/** The base environment variables that are shared between the Admin and Account Consoles. */
export type BaseEnvironment = {
  /**
   * The URL to the root of the Keycloak server, including the path if present, this is **NOT** always equivalent to the URL of the Admin Console.
   * For example, the Keycloak server could be hosted on `auth.example.com` and Admin Console may be hosted on `admin.example.com/some/path`.
   *
   * Note that this URL is normalized not to include a trailing slash, so take this into account when constructing URLs.
   *
   * @see {@link https://www.keycloak.org/server/hostname#_administration_console}
   */
  serverBaseUrl: string;
  /** The identifier of the realm used to authenticate the user. */
  realm: string;
  /** The identifier of the client used to authenticate the user. */
  clientId: string;
  /** The base URL of the resources. */
  resourceUrl: string;
  /** The source URL for the the logo image. */
  logo: string;
  /** The URL to be followed when the logo is clicked. */
  logoUrl: string;
};

/**
 *  Extracts the environment variables from the document, these variables are injected by Keycloak as a script tag, the contents of which can be parsed as JSON. For example:
 *
 *```html
 * <script id="environment" type="application/json">
 *   {
 *     "realm": "master",
 *     "clientId": "security-admin-console",
 *     "etc": "..."
 *   }
 * </script>
 * ```
 */
export function getInjectedEnvironment<T>(): T {
  const element = document.getElementById("environment");
  const contents = element?.textContent;

  if (typeof contents !== "string") {
    throw new Error("Environment variables not found in the document.");
  }

  try {
    return JSON.parse(contents);
  } catch (error) {
    throw new Error("Unable to parse environment variables as JSON.");
  }
}