/**
   * This method downloads the latest vehicle data, processes each vehicle in turn, and create a
   * GTFS-realtime feed of trip updates and vehicle positions as a result.
   */
  private void refreshVehicles() throws IOException, JSONException {

    /** We download the vehicle details as an array of JSON objects. */
    JSONArray vehicleArray = downloadVehicleDetails();

    /**
     * The FeedMessage.Builder is what we will use to build up our GTFS-realtime feeds. We create a
     * feed for both trip updates and vehicle positions.
     */
    FeedMessage.Builder tripUpdates = GtfsRealtimeLibrary.createFeedMessageBuilder();
    FeedMessage.Builder vehiclePositions = GtfsRealtimeLibrary.createFeedMessageBuilder();

    /** We iterate over every JSON vehicle object. */
    for (int i = 0; i < vehicleArray.length(); ++i) {

      JSONObject obj = vehicleArray.getJSONObject(i);
      String trainNumber = obj.getString("trainno");
      String route = obj.getString("dest");
      String stopId = obj.getString("nextstop");
      double lat = obj.getDouble("lat");
      double lon = obj.getDouble("lon");
      int delay = obj.getInt("late");

      /**
       * We construct a TripDescriptor and VehicleDescriptor, which will be used in both trip
       * updates and vehicle positions to identify the trip and vehicle. Ideally, we would have a
       * trip id to use for the trip descriptor, but the SEPTA api doesn't include it, so we settle
       * for a route id instead.
       */
      TripDescriptor.Builder tripDescriptor = TripDescriptor.newBuilder();
      tripDescriptor.setRouteId(route);

      VehicleDescriptor.Builder vehicleDescriptor = VehicleDescriptor.newBuilder();
      vehicleDescriptor.setId(trainNumber);

      /**
       * To construct our TripUpdate, we create a stop-time arrival event for the next stop for the
       * vehicle, with the specified arrival delay. We add the stop-time update to a TripUpdate
       * builder, along with the trip and vehicle descriptors.
       */
      StopTimeEvent.Builder arrival = StopTimeEvent.newBuilder();
      arrival.setDelay(delay * 60);

      StopTimeUpdate.Builder stopTimeUpdate = StopTimeUpdate.newBuilder();
      stopTimeUpdate.setArrival(arrival);
      stopTimeUpdate.setStopId(stopId);

      TripUpdate.Builder tripUpdate = TripUpdate.newBuilder();
      tripUpdate.addStopTimeUpdate(stopTimeUpdate);
      tripUpdate.setTrip(tripDescriptor);
      tripUpdate.setVehicle(vehicleDescriptor);

      /**
       * Create a new feed entity to wrap the trip update and add it to the GTFS-realtime trip
       * updates feed.
       */
      FeedEntity.Builder tripUpdateEntity = FeedEntity.newBuilder();
      tripUpdateEntity.setId(trainNumber);
      tripUpdateEntity.setTripUpdate(tripUpdate);
      tripUpdates.addEntity(tripUpdateEntity);

      /**
       * To construct our VehiclePosition, we create a position for the vehicle. We add the position
       * to a VehiclePosition builder, along with the trip and vehicle descriptors.
       */
      Position.Builder position = Position.newBuilder();
      position.setLatitude((float) lat);
      position.setLongitude((float) lon);

      VehiclePosition.Builder vehiclePosition = VehiclePosition.newBuilder();
      vehiclePosition.setPosition(position);
      vehiclePosition.setTrip(tripDescriptor);
      vehiclePosition.setVehicle(vehicleDescriptor);

      /**
       * Create a new feed entity to wrap the vehicle position and add it to the GTFS-realtime
       * vehicle positions feed.
       */
      FeedEntity.Builder vehiclePositionEntity = FeedEntity.newBuilder();
      vehiclePositionEntity.setId(trainNumber);
      vehiclePositionEntity.setVehicle(vehiclePosition);
      vehiclePositions.addEntity(vehiclePositionEntity);
    }

    /** Build out the final GTFS-realtime feed messagse and save them. */
    _gtfsRealtimeProvider.setTripUpdates(tripUpdates.build());
    _gtfsRealtimeProvider.setVehiclePositions(vehiclePositions.build());

    _log.info("vehicles extracted: " + tripUpdates.getEntityCount());
  }
  @Test
  public void testUpdate() {
    TripUpdate tripUpdate;
    TripUpdate.Builder tripUpdateBuilder;
    TripDescriptor.Builder tripDescriptorBuilder;
    StopTimeUpdate.Builder stopTimeUpdateBuilder;
    StopTimeEvent.Builder stopTimeEventBuilder;

    int trip_1_1_index = timetable.getTripIndex(new AgencyAndId("agency", "1.1"));

    Vertex stop_a = graph.getVertex("agency_A");
    Vertex stop_c = graph.getVertex("agency_C");
    RoutingRequest options = new RoutingRequest();

    ShortestPathTree spt;
    GraphPath path;

    // non-existing trip
    tripDescriptorBuilder = TripDescriptor.newBuilder();
    tripDescriptorBuilder.setTripId("b");
    tripDescriptorBuilder.setScheduleRelationship(TripDescriptor.ScheduleRelationship.CANCELED);
    tripUpdateBuilder = TripUpdate.newBuilder();
    tripUpdateBuilder.setTrip(tripDescriptorBuilder);
    tripUpdate = tripUpdateBuilder.build();
    assertFalse(timetable.update(tripUpdate, "a", timeZone, serviceDate));

    // update trip with bad data
    tripDescriptorBuilder = TripDescriptor.newBuilder();
    tripDescriptorBuilder.setTripId("1.1");
    tripDescriptorBuilder.setScheduleRelationship(TripDescriptor.ScheduleRelationship.SCHEDULED);
    tripUpdateBuilder = TripUpdate.newBuilder();
    tripUpdateBuilder.setTrip(tripDescriptorBuilder);
    stopTimeUpdateBuilder = tripUpdateBuilder.addStopTimeUpdateBuilder(0);
    stopTimeUpdateBuilder.setStopSequence(0);
    stopTimeUpdateBuilder.setScheduleRelationship(StopTimeUpdate.ScheduleRelationship.SKIPPED);
    tripUpdate = tripUpdateBuilder.build();
    assertFalse(timetable.update(tripUpdate, "agency", timeZone, serviceDate));

    // update trip with non-increasing data
    tripDescriptorBuilder = TripDescriptor.newBuilder();
    tripDescriptorBuilder.setTripId("1.1");
    tripDescriptorBuilder.setScheduleRelationship(TripDescriptor.ScheduleRelationship.SCHEDULED);
    tripUpdateBuilder = TripUpdate.newBuilder();
    tripUpdateBuilder.setTrip(tripDescriptorBuilder);
    stopTimeUpdateBuilder = tripUpdateBuilder.addStopTimeUpdateBuilder(0);
    stopTimeUpdateBuilder.setStopSequence(2);
    stopTimeUpdateBuilder.setScheduleRelationship(StopTimeUpdate.ScheduleRelationship.SCHEDULED);
    stopTimeEventBuilder = stopTimeUpdateBuilder.getArrivalBuilder();
    stopTimeEventBuilder.setTime(
        TestUtils.dateInSeconds("America/New_York", 2009, AUGUST, 7, 0, 10, 1));
    stopTimeEventBuilder = stopTimeUpdateBuilder.getDepartureBuilder();
    stopTimeEventBuilder.setTime(
        TestUtils.dateInSeconds("America/New_York", 2009, AUGUST, 7, 0, 10, 0));
    tripUpdate = tripUpdateBuilder.build();
    assertFalse(timetable.update(tripUpdate, "agency", timeZone, serviceDate));

    // ---
    long startTime = TestUtils.dateInSeconds("America/New_York", 2009, AUGUST, 7, 0, 0, 0);
    long endTime;
    options.dateTime = startTime;

    // ---
    options.setRoutingContext(graph, stop_a, stop_c);
    spt = aStar.getShortestPathTree(options);
    path = spt.getPath(stop_c, false);
    assertNotNull(path);
    endTime = startTime + 20 * 60;
    assertEquals(endTime, path.getEndTime());

    // update trip
    tripDescriptorBuilder = TripDescriptor.newBuilder();
    tripDescriptorBuilder.setTripId("1.1");
    tripDescriptorBuilder.setScheduleRelationship(TripDescriptor.ScheduleRelationship.SCHEDULED);
    tripUpdateBuilder = TripUpdate.newBuilder();
    tripUpdateBuilder.setTrip(tripDescriptorBuilder);
    stopTimeUpdateBuilder = tripUpdateBuilder.addStopTimeUpdateBuilder(0);
    stopTimeUpdateBuilder.setStopSequence(1);
    stopTimeUpdateBuilder.setScheduleRelationship(StopTimeUpdate.ScheduleRelationship.SCHEDULED);
    stopTimeEventBuilder = stopTimeUpdateBuilder.getArrivalBuilder();
    stopTimeEventBuilder.setTime(
        TestUtils.dateInSeconds("America/New_York", 2009, AUGUST, 7, 0, 2, 0));
    stopTimeEventBuilder = stopTimeUpdateBuilder.getDepartureBuilder();
    stopTimeEventBuilder.setTime(
        TestUtils.dateInSeconds("America/New_York", 2009, AUGUST, 7, 0, 2, 0));
    tripUpdate = tripUpdateBuilder.build();
    assertEquals(20 * 60, timetable.getTripTimes(trip_1_1_index).getArrivalTime(2));
    assertTrue(timetable.update(tripUpdate, "agency", timeZone, serviceDate));
    assertEquals(20 * 60 + 120, timetable.getTripTimes(trip_1_1_index).getArrivalTime(2));

    // ---
    options.setRoutingContext(graph, stop_a, stop_c);
    spt = aStar.getShortestPathTree(options);
    path = spt.getPath(stop_c, false);
    assertNotNull(path);
    endTime = startTime + 20 * 60 + 120;
    assertEquals(endTime, path.getEndTime());

    // cancel trip
    tripDescriptorBuilder = TripDescriptor.newBuilder();
    tripDescriptorBuilder.setTripId("1.1");
    tripDescriptorBuilder.setScheduleRelationship(TripDescriptor.ScheduleRelationship.CANCELED);
    tripUpdateBuilder = TripUpdate.newBuilder();
    tripUpdateBuilder.setTrip(tripDescriptorBuilder);
    tripUpdate = tripUpdateBuilder.build();
    assertTrue(timetable.update(tripUpdate, "agency", timeZone, serviceDate));

    TripTimes tripTimes = timetable.getTripTimes(trip_1_1_index);
    for (int i = 0; i < tripTimes.getNumStops(); i++) {
      assertEquals(TripTimes.UNAVAILABLE, tripTimes.getDepartureTime(i));
      assertEquals(TripTimes.UNAVAILABLE, tripTimes.getArrivalTime(i));
    }

    // ---
    options.setRoutingContext(graph, stop_a, stop_c);
    spt = aStar.getShortestPathTree(options);
    path = spt.getPath(stop_c, false);
    assertNotNull(path);
    endTime = startTime + 40 * 60;
    assertEquals(endTime, path.getEndTime());

    // update trip arrival time incorrectly
    tripDescriptorBuilder = TripDescriptor.newBuilder();
    tripDescriptorBuilder.setTripId("1.1");
    tripDescriptorBuilder.setScheduleRelationship(TripDescriptor.ScheduleRelationship.SCHEDULED);
    tripUpdateBuilder = TripUpdate.newBuilder();
    tripUpdateBuilder.setTrip(tripDescriptorBuilder);
    stopTimeUpdateBuilder = tripUpdateBuilder.addStopTimeUpdateBuilder(0);
    stopTimeUpdateBuilder.setStopSequence(1);
    stopTimeUpdateBuilder.setScheduleRelationship(StopTimeUpdate.ScheduleRelationship.SCHEDULED);
    stopTimeEventBuilder = stopTimeUpdateBuilder.getArrivalBuilder();
    stopTimeEventBuilder.setDelay(0);
    tripUpdate = tripUpdateBuilder.build();
    assertTrue(timetable.update(tripUpdate, "agency", timeZone, serviceDate));

    // update trip arrival time only
    tripDescriptorBuilder = TripDescriptor.newBuilder();
    tripDescriptorBuilder.setTripId("1.1");
    tripDescriptorBuilder.setScheduleRelationship(TripDescriptor.ScheduleRelationship.SCHEDULED);
    tripUpdateBuilder = TripUpdate.newBuilder();
    tripUpdateBuilder.setTrip(tripDescriptorBuilder);
    stopTimeUpdateBuilder = tripUpdateBuilder.addStopTimeUpdateBuilder(0);
    stopTimeUpdateBuilder.setStopSequence(2);
    stopTimeUpdateBuilder.setScheduleRelationship(StopTimeUpdate.ScheduleRelationship.SCHEDULED);
    stopTimeEventBuilder = stopTimeUpdateBuilder.getArrivalBuilder();
    stopTimeEventBuilder.setDelay(1);
    tripUpdate = tripUpdateBuilder.build();
    assertTrue(timetable.update(tripUpdate, "agency", timeZone, serviceDate));

    // update trip departure time only
    tripDescriptorBuilder = TripDescriptor.newBuilder();
    tripDescriptorBuilder.setTripId("1.1");
    tripDescriptorBuilder.setScheduleRelationship(TripDescriptor.ScheduleRelationship.SCHEDULED);
    tripUpdateBuilder = TripUpdate.newBuilder();
    tripUpdateBuilder.setTrip(tripDescriptorBuilder);
    stopTimeUpdateBuilder = tripUpdateBuilder.addStopTimeUpdateBuilder(0);
    stopTimeUpdateBuilder.setStopSequence(2);
    stopTimeUpdateBuilder.setScheduleRelationship(StopTimeUpdate.ScheduleRelationship.SCHEDULED);
    stopTimeEventBuilder = stopTimeUpdateBuilder.getDepartureBuilder();
    stopTimeEventBuilder.setDelay(-1);
    tripUpdate = tripUpdateBuilder.build();
    assertTrue(timetable.update(tripUpdate, "agency", timeZone, serviceDate));

    // update trip using stop id
    tripDescriptorBuilder = TripDescriptor.newBuilder();
    tripDescriptorBuilder.setTripId("1.1");
    tripDescriptorBuilder.setScheduleRelationship(TripDescriptor.ScheduleRelationship.SCHEDULED);
    tripUpdateBuilder = TripUpdate.newBuilder();
    tripUpdateBuilder.setTrip(tripDescriptorBuilder);
    stopTimeUpdateBuilder = tripUpdateBuilder.addStopTimeUpdateBuilder(0);
    stopTimeUpdateBuilder.setStopId("B");
    stopTimeUpdateBuilder.setScheduleRelationship(StopTimeUpdate.ScheduleRelationship.SCHEDULED);
    stopTimeEventBuilder = stopTimeUpdateBuilder.getDepartureBuilder();
    stopTimeEventBuilder.setDelay(-1);
    tripUpdate = tripUpdateBuilder.build();
    assertTrue(timetable.update(tripUpdate, "agency", timeZone, serviceDate));

    // update trip arrival time at first stop and make departure time incoherent at second stop
    tripDescriptorBuilder = TripDescriptor.newBuilder();
    tripDescriptorBuilder.setTripId("1.1");
    tripDescriptorBuilder.setScheduleRelationship(TripDescriptor.ScheduleRelationship.SCHEDULED);
    tripUpdateBuilder = TripUpdate.newBuilder();
    tripUpdateBuilder.setTrip(tripDescriptorBuilder);
    stopTimeUpdateBuilder = tripUpdateBuilder.addStopTimeUpdateBuilder(0);
    stopTimeUpdateBuilder.setStopSequence(1);
    stopTimeUpdateBuilder.setScheduleRelationship(StopTimeUpdate.ScheduleRelationship.SCHEDULED);
    stopTimeEventBuilder = stopTimeUpdateBuilder.getArrivalBuilder();
    stopTimeEventBuilder.setDelay(0);
    stopTimeUpdateBuilder = tripUpdateBuilder.addStopTimeUpdateBuilder(1);
    stopTimeUpdateBuilder.setStopSequence(2);
    stopTimeUpdateBuilder.setScheduleRelationship(StopTimeUpdate.ScheduleRelationship.SCHEDULED);
    stopTimeEventBuilder = stopTimeUpdateBuilder.getDepartureBuilder();
    stopTimeEventBuilder.setDelay(-1);
    tripUpdate = tripUpdateBuilder.build();
    assertFalse(timetable.update(tripUpdate, "agency", timeZone, serviceDate));
  }