Add Withdraw Token Route/Tool (#3)

Author: bh2smith

.env.example

@@ -1,4 +1,4 @@
-BITTE_API_KEY=''
-NEAR_PK=''
-NEXT_PUBLIC_ACCOUNT_ID=''
-CRON_SECRET=''
+BITTE_API_KEY=
+NEAR_PK=
+NEXT_PUBLIC_ACCOUNT_ID=
+CRON_SECRET=

app/api/withdraw/route.ts

@@ -0,0 +1,76 @@
+import { NextRequest, NextResponse } from "next/server";
+import { BALANCE_UPDATE_DELAY, USDC_CONTRACT } from "@/lib/utils";
+import {
+  initializeNearAccount,
+  depositUSDC,
+  getUSDCBalance,
+  intentsUSDCBalance,
+  withdrawUSDC,
+  withdrawToken,
+  intentsBalance,
+} from "@/lib/near";
+import { formatUnits } from "@/lib/viem";
+
+const bigIntMin = (a: bigint, b: bigint) => (a < b ? a : b);
+const ZERO = BigInt(0);
+
+export async function GET(request: NextRequest) {
+  try {
+    if (process.env.CRON_SECRET) {
+      const authHeader = request.headers.get("Authorization");
+      if (authHeader !== `Bearer ${process.env.CRON_SECRET}`) {
+        return NextResponse.json({ error: "Unauthorized" }, { status: 401 });
+      }
+    }
+
+    const { searchParams } = new URL(request.url);
+    const withdrawStr = searchParams.get("amount");
+    if (!withdrawStr) {
+      return NextResponse.json(
+        { error: "unspecified amount" },
+        { status: 400 },
+      );
+    }
+    const token = searchParams.get("token") || USDC_CONTRACT;
+
+    const accountId = process.env.NEXT_PUBLIC_ACCOUNT_ID;
+    if (!accountId) {
+      return NextResponse.json(
+        { error: "accountId is not configured" },
+        { status: 500 },
+      );
+    }
+
+    const requestedWithdrawAmount = BigInt(withdrawStr);
+
+    const account = await initializeNearAccount(accountId);
+
+    const usdcBalance = await intentsBalance(account, token);
+    let withdrawAmount = bigIntMin(requestedWithdrawAmount, usdcBalance);
+
+    if (withdrawAmount == ZERO) {
+      return NextResponse.json(
+        { message: "Nothing to withdraw" },
+        { status: 200 },
+      );
+    }
+
+    const tx = await withdrawToken(account, token, withdrawAmount);
+
+    await new Promise((resolve) => setTimeout(resolve, BALANCE_UPDATE_DELAY));
+
+    const uiAmount = formatUnits(withdrawAmount, 6);
+
+    return NextResponse.json({
+      message: `Successfully withdrew $${uiAmount} USDC`,
+      transactionHash: tx.transaction.hash,
+      amount: uiAmount,
+    });
+  } catch (error) {
+    console.error("Error in deposit endpoint:", error);
+    return NextResponse.json(
+      { error: "Failed to process deposit request" },
+      { status: 500 },
+    );
+  }
+}

lib/near.ts

@@ -1,9 +1,17 @@
 import { actionCreators } from "@near-js/transactions";
 import { Account, KeyPair, keyStores, Near } from "near-api-js";
 import type { Quote } from "./types";
-import { INTENTS_CONTRACT_ID, NEAR_RPC_URL, TGas } from "./utils";
+import {
+  INTENTS_CONTRACT_ID,
+  NEAR_RPC_URL,
+  TGas,
+  USDC_CONTRACT,
+} from "./utils";
 import { getEnvVar } from "./env";
 
+const FIFTY_TGAS = BigInt(TGas * 50);
+const ONE_YOCTO = BigInt(1);
+
 export async function getTokenBalance(
   account: Account,
   assetId: string,
@@ -57,9 +65,6 @@ export function buildTransactionPayload(quote: Quote) {
   };
 }
 
-const USDC_CONTRACT =
-  "17208628f84f5d6ad33f0da3bbbeb27ffcb398eac501a31bd6ad2011e36133a1";
-
 export async function getUSDCBalance(account: Account): Promise<bigint> {
   try {
     const result = await account.viewFunction({
@@ -74,6 +79,27 @@ export async function getUSDCBalance(account: Account): Promise<bigint> {
   }
 }
 
+export async function intentsUSDCBalance(account: Account): Promise<bigint> {
+  return intentsBalance(account, USDC_CONTRACT);
+}
+
+export async function intentsBalance(
+  account: Account,
+  token: string,
+): Promise<bigint> {
+  try {
+    const result = await account.viewFunction({
+      contractId: INTENTS_CONTRACT_ID,
+      methodName: "mt_balance_of",
+      args: { token_id: `nep141:${token}`, account_id: account.accountId },
+    });
+    return BigInt(result as string);
+  } catch (error) {
+    console.warn("Failed to fetch USDC balance:", error);
+    return BigInt(0);
+  }
+}
+
 export async function depositUSDC(account: Account, amount: bigint) {
   const result = await account.signAndSendTransaction({
     receiverId: USDC_CONTRACT,
@@ -85,8 +111,8 @@ export async function depositUSDC(account: Account, amount: bigint) {
           amount: amount.toString(),
           msg: account.accountId,
         },
-        BigInt(TGas * 50),
-        BigInt(1),
+        FIFTY_TGAS,
+        ONE_YOCTO,
       ),
     ],
   });
@@ -109,3 +135,51 @@ export async function depositUSDC(account: Account, amount: bigint) {
 
   return result;
 }
+
+export async function withdrawUSDC(account: Account, amount: bigint) {
+  return withdrawToken(account, USDC_CONTRACT, amount);
+}
+
+export async function withdrawToken(
+  account: Account,
+  token: string,
+  amount: bigint,
+) {
+  const result = await account.signAndSendTransaction({
+    receiverId: INTENTS_CONTRACT_ID,
+    actions: [
+      actionCreators.functionCall(
+        "ft_withdraw",
+        {
+          token,
+          amount: amount.toString(),
+          receiver_id: account.accountId,
+          // Docs suggest refund is not necessarily possible if msg is specified!
+          // https://docs.near-intents.org/near-intents/market-makers/verifier/deposits-and-withdrawals/withdrawals#refunds-on-failed-withdrawals-warning
+          // msg: null
+        },
+        FIFTY_TGAS,
+        ONE_YOCTO,
+      ),
+    ],
+  });
+
+  const hasSuccess = result.receipts_outcome.some((receipt) =>
+    receipt.outcome.logs.some(
+      (log) => log.includes("ft_transfer") && log.includes(account.accountId),
+    ),
+  );
+  const hasRefund = result.receipts_outcome.some((receipt) =>
+    receipt.outcome.logs.some(
+      (log) => log.includes("ft_transfer") && log.includes('"memo":"refund"'),
+    ),
+  );
+
+  if (hasRefund || !hasSuccess) {
+    throw new Error(
+      `Withdraw failed - transaction was refunded ${result.transaction.hash}`,
+    );
+  }
+
+  return result;
+}

lib/utils.ts

@@ -3,6 +3,8 @@ import type { AgentContext, Token, ToolResult } from "./types";
 
 export const AGENT_ID = "trading-agent-kappa.vercel.app";
 
+export const USDC_CONTRACT =
+  "17208628f84f5d6ad33f0da3bbbeb27ffcb398eac501a31bd6ad2011e36133a1";
 export const INTENTS_CONTRACT_ID = "intents.near";
 export const TGas = 1000000000000;
 export const NEAR_RPC_URL = "https://free.rpc.fastnear.com";