import { createRailDeckPublicClient } from '@raildeck/frontend-sdk/public';

/**
 * Redeem a guest code and read only its authorised layout with an in-memory token.
 * @param baseUrl - Explicit caller-owned value for this operation.
 * @param guestSessionId - Explicit caller-owned value for this operation.
 * @param code - Explicit caller-owned value for this operation.
 * @param signal - Caller-owned cancellation signal.
 * @returns The scoped decoded snapshot; no token is returned, logged or persisted.
 */
export async function readGuestLayoutOnce(
  baseUrl: string,
  guestSessionId: string,
  code: string,
  signal: AbortSignal,
) {
  let guestToken: string | null = null;
  const client = createRailDeckPublicClient({
    baseUrl,
    getGuestAccessToken: () => guestToken,
  });
  try {
    const redemption = await client.sharing.redeemGuestSession(guestSessionId, { code });
    guestToken = redemption.guestAccessToken.accessToken;
    const { accountId, layoutId } = redemption.guestAccess;
    return await client.currentState.getLayoutSnapshot(accountId, layoutId, {
      signal, timeoutMs: 15_000,
    });
  } finally {
    // Clear the capability after this one read, including cancellation or decode failure.
    guestToken = null;
  }
}