Determine correct students count for study courses #713

src/app/events/services/events-state.service.spec.ts

@@ -4,11 +4,13 @@ import * as t from "io-ts/lib/index";
 import { Course } from "src/app/shared/models/course.model";
 import { Event } from "src/app/shared/models/event.model";
 import { StudyClass } from "src/app/shared/models/study-class.model";
+import { Subscription } from "src/app/shared/models/subscription.model";
 import { StorageService } from "src/app/shared/services/storage.service";
 import {
   buildCourse,
   buildFinalGrading,
   buildStudyClass,
+  buildSubscription,
 } from "src/spec-builders";
 import { buildTestModuleMetadata } from "src/spec-helpers";
 import {
@@ -25,6 +27,7 @@ describe("EventsStateService", () => {
   let courseEntries: EventEntry[];
   let studyCourses: Event[];
   let studyCoursesEntries: EventEntry[];
+  let subscriptions: Subscription[];
   let studyClasses: StudyClass[];
   let studyClassEntries: EventEntry[];
   let assessments: StudyClass[];
@@ -197,7 +200,7 @@ describe("EventsStateService", () => {
         Id: 10,
         Designation: "Zentraler Gymnasialer Bildungsgang",
         Leadership: "Jane Doe",
-        StudentCount: 42,
+        StudentCount: 2, // Wrong count, has to be determined via subscriptions
       },
       {
         Id: 20,
@@ -210,11 +213,17 @@ describe("EventsStateService", () => {
       {
         id: 10,
         designation: "Zentraler Gymnasialer Bildungsgang",
-        studentCount: 42,
+        studentCount: 3,
         detailLink: "/events/students/10?returnlink=%2F",
         state: null,
       },
     ];
+
+    subscriptions = [
+      buildSubscription(100, 10, 1),
+      buildSubscription(100, 10, 2),
+      buildSubscription(100, 10, 3),
+    ];
   });
 
   afterEach(() => {
@@ -256,6 +265,7 @@ describe("EventsStateService", () => {
 
       expectCoursesRequest();
       expectStudyCoursesRequest();
+      expectSubscriptionsRequest();
       expectFormativeAssessmentsRequest();
       expectStudyClassesRequest();
 
@@ -308,6 +318,15 @@ describe("EventsStateService", () => {
     httpTestingController.expectOne(url).flush(t.array(Event).encode(response));
   }
 
+  function expectSubscriptionsRequest(response = subscriptions): void {
+    const url =
+      "https://eventotest.api/Subscriptions/?filter.EventId=;10&fields=Id,EventId";
+
+    httpTestingController
+      .expectOne(url)
+      .flush(t.array(Subscription).encode(response));
+  }
+
   function expectFormativeAssessmentsRequest(response = assessments): void {
     const url =
       "https://eventotest.api/StudyClasses/FormativeAssessments?filter.IsActive==true";

src/app/events/services/events-state.service.ts

@@ -20,6 +20,7 @@ import { EventsRestService } from "src/app/shared/services/events-rest.service";
 import { LoadingService } from "src/app/shared/services/loading-service";
 import { StorageService } from "src/app/shared/services/storage.service";
 import { StudyClassesRestService } from "src/app/shared/services/study-classes-rest.service";
+import { SubscriptionsRestService } from "src/app/shared/services/subscriptions-rest.service";
 import { spread } from "src/app/shared/utils/function";
 import { hasRole } from "src/app/shared/utils/roles";
 import { searchEntries } from "src/app/shared/utils/search";
@@ -97,6 +98,7 @@ export class EventsStateService {
     private coursesRestService: CoursesRestService,
     private eventsRestService: EventsRestService,
     private studyClassRestService: StudyClassesRestService,
+    private subscriptionsRestService: SubscriptionsRestService,
     private loadingService: LoadingService,
     private storageService: StorageService,
     private translate: TranslateService,
@@ -153,7 +155,29 @@ export class EventsStateService {
   }
 
   private loadStudyCourses(enabled: boolean): Observable<ReadonlyArray<Event>> {
-    return enabled ? this.eventsRestService.getStudyCourseEvents() : of([]);
+    if (!enabled) return of([]);
+
+    const tokenPayload = this.storageService.getPayload();
+    return this.eventsRestService.getStudyCourseEvents().pipe(
+      map((studyCourses) =>
+        // The user sees only the study courses he/she is leader of
+        studyCourses.filter((studyCourse) =>
+          isStudyCourseLeader(tokenPayload, studyCourse),
+        ),
+      ),
+      switchMap((studyCourses) =>
+        this.subscriptionsRestService
+          .getSubscriptionCountsByEvents(studyCourses.map((s) => s.Id))
+          .pipe(
+            map((subscriptionCounts) =>
+              studyCourses.map((studyCourse) => ({
+                ...studyCourse,
+                StudentCount: subscriptionCounts[studyCourse.Id] ?? 0,
+              })),
+            ),
+          ),
+      ),
+    );
   }
 
   private loadFormativeAssessments(
@@ -216,16 +240,13 @@ export class EventsStateService {
   private createFromStudyCourses(
     studyCourses: ReadonlyArray<Event>,
   ): ReadonlyArray<EventEntry> {
-    const tokenPayload = this.storageService.getPayload();
-    return studyCourses
-      .filter((studyCourse) => isStudyCourseLeader(tokenPayload, studyCourse)) // The user sees only the study courses he/she is leader of
-      .map((studyCourse) => ({
-        id: studyCourse.Id,
-        designation: studyCourse.Designation,
-        detailLink: this.buildStudentsLink(studyCourse.Id),
-        studentCount: studyCourse.StudentCount,
-        state: null,
-      }));
+    return studyCourses.map((studyCourse) => ({
+      id: studyCourse.Id,
+      designation: studyCourse.Designation,
+      detailLink: this.buildStudentsLink(studyCourse.Id),
+      studentCount: studyCourse.StudentCount,
+      state: null,
+    }));
   }
 
   private createFromAssessments(

src/app/shared/services/subscriptions-rest.service.ts

@@ -1,5 +1,6 @@
 import { HttpClient } from "@angular/common/http";
 import { Inject, Injectable } from "@angular/core";
+import * as t from "io-ts";
 import { Observable } from "rxjs";
 import { map, switchMap } from "rxjs/operators";
 import { SETTINGS, Settings } from "../../settings";
@@ -20,33 +21,58 @@ export class SubscriptionsRestService extends RestService<typeof Subscription> {
     personId: number,
     eventIds: number[],
   ): Observable<ReadonlyArray<number>> {
-    return this.getList({
-      params: {
-        "filter.PersonId": `=${personId}`,
-        "filter.EventId": `;${eventIds}`,
-      },
-    }).pipe(
-      switchMap(decodeArray(Identifiable)),
-      map((result) => result.map((i) => i.Id)),
-    );
+    return this.http
+      .get<unknown>(`${this.baseUrl}/`, {
+        params: {
+          "filter.PersonId": `=${personId}`,
+          "filter.EventId": `;${eventIds}`,
+        },
+      })
+      .pipe(
+        switchMap(decodeArray(Identifiable)),
+        map((result) => result.map((i) => i.Id)),
+      );
+  }
+
+  getSubscriptionCountsByEvents(
+    eventIds: ReadonlyArray<number>,
+  ): Observable<Dict<number>> {
+    return this.http
+      .get<unknown>(`${this.baseUrl}/`, {
+        params: {
+          "filter.EventId": `;${eventIds.join(";")}`,
+          fields: ["Id", "EventId"].join(","),
+        },
+      })
+      .pipe(
+        switchMap(decodeArray(t.type({ Id: t.number, EventId: t.number }))),
+        map((subscriptions) =>
+          subscriptions.reduce<Dict<number>>((acc, s) => {
+            acc[s.EventId] = acc[s.EventId] ? acc[s.EventId] + 1 : 1;
+            return acc;
+          }, {}),
+        ),
+      );
   }
 
   getSubscriptionsByCourse(
     eventId: number,
     additionalParams?: Dict<string>,
   ): Observable<ReadonlyArray<Subscription>> {
-    return this.getList({
-      params: {
-        "filter.EventId": `=${eventId}`,
-        ...additionalParams,
-        fields: [
-          "Id",
-          "EventId",
-          "EventDesignation",
-          "PersonId",
-          "Status",
-        ].join(","),
-      },
-    }).pipe(switchMap(decodeArray(Subscription)));
+    return this.http
+      .get<unknown>(`${this.baseUrl}/`, {
+        params: {
+          "filter.EventId": `=${eventId}`,
+          ...additionalParams,
+          fields: [
+            "Id",
+            "EventId",
+            "EventDesignation",
+            "PersonId",
+            "Status",
+          ].join(","),
+        },
+      })
+      .pipe(switchMap(decodeArray(Subscription)));
   }
 }