core.module.ts

import { provideHttpClient, withInterceptorsFromDi } from '@angular/common/http';
import { ModuleWithProviders, NgModule, inject, provideAppInitializer } from '@angular/core';
import { AuthConfig, OAuthModule, OAuthModuleConfig, OAuthStorage } from 'angular-oauth2-oidc';
import { authAppInitializerFactory } from './auth-app-initializer.factory';
import { authConfig } from './auth-config';
import { AuthGuardWithForcedLogin } from './auth-guard-with-forced-login.service';
import { AuthGuard } from './auth-guard.service';
import { authModuleConfig } from './auth-module-config';
import { AuthService } from './auth.service';

// We need a factory since localStorage is not available at AOT build time
export function storageFactory(): OAuthStorage {
  return localStorage;
}

@NgModule({
  imports: [OAuthModule.forRoot()], providers: [
    AuthService,
    AuthGuard,
    AuthGuardWithForcedLogin,
    provideHttpClient(withInterceptorsFromDi()),
  ]
})
export class CoreModule {
  static forRoot(): ModuleWithProviders<CoreModule> {
    return {
      ngModule: CoreModule,
      providers: [
        provideAppInitializer(() => {
        const initializerFn = (authAppInitializerFactory)(inject(AuthService));
        return initializerFn();
      }),
        { provide: AuthConfig, useValue: authConfig },
        { provide: OAuthModuleConfig, useValue: authModuleConfig },
        { provide: OAuthStorage, useFactory: storageFactory },
      ]
    };
  }

  constructor() {
    const parentModule = inject(CoreModule, { optional: true, skipSelf: true });

    if (parentModule) {
      throw new Error('CoreModule is already loaded. Import it in the AppModule only');
    }
  }
}