import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable, catchError, map, of, shareReplay } from 'rxjs';
import { WidgetManifestEntry, WidgetManifestFile } from '../contracts/widget-manifest.contract';

@Injectable({ providedIn: 'root' })
export class WidgetManifestService {
  private readonly manifestUrl = '/assets/mock/bootstrap/widget-manifest.json';
  private manifest$?: Observable<WidgetManifestFile>;

  constructor(private readonly http: HttpClient) {}

  getManifest(): Observable<WidgetManifestFile> {
    if (!this.manifest$) {
      this.manifest$ = this.http.get<WidgetManifestFile>(this.manifestUrl).pipe(
        shareReplay({ bufferSize: 1, refCount: true }),
        catchError(() => {
          this.manifest$ = undefined;
          return of({ widgets: [] });
        })
      );
    }

    return this.manifest$;
  }

  getWidgets(): Observable<WidgetManifestEntry[]> {
    return this.getManifest().pipe(map((manifest) => manifest.widgets ?? []));
  }

  getWidget(type: string): Observable<WidgetManifestEntry | undefined> {
    return this.getWidgets().pipe(map((widgets) => widgets.find((widget) => widget.type === type)));
  }
}