import * as plugins from './smartrx.plugins';
import { Observable, fromEvent } from 'rxjs';
import { Objectmap, Stringmap } from '@pushrocks/lik';
/**
 * bundles an observable with an emitter
 */
export interface ObservableEmitterBundle {
  observable: plugins.rxjs.Observable<any>;
  emitter: plugins.events.EventEmitter;
  event: string;
}

/**
 * manages observables by making sure that only one observable is regsitered per event
 */
export class Observablemap {
  ObservableEmitterBundleObjectmap = new Objectmap<ObservableEmitterBundle>();

  /**
   * creates a new observable if not yet registered for the same event.
   * In case event has been registered before the same observable is returned.
   */
  getObservableForEmitterEvent(emitterArg: plugins.events.EventEmitter, eventArg: string) {
    let existingBundle = this.ObservableEmitterBundleObjectmap.find(bundleArg => {
      return bundleArg.emitter === emitterArg && bundleArg.event === eventArg;
    });
    if (existingBundle) {
      return existingBundle.observable;
    } else {
      let emitterObservable = fromEvent(emitterArg, eventArg);
      this.ObservableEmitterBundleObjectmap.add({
        observable: emitterObservable,
        emitter: emitterArg,
        event: eventArg
      });
      return emitterObservable;
    }
  }
}