add implementation for getEtasForStopId and getEtasForShuttleId

src/repositories/ApiBasedRepository.ts

@@ -84,13 +84,35 @@ export class ApiBasedRepository implements GetterRepository {
     return null;
   }
 
-  public async getEtasForShuttleId(shuttleId: string): Promise<[]> {
+  public async getEtasForShuttleId(shuttleId: string): Promise<IEta[]> {
+    const shuttle = await this.getShuttleById(shuttleId);
+    const systemId = shuttle?.systemId;
+    if (!systemId) {
+      return [];
+    }
+    await this.updateEtasForSystemIfTTL(systemId);
+
+    if (!this.cache?.etasForShuttleId || !this.cache.etasForShuttleId[shuttleId]) {
       return [];
     }
 
-  public async getEtasForStopId(stopId: string): Promise<[]> {
+    return this.cache.etasForShuttleId[shuttleId];
+  }
+
+  public async getEtasForStopId(stopId: string): Promise<IEta[]> {
+    const stop = await this.getStopById(stopId);
+    const systemId = stop?.systemId;
+    if (!systemId) {
       return [];
     }
+    await this.updateEtasForSystemIfTTL(systemId);
+
+    if (!this.cache?.etasForStopId || !this.cache.etasForStopId[stopId]) {
+      return [];
+    }
+
+    return this.cache.etasForStopId[stopId];
+  }
 
   public async updateEtasForSystemIfTTL(systemId: string) {
     try {
@@ -262,7 +284,8 @@ ${json}`);
     }
   }
 
-  public async getStopById(stopId: string): Promise<| null> {
+  public async getStopById(stopId: string): Promise<IStop | null> {
+    // TODO: implement
     return null;
   }