Build TFI Live G2 deployable app

scripts/build-stop-index.mjs

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+import { createReadStream, mkdirSync, readFileSync, writeFileSync } from 'node:fs'
+import { dirname, join } from 'node:path'
+import { fileURLToPath } from 'node:url'
+import { createInterface } from 'node:readline'
+
+export async function buildStopIndex(gtfsDir, outputPath = 'public/stops.json') {
+  const stops = readCsv(join(gtfsDir, 'stops.txt'))
+  const routes = readCsv(join(gtfsDir, 'routes.txt'))
+  const trips = readCsv(join(gtfsDir, 'trips.txt'))
+  const routeById = new Map(routes.map((route) => [route.route_id, route]))
+  const tripRouteById = new Map(trips.map((trip) => [trip.trip_id, trip.route_id]))
+  const routesByStop = new Map()
+  const modesByStop = new Map()
+
+  await eachCsvRow(join(gtfsDir, 'stop_times.txt'), (row) => {
+    const stopId = row.stop_id
+    const routeId = tripRouteById.get(row.trip_id)
+    if (!stopId || !routeId) {
+      return
+    }
+
+    const route = routeById.get(routeId)
+    const routeName = route?.route_short_name || route?.route_long_name || routeId
+    pushUnique(routesByStop, stopId, routeName)
+    pushUnique(modesByStop, stopId, modeFromRouteType(route?.route_type))
+  })
+
+  const index = stops
+    .map((stop) => ({
+      id: stop.stop_id,
+      code: stop.stop_code || stop.stop_id,
+      name: stop.stop_name,
+      lat: Number(stop.stop_lat),
+      lon: Number(stop.stop_lon),
+      modes: modesByStop.get(stop.stop_id) || ['unknown'],
+      routes: routesByStop.get(stop.stop_id) || [],
+    }))
+    .filter((stop) => stop.id && stop.name && Number.isFinite(stop.lat) && Number.isFinite(stop.lon))
+
+  mkdirSync(dirname(outputPath), { recursive: true })
+  writeFileSync(outputPath, `${JSON.stringify({ stops: index })}\n`)
+  return index.length
+}
+
+if (process.argv[1] === fileURLToPath(import.meta.url)) {
+  const [gtfsDir, outputPath = 'public/stops.json'] = process.argv.slice(2)
+
+  if (!gtfsDir) {
+    console.error('Usage: node scripts/build-stop-index.mjs <extracted-gtfs-dir> [output.json]')
+    process.exit(1)
+  }
+
+  const count = await buildStopIndex(gtfsDir, outputPath)
+  console.log(`Wrote ${count} stops to ${outputPath}`)
+}
+
+function readCsv(path) {
+  const [headerLine, ...lines] = readFileSync(path, 'utf8').trim().split(/\r?\n/)
+  const headers = parseCsvLine(headerLine)
+  return lines.map((line) => rowFromValues(headers, parseCsvLine(line)))
+}
+
+async function eachCsvRow(path, callback) {
+  const reader = createInterface({
+    input: createReadStream(path),
+    crlfDelay: Infinity,
+  })
+
+  let headers = []
+  for await (const line of reader) {
+    if (!headers.length) {
+      headers = parseCsvLine(line)
+      continue
+    }
+    callback(rowFromValues(headers, parseCsvLine(line)))
+  }
+}
+
+function rowFromValues(headers, values) {
+  return Object.fromEntries(headers.map((header, index) => [header, values[index] ?? '']))
+}
+
+function parseCsvLine(line) {
+  const values = []
+  let value = ''
+  let quoted = false
+
+  for (let index = 0; index < line.length; index += 1) {
+    const char = line[index]
+    const next = line[index + 1]
+
+    if (char === '"' && quoted && next === '"') {
+      value += '"'
+      index += 1
+    } else if (char === '"') {
+      quoted = !quoted
+    } else if (char === ',' && !quoted) {
+      values.push(value)
+      value = ''
+    } else {
+      value += char
+    }
+  }
+
+  values.push(value)
+  return values
+}
+
+function pushUnique(map, key, value) {
+  if (!value) {
+    return
+  }
+  const values = map.get(key) || []
+  if (!values.includes(value)) {
+    values.push(value)
+    map.set(key, values)
+  }
+}
+
+function modeFromRouteType(routeType) {
+  switch (String(routeType)) {
+    case '0':
+      return 'tram'
+    case '2':
+      return 'rail'
+    case '3':
+      return 'bus'
+    default:
+      return 'unknown'
+  }
+}