import { HttpClient } from '@angular/common/http';
import { APP_INITIALIZER, InjectionToken } from '@angular/core';
import { lastValueFrom } from 'rxjs';

export interface AppConfig {
  apiBaseUrl: string;
}

export const APP_CONFIG = new InjectionToken<AppConfig>('appConfig');

const _appConfig: AppConfig = {
  apiBaseUrl: '',
};

export function appConfigFactory(http: HttpClient) {
  return (): Promise<void> => {
    return lastValueFrom(http.get<AppConfig>('./config.json')).then(
      (config) => {
        Object.assign(_appConfig, config);
      },
      () => {
        // Keep defaults if config.json is not available (dev mode).
      },
    );
  };
}

export const appConfigProvider = {
  provide: APP_CONFIG,
  useValue: _appConfig,
};

export const appConfigInitProvider = {
  provide: APP_INITIALIZER,
  useFactory: appConfigFactory,
  deps: [HttpClient],
  multi: true,
};

export function getAppConfig(): AppConfig {
  return _appConfig;
}