import { Injectable } from '@angular/core';
import { Observable, Subject } from 'rxjs';

/**
 * The state of the subscriptions' socket that the app cares about: when it
 * comes back after a cut. Whatever happened meanwhile was not received, so
 * views reload when it does.
 */
@Injectable({ providedIn: 'root' })
export class RealtimeConnection {
  private readonly back = new Subject<void>();

  /** Each time the socket reconnects (not the first time it connects). */
  readonly reconnected$: Observable<void> = this.back.asObservable();

  /** Called by the GraphQL client. */
  reconnected(): void {
    this.back.next();
  }
}