implemented Matt's formula for lendRate

.gitignore

@@ -1,5 +1,6 @@
 build/
 generated/
+data*/
 
 # Logs
 logs

src/erc-20-pool.ts

@@ -70,7 +70,7 @@ import { getBucketId, getBucketInfo, loadOrCreateBucket } from "./utils/pool/buc
 import { getLendId, loadOrCreateLend } from "./utils/pool/lend"
 import { getBorrowerInfo, getLoanId, loadOrCreateLoan } from "./utils/pool/loan"
 import { getLiquidationAuctionId, getAuctionInfoERC20Pool, loadOrCreateLiquidationAuction, updateLiquidationAuction, getAuctionStatus, loadOrCreateBucketTake } from "./utils/pool/liquidation"
-import { getBurnInfo, updatePool, addLiquidationToPool, addReserveAuctionToPool, getLenderInfo, getRatesAndFees, calculateLendRate } from "./utils/pool/pool"
+import { getBurnInfo, updatePool, addLiquidationToPool, addReserveAuctionToPool, getLenderInfo, getRatesAndFees } from "./utils/pool/pool"
 import { lpbValueInQuote } from "./utils/common"
 import { loadOrCreateReserveAuction, reserveAuctionKickerReward } from "./utils/pool/reserve-auction"
 import { incrementTokenTxCount } from "./utils/token-erc20"

src/utils/pool/pool.ts

@@ -1,13 +1,13 @@
-import { BigDecimal, BigInt, Bytes, Address, dataSource } from '@graphprotocol/graph-ts'
+import { BigDecimal, BigInt, Bytes, Address, dataSource, bigInt } from '@graphprotocol/graph-ts'
 
 import { LiquidationAuction, Pool, ReserveAuction, Token } from "../../../generated/schema"
 import { ERC20Pool } from '../../../generated/templates/ERC20Pool/ERC20Pool'
 import { PoolInfoUtils } from '../../../generated/templates/ERC20Pool/PoolInfoUtils'
 
-import { poolInfoUtilsAddressTable, TEN_BI } from "../constants"
+import { poolInfoUtilsAddressTable, TEN_BI, ZERO_BD, ZERO_BI } from "../constants"
 import { decimalToWad, wadToDecimal } from '../convert'
 import { getTokenBalance } from '../token-erc20'
-import { wmul, wdiv } from '../math'
+import { wmul, wdiv, wmin } from '../math'
 
 export function getPoolAddress(poolId: Bytes): Address {
   return Address.fromBytes(poolId)
@@ -61,7 +61,17 @@ export function getRatesAndFees(poolId: Bytes): RatesAndFees {
   return new RatesAndFees(lim, bfr, dfr);
 }
 
-export function calculateLendRate(borrowRate: BigInt, lenderInterestMargin: BigInt, utilization: BigInt): BigDecimal {
+export function calculateLendRate(
+  poolAddress: Address, 
+  borrowRate: BigInt, 
+  lenderInterestMargin: BigInt, 
+  poolPricesInfo: PoolPricesInfo, 
+  debt: BigInt
+): BigDecimal {
+  const meaningfulPriceIndex = max(poolPricesInfo.lupIndex.toU32(), poolPricesInfo.htpIndex.toU32())
+  const meaningfulDeposit = depositUpToIndex(poolAddress, meaningfulPriceIndex)
+  if (meaningfulDeposit.equals(ZERO_BI)) return ZERO_BD
+  const utilization = wdiv(debt, meaningfulDeposit)
   return wadToDecimal(wmul(wmul(borrowRate,lenderInterestMargin), utilization))
 }
 
@@ -231,9 +241,11 @@ export function updatePool(pool: Pool): void {
     // update lend rate and borrow fee, which change irrespective of borrow rate
     const ratesAndFees = getRatesAndFees(poolAddress)
     pool.lendRate = calculateLendRate(
+      poolAddress,
       decimalToWad(pool.borrowRate), 
       ratesAndFees.lenderInterestMargin, 
-      poolUtilizationInfo.actualUtilization)
+      poolPricesInfo,
+      debtInfo.pendingDebt)
     pool.borrowFeeRate = wadToDecimal(ratesAndFees.borrowFeeRate)
 }
 
@@ -316,3 +328,8 @@ export function getDebtInfo(pool: Pool): DebtInfo {
     debtInfoResult.value3
   )
 }
+
+export function depositUpToIndex(poolAddress: Address, index: u32): BigInt {
+  const poolContract = ERC20Pool.bind(poolAddress)
+  return poolContract.depositUpToIndex(BigInt.fromU32(index));
+}

tests/utils/common.ts

@@ -10,7 +10,7 @@ import { positionManagerAddressTable, poolInfoUtilsAddressTable, ZERO_BI, ONE_BI
 import { BurnInfo, DebtInfo, LoansInfo, PoolPricesInfo, PoolUtilizationInfo, ReservesInfo } from "../../src/utils/pool/pool"
 import { AuctionInfo, AuctionStatus } from "../../src/utils/pool/liquidation"
 import { BorrowerInfo } from "../../src/utils/pool/loan"
-import { wdiv, wmin } from "../../src/utils/math"
+import { wdiv, wmin, wmul } from "../../src/utils/math"
 
 /*************************/
 /*** Bucket Assertions ***/
@@ -555,6 +555,14 @@ export function mockGetTokenInfo(token: Address, expectedName: string, expectedS
         .returns([ethereum.Value.fromUnsignedBigInt(expectedTotalSupply)])
 }
 
+export function mockDepositUpToIndex(pool: Address, index: BigInt, expectedInfo: BigInt): void {
+  createMockedFunction(pool, 'depositUpToIndex', 'depositUpToIndex(uint256):(uint256)')
+      .withArgs([ethereum.Value.fromUnsignedBigInt(index)])
+      .returns([
+        ethereum.Value.fromUnsignedBigInt(expectedInfo)
+      ])
+}
+
 export class PoolMockParams {
     // loans info mock params
     poolSize: BigInt
@@ -631,6 +639,8 @@ export function mockPoolInfoUtilsPoolUpdateCalls(pool: Address, params: PoolMock
       BigInt.fromString("850000000000000000"), // 0.85 * 1e18
       BigInt.fromString("50000000000000000"),  // 0.05 * 1e18
     )
+
+    mockDepositUpToIndex(pool, params.lupIndex, wmul(params.poolSize, params.actualUtilization))
 }
 
 /****************************/