optimize song usage

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

@@ -0,0 +1,65 @@
+import {Injectable, inject} from '@angular/core';
+import {firstValueFrom} from 'rxjs';
+import {take} from 'rxjs/operators';
+import {ShowDataService} from './show-data.service';
+import {ShowSongDataService} from './show-song-data.service';
+import {UserSessionService} from '../../../services/user/user-session.service';
+
+export interface ShowSongIndexMigrationResult {
+  showsProcessed: number;
+  showSongsProcessed: number;
+}
+
+export interface MigrationProgress {
+  processed: number;
+  total: number;
+  showId: string;
+  showSongsProcessed: number;
+}
+
+@Injectable({
+  providedIn: 'root',
+})
+export class ShowSongIndexService {
+  private session = inject(UserSessionService);
+  private showDataService = inject(ShowDataService);
+  private showSongDataService = inject(ShowSongDataService);
+
+  public async rebuildShowSongIds(onProgress?: (progress: MigrationProgress) => void): Promise<ShowSongIndexMigrationResult> {
+    const currentUser = await firstValueFrom(this.session.user$.pipe(take(1)));
+    if (!currentUser || !this.hasAdminRole(currentUser.role)) {
+      throw new Error('Admin role required to rebuild show song ids.');
+    }
+
+    const shows = await firstValueFrom(this.showDataService.listRaw$());
+    let showSongsProcessed = 0;
+    let processed = 0;
+
+    for (const show of shows) {
+      const showSongs = await firstValueFrom(this.showSongDataService.list$(show.id));
+      const songIds = [...new Set(showSongs.map(showSong => showSong.songId).filter(Boolean))];
+      showSongsProcessed += showSongs.length;
+      await this.showDataService.update(show.id, {songIds});
+      processed += 1;
+      onProgress?.({
+        processed,
+        total: shows.length,
+        showId: show.id,
+        showSongsProcessed,
+      });
+    }
+
+    return {
+      showsProcessed: shows.length,
+      showSongsProcessed,
+    };
+  }
+
+  private hasAdminRole(role: string | null | undefined): boolean {
+    if (!role) {
+      return false;
+    }
+
+    return role.split(';').includes('admin');
+  }
+}