import { createStore } from "./store";

// A one-shot "…and surprise me straight away" request for the Home surface (E24), handed over by
// callers that cannot reach its state — today the command palette's "Meglepetés".
//
// A TOKEN that waits, not an event that fires: Home is a lazy module and is normally NOT mounted
// when the request is made (the palette navigates to it in the same click), so an event would be
// shouted into an empty room. Home takes the token on arrival, which clears it, so walking back to
// Home an hour later does not replay the press — a stale reroll would look like the page deciding
// on its own that the answer you came back for was wrong.
const surprise = createStore(0);

/** Ask Home to reroll its hero as soon as it is on screen. Pair it with a `setPage("home")`. */
export const requestSurprise = (): void => surprise.set((n) => n + 1);

/** The pending token (0 = nothing pending) — the render subscription that wakes Home up. Home only. */
export const useSurpriseRequest = (): number => surprise.use();

/** Take the pending request, clearing it; false when there was nothing to take.
 *
 *  Compare-and-clear rather than a plain read + `consume()`, because a reroll is NOT idempotent — it
 *  spends a `/discover/pick` and steps the tier rotation — and React 18's StrictMode invokes a mount
 *  effect twice with the same render snapshot. Measured in the browser (2026-09-07): the palette's
 *  "Meglepetés" from another module arrived at Home as `start=2`, two picks deep, before the page had
 *  painted once. Checking the LIVE store is what makes the second pass a no-op. */
export const takeSurprise = (): boolean => {
  if (!surprise.get()) return false;
  surprise.set(0);
  return true;
};