improve(ProfitClient): Simulate v3 fills (#1269)

The ProfitClient has, until now, used v2 fill estimates for its
profitability calculations. This change upgrades to using v3 fills,
which are slightly less expensive and should improve the relayer's
perceived profitability when evaluating fills.

This is a pre-requisite for deprecating fillRelay() in the contracts.

src/clients/ProfitClient.ts

@@ -1,4 +1,3 @@
-import { random } from "lodash";
 import { Provider } from "@ethersproject/abstract-provider";
 import { utils as ethersUtils } from "ethers";
 import {
@@ -11,8 +10,8 @@ import {
 import * as constants from "../common/Constants";
 import {
   assert,
+  bnOne,
   bnZero,
-  bnUint32Max as uint32Max,
   bnUint256Max as uint256Max,
   fixedPointAdjustment as fixedPoint,
   BigNumber,
@@ -26,13 +25,13 @@ import {
   assign,
   CHAIN_IDs,
   TOKEN_SYMBOLS_MAP,
+  ZERO_ADDRESS,
 } from "../utils";
 import {
   Deposit,
   DepositWithBlock,
   L1Token,
   SpokePoolClientsByChain,
-  V2Deposit,
   V3Deposit,
   V3DepositWithBlock,
 } from "../interfaces";
@@ -566,45 +565,48 @@ export class ProfitClient {
 
   private async updateGasCosts(): Promise<void> {
     const { enabledChainIds, hubPoolClient, relayerFeeQueries } = this;
-    const depositId = random(uint32Max.toNumber()); // random depositId + "" originToken => ~impossible to collide.
-    const fillAmount = toBN(100); // Avoid rounding to zero but ensure the relayer has sufficient balance to estimate.
-    const feePct = toBNWei("0.0001"); // 1bps
-    const quoteTimestamp = getCurrentTime();
+    const outputAmount = toBN(100); // Avoid rounding to zero but ensure the relayer has sufficient balance to estimate.
+    const currentTime = getCurrentTime();
 
     // Prefer USDC on mainnet because it's consistent in terms of gas estimation (no unwrap conditional).
     // Prefer WETH on testnet because it's more likely to be configured for the destination SpokePool.
     const [testSymbol, relayer] =
       this.hubPoolClient.chainId === CHAIN_IDs.MAINNET ? ["USDC", PROD_RELAYER] : ["WETH", TEST_RELAYER];
 
+    // @dev The relayer _cannot_ be the recipient because the SpokePool skips the ERC20 transfer. Instead,
+    // use the main RL address because it has all supported tokens and approvals in place on all chains.
+    const sampleDeposit: V3Deposit = {
+      depositId: 0,
+      depositor: TEST_RECIPIENT,
+      recipient: TEST_RECIPIENT,
+      inputToken: ZERO_ADDRESS, // Not verified by the SpokePool.
+      inputAmount: outputAmount.add(bnOne),
+      outputToken: "", // SpokePool-specific, overwritten later.
+      outputAmount,
+      originChainId: 0, // Not verified by the SpokePool.
+      destinationChainId: 0, // SpokePool-specific, overwritten later.
+      quoteTimestamp: currentTime - 60,
+      fillDeadline: currentTime + 60,
+      exclusivityDeadline: 0,
+      exclusiveRelayer: ZERO_ADDRESS,
+      message: EMPTY_MESSAGE,
+    };
+
     // Pre-fetch total gas costs for relays on enabled chains.
     const hubToken = TOKEN_SYMBOLS_MAP[testSymbol].addresses[this.hubPoolClient.chainId];
     await sdkUtils.mapAsync(enabledChainIds, async (destinationChainId) => {
-      const destinationToken =
+      const outputToken =
         destinationChainId === hubPoolClient.chainId
           ? hubToken
           : hubPoolClient.getL2TokenForL1TokenAtBlock(hubToken, destinationChainId);
-      assert(isDefined(destinationToken), `Chain ${destinationChainId} SpokePool is not configured for ${testSymbol}`);
-
-      const deposit: V2Deposit = {
-        depositId,
-        depositor: TEST_RECIPIENT,
-        recipient: TEST_RECIPIENT,
-        originToken: destinationToken, // Not verified by the SpokePool.
-        amount: fillAmount,
-        originChainId: destinationChainId, // Not verified by the SpokePool.
-        destinationChainId,
-        relayerFeePct: feePct,
-        realizedLpFeePct: feePct,
-        destinationToken,
-        quoteTimestamp,
-        message: EMPTY_MESSAGE,
-      };
+      assert(isDefined(outputToken), `Chain ${destinationChainId} SpokePool is not configured for ${testSymbol}`);
 
       // @dev The relayer _cannot_ be the recipient because the SpokePool skips the ERC20 transfer. Instead,
       // use the main RL address because it has all supported tokens and approvals in place on all chains.
+      const deposit = { ...sampleDeposit, destinationChainId, outputToken };
       this.totalGasCosts[destinationChainId] = await relayerFeeQueries[destinationChainId].getGasCosts(
         deposit,
-        fillAmount,
+        outputAmount,
         relayer
       );
     });