From d8c05dd8d3173a67200f2374e1e8b3fa58a3f57e Mon Sep 17 00:00:00 2001
From: jsy1218 <91580504+jsy1218@users.noreply.github.com>
Date: Tue, 17 Oct 2023 15:34:11 -0700
Subject: [PATCH] Fix: FOT token tax retrieval source (#148)

* v3.2.2

* fix fot token tax retrieval source

* Fix code style issues with Prettier

* revert version change here

---------

Co-authored-by: Lint Action <lint-action@samuelmeuli.com>
---
 src/entities/pair.test.ts | 24 ++++++++++++++++++++----
 src/entities/pair.ts      |  9 +++++++--
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/src/entities/pair.test.ts b/src/entities/pair.test.ts
index a819dbffc..ccc45bc4a 100644
--- a/src/entities/pair.test.ts
+++ b/src/entities/pair.test.ts
@@ -186,6 +186,14 @@ describe('Pair', () => {
       BLASTBuyFeeBps,
       BLASTSellFeeBps
     )
+    const BLAST_WIHTOUT_TAX = new Token(
+      ChainId.MAINNET,
+      '0x3ed643e9032230f01c6c36060e305ab53ad3b482',
+      18,
+      'BLAST',
+      'BLAST',
+      false
+    )
     const BLASTERSBuyFeeBps = BigNumber.from(300)
     const BLASTERSSellFeeBps = BigNumber.from(350)
     const BLASTERS = new Token(
@@ -198,6 +206,14 @@ describe('Pair', () => {
       BLASTERSBuyFeeBps,
       BLASTERSSellFeeBps
     )
+    const BLASTERS_WITHOUT_TAX = new Token(
+      ChainId.MAINNET,
+      '0xab98093C7232E98A47D7270CE0c1c2106f61C73b',
+      9,
+      'BLAST',
+      'BLASTERS',
+      false
+    )
 
     let calculateFotFees: boolean = false
 
@@ -213,7 +229,7 @@ describe('Pair', () => {
 
           const pair = new Pair(reserveBlasterAmount, reserveBlastAmount)
 
-          const inputBlastersAmount = CurrencyAmount.fromRawAmount(BLASTERS, '100')
+          const inputBlastersAmount = CurrencyAmount.fromRawAmount(BLASTERS_WITHOUT_TAX, '100')
           const [outputBlastAmount] = pair.getOutputAmount(inputBlastersAmount, calculateFotFees)
 
           // Theoretical amount out:
@@ -246,7 +262,7 @@ describe('Pair', () => {
 
           const pair = new Pair(reserveBlasterAmount, reserveBlastAmount)
 
-          const outputBlastAmount = CurrencyAmount.fromRawAmount(BLAST, '91')
+          const outputBlastAmount = CurrencyAmount.fromRawAmount(BLAST_WIHTOUT_TAX, '91')
           const [inputBlasterAmount] = pair.getInputAmount(outputBlastAmount, calculateFotFees)
 
           // Theoretical amount in:
@@ -294,7 +310,7 @@ describe('Pair', () => {
 
           const pair = new Pair(reserveBlasterAmount, reserveBlastAmount)
 
-          const inputBlastersAmount = CurrencyAmount.fromRawAmount(BLASTERS, '100')
+          const inputBlastersAmount = CurrencyAmount.fromRawAmount(BLASTERS_WITHOUT_TAX, '100')
           const [outputBlastAmount] = pair.getOutputAmount(inputBlastersAmount, calculateFotFees)
 
           const expectedOutputBlastAmount = '0.000000000000000098'
@@ -307,7 +323,7 @@ describe('Pair', () => {
 
           const pair = new Pair(reserveBlasterAmount, reserveBlastAmount)
 
-          const outputBlastAmount = CurrencyAmount.fromRawAmount(BLAST, '91')
+          const outputBlastAmount = CurrencyAmount.fromRawAmount(BLAST_WIHTOUT_TAX, '91')
           const [inputBlasterAmount] = pair.getInputAmount(outputBlastAmount, calculateFotFees)
 
           const expectedInputBlasterAmount = '0.000000093'
diff --git a/src/entities/pair.ts b/src/entities/pair.ts
index 4bac5e43c..aff809f01 100644
--- a/src/entities/pair.ts
+++ b/src/entities/pair.ts
@@ -177,6 +177,7 @@ export class Pair {
    * outputAmountWithTax = amountOut * (1 - amountOut.buyFeesBips / 10000)
    *
    * @param inputAmount
+   * @param calculateFotFees
    */
   public getOutputAmount(
     inputAmount: CurrencyAmount<Token>,
@@ -379,7 +380,9 @@ export class Pair {
   }
 
   private derivePercentAfterSellFees(inputAmount: CurrencyAmount<Token>): Percent {
-    const sellFeeBips = inputAmount.currency.sellFeeBps
+    const sellFeeBips = this.token0.wrapped.equals(inputAmount.wrapped.currency)
+      ? this.token0.wrapped.sellFeeBps
+      : this.token1.wrapped.sellFeeBps
     if (sellFeeBips?.gt(BigNumber.from(0))) {
       return ONE_HUNDRED_PERCENT.subtract(new Percent(JSBI.BigInt(sellFeeBips)).divide(BASIS_POINTS))
     } else {
@@ -388,7 +391,9 @@ export class Pair {
   }
 
   private derivePercentAfterBuyFees(outputAmount: CurrencyAmount<Token>): Percent {
-    const buyFeeBps = outputAmount.currency.buyFeeBps
+    const buyFeeBps = this.token0.wrapped.equals(outputAmount.wrapped.currency)
+      ? this.token0.wrapped.buyFeeBps
+      : this.token1.wrapped.buyFeeBps
     if (buyFeeBps?.gt(BigNumber.from(0))) {
       return ONE_HUNDRED_PERCENT.subtract(new Percent(JSBI.BigInt(buyFeeBps)).divide(BASIS_POINTS))
     } else {