import { Component, Input, OnInit } from '@angular/core';
import { BehaviorSubject, Observable } from 'rxjs';
import { BitstreamDataService } from '../../../../core/data/bitstream-data.service';

import { Bitstream } from '../../../../core/shared/bitstream.model';
import { Item } from '../../../../core/shared/item.model';
import { followLink } from '../../../../shared/utils/follow-link-config.model';
import { FileSectionComponent } from '../../../simple/field-components/file-section/file-section.component';
import { PaginationComponentOptions } from '../../../../shared/pagination/pagination-component-options.model';
import { PaginatedList } from '../../../../core/data/paginated-list.model';
import { RemoteData } from '../../../../core/data/remote-data';
import { switchMap, tap } from 'rxjs/operators';
import { NotificationsService } from '../../../../shared/notifications/notifications.service';
import { TranslateService } from '@ngx-translate/core';
import { hasValue, isEmpty } from '../../../../shared/empty.util';

/**
 * This component renders the file section of the item
 * inside a 'ds-metadata-field-wrapper' component.
 */

@Component({
  selector: 'ds-item-page-full-file-section',
  styleUrls: ['./full-file-section.component.scss'],
  templateUrl: './full-file-section.component.html'
})
export class FullFileSectionComponent extends FileSectionComponent implements OnInit {

  @Input() item: Item;

  label: string;

  originals$: Observable<RemoteData<PaginatedList<Bitstream>>>;
  licenses$: Observable<RemoteData<PaginatedList<Bitstream>>>;

  pageSize = 5;
  originalOptions = Object.assign(new PaginationComponentOptions(), {
    id: 'original-bitstreams-options',
    currentPage: 1,
    pageSize: this.pageSize
  });
  originalCurrentPage$ = new BehaviorSubject<number>(1);

  licenseOptions = Object.assign(new PaginationComponentOptions(), {
    id: 'license-bitstreams-options',
    currentPage: 1,
    pageSize: this.pageSize
  });
  licenseCurrentPage$ = new BehaviorSubject<number>(1);

  constructor(
    bitstreamDataService: BitstreamDataService,
    protected notificationsService: NotificationsService,
    protected translateService: TranslateService
  ) {
    super(bitstreamDataService, notificationsService, translateService);
  }

  ngOnInit(): void {
    this.initialize();
  }

  initialize(): void {
    this.originals$ = this.originalCurrentPage$.pipe(
      switchMap((pageNumber: number) => this.bitstreamDataService.findAllByItemAndBundleName(
        this.item,
        'ORIGINAL',
        {elementsPerPage: this.pageSize, currentPage: pageNumber},
        true,
        true,
        followLink('format')
      )),
      tap((rd: RemoteData<PaginatedList<Bitstream>>) => {
          if (hasValue(rd.errorMessage)) {
            this.notificationsService.error(this.translateService.get('file-section.error.header'), `${rd.statusCode} ${rd.errorMessage}`);
          }
        }
      )
    );

    this.licenses$ = this.licenseCurrentPage$.pipe(
      switchMap((pageNumber: number) => this.bitstreamDataService.findAllByItemAndBundleName(
        this.item,
        'LICENSE',
        {elementsPerPage: this.pageSize, currentPage: pageNumber},
        true,
        true,
        followLink('format')
      )),
      tap((rd: RemoteData<PaginatedList<Bitstream>>) => {
          if (hasValue(rd.errorMessage)) {
            this.notificationsService.error(this.translateService.get('file-section.error.header'), `${rd.statusCode} ${rd.errorMessage}`);
          }
        }
      )
    );

  }

  /**
   * Update the current page for the original bundle bitstreams
   * @param page
   */
  switchOriginalPage(page: number) {
    this.originalOptions.currentPage = page;
    this.originalCurrentPage$.next(page);
  }

  /**
   * Update the current page for the license bundle bitstreams
   * @param page
   */
  switchLicensePage(page: number) {
    this.licenseOptions.currentPage = page;
    this.licenseCurrentPage$.next(page);
  }

  hasValuesInBundle(bundle: PaginatedList<Bitstream>) {
    return hasValue(bundle) && !isEmpty(bundle.page);
  }
}