AI Implementation feature(871): Admin Area System: Database Backup/Restore and Danger Zone (#61)

frontend/src/app/features/scoreboard/scoreboard.store.ts

@@ -1,4 +1,4 @@
-import { DestroyRef, Injectable, computed, inject, signal } from '@angular/core';
+import { DestroyRef, Injectable, computed, effect, inject, signal } from '@angular/core';
 import { ScoreboardApiService } from './scoreboard.service';
 import {
   EventLogRow,
@@ -15,11 +15,13 @@ import {
   parseSolveEventIntoRanking,
 } from './scoreboard.pure';
 import { EventSourceLike } from '../../core/services/event-status.pure';
+import { SystemDataChangeService } from '../../core/services/system-data-change.service';
 
 @Injectable({ providedIn: 'root' })
 export class ScoreboardStore {
   private readonly api: ScoreboardApiService;
   private readonly destroyRef: DestroyRef;
+  private readonly dataChanges: SystemDataChangeService | null;
 
   private readonly _ranking = signal<RankingRow[] | null>(null);
   private readonly _matrix = signal<MatrixView | null>(null);
@@ -35,10 +37,26 @@ export class ScoreboardStore {
   private createSource: (() => EventSourceLike) | null = null;
   private loadAllInFlight: Promise<void> | null = null;
 
-  constructor(api?: ScoreboardApiService, destroyRef?: DestroyRef) {
+  constructor(api?: ScoreboardApiService, destroyRef?: DestroyRef, dataChanges?: SystemDataChangeService) {
     this.api = api ?? inject(ScoreboardApiService);
     this.destroyRef = destroyRef ?? inject(DestroyRef);
+    this.dataChanges = dataChanges ?? null;
     this.destroyRef.onDestroy(() => this.stop());
+    if (!this.dataChanges) return;
+    const lastSeen = { ts: 0 };
+    const dc = this.dataChanges;
+    effect(() => {
+      const evts = dc.events();
+      const latest = evts[evts.length - 1];
+      if (!latest || latest.ts === lastSeen.ts) return;
+      lastSeen.ts = latest.ts;
+      if (latest.kind === 'scores-reset' || latest.kind === 'restore-completed' || latest.kind === 'challenges-wiped') {
+        this._ranking.set(null);
+        this._matrix.set(null);
+        this._eventLog.set(null);
+        this._graph.set(null);
+      }
+    });
   }
 
   readonly ranking = this._ranking.asReadonly();