From 321631e6c9b0636a02ae2a485ad17e4bee2a5cc1 Mon Sep 17 00:00:00 2001
From: Brendan Chen <me@bchen.dev>
Date: Mon, 10 Nov 2025 14:49:41 -0800
Subject: [PATCH] Add partial implementation and scaffolding of historical ETA
 update

---
 .../shuttle/RedisShuttleRepository.ts         | 48 ++++++++++++++++++-
 1 file changed, 46 insertions(+), 2 deletions(-)

diff --git a/src/repositories/shuttle/RedisShuttleRepository.ts b/src/repositories/shuttle/RedisShuttleRepository.ts
index cf6e063..d6e03d6 100644
--- a/src/repositories/shuttle/RedisShuttleRepository.ts
+++ b/src/repositories/shuttle/RedisShuttleRepository.ts
@@ -1,7 +1,7 @@
 import EventEmitter from "node:events";
 import { createClient } from 'redis';
 import { ShuttleGetterSetterRepository } from "./ShuttleGetterSetterRepository";
-import { IEta, IOrderedStop, IRoute, IShuttle, IStop } from "../../entities/ShuttleRepositoryEntities";
+import { IEta, IOrderedStop, IRoute, IShuttle, IStop, shuttleHasArrivedAtStop } from "../../entities/ShuttleRepositoryEntities";
 import { REDIS_RECONNECT_INTERVAL } from "../../environment";
 import {
   ShuttleRepositoryEvent,
@@ -10,6 +10,11 @@ import {
   ShuttleRepositoryEventPayloads,
 } from "./ShuttleGetterRepository";
 
+export interface ShuttleStopArrival {
+  stopId: string;
+  timestamp: Date;
+}
+
 export class RedisShuttleRepository extends EventEmitter implements ShuttleGetterSetterRepository {
   protected redisClient;
 
@@ -405,9 +410,48 @@ export class RedisShuttleRepository extends EventEmitter implements ShuttleGette
   public async addOrUpdateShuttle(shuttle: IShuttle): Promise<void> {
     const key = this.createShuttleKey(shuttle.id);
     await this.redisClient.hSet(key, this.createRedisHashFromShuttle(shuttle));
+
+    await this.updateHistoricalEtasForShuttle(shuttle);
   }
 
-  public async addOrUpdateStop(stop: IStop): Promise<void> {
+  private async updateHistoricalEtasForShuttle(shuttle: IShuttle) {
+    const arrivedStop = await this.getArrivedStopIfExists(shuttle);
+
+    if (arrivedStop != undefined) {
+      const lastStopTimestamp = await this.getShuttleLastStopTimestamp(shuttle)
+      if (lastStopTimestamp != undefined) {
+        const now = Date();
+        const routeId = shuttle.routeId
+        const fromStopId = lastStopTimestamp.stopId;
+        const toStopId = arrivedStop.id;
+
+        // Create an entry in Redis time series
+        // Key: routeId:fromStopId:toStopId:
+        // Value: seconds it took to get from lastStopTimestamp.stopId to arrivedStop.id
+      }
+
+      // TODO: Update the "last stop timestamp"
+    }
+  }
+
+  public async getArrivedStopIfExists(shuttle: IShuttle): Promise<IStop | undefined> {
+    const orderedStops = await this.getOrderedStopsByRouteId(shuttle.routeId);
+
+    for (const orderedStop of orderedStops) {
+      const stop = await this.getStopById(orderedStop.stopId);
+      if (stop != null && shuttleHasArrivedAtStop(shuttle, stop)) {
+        return stop;
+      }
+      return undefined;
+    }
+  }
+
+  public async getShuttleLastStopTimestamp(shuttle: IShuttle): Promise<ShuttleStopArrival> {
+    throw new Error("Method not implemented.");
+  }
+
+
+   public async addOrUpdateStop(stop: IStop): Promise<void> {
     const key = this.createStopKey(stop.id);
     await this.redisClient.hSet(key, this.createRedisHashFromStop(stop));
   }