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

@Injectable()
export class AppState {

  private _data = new Subject<Object>();
  private _dataStream$ = this._data.asObservable();

  private _subscriptions: Map<string, Array<Function>> = new Map<string, Array<Function>>();

  constructor() {
    this._dataStream$.subscribe((data) => this._onEvent(data));
  }

  notifyDataChanged(event: any, value: string) {

    // const current:any = this._data[event];
    // if (current !== value) {
    //   this._data[event] = value;

    //   this._data.next({
    //     event: event,
    //     data: this._data[event]
    //   });
    // }
  }

  subscribe(event: string, callback: Function) {
    const subscribers = this._subscriptions.get(event) || [];
    subscribers.push(callback);

    this._subscriptions.set(event, subscribers);
  }

  _onEvent(data: any) {
    const subscribers = this._subscriptions.get(data['event']) || [];

    subscribers.forEach((callback) => {
      callback.call(null, data['data']);
    });
  }
}