class Listen::Adapter::Darwin

def self.usable?
  version = RbConfig::CONFIG['target_os'][OS_REGEXP, :major_version]
  return false unless version
  return true if version.to_i >= 13 # darwin13 is OS X 10.9
  require 'rb-fsevent'
  fsevent_version = Gem::Version.new(FSEvent::VERSION)
  return true if fsevent_version <= Gem::Version.new('0.9.4')
  Listen.adapter_warn(INCOMPATIBLE_GEM_VERSION)
  false
end

def _configure(dir, &callback)
  @callbacks[dir] = callback
end

def _process_changes(dirs)
  dirs.each do |dir|
    dir = Pathname.new(dir.sub(%r{/$}, ''))
    @callbacks.each do |watched_dir, callback|
      if watched_dir.eql?(dir) || Listen::Directory.ascendant_of?(watched_dir, dir)
        callback.call(dir)
      end
    end
  end
end

def _process_event(dir, path)
  Listen.logger.debug { "fsevent: processing path: #{path.inspect}" }
  # TODO: does this preserve symlinks?
  rel_path = path.relative_path_from(dir).to_s
  _queue_change(:dir, dir, rel_path, recursive: true)
end

def _run
  require 'rb-fsevent'
  worker = FSEvent.new
  dirs_to_watch = @callbacks.keys.map(&:to_s)
  Listen.logger.info { "fsevent: watching: #{dirs_to_watch.inspect}" }
  worker.watch(dirs_to_watch, { latency: options.latency }, &method(:_process_changes))
  @worker_thread = Listen::Thread.new("worker_thread") { worker.run }
end

def _stop
  @worker_thread&.kill
  super
end