fix(swaps): band-aid fix for gas estimates to disable multihop for eth-ampl

Author: moodysalem

src/hooks/Trades.ts

@@ -4,6 +4,7 @@ import { useMemo } from 'react'
 
 import { BASES_TO_CHECK_TRADES_AGAINST } from '../constants'
 import { PairState, usePairs } from '../data/Reserves'
+import { maxHopsFor } from '../utils/maxHopsFor'
 import { wrappedCurrency } from '../utils/wrappedCurrency'
 
 import { useActiveWeb3React } from './index'
@@ -58,8 +59,9 @@ export function useTradeExactIn(currencyAmountIn?: CurrencyAmount, currencyOut?:
 
   return useMemo(() => {
     if (currencyAmountIn && currencyOut && allowedPairs.length > 0) {
+      const maxHops = maxHopsFor(currencyAmountIn.currency, currencyOut)
       return (
-        Trade.bestTradeExactIn(allowedPairs, currencyAmountIn, currencyOut, { maxHops: 3, maxNumResults: 1 })[0] ?? null
+        Trade.bestTradeExactIn(allowedPairs, currencyAmountIn, currencyOut, { maxHops, maxNumResults: 1 })[0] ?? null
       )
     }
     return null
@@ -74,9 +76,9 @@ export function useTradeExactOut(currencyIn?: Currency, currencyAmountOut?: Curr
 
   return useMemo(() => {
     if (currencyIn && currencyAmountOut && allowedPairs.length > 0) {
+      const maxHops = maxHopsFor(currencyIn, currencyAmountOut.currency)
       return (
-        Trade.bestTradeExactOut(allowedPairs, currencyIn, currencyAmountOut, { maxHops: 3, maxNumResults: 1 })[0] ??
-        null
+        Trade.bestTradeExactOut(allowedPairs, currencyIn, currencyAmountOut, { maxHops, maxNumResults: 1 })[0] ?? null
       )
     }
     return null

src/utils/maxHopsFor.ts

@@ -0,0 +1,32 @@
+import { ChainId, Currency, ETHER, Token, WETH } from '@uniswap/sdk'
+
+function isEtherish(currency: Currency): boolean {
+  return currency === ETHER || (currency instanceof Token && WETH[currency.chainId].equals(currency))
+}
+
+const AMPL_TOKEN_ADDRESS = '0xD46bA6D942050d489DBd938a2C909A5d5039A161'
+
+/**
+ * Band-aid on maxHops because some tokens seems to always fail with multihop swaps
+ * @param currencyIn currency in
+ * @param currencyOut currency out
+ */
+export function maxHopsFor(currencyIn: Currency, currencyOut: Currency): number {
+  if (
+    isEtherish(currencyIn) &&
+    currencyOut instanceof Token &&
+    currencyOut.chainId === ChainId.MAINNET &&
+    currencyOut.address === AMPL_TOKEN_ADDRESS
+  ) {
+    return 1
+  } else if (
+    isEtherish(currencyOut) &&
+    currencyIn instanceof Token &&
+    currencyIn.chainId === ChainId.MAINNET &&
+    currencyIn.address === AMPL_TOKEN_ADDRESS
+  ) {
+    return 1
+  }
+
+  return 3
+}