/**
 * Reading the authenticated staff member off the request.
 *
 * `JwtGuard` (from `@tria-plc/api-common`) puts the decoded IAM user on `request.user`.
 * Sibling controllers reach for `req.user?.id ?? req.user?.sub`, because the shape differs
 * slightly between token versions. This module centralises that so callers get a small,
 * typed value object instead of an `any` bag.
 */

/** Bilingual name as IAM stores it. */
interface ActingUserName {
  en?: string;
  am?: string;
}

/** The slice of `request.user` this app actually reads. */
export interface ActingUserClaims {
  id?: string;
  /** Older tokens carry the subject as `sub` rather than `id`. */
  sub?: string;
  name?: ActingUserName | string | null;
  username?: string;
  email?: string;
}

/** The minimal Express request shape needed to reach the authenticated user. */
export interface RequestWithActingUser {
  user?: ActingUserClaims;
}

/** Who performed an action, resolved once at write time so readers need no IAM lookup. */
export interface ActingUser {
  /** IAM user id. */
  id: string;
  /** Human-readable name, denormalized alongside the id. */
  name: string;
}

/**
 * Resolves the acting staff member from a guarded request.
 *
 * Returns `null` when no user is attached — callers decide what that means. Endpoints behind
 * `@PassengerStaff(...)` always have one, since the guard rejects anonymous requests; system
 * paths (ticketing, cleanup jobs) legitimately have none and record themselves explicitly.
 */
export function resolveActingUser(req: RequestWithActingUser): ActingUser | null {
  const claims = req.user;
  const id = claims?.id ?? claims?.sub;
  if (!id) return null;

  return { id, name: resolveActingUserName(claims) };
}

function resolveActingUserName(claims: ActingUserClaims | undefined): string {
  if (!claims) return 'Unknown';
  const { name } = claims;
  if (typeof name === 'string' && name.trim()) return name.trim();
  if (name && typeof name === 'object') {
    const localized = name.en?.trim() || name.am?.trim();
    if (localized) return localized;
  }
  return claims.username?.trim() || claims.email?.trim() || 'Unknown';
}