fix: close to collateral logic when fee is collected from from token

OasisDEX · Aug 18, 2023 · abc8f1a · abc8f1a
1 parent b22c1c5
commit abc8f1a
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Showing 2 changed files with 13 additions and 9 deletions.
diff --git a/packages/dma-common/utils/swap/calculate-fee.ts b/packages/dma-common/utils/swap/calculate-fee.ts
@@ -4,7 +4,7 @@ import BigNumber from 'bignumber.js'
 export function calculateFee(amountWei: BigNumber, fee: number = DEFAULT_FEE): BigNumber {
   return amountWei
     .times(fee)
-    .div(new BigNumber(fee).plus(FEE_BASE))
+    .div(new BigNumber(fee).plus(new BigNumber(FEE_BASE)))
     .abs()
     .integerValue(BigNumber.ROUND_DOWN)
 }
diff --git a/packages/dma-library/src/strategies/common/close-to-coll-swap-data.ts b/packages/dma-library/src/strategies/common/close-to-coll-swap-data.ts
@@ -102,20 +102,15 @@ export async function getSwapDataForCloseToCollateral({
 
   // 4. Get Swap Data
   // This is the actual swap data that will be used in the transaction.
+  // We're inflating the needed collateral by the fee amount
+  // This is for when fees is collected on the other end of the swap
   const amountNeededToEnsureRemainingDebtIsRepaid = calculateNeededCollateralToPaybackDebt(
     debtPrice,
     debtTokenPrecision,
     colPrice,
     collateralTokenPrecision,
     outstandingDebt,
-    fee.div(FEE_BASE),
-    slippage,
-  )
-
-  const swapData = await getSwapData(
-    collateralToken.address,
-    debtToken.address,
-    amountNeededToEnsureRemainingDebtIsRepaid,
+    fee.div(new BigNumber(FEE_BASE).plus(fee)),
     slippage,
   )
 
@@ -129,6 +124,15 @@ export async function getSwapDataForCloseToCollateral({
       ? calculateFee(amountNeededToEnsureRemainingDebtIsRepaid, fee.toNumber())
       : ZERO
 
+  // 5. Get Swap Data
+  // The swap amount needs to be the collateral needed minus the preSwapFee
+  const swapData = await getSwapData(
+    collateralToken.address,
+    debtToken.address,
+    amountNeededToEnsureRemainingDebtIsRepaid.minus(preSwapFee),
+    slippage,
+  )
+
   return {
     swapData,
     collectFeeFrom,