import { NgModule, APP_INITIALIZER, ModuleWithProviders, Optional, SkipSelf } from '@angular/core';
import { NaStartupService, IStartupConfigResource, NA_STARTUP_CONFIG } from './na-startup.service';
import { throwIfAlreadyLoaded } from '../already-loaded';
import { NaTranslateModule } from '../translate/na-translate.module';

@NgModule({
  imports: [
    NaTranslateModule
  ]
})
export class NaStartupModule {
  constructor(@Optional() @SkipSelf() parentModule: NaStartupModule) {
    throwIfAlreadyLoaded(parentModule, 'NaStartupModule');
  }

  static forRoot(startupConfig: IStartupConfigResource): ModuleWithProviders<NaStartupModule> {
    return {
      ngModule: NaStartupModule,
      providers: [
        { provide: NA_STARTUP_CONFIG, useValue: startupConfig },
        NaStartupService,
        {
          provide: APP_INITIALIZER,
          useFactory: NaStartupServiceFactory,
          deps: [NaStartupService, NA_STARTUP_CONFIG],
          multi: true,
        }
      ]
    };
  }
}

export function NaStartupServiceFactory(startupService: NaStartupService, startupConfig: IStartupConfigResource): Function {
  const initializer = () => {
    return startupService.load(startupConfig);
  };
  return initializer;
}