From 7ed780a45974ff77237f84b48c4732ea33ec245e Mon Sep 17 00:00:00 2001
From: Brendan Chen <me@bchen.dev>
Date: Fri, 26 Sep 2025 15:40:58 -0700
Subject: [PATCH] Implement filtering of shuttles by proximity to the closest
 route polyline coordinate

---
 .../ApiBasedShuttleRepositoryLoader.ts        | 54 +++++++++++++++++--
 .../shuttle/ShuttleRepositoryLoader.ts        |  2 +-
 2 files changed, 50 insertions(+), 6 deletions(-)

diff --git a/src/loaders/shuttle/ApiBasedShuttleRepositoryLoader.ts b/src/loaders/shuttle/ApiBasedShuttleRepositoryLoader.ts
index e79dd45..fb7352a 100644
--- a/src/loaders/shuttle/ApiBasedShuttleRepositoryLoader.ts
+++ b/src/loaders/shuttle/ApiBasedShuttleRepositoryLoader.ts
@@ -1,7 +1,7 @@
 import { ShuttleGetterSetterRepository } from "../../repositories/shuttle/ShuttleGetterSetterRepository";
 import { IEta, IRoute, IShuttle, IStop } from "../../entities/ShuttleRepositoryEntities";
 import { ShuttleRepositoryLoader } from "./ShuttleRepositoryLoader";
-import { IEntityWithId } from "../../entities/SharedEntities";
+import { ICoordinates, IEntityWithId } from "../../entities/SharedEntities";
 import { ApiResponseError } from "../ApiResponseError";
 
 /**
@@ -10,12 +10,13 @@ import { ApiResponseError } from "../ApiResponseError";
  * which inherit from `IEntityWithId`.
  */
 export class ApiBasedShuttleRepositoryLoader implements ShuttleRepositoryLoader {
-  baseUrl = "https://passiogo.com/mapGetData.php";
+  readonly baseUrl = "https://passiogo.com/mapGetData.php";
 
   constructor(
     public passioSystemId: string,
     public systemIdForConstructedData: string,
     public repository: ShuttleGetterSetterRepository,
+    readonly shuttleToRouteCoordinateMaximumDistanceMiles = 10,
   ) {
   }
 
@@ -31,7 +32,7 @@ export class ApiBasedShuttleRepositoryLoader implements ShuttleRepositoryLoader
   public async updateAll() {
     await this.updateRouteDataForSystem();
     await this.updateStopAndPolylineDataForRoutesInSystem();
-    await this.updateShuttleDataForSystem();
+    await this.updateShuttleDataForSystemBasedOnProximityToRoutes();
 
     // Because ETA method doesn't support pruning yet,
     // add a call to the clear method here
@@ -155,11 +156,12 @@ export class ApiBasedShuttleRepositoryLoader implements ShuttleRepositoryLoader
     return await response.json();
   }
 
-  public async updateShuttleDataForSystem() {
+  public async updateShuttleDataForSystemBasedOnProximityToRoutes() {
     try {
       const json = await this.fetchShuttleDataJson();
-      const shuttles = this.constructShuttlesFromJson(json);
+      let shuttles = this.constructShuttlesFromJson(json);
       if (shuttles !== null) {
+        shuttles = await this.filterShuttlesByDistanceFromCorrespondingRoute(shuttles);
         await this.updateShuttleDataInRepository(shuttles);
       } else {
         console.warn(`Shuttle update failed for the following JSON: ${JSON.stringify(json)}`)
@@ -391,4 +393,46 @@ export class ApiBasedShuttleRepositoryLoader implements ShuttleRepositoryLoader
     }
   }
 
+  private filterShuttlesByDistanceFromCorrespondingRoute = async (shuttles: IShuttle[]) => {
+    let filteredShuttles: IShuttle[] = [];
+
+    await Promise.all(shuttles.map(async (shuttle) => {
+      const route = await this.repository.getRouteById(shuttle.routeId);
+      if (route != null) {
+        let closestDistanceMiles = Number.MAX_VALUE;
+
+        route.polylineCoordinates.forEach((coordinate) => {
+          const calculatedDistance = ApiBasedShuttleRepositoryLoader.convertDistanceBetweenCoordinatesToMiles(coordinate, shuttle.coordinates)
+          if (closestDistanceMiles > calculatedDistance) {
+            closestDistanceMiles = calculatedDistance;
+          }
+        });
+
+        if (closestDistanceMiles <= this.shuttleToRouteCoordinateMaximumDistanceMiles) {
+          filteredShuttles.push(shuttle);
+        }
+      } else {
+        console.warn(`No corresponding route found for ID ${shuttle.routeId} of shuttle ${shuttle.id}`)
+      }
+    }));
+
+    return filteredShuttles;
+  };
+
+  public static convertDistanceBetweenCoordinatesToMiles = (fromCoordinate: ICoordinates, toCoordinate: ICoordinates): number => {
+    const earthRadiusMiles = 3959;
+
+    const lat1Rad = fromCoordinate.latitude * Math.PI / 180;
+    const lat2Rad = toCoordinate.latitude * Math.PI / 180;
+    const deltaLatRad = (toCoordinate.latitude - fromCoordinate.latitude) * Math.PI / 180;
+    const deltaLonRad = (toCoordinate.longitude - fromCoordinate.longitude) * Math.PI / 180;
+
+    const a = Math.sin(deltaLatRad / 2) * Math.sin(deltaLatRad / 2) +
+              Math.cos(lat1Rad) * Math.cos(lat2Rad) *
+              Math.sin(deltaLonRad / 2) * Math.sin(deltaLonRad / 2);
+
+    const c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
+
+    return earthRadiusMiles * c;
+  };
 }
diff --git a/src/loaders/shuttle/ShuttleRepositoryLoader.ts b/src/loaders/shuttle/ShuttleRepositoryLoader.ts
index 6c4eb3e..d556455 100644
--- a/src/loaders/shuttle/ShuttleRepositoryLoader.ts
+++ b/src/loaders/shuttle/ShuttleRepositoryLoader.ts
@@ -3,7 +3,7 @@ import { RepositoryLoader } from "../RepositoryLoader";
 export interface ShuttleRepositoryLoader extends RepositoryLoader {
   updateRouteDataForSystem(): Promise<void>;
   updateStopAndPolylineDataForRoutesInSystem(): Promise<void>;
-  updateShuttleDataForSystem(): Promise<void>;
+  updateShuttleDataForSystemBasedOnProximityToRoutes(): Promise<void>;
   updateEtaDataForExistingStopsForSystem(): Promise<void>;
   updateEtaDataForStopId(stopId: string): Promise<void>;
 }