Add getAverageTravelTimeSeconds in SelfUpdatingETARepository definition

src/repositories/shuttle/eta/SelfUpdatingETARepository.ts

@@ -1,3 +1,4 @@
+import { ShuttleTravelTimeDataIdentifier, ShuttleTravelTimeDateFilterArguments } from "../ShuttleGetterRepository";
 import { ETAGetterRepository } from "./ETAGetterRepository";
 
 export interface SelfUpdatingETARepository extends ETAGetterRepository {
@@ -6,4 +7,15 @@ export interface SelfUpdatingETARepository extends ETAGetterRepository {
    * shuttle updates
    */
   startListeningForUpdates(): void;
+
+  /**
+   * Get average travel time between two stops based on historical data.
+   * Returns undefined if no data exists for the specified time range.
+   * @param identifier - The route and stop IDs to query
+   * @param dateFilter - The date range to filter data
+   */
+  getAverageTravelTimeSeconds(
+    identifier: ShuttleTravelTimeDataIdentifier,
+    dateFilter: ShuttleTravelTimeDateFilterArguments
+  ): Promise<number | undefined>;
 }