// The path the backend is served under, read from its base URL (SEMAPPS_HOME_URL): `/` when the
// backend owns its origin (http://localhost:3005 locally), `/api/` when it shares the front end's
// origin (https://<host>/api/, the Coolify layout, where one base URL per environment keeps pull
// request previews on a single host). The proxy in front passes the path through unchanged; SemApps
// mounts every route it adds under the base path, except the `/.well-known` ones, which stay at the
// origin root. Festipod's own routes and its public-surface allow-list follow the same split.

const urlJoin = require('url-join');

/** basePathOf(baseUrl) → the base URL's path, always ending with `/` (`/` when it has none or is unset). */
function basePathOf(baseUrl) {
  if (!baseUrl) return '/';
  const { pathname } = new URL(baseUrl);
  return pathname.endsWith('/') ? pathname : `${pathname}/`;
}

/** underBasePath(basePath, path) → the absolute `path` (e.g. `/catalog`) as mounted under `basePath`. */
function underBasePath(basePath, path) {
  return basePath + path.replace(/^\/+/, '');
}

/**
 * requestUri(baseUrl, requestPath) → the absolute URI a request was made to. `requestPath` is the raw
 * path the gateway received (moleculer-web's `originalUrl`), base path included: the base path is
 * taken off before joining it to the base URL, which would otherwise repeat it. Joining (rather than
 * resolving with `new URL`) keeps the base URL exactly as written — host case, explicit port — so the
 * result matches the URIs the backend mints from the same base URL, its actor's first.
 */
function requestUri(baseUrl, requestPath) {
  const basePath = basePathOf(baseUrl);
  const relative = requestPath.startsWith(basePath) ? requestPath.slice(basePath.length - 1) : requestPath;
  return urlJoin(baseUrl, relative);
}

module.exports = { basePathOf, underBasePath, requestUri };