module Aruba::Api::Core

def cd(dir, &block)
  if block
    begin
      unless Aruba.platform.directory?(expand_path(dir))
        raise ArgumentError,
              "#{expand_path(dir)} is not a directory or does not exist."
      end
      old_directory = expand_path(".")
      aruba.current_directory << dir
      new_directory = expand_path(".")
      aruba.event_bus.notify Events::ChangedWorkingDirectory.new(old: old_directory,
                                                                 new: new_directory)
      old_dir = Aruba.platform.getwd
      real_new_directory = File.expand_path(aruba.current_directory,
                                            aruba.root_directory)
      Aruba.platform.chdir real_new_directory
      result = with_environment(
        "OLDPWD" => old_dir,
        "PWD" => real_new_directory,
        &block
      )
    ensure
      aruba.current_directory.pop
      Aruba.platform.chdir old_dir
    end
    return result
  end
  unless Aruba.platform.directory?(expand_path(dir))
    raise ArgumentError, "#{expand_path(dir)} is not a directory or does not exist."
  end
  old_directory = expand_path(".")
  aruba.current_directory << dir
  new_directory = expand_path(".")
  aruba.event_bus.notify Events::ChangedWorkingDirectory.new(old: old_directory,
                                                             new: new_directory)
  self
end