optimize song usage

src/app/modules/shows/services/show-song-index.service.spec.ts

@@ -0,0 +1,60 @@
+import {TestBed} from '@angular/core/testing';
+import {of} from 'rxjs';
+import {ShowDataService} from './show-data.service';
+import {ShowSongDataService} from './show-song-data.service';
+import {ShowSongIndexService} from './show-song-index.service';
+import {UserSessionService} from '../../../services/user/user-session.service';
+import {User} from '../../../services/user/user';
+
+describe('ShowSongIndexService', () => {
+  let service: ShowSongIndexService;
+  let showDataServiceSpy: jasmine.SpyObj<ShowDataService>;
+  let showSongDataServiceSpy: jasmine.SpyObj<ShowSongDataService>;
+  let sessionSpy: jasmine.SpyObj<UserSessionService>;
+
+  beforeEach(async () => {
+    showDataServiceSpy = jasmine.createSpyObj<ShowDataService>('ShowDataService', ['listRaw$', 'update']);
+    showSongDataServiceSpy = jasmine.createSpyObj<ShowSongDataService>('ShowSongDataService', ['list$']);
+    sessionSpy = jasmine.createSpyObj<UserSessionService>('UserSessionService', ['update$'], {
+      user$: of({id: 'admin-1', name: 'Admin', role: 'admin', chordMode: 'onlyFirst', songUsage: {}} as User),
+    });
+
+    showDataServiceSpy.listRaw$.and.returnValue(of([{id: 'show-1'}, {id: 'show-2'}] as never) as unknown as ReturnType<ShowDataService['listRaw$']>);
+    showDataServiceSpy.update.and.resolveTo();
+    showSongDataServiceSpy.list$.and.callFake((showId: string) => {
+      if (showId === 'show-1') {
+        return of([{songId: 'song-1'}, {songId: 'song-2'}, {songId: 'song-1'}] as never) as never;
+      }
+
+      return of([{songId: 'song-3'}] as never) as never;
+    });
+
+    await TestBed.configureTestingModule({
+      providers: [
+        {provide: ShowDataService, useValue: showDataServiceSpy},
+        {provide: ShowSongDataService, useValue: showSongDataServiceSpy},
+        {provide: UserSessionService, useValue: sessionSpy},
+      ],
+    });
+
+    service = TestBed.inject(ShowSongIndexService);
+  });
+
+  it('should rebuild the distinct songIds index for all shows', async () => {
+    await expectAsync(service.rebuildShowSongIds()).toBeResolvedTo({
+      showsProcessed: 2,
+      showSongsProcessed: 4,
+    });
+
+    expect(showDataServiceSpy.update).toHaveBeenCalledWith('show-1', {songIds: ['song-1', 'song-2']});
+    expect(showDataServiceSpy.update).toHaveBeenCalledWith('show-2', {songIds: ['song-3']});
+  });
+
+  it('should reject index rebuilds for non-admin users', async () => {
+    Object.defineProperty(sessionSpy, 'user$', {
+      value: of({id: 'user-1', name: 'User', role: 'leader', chordMode: 'onlyFirst', songUsage: {}} as User),
+    });
+
+    await expectAsync(service.rebuildShowSongIds()).toBeRejectedWithError('Admin role required to rebuild show song ids.');
+  });
+});