import { Inject, Injectable, PLATFORM_ID } from '@angular/core';
import { isPlatformBrowser } from '@angular/common';
import { EMPTY, Observable, Subject, fromEvent, merge } from 'rxjs';
import { filter, map } from 'rxjs';

@Injectable({ providedIn: 'root' })
export class TenantSyncService {
  private readonly storageKey = 'linegestao.tenants.updatedAt';
  private readonly localChangesSubject = new Subject<void>();
  readonly changes$: Observable<void>;

  private readonly isBrowser: boolean;

  constructor(@Inject(PLATFORM_ID) platformId: object) {
    this.isBrowser = isPlatformBrowser(platformId);

    const storageChanges$ = this.isBrowser
      ? fromEvent<StorageEvent>(window, 'storage').pipe(
          filter((event) => event.key === this.storageKey && !!event.newValue),
          map(() => void 0)
        )
      : EMPTY;

    this.changes$ = merge(this.localChangesSubject.asObservable(), storageChanges$);
  }

  notifyTenantsChanged(): void {
    this.localChangesSubject.next();

    if (!this.isBrowser) return;

    try {
      localStorage.setItem(this.storageKey, String(Date.now()));
    } catch {
      // ignore
    }
  }
}