From da0e230c3345d641c91f503ef56cebb0343b8419 Mon Sep 17 00:00:00 2001
From: Landon Reed <landontreed@gmail.com>
Date: Tue, 19 Feb 2019 11:32:33 -0500
Subject: [PATCH] refactor(gtfs+): simplify lookupMissingEntities function

---
 lib/gtfsplus/actions/gtfsplus.js | 50 +++++++++++++++-----------------
 lib/types/reducers.js            |  5 +++-
 2 files changed, 28 insertions(+), 27 deletions(-)

diff --git a/lib/gtfsplus/actions/gtfsplus.js b/lib/gtfsplus/actions/gtfsplus.js
index cc56ff731..c65d2e490 100644
--- a/lib/gtfsplus/actions/gtfsplus.js
+++ b/lib/gtfsplus/actions/gtfsplus.js
@@ -213,7 +213,7 @@ export function loadGtfsEntities (
         })
       : rows
     const {namespace} = feedVersion
-    const {routesToLoad, stopsToLoad} = lookupMissingEntities(tableId, filteredRows, getState().gtfsplus.gtfsEntityLookup)
+    const {routesToLoad, stopsToLoad} = lookupMissingEntities(filteredRows, getState().gtfsplus.gtfsEntityLookup)
     if (routesToLoad.length === 0 && stopsToLoad.length === 0) {
       return
     }
@@ -225,40 +225,38 @@ export function loadGtfsEntities (
   }
 }
 
-function lookupMissingEntities (tableId: string, rows: Array<GTFSPlusEntity>, currentLookup: Object) {
-  // lookup table for mapping tableId:fieldName keys to inputType values
-  const typeLookup = {}
-  const getDataType = function (tableId, fieldName) {
-    const lookupKey = tableId + ':' + fieldName
-    if (lookupKey in typeLookup) return typeLookup[lookupKey]
-    const specTable = getGtfsPlusSpec().find(t => t.id === tableId)
-    if (!specTable) {
-      console.warn(`unable to find spec table for tableId: ${tableId}`)
-      return null
-    }
-    const fieldInfo = specTable.fields.find(f => f.name === fieldName)
-    if (!fieldInfo) return null
-    typeLookup[lookupKey] = fieldInfo.inputType
-    return fieldInfo.inputType
-  }
-
-  // Determine which routes, stops, etc. aren't currently in the
+/**
+ * Given a set of GTFS+ rows, determine (from the current state's lookup) if the
+ * rows contain references to GTFS routes or stops that have not yet been fetched
+ * from the GraphQL GTFS API and return the list of unfetched/missing stops and
+ * routes. NOTE: only a single feed version is considered at once, so there is
+ * no need to scope the route/stop IDs by feed.
+ */
+function lookupMissingEntities (
+  gtfsPlusRows: Array<GTFSPlusEntity>,
+  currentLookup: {[string]: GtfsRoute | GtfsStop}
+) {
+  // Determine which routes and stops aren't currently in the
   // gtfsEntityLookup table and need to be loaded from the API.
   const routesToLoad: string[] = []
   const stopsToLoad: string[] = []
-  for (const rowData of rows) {
+  for (const rowData of gtfsPlusRows) {
     for (const fieldName in rowData) {
-      const dataType = getDataType(tableId, fieldName)
-      switch (dataType) {
-        case 'GTFS_ROUTE':
-          const routeId = rowData.route_id
+      // Currently, the only references to stops/routes in GTFS+ are fields named
+      // route_id or stop_id. If this changes, this logic should revert to
+      // commit 7d150d85e203b336147ba106eef7c3be90b39fb7 which contained a way
+      // to lookup based on inputType in gtfsplus.yml.
+      switch (fieldName) {
+        case 'route_id':
+          const {route_id: routeId} = rowData
           if (routeId && !(`route_${routeId}` in currentLookup)) routesToLoad.push(routeId)
           break
-        case 'GTFS_STOP':
-          const stopId = rowData.stop_id
+        case 'stop_id':
+          const {stop_id: stopId} = rowData
           if (stopId && !(`stop_${stopId}` in currentLookup)) stopsToLoad.push(stopId)
           break
         default:
+          // No entities to search for.
           break
       }
     }
diff --git a/lib/types/reducers.js b/lib/types/reducers.js
index 5d663b09e..195fb3623 100644
--- a/lib/types/reducers.js
+++ b/lib/types/reducers.js
@@ -9,6 +9,7 @@ import type {
   Alert,
   ControlPoint,
   FetchStatus,
+  GtfsRoute,
   GtfsStop,
   Organization,
   Project,
@@ -443,7 +444,9 @@ export type GtfsPlusReducerState = {
   activeTableId: 'realtime_routes',
   currentPage: number,
   feedVersionId: null | string,
-  gtfsEntityLookup: Object, // TODO specify more exact type
+  gtfsEntityLookup: {
+    [string]: GtfsStop | GtfsRoute
+  },
   pageCount: number,
   recordsPerPage: number,
   tableData: null | any, // TODO specify more exact type