Owner Signing

import { createAgentApi, createGrantCredential } from "@near-intents-agent-api/sdk";
import type { GenerateIntentResponse, SignedData } from "@near-intents-agent-api/sdk";

const api = createAgentApi({ apiKey: process.env.NEAR_INTENTS_AGENT_API_KEY! });

// Owner intents waiting for a signature, by correlation_id. Use your database in production.
const pending = new Map<string, { userId: string; type: GenerateIntentResponse["type"] }>();

// Route 1: the signed-in owner's browser asks for a grant. Check first that userId owns agentId.
export async function generateGrant(userId: string, agentId: string, sessionId: string) {
  const { token, commitment } = createGrantCredential(); // store `token` encrypted, never send it out
  const generated = await api.generateIntent(
    {
      type: "grant_issue",
      agent_id: agentId,
      label: "Trading assistant",
      credential: commitment,
      expires_at: new Date(Date.now() + 30 * 24 * 60 * 60 * 1000).toISOString(),
    },
    { idempotencyKey: `grant-${agentId}-${sessionId}` },
  );
  pending.set(generated.correlation_id, { userId, type: generated.type });
  // Only these three go to the browser.
  return { correlation_id: generated.correlation_id, intent: generated.intent, preview: generated.preview };
}

// Route 2: the browser sends back the wallet's output.
export async function submitSigned(userId: string, body: { correlation_id: string; signed_data: SignedData }) {
  const stored = pending.get(body.correlation_id);
  if (!stored || stored.userId !== userId) throw new Error("not this user's intent");
  await api.submitIntent({
    type: stored.type,
    correlation_id: body.correlation_id,
    signed_data: body.signed_data,
  });
  return api.getStatus(body.correlation_id, { waitMs: 30_000 });
}

// signWithWallet is defined below, under "What the owner signs".
const generated = await fetch("/api/owner-intents/grant", { method: "POST" }).then((r) => r.json());

showPreview(generated.preview); // your UI: what the owner is agreeing to
const signed_data = await signWithWallet(generated.intent);

await fetch("/api/owner-intents/submit", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({ correlation_id: generated.correlation_id, signed_data }),
});

import type { GenerateIntentResponse, SignedData } from "@near-intents-agent-api/sdk";

// wallet, walletClient, account and startAuthentication come from your own wallet
// integration: a NEAR wallet selector, viem and @simplewebauthn/browser. The SDK has no signers.
export async function signWithWallet(intent: GenerateIntentResponse["intent"]): Promise<SignedData> {
  switch (intent.standard) {
    case "nep366": {
      const { signedDelegateActions } = await wallet.signDelegateActions({ delegateActions: [intent.payload] });
      return { ...intent, signed_delegate: signedDelegateActions[0] };
    }
    case "nep413": {
      const nonce = Uint8Array.from(atob(intent.payload.nonce), (c) => c.charCodeAt(0));
      const { publicKey, signature } = await wallet.signMessage({ ...intent.payload, nonce });
      return { ...intent, public_key: publicKey, signature };
    }
    case "eip712":
      return { ...intent, signature: await walletClient.signTypedData({ account, ...intent.payload }) };
    case "webauthn":
      return { ...intent, credential: await startAuthentication({ optionsJSON: intent.payload }) };
  }
}