optimize firebase reads

src/app/services/config.service.ts

@@ -2,13 +2,21 @@ import {Injectable} from '@angular/core';
 import {DbService} from './db.service';
 import {firstValueFrom, Observable} from 'rxjs';
 import {Config} from './config';
+import {shareReplay} from 'rxjs/operators';
 
 @Injectable({
   providedIn: 'root',
 })
 export class ConfigService {
+  private readonly config$ = this.db.doc$<Config>('global/config').pipe(
+    shareReplay({
+      bufferSize: 1,
+      refCount: true,
+    })
+  );
+
   public constructor(private db: DbService) {}
 
-  public get$ = (): Observable<Config | null> => this.db.doc$<Config>('global/config');
+  public get$ = (): Observable<Config | null> => this.config$;
   public get = (): Promise<Config | null> => firstValueFrom(this.get$());
 }

src/app/services/global-settings.service.ts

@@ -8,15 +8,17 @@ import {shareReplay} from 'rxjs/operators';
   providedIn: 'root',
 })
 export class GlobalSettingsService {
+  private readonly settings$ = this.db.doc$<GlobalSettings>('global/static').pipe(
+    shareReplay({
+      bufferSize: 1,
+      refCount: true,
+    })
+  );
+
   public constructor(private db: DbService) {}
 
   public get get$(): Observable<GlobalSettings | null> {
-    return this.db.doc$<GlobalSettings>('global/static').pipe(
-      shareReplay({
-        bufferSize: 1,
-        refCount: true,
-      })
-    );
+    return this.settings$;
   }
 
   public async set(data: Partial<GlobalSettings>): Promise<void> {

src/app/services/user/user.service.ts

@@ -1,13 +1,20 @@
 import {Injectable} from '@angular/core';
 import {AngularFireAuth} from '@angular/fire/compat/auth';
 import {BehaviorSubject, firstValueFrom, Observable} from 'rxjs';
-import {filter, map, shareReplay, switchMap, tap} from 'rxjs/operators';
+import {filter, map, shareReplay, switchMap, take, tap} from 'rxjs/operators';
 import {User} from './user';
 import {DbService} from '../db.service';
 import {environment} from '../../../environments/environment';
 import {Router} from '@angular/router';
 import {ShowDataService} from '../../modules/shows/services/show-data.service';
 import {ShowSongDataService} from '../../modules/shows/services/show-song-data.service';
+import firebase from 'firebase/compat/app';
+
+export interface SongUsageMigrationResult {
+  usersProcessed: number;
+  showsProcessed: number;
+  showSongsProcessed: number;
+}
 
 @Injectable({
   providedIn: 'root',
@@ -51,6 +58,7 @@ export class UserService {
     const aUser = await this.afAuth.signInWithEmailAndPassword(user, password);
     if (!aUser.user) return null;
     const dUser = await this.readUser(aUser.user.uid);
+    if (!dUser) return null;
     await this.initSongUsage(dUser);
     this.iUser$.next(dUser);
     this.iUserId$.next(aUser.user.uid);
@@ -81,8 +89,9 @@ export class UserService {
     const aUser = await this.afAuth.createUserWithEmailAndPassword(user, password);
     if (!aUser.user) return;
     const userId = aUser.user.uid;
-    await this.db.doc('users/' + userId).set({name, chordMode: 'onlyFirst'});
+    await this.db.doc('users/' + userId).set({name, chordMode: 'onlyFirst', songUsage: {}});
     const dUser = await this.readUser(aUser.user.uid);
+    if (!dUser) return;
     this.iUser$.next(dUser);
     await this.router.navigateByUrl('/brand/new-user');
   }
@@ -90,35 +99,71 @@ export class UserService {
   public incSongCount = (songId: string) => this.updateSongUsage(songId, 1);
   public decSongCount = (songId: string) => this.updateSongUsage(songId, -1);
 
+  public async rebuildSongUsage(): Promise<SongUsageMigrationResult> {
+    const currentUser = await firstValueFrom(this.iUser$.pipe(take(1)));
+    if (!currentUser || !this.hasAdminRole(currentUser.role)) {
+      throw new Error('Admin role required to rebuild songUsage.');
+    }
+
+    const [users, shows] = await Promise.all([firstValueFrom(this.users$), firstValueFrom(this.showDataService.listRaw$())]);
+    const songUsageByUserId: Record<string, Record<string, number>> = {};
+
+    users.forEach(user => {
+      songUsageByUserId[user.id] = {};
+    });
+
+    let showSongsProcessed = 0;
+    for (const show of shows) {
+      const ownerId = show.owner;
+      if (!ownerId) {
+        continue;
+      }
+
+      const showSongs = await firstValueFrom(this.showSongDataService.list$(show.id));
+      const usage = songUsageByUserId[ownerId] ?? {};
+      songUsageByUserId[ownerId] = usage;
+
+      for (const showSong of showSongs) {
+        showSongsProcessed += 1;
+        usage[showSong.songId] = (usage[showSong.songId] ?? 0) + 1;
+      }
+    }
+
+    await Promise.all(
+      users.map(user =>
+        this.update$(user.id, {
+          songUsage: songUsageByUserId[user.id] ?? {},
+        })
+      )
+    );
+
+    return {
+      usersProcessed: users.length,
+      showsProcessed: shows.length,
+      showSongsProcessed,
+    };
+  }
+
   private async updateSongUsage(songId: string, direction: number) {
     const user = await firstValueFrom(this.user$);
     if (!user) return null;
 
-    const songUsage = user?.songUsage ?? {};
-    let currentSongCount = songUsage[songId];
-    if (currentSongCount === null || currentSongCount === undefined) currentSongCount = 0;
-    else currentSongCount = currentSongCount + direction;
-    songUsage[songId] = Math.max(0, currentSongCount);
-
-    await this.update$(user.id, {songUsage});
+    await this.db.doc<User>('users/' + user.id).update({
+      [`songUsage.${songId}`]: firebase.firestore.FieldValue.increment(direction),
+    });
   }
 
   private async initSongUsage(user: User) {
     if (user.songUsage) return;
+    await this.update$(user.id, {songUsage: {}});
+  }
 
-    const shows = await firstValueFrom(this.showDataService.listRaw$());
-    const myShows = shows.filter(show => show.owner === user.id);
-    const songUsage: {[songId: string]: number} = {};
-    for (const show of myShows) {
-      const showSongs = await firstValueFrom(this.showSongDataService.list$(show.id));
-      for (const showSong of showSongs) {
-        const current = songUsage[showSong.songId] ?? 0;
-        songUsage[showSong.songId] = current + 1;
-      }
+  private hasAdminRole(role: string | null | undefined): boolean {
+    if (!role) {
+      return false;
     }
 
-    await this.update$(user.id, {songUsage});
-    return;
+    return role.split(';').includes('admin');
   }
 
   private readUser$ = (uid: string) => this.db.doc$<User>('users/' + uid);