Refactor getBrokerUserPositions to utilize calculateDynamicLoanRepayment for dynamic outstanding calculations, improving accuracy by converting rates to WAD format. Introduce helper functions for rate normalization and outstanding calculation, enhancing code clarity and maintainability.

Author: tyler-tsai

packages/moolah-lending-sdk/CHANGELOG.md

@@ -1,5 +1,11 @@
 # @lista-dao/moolah-lending-sdk
 
+## 1.0.9
+
+### Patch Changes
+
+- Refactor getBrokerUserPositions to utilize calculateDynamicLoanRepayment for dynamic outstanding calculations, improving accuracy by converting rates to WAD format. Introduce helper functions for rate normalization and outstanding calculation, enhancing code clarity and maintainability.
+
 ## 1.0.8
 
 ### Patch Changes

packages/moolah-lending-sdk/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@lista-dao/moolah-lending-sdk",
-  "version": "1.0.8",
+  "version": "1.0.9",
   "type": "module",
   "main": "./dist/index.js",
   "module": "./dist/index.js",

packages/moolah-lending-sdk/src/__tests__/read/broker/getBrokerUserPositions.test.ts

@@ -1,5 +1,6 @@
 import { beforeEach, describe, expect, it, vi } from "vitest";
 import type { Address, PublicClient } from "viem";
+import { calculateDynamicLoanRepayment } from "@lista-dao/moolah-sdk-core";
 
 import { getBrokerUserPositions } from "../../../read/broker/getBrokerUserPositions.js";
 
@@ -12,18 +13,26 @@ const BROKER = "0x1111111111111111111111111111111111111111" as Address;
 const RATE_CALCULATOR =
   "0x2222222222222222222222222222222222222222" as Address;
 const USER = "0x3333333333333333333333333333333333333333" as Address;
-const RAY = 10n ** 27n;
+const WAD = 10n ** 18n;
 
 describe("getBrokerUserPositions - dynamic debt", () => {
   beforeEach(() => {
     vi.clearAllMocks();
   });
 
-  it("computes dynamic outstanding with normalizedDebt * rate / 1e27", async () => {
+  it("computes dynamic outstanding with legacy decimal-normalized dynamic rate", async () => {
     const principal = 17061806491632102441n;
     const normalizedDebt = 16878807815476167930n;
     const rate = 1011624315990879851775155575n;
-    const expectedOutstanding = (normalizedDebt * rate) / RAY;
+    const { totalRepay } = calculateDynamicLoanRepayment(
+      {
+        principal,
+        normalizedDebt,
+        rate: rate / WAD,
+      },
+      18,
+    );
+    const expectedOutstanding = totalRepay.roundDown(18).numerator;
 
     mockReadContract.mockImplementation(async ({ functionName }) => {
       switch (functionName) {

packages/moolah-lending-sdk/src/read/broker/getBrokerUserPositions.ts

@@ -3,24 +3,84 @@ import {
   Decimal,
   LENDING_BROKER_ABI,
   BROKER_RATE_CALCULATOR_ABI,
+  calculateDynamicLoanRepayment,
   calculateFixedLoanRepayment,
   type BrokerUserPositionsData,
   type FixedLoanPosition,
   type DynamicLoanPosition,
   type RawFixedTerm,
 } from "@lista-dao/moolah-sdk-core";
 
+const ONE_E27 = 10n ** 27n;
 const SECONDS_PER_WEEK = 604800n;
+const RATE_SCALE_18 = 10n ** 18n;
+const FLEXIBLE_RATE_NUMERATOR = 100n;
+const FLEXIBLE_RATE_DENOMINATOR = 95n;
 
 /**
  * Normalize APR rate from contract format
  * Contract stores APR as (1 + rate) * 1e27, we convert to rate * 1e27
  */
 function normalizeAprRate(apr: bigint): bigint {
-  const ONE_E27 = 10n ** 27n;
   return apr > ONE_E27 ? apr - ONE_E27 : apr;
 }
 
+/**
+ * Convert broker dynamic rate (27 decimals) to WAD (18 decimals)
+ * expected by calculateDynamicLoanRepayment.
+ */
+function normalizeDynamicRateToWad(dynamicRate: bigint): bigint {
+  return dynamicRate / RATE_SCALE_18;
+}
+
+function buildTermRateData(terms: readonly RawFixedTerm[]) {
+  const termRateByDuration = new Map<string, Decimal>();
+  let currentFlexibleRate = Decimal.ZERO;
+
+  for (const term of terms) {
+    const normalizedRate = normalizeAprRate(term.apr);
+
+    if (term.duration === SECONDS_PER_WEEK) {
+      currentFlexibleRate = new Decimal(
+        (normalizedRate * FLEXIBLE_RATE_NUMERATOR) / FLEXIBLE_RATE_DENOMINATOR,
+        27,
+      );
+    }
+
+    termRateByDuration.set(
+      term.duration.toString(),
+      new Decimal(normalizedRate, 27),
+    );
+  }
+
+  return { termRateByDuration, currentFlexibleRate };
+}
+
+function calculateDynamicOutstanding(
+  dynamicPosition: DynamicLoanPosition,
+  dynamicRate: bigint,
+  loanDecimals: number,
+): Decimal | null {
+  if (dynamicPosition.principal <= 0n) {
+    return null;
+  }
+
+  const { totalRepay } = calculateDynamicLoanRepayment(
+    {
+      principal: dynamicPosition.principal,
+      normalizedDebt: dynamicPosition.normalizedDebt,
+      rate: normalizeDynamicRateToWad(dynamicRate),
+    },
+    loanDecimals,
+  );
+
+  return totalRepay.roundDown(loanDecimals);
+}
+
+function getPositionDuration(position: FixedLoanPosition): bigint {
+  return position.end > position.start ? position.end - position.start : 0n;
+}
+
 /**
  * Get broker user positions data
  */
@@ -60,34 +120,12 @@ export async function getBrokerUserPositions(
       }) as Promise<bigint>,
     ]);
 
-  // Build term rate map
-  const termRateByDuration = new Map<string, Decimal>();
-  let currentFlexibleRate = Decimal.ZERO;
-
-  terms.forEach((term) => {
-    if (term.duration === SECONDS_PER_WEEK) {
-      // Flexible rate = term rate * 100 / 95
-      currentFlexibleRate = new Decimal(
-        (normalizeAprRate(term.apr) * 100n) / 95n,
-        27,
-      );
-    }
-    const normalizedRate = new Decimal(normalizeAprRate(term.apr), 27);
-    termRateByDuration.set(term.duration.toString(), normalizedRate);
-  });
-
-  // Calculate dynamic position data
-  let dynamicOutstanding: Decimal | null = null;
-
-  if (dynamicPosition?.principal && dynamicPosition.principal > 0n) {
-    const normalizedDebt = new Decimal(
-      dynamicPosition.normalizedDebt ?? dynamicPosition.principal,
-      loanDecimals,
-    );
-    dynamicOutstanding = normalizedDebt
-      .mul(new Decimal(dynamicRate, 27))
-      .roundDown(loanDecimals);
-  }
+  const { termRateByDuration, currentFlexibleRate } = buildTermRateData(terms);
+  const dynamicOutstanding = calculateDynamicOutstanding(
+    dynamicPosition,
+    dynamicRate,
+    loanDecimals,
+  );
 
   // Calculate fixed positions data
   let fixedOutstanding = Decimal.ZERO;
@@ -98,23 +136,18 @@ export async function getBrokerUserPositions(
   // Add dynamic position to totals
   if (dynamicOutstanding && dynamicOutstanding.gt(Decimal.ZERO)) {
     totalOutstanding = totalOutstanding.add(dynamicOutstanding);
-    weightedSum = weightedSum.add(
-      dynamicOutstanding.mul(currentFlexibleRate ?? Decimal.ZERO),
-    );
+    weightedSum = weightedSum.add(dynamicOutstanding.mul(currentFlexibleRate));
   }
 
   // Process fixed positions
   const currentTimestamp = Math.floor(Date.now() / 1000);
-  fixedPositions.forEach((position) => {
-    const principal = BigInt(position.principal ?? 0n);
-    const principalRepaid = BigInt(position.principalRepaid ?? 0n);
-
+  for (const position of fixedPositions) {
     // Skip fully repaid or matured positions
-    if (principal <= principalRepaid) {
-      return;
+    if (position.principal <= position.principalRepaid) {
+      continue;
     }
-    if (Number(position.end ?? 0n) <= currentTimestamp) {
-      return;
+    if (Number(position.end) <= currentTimestamp) {
+      continue;
     }
 
     const {
@@ -130,18 +163,13 @@ export async function getBrokerUserPositions(
     fixedOutstanding = fixedOutstanding.add(totalRepayNoPenalty);
     totalPenalty = totalPenalty.add(new Decimal(penalty, loanDecimals));
 
-    const duration =
-      BigInt(position.end ?? 0n) > BigInt(position.start ?? 0n)
-        ? BigInt(position.end ?? 0n) - BigInt(position.start ?? 0n)
-        : 0n;
-
     const normalizedFixedRate =
-      termRateByDuration.get(duration.toString()) ??
+      termRateByDuration.get(getPositionDuration(position).toString()) ??
       new Decimal(normalizeAprRate(position.apr), 27);
 
     totalOutstanding = totalOutstanding.add(totalRepayNoPenalty);
     weightedSum = weightedSum.add(totalRepayNoPenalty.mul(normalizedFixedRate));
-  });
+  }
 
   // Calculate weighted borrow rate
   const weightedBorrowRate = totalOutstanding.gt(Decimal.ZERO)