/** Raised when the OAuth client can't restore a user's session: the grant
 *  was revoked, the refresh token expired, or the client deleted the stored
 *  session after an invalid_grant. Mapped to non-retryable 401 in
 *  parsePdsError so we don't retry-spam a session that won't come back.
 *
 *  Lives in its own module so action test mocks of ./pds.js don't have to
 *  re-export it for `instanceof` checks in delivery.ts to keep working. */
export class PdsSessionMissingError extends Error {
  readonly did: string;
  constructor(did: string, cause?: unknown) {
    super(`OAuth session for ${did} is missing; user must reconnect Airglow.`, { cause });
    this.name = "PdsSessionMissingError";
    this.did = did;
  }
}

/** Raised when a PDS XRPC call answers with a non-2xx status. Carries the
 *  status and the rate-limit reset so callers can park on a 429 until the
 *  PDS says the window resets. The message keeps the `(NNN)` status format
 *  that `parsePdsError` in lib/actions/delivery.ts matches, so existing
 *  callers keep classifying it exactly as before. */
export class PdsHttpError extends Error {
  readonly status: number;
  /** `ratelimit-reset` header as epoch seconds, when the PDS sent one. */
  readonly rateLimitReset: number | null;
  readonly body: string;
  constructor(nsid: string, status: number, body: string, rateLimitReset: number | null) {
    super(`PDS ${nsid} failed (${status}): ${body}`);
    this.name = "PdsHttpError";
    this.status = status;
    this.body = body;
    this.rateLimitReset = rateLimitReset;
  }
}

/** Parse a `ratelimit-reset` header (epoch seconds) into a number, or null. */
export function parseRateLimitReset(header: string | null): number | null {
  if (!header) return null;
  const value = Number(header.trim());
  return Number.isFinite(value) && value > 0 ? value : null;
}