/**
 * The page that fetches a wallet's bytes — bundled and served by `exportWalletFile`.
 *
 * ── Why a page has to do this at all ─────────────────────────────────────────
 * A wallet's bytes exist only inside the broker iframe: `wallet_get_file()` is an RPC to the
 * wallet the broker holds, so nothing in Node can produce one. This page is the smallest thing
 * that can ask — it opens a NextGraph session the way any application does, and exposes one
 * function.
 *
 * It talks to `@ng-org/web` and to nothing else, deliberately: the machinery around it must
 * stay usable by an application that has never heard of any particular compatibility layer.
 * `init(callback, true, [])` is the shape an application writes; the broker (which loaded this
 * page in its iframe) drives the connection and calls back with the session.
 */

import { ng, init } from "@ng-org/web";

/** What crosses back to Node: base64, because a `Uint8Array` does not survive `evaluate`. */
export interface ExportedWallet {
  readonly walletName: string;
  readonly b64: string;
  readonly len: number;
}

/**
 * The two calls this page needs, named. A narrow local shape rather than the SDK's own types:
 * the wallet functions are not in its published surface at this version, and asserting the two
 * signatures we actually use says more than widening everything.
 */
interface WalletFunctions {
  get_wallets(): Promise<Record<string, unknown> | null | undefined>;
  wallet_get_file(name: string): Promise<Uint8Array | ArrayLike<number>>;
}

const wallet = ng as unknown as WalletFunctions;

const state: { status: string } = { status: "connecting" };

void (async () => {
  try {
    await init(() => {
      state.status = "connected";
    }, true, []);
  } catch (e) {
    state.status = `error: ${e instanceof Error ? e.message : String(e)}`;
  }
})();

(globalThis as unknown as { __ngWalletExport: unknown }).__ngWalletExport = {
  status: (): string => state.status,
  async file(): Promise<ExportedWallet> {
    const wallets = await wallet.get_wallets();
    const walletName = Object.keys(wallets ?? {})[0];
    if (walletName === undefined) throw new Error("no wallet is open in this session");
    const file = await wallet.wallet_get_file(walletName);
    const bytes = file instanceof Uint8Array ? file : new Uint8Array(Array.from(file));
    let binary = "";
    for (let i = 0; i < bytes.length; i++) binary += String.fromCharCode(bytes[i]!);
    return { walletName, b64: btoa(binary), len: bytes.length };
  },
};