dspace-angular/src/app/shared/object-collection/object-collection.component.ts

import {
  ChangeDetectorRef,
  Component, ElementRef,
  EventEmitter, Inject,
  Input,
  OnInit,
  Output, PLATFORM_ID,
} from '@angular/core';
import { ActivatedRoute, Router } from '@angular/router';

import { Observable } from 'rxjs';
import { distinctUntilChanged, map } from 'rxjs/operators';

import { RemoteData } from '../../core/data/remote-data';
import { PageInfo } from '../../core/shared/page-info.model';
import { PaginationComponentOptions } from '../pagination/pagination-component-options.model';
import { SortDirection, SortOptions } from '../../core/cache/models/sort-options.model';
import { ListableObject } from './shared/listable-object.model';
import { isEmpty } from '../empty.util';
import { ViewMode } from '../../core/shared/view-mode.model';
import { CollectionElementLinkType } from './collection-element-link.type';
import { PaginatedList } from '../../core/data/paginated-list.model';
import { Context } from '../../core/shared/context.model';
import { setPlaceHolderAttributes } from '../utils/object-list-utils';
import { isPlatformBrowser } from '@angular/common';

/**
 * Component that can render a list of listable objects in different view modes
 */
@Component({
  selector: 'ds-viewable-collection',
  styleUrls: ['./object-collection.component.scss'],
  templateUrl: './object-collection.component.html',
})
export class ObjectCollectionComponent implements OnInit {
  /**
   * The list of listable objects to render in this component
   */
  @Input() objects: RemoteData<PaginatedList<ListableObject>>;

  /**
   * The current pagination configuration
   */
  @Input() config?: PaginationComponentOptions;

  /**
   * The current sorting configuration
   */
  @Input() sortConfig: SortOptions;

  /**
   * Whether or not the list elements have a border or not
   */
  @Input() hasBorder = false;

  /**
   * Whether or not to hide the gear to change the sort and pagination configuration
   */
  @Input() hideGear = false;
  @Input() selectable = false;
  @Input() selectionConfig: {repeatable: boolean, listId: string};
  @Output() deselectObject: EventEmitter<ListableObject> = new EventEmitter<ListableObject>();
  @Output() selectObject: EventEmitter<ListableObject> = new EventEmitter<ListableObject>();

  /**
   * Emit when one of the collection's object has changed.
   */
  @Output() contentChange = new EventEmitter<any>();

  /**
   * Whether or not to add an import button to the object elements
   */
  @Input() importable = false;

  /**
   * The config to use for the import button
   */
  @Input() importConfig: { buttonLabel: string };

  /**
   * Send an import event to the parent component
   */
  @Output() importObject: EventEmitter<ListableObject> = new EventEmitter<ListableObject>();

  /**
   * The link type of the rendered list elements
   */
  @Input() linkType: CollectionElementLinkType;

  /**
   * The context of the rendered list elements
   */
  @Input() context: Context;

  /**
   * Option for hiding the pagination detail
   */
  @Input() hidePaginationDetail = false;

  /**
   * Whether or not the pagination should be rendered as simple previous and next buttons instead of the normal pagination
   */
  @Input() showPaginator = true;

  /**
   * the page info of the list
   */
  pageInfo: Observable<PageInfo>;

  /**
   * An event fired when the page is changed.
   * Event's payload equals to the newly selected page.
   */
  @Output() pageChange: EventEmitter<number> = new EventEmitter<number>();

  /**
   * An event fired when the page wsize is changed.
   * Event's payload equals to the newly selected page size.
   */
  @Output() pageSizeChange: EventEmitter<number> = new EventEmitter<number>();

  /**
   * An event fired when the sort direction is changed.
   * Event's payload equals to the newly selected sort direction.
   */
  @Output() sortDirectionChange: EventEmitter<SortDirection> = new EventEmitter<SortDirection>();

  /**
   * An event fired one of the pagination parameters is changed
   */
  @Output() paginationChange: EventEmitter<SortDirection> = new EventEmitter<any>();

  /**
   * An event fired when the sort field is changed.
   * Event's payload equals to the newly selected sort field.
   */
  @Output() sortFieldChange: EventEmitter<string> = new EventEmitter<string>();

  /**
   * If showPaginator is set to true, emit when the previous button is clicked
   */
  @Output() prev = new EventEmitter<boolean>();

  /**
   * If showPaginator is set to true, emit when the next button is clicked
   */
  @Output() next = new EventEmitter<boolean>();

  /**
   * Emits the current view mode
   */
  currentMode$: Observable<ViewMode>;

  /**
   * The available view modes
   */
  viewModeEnum = ViewMode;

  /**
   * Placeholder class (defined in global-styles)
   */
  placeholderFontClass: string;




  /**
   * @param cdRef
   *    ChangeDetectorRef service provided by Angular.
   * @param route
   *    Route is a singleton service provided by Angular.
   * @param router
   *    Router is a singleton service provided by Angular.
   * @param elementRef
   *    Used only to read DOM for the element width
   */
  constructor(
    private cdRef: ChangeDetectorRef,
    private route: ActivatedRoute,
    private router: Router,
    private elementRef: ElementRef,
    @Inject(PLATFORM_ID) private platformId: Object) {
  }

  ngOnInit(): void {
    this.currentMode$ = this.route
      .queryParams
      .pipe(
        map((params) => isEmpty(params?.view) ? ViewMode.ListElement : params.view),
        distinctUntilChanged()
      );
    if (isPlatformBrowser(this.platformId)) {
      const width = this.elementRef.nativeElement.offsetWidth;
      this.placeholderFontClass = setPlaceHolderAttributes(width);
    } else {
      this.placeholderFontClass = 'hide-placeholder-text';
    }
  }

  /**
   * Updates the page
   * @param event The new page number
   */
  onPageChange(event) {
    this.pageChange.emit(event);
  }
  /**
   * Updates the page size
   * @param event The new page size
   */
  onPageSizeChange(event) {
    this.pageSizeChange.emit(event);
  }
  /**
   * Updates the sort direction
   * @param event The new sort direction
   */
  onSortDirectionChange(event) {
    this.sortDirectionChange.emit(event);
  }
  /**
   * Updates the sort field
   * @param event The new sort field
   */
  onSortFieldChange(event) {
    this.sortFieldChange.emit(event);
  }

  /**
   * Updates the pagination
   * @param event The new pagination
   */
  onPaginationChange(event) {
    this.paginationChange.emit(event);
  }

  /**
   * Go to the previous page
   */
  goPrev() {
      this.prev.emit(true);
  }

 /**
  * Go to the next page
  */
  goNext() {
      this.next.emit(true);
  }

}