import { ChangeDetectionStrategy, Component, effect, inject, signal, untracked } from '@angular/core';
import { CommonModule } from '@angular/common';
import { RouterLink } from '@angular/router';
import { YoutubeApiService } from '../../services/youtube-api.service';
import { Video } from '../../models/video.model';
import { InstanceService } from '../../services/instance.service';
import { InfiniteAnchorComponent } from '../shared/infinite-anchor/infinite-anchor.component';
import { formatRelativeFr } from '../../utils/date.util';
import { TranslatePipe } from '../../pipes/translate.pipe';
import { LikeButtonComponent } from '../shared/components/like-button/like-button.component';

@Component({
  selector: 'app-home',
  templateUrl: './home.component.html',
  standalone: true,
  changeDetection: ChangeDetectionStrategy.OnPush,
  imports: [
    CommonModule, 
    RouterLink, 
    InfiniteAnchorComponent, 
    TranslatePipe,
    LikeButtonComponent
  ]
})
export class HomeComponent {
  private apiService = inject(YoutubeApiService);
  private instances = inject(InstanceService);
  
  trendingVideos = signal<Video[]>([]);
  loading = signal(true);
  busyMore = signal(false);
  nextCursor = signal<string | null>(null);
  notice = signal<string | null>(null);

  constructor() {
    this.reloadTrending();
    // React to provider/region changes to refresh trending automatically
    effect(() => {
      // Rerun when these signals change
      const provider = this.instances.selectedProvider();
      const region = this.instances.region();
      const ptInstance = this.instances.activePeerTubeInstance();

      // Reset notice and trigger reload, but without re-triggering the effect
      untracked(() => {
        this.notice.set(null);
        this.reloadTrending();
      });
    }, { allowSignalWrites: true });
  }

  reloadTrending() {
    const readiness = this.instances.getProviderReadiness();
    if (!readiness.ready) {
      this.notice.set(readiness.reason || 'Le provider sélectionné n\'est pas prêt.');
      this.trendingVideos.set([]);
      this.nextCursor.set(null);
      this.loading.set(false);
      return;
    }
    this.loading.set(true);
    this.trendingVideos.set([]);
    this.nextCursor.set(null);
    // Important: reset busy flag so a previous pending state doesn't block new loads
    this.busyMore.set(false);
    this.fetchNextPage();
  }

  fetchNextPage() {
    if (this.busyMore()) return;
    const readiness = this.instances.getProviderReadiness();
    if (!readiness.ready) {
      if (!this.notice()) this.notice.set(readiness.reason || 'Le provider sélectionné n\'est pas prêt.');
      return;
    }
    this.busyMore.set(true);
    this.apiService.getTrendingPage(this.nextCursor()).subscribe(res => {
      const merged = [...this.trendingVideos(), ...res.items];
      this.trendingVideos.set(merged);
      this.nextCursor.set(res.nextCursor || null);
      this.busyMore.set(false);
      this.loading.set(false);
      const provider = this.instances.selectedProvider();
      if (merged.length === 0 && !this.notice()) {
        const readiness2 = this.instances.getProviderReadiness();
        if (!readiness2.ready) {
          this.notice.set(readiness2.reason || 'Le provider sélectionné n\'est pas prêt.');
        } else if (provider === 'youtube') {
          this.notice.set('Aucune vidéo tendance YouTube chargée. Vérifiez que votre YOUTUBE_API_KEY est valide et que les restrictions HTTP referrer incluent http://localhost:4200/*.');
        } else if (provider === 'peertube') {
          const inst = this.instances.activePeerTubeInstance();
          this.notice.set(`PeerTube: les vidéos ne sont pas disponibles depuis l'instance "${inst}" pour le moment. Essayez une autre instance dans l'en-tête.`);
        } else if (provider === 'rumble') {
          const label = this.instances.selectedProviderLabel();
          this.notice.set(`Les vidéos ne sont pas disponibles pour le provider "${label}" pour le moment. Réessayez plus tard ou choisissez un autre provider.`);
        }
      }
    });
  }

  formatViews(views: number): string {
    if (views >= 1_000_000_000) {
      return (views / 1_000_000_000).toFixed(1) + 'B';
    }
    if (views >= 1_000_000) {
      return (views / 1_000_000).toFixed(1) + 'M';
    }
    if (views >= 1_000) {
      return (views / 1_000).toFixed(1) + 'K';
    }
    return views.toString();
  }

  // Relative date for cards (e.g., "il y a 2 heures")
  formatRelative(dateIso?: string): string {
    if (!dateIso) return '';
    return formatRelativeFr(dateIso);
  }

  // Build query params for Watch page (provider + optional odysee slug)
  watchQueryParams(v: Video): Record<string, any> | null {
    const p = this.instances.selectedProvider();
    const qp: any = { p };
    if (p === 'odysee' && v.url?.startsWith('https://odysee.com/')) {
      let slug = v.url.substring('https://odysee.com/'.length);
      if (slug.startsWith('/')) slug = slug.slice(1);
      qp.slug = slug;
    }
    return qp;
  }
}