import { Injectable, InjectionToken, Inject } from '@angular/core';
import { BehaviorSubject, Observable } from 'rxjs';
import { HttpConfig } from '../types';

export const HTTP_CONFIG = new InjectionToken('HttpCustomConfig');

@Injectable()
export class MwHttpConfigService {
  private configSubject$: BehaviorSubject<any>;
  private readonly defaultConfig: any;

  constructor(@Inject(HTTP_CONFIG) config: any) {
    // Set the default config from the user provided config (from forRoot)
    this.defaultConfig = config;

    this.configSubject$ = new BehaviorSubject(
      Object.assign({}, this.defaultConfig)
    );
  }

  set config(value) {
    this.setConfig(value);
  }

  get config(): any | Observable<any> {
    return this.getConfig();
  }

  setConfig(value: HttpConfig, opts = { emitEvent: true }): void {
    // Get the value from the behavior subject
    let config = this.configSubject$.getValue();

    // Merge the new config
    config = Object.assign({}, config, value);

    // If emitEvent option is true...
    if (opts.emitEvent === true) {
      // Notify the observers
      this.configSubject$.next(config);
    }
  }

  getConfig(): Observable<any> {
    return this.configSubject$.asObservable();
  }
}