Groundwork for filtering services based on STP indicator

src/services/trainService.services.js

@@ -16,9 +16,7 @@ async function findByHeadcodeToday(headcode) {
     daysRun: {$in: [shortDay]}
   };
   const queryData = await db.query('timetable', query);
-  let trainData = queryData;
-  // At this point, the returned objects need sorting to ensure the correct object is returned.
-  // C, N, O, P is the order - C being the preferred, then N, then O and finally P.
+  let trainData = await parseTrains(queryData, now);
   let preparedData = [];
   for (const trainService in trainData) {
     // Search for PIS Code for each service
@@ -30,6 +28,12 @@ async function findByHeadcodeToday(headcode) {
   return preparedData;
 }
 
+module.exports = {
+  findByHeadcodeToday,
+};
+
+/* Internal Functions, not to be exported */
+
 async function getPublicStops(data) {
   let tiplocList = [];
   for (const publicStop in data) {
@@ -40,6 +44,18 @@ async function getPublicStops(data) {
   return tiplocList;
 }
 
-module.exports = {
-  findByHeadcodeToday,
-};
+async function parseTrains(data, date = new Date() {
+  // Parses an array returned from a db-query and removes any service entries that don't apply to {date}
+  // {date} shoule be a datetime object and defaults to now if not provided - as a general rule it should always be provided for clarity
+  
+    // At this point, the returned objects need sorting to ensure the correct object is returned.
+  // C, N, O, P is the order - C being the preferred, then N, then O and finally P.
+  // If stpindicator == "C" && trainUid (isSame as N, O or P entry) => DO NOT DISPLAY SERVICE ("C" records do not contain the headcode (signalling_id)) so an additional lookup needs to be performed for the trainUid.
+  // If stpIndicator == "N" && trainUid (isSame as O or P entry) => Display this instead of "O", or "P"
+  // If stpIndicaor == "O" && trainUid (isSame as P entry) => Display this instead of "P"
+  // Obviously, remember that several trains can share a headcode, but the trainUid is unique for each service.
+  // Probably best to loop through each return here and add to a new [], then if another entry supersedes it, overwrite it in the [].  Then pass to the below part of the function to process the data for sending.
+  // Maybe break in to a new function parseTrains() which can take in any dbquery array and remove any services that are not meant to be displayed based on the data provided.  Maybe have a date as an input so it can be used in the future to fetch trains for a given date in the future - due to database cleaning in db-manager, past dates would need adjustments to how the database is cleaned leaving outdated services available.
+  const parsedDate = data;
+  return parsedData;
+};