class ActionDispatch::Routing::RoutesInspector

def collect_engine_routes(route)
  name = route.endpoint
  return unless route.engine?
  return if @engines[name]
  routes = route.rack_app.routes
  if routes.is_a?(ActionDispatch::Routing::RouteSet)
    @engines[name] = collect_routes(routes.routes)
  end
end

def collect_routes(routes)
  routes.collect do |route|
    RouteWrapper.new(route)
  end.reject do |route|
    route.internal?
  end.collect do |route|
    collect_engine_routes(route)
    { name:   route.name,
      verb:   route.verb,
      path:   route.path,
      reqs:   route.reqs,
      regexp: route.json_regexp }
  end
end

def filter_routes(filter)
  if filter
    @routes.select { |route| route.defaults[:controller] == filter }
  else
    @routes
  end
end

def format(formatter, filter = nil)
  routes_to_display = filter_routes(filter)
  routes = collect_routes(routes_to_display)
  if routes.none?
    formatter.no_routes
    return formatter.result
  end
  formatter.header routes
  formatter.section routes
  @engines.each do |name, engine_routes|
    formatter.section_title "Routes for #{name}"
    formatter.section engine_routes
  end
  formatter.result
end

def initialize(routes)
  @engines = {}
  @routes = routes
end