import { Injectable } from '@angular/core';
import { LoaderComponent } from './loader.component';

/** The loader service registers promises */
@Injectable()
export class LoaderService {
  /** The global loader that should be used if not loader is passed to wait. */
  loader: LoaderComponent;

  /** Sets a global loader that can be triggered without having the reference. */
  use(loader: LoaderComponent) {
    this.loader = loader;
  }

  /** Tells the given loader to wait for the given promise. If no loader is given, the global loader is used (if set)*/
  wait(promise: Promise<any>, loader: LoaderComponent = this.loader) {
    if (!loader || !promise) {
      console.warn('cannot trigger loader: no promise or loader given');
      return;
    }
    return loader.wait(promise);
  }
}