Add support for partial PIS matches by skipping first n stops

Signed-off-by: Fred Boniface <fred@fjla.uk>

package.json

@@ -33,7 +33,7 @@
     "zlib": "^1.0.5"
   },
   "devDependencies": {
-    "@owlboard/ts-types": "^0.1.0",
+    "@owlboard/ts-types": "^0.1.2",
     "@types/jest": "^29.5.3",
     "eslint": "^8.39.0",
     "jest": "^29.6.2",

src/controllers/pis.controllers.js

@@ -48,13 +48,13 @@ async function random(req, res, next) {
 }
 
 async function testingTiplocArray(req, res, next) {
-  let array = JSON.parse(req.params.array)
+  let array = JSON.parse(req.params.array);
-  return pis.findByTiplocArray(array)
+  res.json(await pis.findByTiplocArray(array));
 }
 
 module.exports = {
   byStartEndCRS,
   byCode,
   random,
-  testingTiplocArray
+  testingTiplocArray,
 };

src/middlewares/auth.middlewares.js

@@ -5,9 +5,9 @@ module.exports = async function authCheck(req, res, next) {
   //log.out("authMiddlewares: Checking authentication", "dbug");
   logger.logger.debug("Auth check starting");
   if (process.env.NODE_ENV === "development") {
-    logger.logger.warn("DEVELOPMENT MODE - AUTHENTICATION DISABLED")
+    logger.logger.warn("DEVELOPMENT MODE - AUTHENTICATION DISABLED");
     res.isAuthed = true;
-    return next()
+    return next();
   }
   try {
     var uuid = req.headers.uuid;

src/services/pis.services.ts

@@ -3,8 +3,15 @@
 const db = require("../services/dbAccess.services");
 const clean = require("../utils/sanitizer.utils");
 
+import type { OB_Pis_SimpleObject } from "@owlboard/ts-types";
+
 import { logger } from "../utils/logger.utils";
 import { queryAggregate } from "./dbAccess.services";
+import {
+  getPartialEndTiplocMatchPipeline,
+  getFullTiplocMatchPipeline,
+} from "../utils/pis.utils";
+import { Document } from "mongodb";
 
 const supported = ["GW", "UK"];
 
@@ -33,7 +40,9 @@ async function findPisByOrigDest(start: string, end: string) {
   return search;
 }
 
-async function findPisByCode(code: string) {
+async function findPisByCode(
+  code: string
+): Promise<OB_Pis_SimpleObject | null> {
   logger.debug(`pisServices.findPisByCode: Searching for PIS code: ${code}`);
   const cleanCode = clean.removeNonNumeric(code);
   const query = {
@@ -43,75 +52,73 @@ async function findPisByCode(code: string) {
   return await search;
 }
 
-export async function findByTiplocArray(tiplocArray: string[]) {
+// Queries the database for PIS codes that match the given TIPLOC array
-  // If any of the TIPLOCS in an array is RDG4AB - Replace it with READING.
+export async function findByTiplocArray(
-  // ^^ Double check those though before doing it.
+  tiplocArray: string[]
-  const query = {
+): Promise<OB_Pis_SimpleObject | null> {
-    tiplocs: tiplocArray,
+  // Firstly fix errant TIPLOCS such as RDNG4AB which will never return a result
-  };
+  // currently only works with RDNG4AB - checks for presence of RDNG4AB first to
-  const res = await db.query("pis", query);
+  // avoid iterating over every array ever searched for.
-  // If res is empty then try to find partial match
+  if (tiplocArray.includes("RDNG4AB")) {
-  if (res.length) {
+    fixErrantTiplocs(tiplocArray);
-    return res;
+  }
+
+  // PERFORMANCE NOTE:
+  //   The majority of queries will return a full match,
+  //   this means that a more performant pipeline is used
+  //   to find a full match and only then are more
+  //   complicated pipelines used to find partial matches
+  //   if the first pipeline returns nothing.
+  try {
+    const exactMatch = await findExactMatchByTiploc(tiplocArray);
+    if (exactMatch) {
+      return convertDocument(exactMatch, "none");
     } else {
-    let partial = await findPartialMatchByTiploc(tiplocArray);
+      const partialEnd = await findPartialEndMatchByTiploc(tiplocArray);
-    return partial;
+      if (partialEnd) {
+        return convertDocument(partialEnd, "first");
+      } else {
+        // Here, I should search for a partialStart match.  For now return null.
+        return null;
+      }
+    }
+  } catch (err) {
+    logger.error(err, "Error in findByTiplocArray");
+    return null;
   }
 }
 
-async function findPartialMatchByTiploc(tiplocArray: string[]) {
+// Uses a pipeline to find an exact match
-  // Do some magic here, similar to findPisByOrigDest but
+async function findExactMatchByTiploc(array: string[]): Promise<Document> {
-  // ensuring that the stops in the array match the last
+  const pipeline = getFullTiplocMatchPipeline(array);
-  // x number of items in the array.
+  const res = await queryAggregate("pis", pipeline);
-
+  return res[0];
-  const pipeline = [
-    {
-      $addFields: {
-        reversedTiplocs: {
-          $reverseArray: "$tiplocs",
-        },
-        reversedQueryArray: {
-          $reverseArray: tiplocArray,
-        },
-      },
-    },
-    {
-      $match: {
-        $expr: {
-          $gt: [
-            {
-              $indexOfArray: [
-                "$reversedTiplocs",
-                {
-                  $arrayElemAt: ["$reversedQueryArray", 0],
 }
-              ],
-            },
-            -1,
-          ],
-        },
-      },
-    },
-    {
-      $project: {
-        code: 1,
-        skipStops: {
-          $subtract: [
-            {
-              $size: "$tiplocs",
-            },
-            {
-              $size: tiplocArray,
-            },
-          ],
-        },
-      },
-    },
-  ];
 
-  const res = await queryAggregate('pis', pipeline)
+// Uses a pipeline to find a partial match - only supporting
-  console.log(JSON.stringify(res))
+// codes ending with the correct stops for now.
-  return res
+async function findPartialEndMatchByTiploc(array: string[]): Promise<Document> {
+  const pipeline = getPartialEndTiplocMatchPipeline(array);
+  const res = await queryAggregate("pis", pipeline);
+  return res[0];
+}
+
+function convertDocument(doc: Document, skipType: string): OB_Pis_SimpleObject {
+  return {
+    code: doc.code,
+    toc: doc.toc,
+    skipCount: doc.skipStops,
+    skipType: skipType,
+  };
+}
+
+// Changes any instance of 'RDNG4AB' to 'RDNGSTN'
+function fixErrantTiplocs(input: string[]): void {
+  input.forEach((value, index, array) => {
+    if (value === "RDNG4AB") {
+      array[index] = "RDNGSTN";
+    }
+  });
 }
 
 module.exports = {

src/utils/pis.utils.ts

@@ -0,0 +1,102 @@
+export function getPartialEndTiplocMatchPipeline(query: string[]) {
+  return [
+    {
+      $match: {
+        tiplocs: {
+          $all: query,
+        },
+      },
+    },
+    {
+      $addFields: {
+        reversedTiplocs: {
+          $reverseArray: "$tiplocs",
+        },
+        query: {
+          $literal: query,
+        },
+      },
+    },
+    {
+      $addFields: {
+        reversedQuery: {
+          $reverseArray: "$query",
+        },
+      },
+    },
+    {
+      $match: {
+        $expr: {
+          $eq: [
+            {
+              $slice: [
+                "$reversedTiplocs",
+                0,
+                {
+                  $size: "$reversedQuery",
+                },
+              ],
+            },
+            "$reversedQuery",
+          ],
+        },
+      },
+    },
+    {
+      $addFields: {
+        skipStops: {
+          $subtract: [
+            {
+              $size: "$tiplocs",
+            },
+            {
+              $size: "$reversedQuery",
+            },
+          ],
+        },
+      },
+    },
+    {
+      $sort: {
+        skipStops: 1,
+      },
+    },
+    {
+      $limit: 1,
+    },
+    {
+      $project: {
+        code: 1,
+        skipStops: 1,
+        toc: 1,
+        _id: 0,
+      },
+    },
+  ];
+}
+
+export function getFullTiplocMatchPipeline(query: string[]) {
+  return [
+    {
+      $match: {
+        tiplocs: query,
+      },
+    },
+    {
+      $limit: 1,
+    },
+    {
+      $addFields: {
+        skipStops: 0,
+      },
+    },
+    {
+      $project: {
+        code: 1,
+        toc: 1,
+        skipStops: 1,
+        _id: 0,
+      },
+    },
+  ];
+}