Track an Escrow Fill

import "dotenv/config";

const DFLOW_TRADE_API_URL = process.env.DFLOW_TRADE_API_URL ?? "https://dev-quote-api.dflow.net";
const DFLOW_API_KEY = process.env.DFLOW_API_KEY; // optional; not needed for dev endpoints

const headers: HeadersInit = {};
if (DFLOW_API_KEY) headers["x-api-key"] = DFLOW_API_KEY;

// From the transaction that opened the escrow fill and its order response.
const openingSignature = "OPENING_SIGNATURE";
const lastValidBlockHeight = Number("LAST_VALID_BLOCK_HEIGHT");
if (openingSignature === "OPENING_SIGNATURE" || Number.isNaN(lastValidBlockHeight)) {
  throw new Error("Replace the placeholders with the escrow fill's opening signature and lastValidBlockHeight.");
}

type Fill = {
  signature: string;
  inputMint: string;
  inAmount: string;
  outputMint: string;
  outAmount: string;
};
type Revert = { signature: string; mint: string; amount: string };
type OrderStatusResponse = {
  status: "pending" | "expired" | "failed" | "open" | "pendingClose" | "closed";
  inAmount: string;
  outAmount: string;
  fills?: Fill[];
  reverts?: Revert[];
};

const TERMINAL_STATUSES = new Set(["expired", "failed", "closed"]);

async function waitForEscrowFill(
  signature: string,
  lastValidBlockHeight: number
): Promise<OrderStatusResponse> {
  let delayMs = 1_000;

  while (true) {
    const params = new URLSearchParams({
      signature,
      lastValidBlockHeight: lastValidBlockHeight.toString(),
    });
    const response = await fetch(`${DFLOW_TRADE_API_URL}/order-status?${params}`, { headers });

    if (response.ok) {
      const status: OrderStatusResponse = await response.json();
      console.log("Status:", status.status);
      if (TERMINAL_STATUSES.has(status.status)) return status;
    } else if (response.status !== 429 && response.status < 500) {
      throw new Error(`GET /order-status failed: ${response.status} ${await response.text()}`);
    }

    await new Promise((resolve) => setTimeout(resolve, delayMs));
    delayMs = Math.min(delayMs * 2, 10_000);
  }
}

const result = await waitForEscrowFill(openingSignature, lastValidBlockHeight);

switch (result.status) {
  case "expired":
    console.log("The opening transaction never landed. Call the order endpoint again.");
    break;
  case "failed":
    console.log("The opening transaction failed. The user paid only the network fee.");
    break;
  case "closed":
    console.log({ fills: result.fills ?? [], reverts: result.reverts ?? [] });
    break;
}

function addTo(totals: Map<string, bigint>, mint: string, amount: string) {
  totals.set(mint, (totals.get(mint) ?? 0n) + BigInt(amount));
}

const filledIn = new Map<string, bigint>();
const filledOut = new Map<string, bigint>();
const returned = new Map<string, bigint>();

for (const fill of result.fills ?? []) {
  addTo(filledIn, fill.inputMint, fill.inAmount);
  addTo(filledOut, fill.outputMint, fill.outAmount);
}
for (const revert of result.reverts ?? []) {
  addTo(returned, revert.mint, revert.amount);
}

const outcome = !result.fills?.length
  ? "not filled, input returned"
  : result.reverts?.length
    ? "filled with input returned"
    : "filled";

console.log({ outcome, filledIn, filledOut, returned });