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

const CHANNELS: BomChannels[] = [
  'ch:loader',
  'ch:filters',
  'ch:cart',
  'ch:sbo',
  'ch:notification'
];

export class BomMessage {
  name?: string;
  payload: any;
}

export type BomChannels =
  | 'ch:loader'
  | 'ch:filters'
  | 'ch:cart'
  | 'ch:sbo'
  | 'ch:notification';

@Injectable({
  providedIn: 'root'
})
export class MessageBusService {
  private _channelMap: Map<string, Subject<BomMessage>> = new Map<
    string,
    Subject<BomMessage>
  >();

  constructor() {
    for (const channel of CHANNELS) {
      this._initChannel(channel);
    }
  }

  private _initChannel(channel: BomChannels): void {
    this._channelMap.set(channel, new Subject<BomMessage>());
  }

  from(channel: BomChannels): Observable<BomMessage> {
    return this._channelMap.get(channel).asObservable();
  }

  to(channel: BomChannels, message: BomMessage): MessageBusService {
    this._channelMap.get(channel).next(message);
    return this;
  }
}