import { Injectable } from '@angular/core';
import { Observable, Subject } from 'rxjs';
import { DraggableDirective } from '../directives/draggable.directive';

/**
 * Service to transfer data when executing a drag and drop action in the ListBox.
 *
 * @export
 * @class DragDropService
 */
@Injectable({
  providedIn: 'root',
})
export class DragDropService {
  /**
   * Current draggable being dragged
   *
   * @private
   * @type {DraggableDirective}
   * @memberof DragDropService
   */
  public currentDragging: DraggableDirective;

  /**
   * Subject to handle data transfer when executing a drag and drop action.
   *
   * @private
   * @type {Subject<any>}
   * @memberof DragDropService
   */
  private dataTransfer: Subject<any> = new Subject<any>();

  /**
   * Observable to get if theres is any data.
   *
   * @readonly
   * @type {Observable<any>}
   * @memberof DragDropService
   */
  get dataTransferObservable(): Observable<any> {
    return this.dataTransfer.asObservable();
  }

  /**
   * Notify theres is new data to transfer
   *
   * @param {any} value
   * @memberof DragDropService
   */
  notifyDataTransfer(value: any): void {
    this.dataTransfer.next(value);
  }
}