From 70893de6c03e3041655bacf4cc75fa3750737e8c Mon Sep 17 00:00:00 2001
From: hzhu <hz@henryzhu.me>
Date: Sat, 10 Aug 2024 23:55:42 -0700
Subject: [PATCH] fix: remove hardcoded settler meta txn contract

Settler contract addresses are dynamic. To distinguish the contract,
function selector for executeMetaTxn instead.
---
 src/constants.ts        | 14 ++------------
 src/index.ts            | 13 ++-----------
 src/tests/index.test.ts | 31 +++++++++++++++++++++++++++++++
 3 files changed, 35 insertions(+), 23 deletions(-)

diff --git a/src/constants.ts b/src/constants.ts
index 007362e..c762cfc 100644
--- a/src/constants.ts
+++ b/src/constants.ts
@@ -29,6 +29,8 @@ export const SETTLER_ABI = [
   },
 ];
 
+export const FUNCTION_SELECTORS = { EXECUTE_META_TXN: "0xfd3ad6d4" };
+
 export const NATIVE_TOKEN_ADDRESS =
   "0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE";
 
@@ -43,18 +45,6 @@ export const NATIVE_SYMBOL_BY_CHAIN_ID: { [key in SupportedChainId]: string } =
     43114: "AVAX", // Avalanche
   };
 
-export const SETTLER_META_TXN_BY_CHAIN_ID: {
-  [key in SupportedChainId]: string;
-} = {
-  1: "0x7C39a136EA20B3483e402EA031c1f3C019bAb24b",
-  10: "0x4069560a180EbD76bB1aF947f5119Fe555BB4eA0",
-  56: "0x73C25Ef091Ce3F2451946Be3f982549776bFED31",
-  137: "0xF9332450385291b6dcE301917aF6905e28E8f35f",
-  8453: "0x5CE929DDB01804bfF35B2F5c77b735bdB094AAc8",
-  42161: "0x1aa84EB5cb62f686FC0D908AFd85864f4A05d5Ee",
-  43114: "0x2adb2cE26848B94E13d2f7fE0fF7E945050D741c",
-};
-
 export const MULTICALL3_ADDRESS = "0xcA11bde05977b3631167028862bE2a173976CA11";
 
 export const NATIVE_ETH_ADDRESS = "0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE";
diff --git a/src/index.ts b/src/index.ts
index 3a1925f..0649ea6 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -8,9 +8,9 @@ import {
 import {
   SETTLER_ABI,
   MULTICALL3_ADDRESS,
+  FUNCTION_SELECTORS,
   NATIVE_TOKEN_ADDRESS,
   NATIVE_SYMBOL_BY_CHAIN_ID,
-  SETTLER_META_TXN_BY_CHAIN_ID,
 } from "./constants";
 import {
   transferLogs,
@@ -106,10 +106,7 @@ export async function parseSwap({
     }
   }
 
-  const isSettlerMetaTxn =
-    to?.toLowerCase() === SETTLER_META_TXN_BY_CHAIN_ID[chainId].toLowerCase();
-
-  if (isSettlerMetaTxn) {
+  if (transaction.input.startsWith(FUNCTION_SELECTORS.EXECUTE_META_TXN)) {
     const { args } = decodeFunctionData<any[]>({
       abi: SETTLER_ABI,
       data: transaction.input,
@@ -173,12 +170,6 @@ export async function parseSwap({
     };
   }
 
-  if (!output && input.from) {
-    output = logs.find(
-      (log) => log.to.toLowerCase() === input.from.toLowerCase()
-    );
-  }
-
   /* v8 ignore start */
   if (!output) {
     console.error(
diff --git a/src/tests/index.test.ts b/src/tests/index.test.ts
index 2f12068..3dea4b0 100644
--- a/src/tests/index.test.ts
+++ b/src/tests/index.test.ts
@@ -476,6 +476,37 @@ test("parse a gasless swap on Base (USDC for ETH) for SettlerMetaTxn", async ()
   });
 });
 
+// https://basescan.org/tx/0x29b3f7bcd154e20e050793aa62d90309a860296aa846fd1158dc21356d1a3deb
+test("parse a gasless swap on Base (weirdo for ETH) for SettlerMetaTxn", async () => {
+  const publicClient = createPublicClient({
+    chain: base,
+    transport: http(
+      `https://base-mainnet.g.alchemy.com/v2/${process.env.ALCHEMY_API_KEY}`
+    ),
+  }) as PublicClient<Transport, Chain>;
+
+  const transactionHash =
+    "0x29b3f7bcd154e20e050793aa62d90309a860296aa846fd1158dc21356d1a3deb";
+
+  const result = await parseSwap({
+    publicClient,
+    transactionHash,
+  });
+
+  expect(result).toEqual({
+    tokenIn: {
+      symbol: "weirdo",
+      amount: "3145398.30971883",
+      address: "0x76734B57dFe834F102fB61E1eBF844Adf8DD931e",
+    },
+    tokenOut: {
+      symbol: "ETH",
+      amount: "0.039633073597929391",
+      address: NATIVE_ETH_ADDRESS,
+    },
+  });
+});
+
 // https://basescan.org/tx/0xe595dec22a7e2c2c5bdb0c1a7e59b2302ede72e5d2210c6cd7071222ea6dc2b2
 test("parse a gasless swap on Base (DEGEN for USDC) for SettlerMetaTxn", async () => {
   const publicClient = createPublicClient({