import { Component, Inject, OnDestroy, OnInit } from '@angular/core';

import { BehaviorSubject, EMPTY, Observable } from 'rxjs';
import { mergeMap, tap } from 'rxjs/operators';

import { ViewMode } from '../../../../core/shared/view-mode.model';
import { RemoteData } from '../../../../core/data/remote-data';
import { WorkflowItem } from '../../../../core/submission/models/workflowitem.model';
import { PoolTask } from '../../../../core/tasks/models/pool-task-object.model';
import { listableObjectComponent } from '../../../object-collection/shared/listable-object/listable-object.decorator';
import { PoolTaskSearchResult } from '../../../object-collection/shared/pool-task-search-result.model';
import {
  SearchResultListElementComponent
} from '../../search-result-list-element/search-result-list-element.component';
import { TruncatableService } from '../../../truncatable/truncatable.service';
import { followLink } from '../../../utils/follow-link-config.model';
import { LinkService } from '../../../../core/cache/builders/link.service';
import { DSONameService } from '../../../../core/breadcrumbs/dso-name.service';
import { APP_CONFIG, AppConfig } from '../../../../../config/app-config.interface';
import { ObjectCacheService } from '../../../../core/cache/object-cache.service';
import { getFirstCompletedRemoteData } from '../../../../core/shared/operators';
import { Item } from '../../../../core/shared/item.model';
import { isNotEmpty, hasValue } from '../../../empty.util';
import { Context } from '../../../../core/shared/context.model';

/**
 * This component renders pool task object for the search result in the list view.
 */
@Component({
  selector: 'ds-pool-search-result-list-element',
  styleUrls: ['../../search-result-list-element/search-result-list-element.component.scss'],
  templateUrl: './pool-search-result-list-element.component.html',
})

@listableObjectComponent(PoolTaskSearchResult, ViewMode.ListElement)
export class PoolSearchResultListElementComponent extends SearchResultListElementComponent<PoolTaskSearchResult, PoolTask>  implements OnInit, OnDestroy {

  /**
   * A boolean representing if to show submitter information
   */
  public showSubmitter = true;

  /**
   * Represents the badge Context
   */
  public badgeContext = Context.MyDSpaceWaitingController;

  /**
   * The item object that belonging to the result object
   */
  public item$: BehaviorSubject<Item> = new BehaviorSubject<Item>(null);

  /**
   * The workflowitem object that belonging to the result object
   */
  public workflowitem$: BehaviorSubject<WorkflowItem> = new BehaviorSubject<WorkflowItem>(null);

  /**
   * The index of this list element
   */
  public index: number;

  /**
   * Display thumbnails if required by configuration
   */
  showThumbnails: boolean;

  constructor(
    protected linkService: LinkService,
    protected truncatableService: TruncatableService,
    public dsoNameService: DSONameService,
    protected objectCache: ObjectCacheService,
    @Inject(APP_CONFIG) protected appConfig: AppConfig
  ) {
    super(truncatableService, dsoNameService, appConfig);
  }

  /**
   * Initialize all instance variables
   */
  ngOnInit() {
    super.ngOnInit();
    this.linkService.resolveLinks(this.dso, followLink('workflowitem', {},
      followLink('item', {}, followLink('bundles')),
      followLink('submitter')
    ), followLink('action'));

    (this.dso.workflowitem as Observable<RemoteData<WorkflowItem>>).pipe(
      getFirstCompletedRemoteData(),
      mergeMap((wfiRD: RemoteData<WorkflowItem>) => {
        if (wfiRD.hasSucceeded) {
          this.workflowitem$.next(wfiRD.payload);
          return (wfiRD.payload.item as Observable<RemoteData<Item>>).pipe(
            getFirstCompletedRemoteData()
          );
        } else {
          return EMPTY;
        }
      }),
      tap((itemRD: RemoteData<Item>) => {
        if (isNotEmpty(itemRD) && itemRD.hasSucceeded) {
          this.item$.next(itemRD.payload);
        }
      })
    ).subscribe();

    this.showThumbnails = this.appConfig.browseBy.showThumbnails;
  }

  ngOnDestroy() {
    // This ensures the object is removed from cache, when action is performed on task
    if (hasValue(this.dso)) {
      this.objectCache.remove(this.dso._links.workflowitem.href);
    }
  }
}
