Add code to mark shuttle at a stop (Redis set)

src/repositories/shuttle/RedisShuttleRepository.ts

@@ -84,6 +84,11 @@ export class RedisShuttleRepository extends BaseRedisRepository implements Shutt
     return `shuttle:eta:historical:${routeId}:${fromStopId}:${toStopId}`;
   }
 
+  /**
+   * Represents a set storing the shuttles that are currently at a stop.
+   */
+  private readonly shuttleIsAtStopKey = "shuttle:atstop";
+
   // Helper methods for converting entities to Redis hashes
   private createRedisHashFromStop = (stop: IStop): Record<string, string> => ({
     id: stop.id,
@@ -409,10 +414,19 @@ export class RedisShuttleRepository extends BaseRedisRepository implements Shutt
         lastStopArrival: lastStop,
         willArriveAt: shuttleArrival,
       });
+      await this.markShuttleAsAtStop(shuttleArrival.shuttleId);
       await this.updateShuttleLastStopArrival(shuttleArrival);
     }
   }
 
+  private async markShuttleAsAtStop(shuttleId: string) {
+    await this.redisClient.sAdd(this.shuttleIsAtStopKey, shuttleId);
+  }
+
+  private async checkIfShuttleIsAtStop(shuttleId: string) {
+    return await this.redisClient.sIsMember(this.shuttleIsAtStopKey, shuttleId);
+  }
+
   public async getAverageTravelTimeSeconds(
     { routeId, fromStopId, toStopId }: ShuttleTravelTimeDataIdentifier,
     { from, to }: ShuttleTravelTimeDateFilterArguments,