// Route 5 bus monitor — parses GTFS-RT feed for real-time vehicle positions
// Usage: node monitor-route5.js
const https = require('https');
const fs = require('fs');
const protobuf = require('/tmp/gtfs-rt/node_modules/protobufjs');

const FEED_URL = 'https://data.texas.gov/download/i5qp-g5fd/application/octet-stream';
const ROUTE_ID = '5';
const FIRST_STOP = '5854'; // Anderson/Northcross
const USER_STOP = '964';   // Woodrow/Choquette
const TRAVEL_SECS = 446;   // 7 min 26 sec from first stop to user stop

// GTFS-RT proto definition (minimal, inline)
const PROTO = `
syntax = "proto2";
package transit_realtime;

message FeedMessage {
  required FeedHeader header = 1;
  repeated FeedEntity entity = 2;
}
message FeedHeader {
  required string gtfs_realtime_version = 1;
  optional uint64 timestamp = 2;
}
message FeedEntity {
  required string id = 1;
  optional TripUpdate trip_update = 3;
  optional VehiclePosition vehicle = 4;
  optional Alert alert = 5;
}
message TripUpdate {
  optional TripDescriptor trip = 1;
  optional VehicleDescriptor vehicle = 3;
  repeated StopTimeUpdate stop_time_update = 2;
  optional uint64 timestamp = 4;
  message StopTimeUpdate {
    optional uint32 stop_sequence = 1;
    optional string stop_id = 4;
    optional StopTimeEvent arrival = 2;
    optional StopTimeEvent departure = 3;
    enum ScheduleRelationship { SCHEDULED = 0; SKIPPED = 1; NO_DATA = 2; }
    optional ScheduleRelationship schedule_relationship = 5;
  }
}
message StopTimeEvent {
  optional int32 delay = 1;
  optional int64 time = 2;
  optional int32 uncertainty = 3;
}
message VehiclePosition {
  optional TripDescriptor trip = 1;
  optional VehicleDescriptor vehicle = 8;
  optional Position position = 2;
  optional uint32 current_stop_sequence = 3;
  optional string stop_id = 7;
  enum VehicleStopStatus { INCOMING_AT = 0; STOPPED_AT = 1; IN_TRANSIT_TO = 2; }
  optional VehicleStopStatus current_status = 4;
  optional uint64 timestamp = 5;
  enum CongestionLevel { UNKNOWN = 0; RUNNING_SMOOTHLY = 1; STOP_AND_GO = 2; CONGESTION = 3; SEVERE_CONGESTION = 4; }
  optional CongestionLevel congestion_level = 6;
  enum OccupancyStatus { EMPTY = 0; MANY_SEATS = 1; FEW_SEATS = 2; STANDING_ROOM = 3; CRUSHED = 4; FULL = 5; NOT_ACCEPTING = 6; }
  optional OccupancyStatus occupancy_status = 9;
}
message TripDescriptor {
  optional string trip_id = 1;
  optional string route_id = 5;
  optional uint32 direction_id = 6;
  optional string start_time = 2;
  optional string start_date = 3;
  enum ScheduleRelationship { SCHEDULED = 0; ADDED = 1; UNSCHEDULED = 2; CANCELED = 3; }
  optional ScheduleRelationship schedule_relationship = 4;
}
message VehicleDescriptor {
  optional string id = 1;
  optional string label = 2;
  optional string license_plate = 3;
}
message Position {
  required float latitude = 1;
  required float longitude = 2;
  optional float bearing = 3;
  optional double odometer = 4;
  optional float speed = 5;
}
message Alert {
  repeated TimeRange active_period = 1;
  repeated EntitySelector informed_entity = 5;
  optional TranslatedString header_text = 10;
  optional TranslatedString description_text = 11;
}
message TimeRange { optional uint64 start = 1; optional uint64 end = 2; }
message EntitySelector { optional string agency_id = 1; optional string route_id = 3; optional TripDescriptor trip = 4; optional string stop_id = 6; }
message TranslatedString { repeated Translation translation = 1; message Translation { required string text = 1; optional string language = 2; } }
`;

function fetch(url) {
  return new Promise((resolve, reject) => {
    https.get(url, (res) => {
      const chunks = [];
      res.on('data', c => chunks.push(c));
      res.on('end', () => resolve(Buffer.concat(chunks)));
      res.on('error', reject);
    }).on('error', reject);
  });
}

async function main() {
  const root = protobuf.parse(PROTO, { keepCase: true }).root;
  const FeedMessage = root.lookupType('transit_realtime.FeedMessage');

  const buf = await fetch(FEED_URL);
  const feed = FeedMessage.decode(buf);

  const now = Math.floor(Date.now() / 1000);
  const cst = new Date((now - 6*3600) * 1000); // CST offset
  const timeStr = cst.toISOString().replace('T', ' ').substring(0, 19) + ' CST';

  // Filter Route 5 vehicles
  const vehicles = feed.entity
    .filter(e => e.vehicle && e.vehicle.trip && e.vehicle.trip.route_id === ROUTE_ID)
    .map(e => {
      const v = e.vehicle;
      const age = now - (v.timestamp?.low || v.timestamp || 0);
      const status = ['INCOMING_AT', 'STOPPED_AT', 'IN_TRANSIT_TO'][v.current_status] || 'UNKNOWN';
      return {
        vehicleId: v.vehicle?.label || v.vehicle?.id || 'unknown',
        tripId: v.trip?.trip_id,
        directionId: v.trip?.direction_id,
        stopId: v.stop_id,
        stopSequence: v.current_stop_sequence,
        status,
        lat: v.position?.latitude,
        lon: v.position?.longitude,
        speed: v.position?.speed,
        bearing: v.position?.bearing,
        ageSec: age,
        timestamp: v.timestamp
      };
    });

  // Filter Route 5 trip updates
  const tripUpdates = feed.entity
    .filter(e => e.trip_update && e.trip_update.trip && e.trip_update.trip.route_id === ROUTE_ID)
    .map(e => {
      const tu = e.trip_update;
      const userStopUpdate = tu.stop_time_update?.find(s => s.stop_id === USER_STOP);
      const firstStopUpdate = tu.stop_time_update?.find(s => s.stop_id === FIRST_STOP);
      return {
        tripId: tu.trip?.trip_id,
        directionId: tu.trip?.direction_id,
        vehicleId: tu.vehicle?.label || tu.vehicle?.id,
        userStopDelay: userStopUpdate?.departure?.delay || userStopUpdate?.arrival?.delay || null,
        userStopTime: userStopUpdate?.arrival?.time || userStopUpdate?.departure?.time || null,
        firstStopDelay: firstStopUpdate?.departure?.delay || null,
        firstStopTime: firstStopUpdate?.departure?.time || null,
        totalStops: tu.stop_time_update?.length || 0
      };
    });

  // Eastbound (direction 0) only
  const ebVehicles = vehicles.filter(v => v.directionId === 0);
  const ebUpdates = tripUpdates.filter(t => t.directionId === 0);

  const result = {
    timestamp: timeStr,
    feedTimestamp: feed.header?.timestamp?.toString(),
    route5_eastbound: {
      activeVehicles: ebVehicles.length,
      vehicles: ebVehicles,
      tripUpdates: ebUpdates.filter(t => t.userStopDelay !== null || t.userStopTime !== null)
    },
    route5_all: {
      totalVehicles: vehicles.length,
      totalTripUpdates: tripUpdates.length
    }
  };

  console.log(JSON.stringify(result, null, 2));
}

main().catch(e => console.error(JSON.stringify({ error: e.message })));