.puts "ruby_engine = defined?(RUBY_ENGINE) ? RUBY_ENGINE : 'ruby'"
    file.puts "ruby_version = RbConfig::CONFIG[\"ruby_version\"]"
    file.puts "path = File.expand_path('..', __FILE__)"
    paths.each do |path|
      file.puts %{$:.unshift File.expand_path("\#{path}/#{path}")}
    end
  end
end