class Guard::Internals::Queue

def <<(changes)
  @queue << changes
end

def _run_actions(actions)
  actions.each do |action_args|
    args = action_args.dup
    namespaced_action = args.shift
    action = namespaced_action.to_s.sub(/^guard_/, "")
    if @commander.respond_to?(action)
      @commander.send(action, *args)
    else
      fail "Unknown action: #{action.inspect}"
    end
  end
end

def initialize(commander)
  @commander = commander
  @queue = ::Queue.new
end

def pending?
  !@queue.empty?
end

def process
  actions = []
  changes = { modified: [], added: [], removed: [] }
  while pending?
    if (item = @queue.pop).first.is_a?(Symbol)
      actions << item
    else
      item.each { |key, value| changes[key] += value }
    end
  end
  _run_actions(actions)
  return if changes.values.all?(&:empty?)
  Runner.new.run_on_changes(*changes.values)
end