import { Subject, Observable } from 'rxjs';
import { Injectable } from '@angular/core';

@Injectable()
export class TabItemService {
  private tabItemVisibilityEmitted: Subject<any> = new Subject<any>();
  private tabSelectedEmitted: Subject<any> = new Subject<any>();
  private clearLoadFlagEmitted: Subject<any> = new Subject<any>();
  private selectedTab: number;

  /**
   * Clears the loaded flag for every component inside
   * the selected tabitem
   *
   * @memberof TabItemService
   */
  emitClearLoadFlag(): void {
    this.clearLoadFlagEmitted.next(true);
  }

  /**
   * Emit the selection action to trigger the
   * load event every time the component is selected
   *
   * @param {*} data
   * @memberof TabItemService
   */
  emitTabSelectionChanged(data: any): void {
    this.selectedTab = data;
    this.tabSelectedEmitted.next(data);
  }

  /**
   * Subscribe to this to trigger the load event when
   * the tab is selected.
   *
   * @readonly
   * @type {Observable<any>}
   * @memberof TabItemService
   */
  get tabSelectedEvent(): Observable<any> {
    return this.tabSelectedEmitted.asObservable();
  }

  /**
   * Returns the current selected Tab index
   * in case it is changed quickly and not all the loaded
   * events were triggered
   *
   * @readonly
   * @type {number}
   * @memberof TabItemService
   */
  get selectedTabIndex(): number {
    return this.selectedTab;
  }

  /**
   * Sends vibility changed message
   *
   * @param  {any} data
   * @returns any
   */
  emitTabItemVisibilityChanged(data: any): any {
    this.tabItemVisibilityEmitted.next(data);
  }

  /**
   * Gets current subscribers list
   *
   * @returns Observable
   */
  get events(): Observable<any> {
    return this.tabItemVisibilityEmitted.asObservable();
  }

  /**
   * Gets subscriber to clear loaded flag
   * this allows load event to be triggered
   * when the tab is selected
   *
   * @readonly
   * @type {Observable<any>}
   * @memberof TabItemService
   */
  get loadTabCleared(): Observable<any> {
    return this.clearLoadFlagEmitted.asObservable();
  }
}