fix: patch user est net apy calc

Author: mootz12

package-lock.json

@@ -1,6 +1,6 @@
 {
   "name": "@blend-capital/blend-sdk",
-  "version": "3.2.0-beta",
+  "version": "3.2.0-beta.2",
   "description": "Javascript SDK for the Blend Protocol",
   "type": "module",
   "scripts": {

package.json

@@ -120,9 +120,11 @@ export class PositionsEstimate {
     const borrowLimit =
       totalEffectiveCollateral == 0 ? 0 : totalEffectiveLiabilities / totalEffectiveCollateral;
     const netApy =
-      totalBorrowed + totalSupplied == 0
-        ? 0
-        : (supplyApy - borrowApy) / (totalBorrowed + totalSupplied);
+      totalSupplied == 0
+        ? // if user has no supplied funds and has borrowed funds (e.g. a bad debt position), the debt will
+          // be forgiven as bad debt so the net APY is still 0
+          0
+        : (supplyApy - borrowApy) / totalSupplied;
     supplyApy = totalSupplied == 0 ? 0 : supplyApy / totalSupplied;
     borrowApy = totalBorrowed == 0 ? 0 : borrowApy / totalBorrowed;
 

src/pool/user_positions_est.ts

@@ -0,0 +1,154 @@
+import { PoolOracle, PoolV2, Positions, PositionsEstimate } from '../../src/index.js';
+import { toFixed } from '../../src/math.js';
+import { ReserveV2 } from '../../src/pool/reserve.js';
+
+describe('user position estimation', () => {
+  const timestamp = Math.floor(Date.now() / 1000);
+  const reserve_0 = new ReserveV2(
+    'pool_id',
+    'asset_0',
+    {
+      index: 0,
+      c_factor: 9500000,
+      l_factor: 9000000,
+      decimals: 7,
+    } as any,
+    {
+      dRate: BigInt(1_400_000_000_000), // d_rate
+      bRate: BigInt(1_250_000_000_000), // b_rate
+      lastTime: timestamp,
+    } as any,
+    undefined, // borrow emissions
+    undefined, // supply emissions
+    0.08, // borrow APR
+    0.09, // estBorrowApy
+    0.05, // supply APR
+    0.06, // estSupplyApy
+    0 // latestLedger
+  );
+
+  const reserve_1 = new ReserveV2(
+    'pool_id',
+    'asset_1',
+    {
+      index: 1,
+      c_factor: 0,
+      l_factor: 5000000,
+      decimals: 7,
+    } as any,
+    {
+      dRate: BigInt(1_200_000_000_000), // d_rate
+      bRate: BigInt(1_100_000_000_000), // b_rate
+      lastTime: timestamp,
+    } as any,
+    undefined, // borrow emissions
+    undefined, // supply emissions
+    0.02, // borrow APR
+    0.03, // estBorrowApy
+    0.01, // supply APR
+    0.02, // estSupplyApy
+    0 // latestLedger
+  );
+
+  const reserve_2 = new ReserveV2(
+    'pool_id',
+    'asset_2',
+    {
+      index: 2,
+      c_factor: 9000000,
+      l_factor: 8500000,
+      decimals: 7,
+    } as any,
+    {
+      dRate: BigInt(1_150_000_000_000), // d_rate
+      bRate: BigInt(1_050_000_000_000), // b_rate
+      lastTime: timestamp,
+    } as any,
+    undefined, // borrow emissions
+    undefined, // supply emissions
+    0.12, // borrow APR
+    0.15, // estBorrowApy
+    0.09, // supply APR
+    0.11, // estSupplyApy
+    0 // latestLedger
+  );
+
+  const pool_oracle = new PoolOracle(
+    'oracle_id',
+    new Map([
+      ['asset_0', { price: toFixed(1, 7), timestamp }],
+      ['asset_1', { price: toFixed(0.3, 7), timestamp }],
+      ['asset_2', { price: toFixed(200, 7), timestamp }],
+    ]),
+    7,
+    0
+  );
+
+  const pool = new PoolV2(
+    {} as any,
+    'pool_id',
+    {} as any,
+    new Map([
+      ['asset_0', reserve_0],
+      ['asset_1', reserve_1],
+      ['asset_2', reserve_2],
+    ]),
+    timestamp
+  );
+
+  it('calculates positions estimate correctly', () => {
+    const user_positions = new Positions(
+      // liabilities
+      new Map([[2, toFixed(10, 7)]]),
+      // collateral
+      new Map([[0, toFixed(4_000, 7)]]),
+      // supply
+      new Map([[1, toFixed(10_000, 7)]])
+    );
+
+    const estimate = PositionsEstimate.build(pool, pool_oracle, user_positions);
+
+    expect(estimate.totalBorrowed).toBeCloseTo(10 * 200 * 1.15);
+    expect(estimate.totalSupplied).toBeCloseTo(4000 * 1 * 1.25 + 10_000 * 0.3 * 1.1);
+    expect(estimate.totalEffectiveLiabilities).toBeCloseTo((10 * 200 * 1.15) / 0.85);
+    expect(estimate.totalEffectiveCollateral).toBeCloseTo(4000 * 1 * 1.25 * 0.95);
+    expect(estimate.borrowCap).toBeCloseTo(
+      estimate.totalEffectiveCollateral - estimate.totalEffectiveLiabilities
+    );
+    expect(estimate.borrowLimit).toBeCloseTo(
+      estimate.totalEffectiveLiabilities / estimate.totalEffectiveCollateral
+    );
+    expect(estimate.netApy).toBeCloseTo(
+      (estimate.supplyApy - estimate.borrowApy) / estimate.totalSupplied
+    );
+    expect(estimate.supplyApy).toBeCloseTo(
+      (4000 * 1 * 1.25 * 0.06 + 10_000 * 0.3 * 1.1 * 0.02) / estimate.totalSupplied
+    );
+    expect(estimate.borrowApy).toBeCloseTo((10 * 200 * 1.15 * 0.15) / estimate.totalBorrowed);
+  });
+
+  it('calculates positions estimate correctly for bad debt user', () => {
+    const user_positions = new Positions(
+      // liabilities
+      new Map([[2, toFixed(10, 7)]]),
+      // collateral
+      new Map(),
+      // supply
+      new Map()
+    );
+
+    const estimate = PositionsEstimate.build(pool, pool_oracle, user_positions);
+
+    expect(estimate.totalBorrowed).toBeCloseTo(10 * 200 * 1.15);
+    expect(estimate.totalSupplied).toBeCloseTo(0);
+    expect(estimate.totalEffectiveLiabilities).toBeCloseTo((10 * 200 * 1.15) / 0.85);
+    expect(estimate.totalEffectiveCollateral).toBeCloseTo(0);
+    expect(estimate.borrowCap).toBeCloseTo(
+      estimate.totalEffectiveCollateral - estimate.totalEffectiveLiabilities
+    );
+    expect(estimate.borrowLimit).toBeCloseTo(0);
+    expect(estimate.netApy).toBeCloseTo(0);
+    expect(estimate.supplyApy).toBeCloseTo(0);
+    expect(estimate.borrowApy).toBeCloseTo((10 * 200 * 1.15 * 0.15) / estimate.totalBorrowed);
+  });
+});