import { CollectionViewer, DataSource } from "@angular/cdk/collections";
import { Package } from "../api/models/package"
import { BehaviorSubject, Observable, retry, map, catchError, of, finalize } from "rxjs";
import { PkgdashService } from "../api/services";

export class PackagesDataSource extends DataSource<Package> {

    private packageSubject = new BehaviorSubject<Package[]>([]);
    private loadingSubject = new BehaviorSubject<boolean>(false);

    public loading$ = this.loadingSubject.asObservable();

    constructor(
      private pkgdashService: PkgdashService
    ) {
      super();
    }

    connect(): Observable<Package[]> {
      return this.packageSubject.asObservable();
    }

    disconnect(): void {
      this.packageSubject.complete();
      this.loadingSubject.complete();
    }

    list(filter = '', sortField = 'name', sortOrder = 'asc', page = 0, limit = 20) {
      this.loadingSubject.next(true);
      this.pkgdashService.packagesList().pipe(
        retry(2),
        map(rsp => rsp.packages || []),
        catchError(this.handleError('getPackages', [])),
        finalize(() => this.loadingSubject.next(false))
      ).subscribe(packages => this.packageSubject.next(packages));
    }
  
    lookup(id: string, filter: string,
                sortDirection: string, pageIndex: number, pageSize: number) {
      
    }  

    private handleError<T>(operation = 'operation', result?: T) {
      return (error: any): Observable<T> => {
  
        // TODO: send the error to remote logging infrastructure
        console.error(error); // log to console instead
  
        // Let the app keep running by returning an empty result.
        return of(result as T);
      };
    };
}