const API = "https://preprod.api.andamio.io/api/v2";
const headers = {
  "Content-Type": "application/json",
  "X-API-Key": APP_API_KEY,
  "Authorization": `Bearer ${userJwt}`,
};

// 1. Build — request unsigned CBOR from the API
const { unsigned_tx } = await fetch(`${API}/tx/course/student/assignment/commit`, {
  method: "POST",
  headers,
  body: JSON.stringify({
    alias: "student1",
    course_id: "abc123...",
    slt_hash: "deadbeef...",
    assignment_info: "sha256:...",
    initiator_data: { usedAddresses: [...], changeAddress: "addr1..." },
  }),
}).then(r => r.json());

// 2. Sign — user approves in their wallet
const signedTx = await wallet.signTx(unsigned_tx);

// 3. Submit — send to Cardano
const txHash = await wallet.submitTx(signedTx);

// 4. Register — tell Andamio to track it
await fetch(`${API}/tx/register`, {
  method: "POST",
  headers,
  body: JSON.stringify({ tx_hash: txHash, tx_type: "assignment_submit" }),
});

// 5. Monitor — wait for DB sync via SSE
const events = new EventSource(`${API}/tx/stream/${txHash}`);
events.addEventListener("complete", (e) => {
  const { final_state } = JSON.parse(e.data);
  events.close();
  if (final_state === "updated") {
    // Success — safe to refetch data
  }
});