import { Component, OnDestroy, OnInit, inject, signal } from '@angular/core';
import { MatProgressSpinnerModule } from '@angular/material/progress-spinner';
import { Observable, Subscription } from 'rxjs';
import { PublicationListComponent } from '../../components/publication-list/publication-list.component';
import { Publication } from '../../core/rest-services/publications/model/publication';
import { HomeService } from './home.service';
import { CommonModule } from '@angular/common';

@Component({
  selector: 'app-home',
  standalone: true,
  imports: [
    CommonModule,
    MatProgressSpinnerModule,
    PublicationListComponent
  ],
  templateUrl: './home.component.html',
  styleUrl: './home.component.scss',
  providers: [HomeService]
})
export class HomeComponent implements OnInit, OnDestroy {
  private homeService = inject(HomeService);
  private isLoadingSubscription?: Subscription;
  private publicationsSubscription?: Subscription;
  isLoading = signal(false);
  publicationsIsEmpty = signal(true);

  get publications$(): Observable<Publication[]> {
    return this.homeService.publications$;
  }
  
  ngOnInit(): void {
    this.isLoadingSubscription = this.homeService.isLoading$
      .subscribe(isLoading => this.isLoading.set(isLoading));
    this.publicationsSubscription = this.homeService.publications$
      .subscribe(publications => this.publicationsIsEmpty.set(publications.length > 0));
    this.homeService.startLatestPublicationsRetrieving();
  }

  ngOnDestroy(): void {
    this.isLoadingSubscription?.unsubscribe();
    this.publicationsSubscription?.unsubscribe();
  }
}