async function waitForOperation(operationId: string, deadlineMs = 300_000) {
  const deadline = Date.now() + deadlineMs;

  while (Date.now() < deadline) {
    const { data, metadata } = await blank.operations.get(operationId);

    if (data.status !== "queued" && data.status !== "running") return data;

    const waitSeconds = metadata.retryAfterSeconds ?? 2;
    await new Promise((resolve) => setTimeout(resolve, waitSeconds * 1_000));
  }

  throw new Error(`Operation ${operationId} did not settle in time`);
}

const intent = await blank.transactionIntents.get(intentId);

if (intent.data.status !== "prepared") {
  throw new Error(`Intent is ${intent.data.status}, not prepared`);
}

// Inspect the transaction before signing, then sign the exact bytes.
const signedTransaction = await signBase64Transaction(
  intent.data.serializedTransaction,
  intent.data.expectedSigner
);

const submitted = await blank.transactionIntents.submit(
  intent.data.id,
  { signedTransaction, version: intent.data.version },
  { idempotencyKey: `intent-${intent.data.id}-submit` }
);

console.log(submitted.data.status); // "submitted"

curl -s -X POST \
  "https://api.blank.build/api/v2/transaction-intents/$INTENT_ID/submissions" \
  -H "Authorization: Bearer $BLANK_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: intent-$INTENT_ID-submit" \
  -H 'If-Match: "1"' \
  -d '{"signedTransaction":"'"$SIGNED_TRANSACTION_BASE64"'"}'

async function reconcileIntent(intentId: string, deadlineMs = 120_000) {
  const deadline = Date.now() + deadlineMs;

  while (Date.now() < deadline) {
    const { data, metadata } = await blank.transactionIntents.get(intentId);
    if (data.status === "confirmed") return data.transactionSignature;
    if (data.status === "failed" || data.status === "expired") {
      throw new Error(`Intent ${intentId} ${data.status}: ${data.error?.code}`);
    }
    await new Promise((r) =>
      setTimeout(r, (metadata.retryAfterSeconds ?? 2) * 1_000)
    );
  }

  throw new Error(`Intent ${intentId} did not settle in time`);
}