const DEFAULT_AUTH_BASE_URL = 'https://accounts-staging.gooyal.ir';
const DEFAULT_API_BASE_URL = 'http://localhost:3000';

const readEnv = (key: string, fallback?: string) => {
  const value = import.meta.env[key as keyof ImportMetaEnv] as string | boolean | undefined;

  if (typeof value === 'string' && value.trim()) {
    return value.trim();
  }

  if (fallback !== undefined) {
    return fallback;
  }

  throw new Error('Authentication client credentials are missing.');
};

const authClientId = readEnv('VITE_AUTH_CLIENT_ID');
const authClientSecret = readEnv('VITE_AUTH_CLIENT_SECRET');

export const env = {
  authClientId,
  authClientSecret,
  authBaseUrl: readEnv('VITE_AUTH_BASE_URL', DEFAULT_AUTH_BASE_URL),
  apiBaseUrl: readEnv('VITE_API_BASE_URL', DEFAULT_API_BASE_URL),
};

export const createBasicAuthHeader = (clientId = env.authClientId, clientSecret = env.authClientSecret) => {
  if (!clientId || !clientSecret) {
    throw new Error('Authentication client credentials are missing.');
  }

  return `Basic ${btoa(`${clientId}:${clientSecret}`)}`;
};