refactor: add calculateFutureLeverage

Author: fedorovdg

src/lendMarkets/LendMarketTemplate.ts

@@ -21,6 +21,7 @@ import {
     _getUsdRate,
     DIGas,
     smartNumber,
+    calculateFutureLeverage,
 } from "../utils.js";
 import {IDict, TGas, TAmount, IReward, IQuoteOdos, IOneWayMarket, IPartialFrac} from "../interfaces.js";
 import { _getExpectedOdos, _getQuoteOdos, _assembleTxOdos, _getUserCollateral, _getUserCollateralForce, _getMarketsData } from "../external-api.js";
@@ -1755,10 +1756,8 @@ export class LendMarketTemplate {
         ]);
 
         const total_deposit_from_user = userCollateral.total_deposit_from_user_precise;
-        const collateralBN = BN(collateral);
-        const currentCollateralBN = BN(currentCollateral);
 
-        return currentCollateralBN.plus(collateralBN).div(BN(total_deposit_from_user).plus(collateralBN)).toString();
+        return calculateFutureLeverage(currentCollateral, total_deposit_from_user, collateral, 'add');
     }
 
     // ---------------- REMOVE COLLATERAL ----------------
@@ -1835,10 +1834,8 @@ export class LendMarketTemplate {
         ]);
 
         const total_deposit_from_user = userCollateral.total_deposit_from_user_precise;
-        const collateralBN = BN(collateral);
-        const currentCollateralBN = BN(currentCollateral);
 
-        return currentCollateralBN.minus(collateralBN).div(BN(total_deposit_from_user).minus(collateralBN)).toString();
+        return calculateFutureLeverage(currentCollateral, total_deposit_from_user, collateral, 'remove');
     }
 
     // ---------------- REPAY ----------------

src/mintMarkets/MintMarketTemplate.ts

@@ -19,6 +19,7 @@ import {
     MAX_ACTIVE_BAND,
     _mulBy1_3,
     DIGas,
+    calculateFutureLeverage,
 } from "../utils.js";
 import {IDict, ILlamma, TGas} from "../interfaces.js";
 import {_getUserCollateralCrvUsd, _getUserCollateralCrvUsdFull} from "../external-api.js";
@@ -1010,10 +1011,8 @@ export class MintMarketTemplate {
         ]);
 
         const total_deposit_from_user = userCollateral.total_deposit_from_user_precise ?? userCollateral.total_deposit_precise;
-        const collateralBN = BN(collateral);
-        const currentCollateralBN = BN(currentCollateral);
 
-        return currentCollateralBN.plus(collateralBN).div(BN(total_deposit_from_user).plus(collateralBN)).toString();
+        return calculateFutureLeverage(currentCollateral, total_deposit_from_user, collateral, 'add');
     }
 
     // ---------------- REMOVE COLLATERAL ----------------
@@ -1093,10 +1092,8 @@ export class MintMarketTemplate {
         ]);
 
         const total_deposit_from_user = userCollateral.total_deposit_from_user_precise ?? userCollateral.total_deposit_precise;
-        const collateralBN = BN(collateral);
-        const currentCollateralBN = BN(currentCollateral);
 
-        return currentCollateralBN.minus(collateralBN).div(BN(total_deposit_from_user).minus(collateralBN)).toString();
+        return calculateFutureLeverage(currentCollateral, total_deposit_from_user, collateral, 'remove');
     }
 
     // ---------------- REPAY ----------------

src/utils.ts

@@ -498,4 +498,21 @@ export const getLsdApy = memoize(async(name: 'wstETH' | 'sfrxETH'): Promise<{
 {
     promise: true,
     maxAge: 60 * 1000, // 1m
-});
+});
+
+export const calculateFutureLeverage = (
+    currentCollateral: number | string,
+    totalDepositFromUser: number | string,
+    collateral: number | string,
+    operation: 'add' | 'remove'
+): string => {
+    const collateralBN = BN(collateral);
+    const currentCollateralBN = BN(currentCollateral);
+    const totalDepositBN = BN(totalDepositFromUser);
+
+    if (operation === 'add') {
+        return currentCollateralBN.plus(collateralBN).div(totalDepositBN.plus(collateralBN)).toString();
+    } else {
+        return currentCollateralBN.minus(collateralBN).div(totalDepositBN.minus(collateralBN)).toString();
+    }
+};