From 80c0d98041d7fa2254ad0c2d9b50725fe4de2e8e Mon Sep 17 00:00:00 2001
From: Filippo Fontana <filippo@embriotech.ch>
Date: Fri, 19 Apr 2024 12:51:16 +0200
Subject: [PATCH] feat: track accrued interest per period Fixes #234

---
 schema.graphql                         | 6 ++++++
 src/mappings/handlers/blockHandlers.ts | 2 +-
 src/mappings/services/assetService.ts  | 7 ++++++-
 src/mappings/services/poolService.ts   | 6 ++++++
 4 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/schema.graphql b/schema.graphql
index fd15f26f..42321352 100644
--- a/schema.graphql
+++ b/schema.graphql
@@ -54,6 +54,7 @@ type Pool @entity {
   sumDebtOverdue: BigInt
   sumDebtWrittenOffByPeriod: BigInt
   deltaPortfolioValuationByPeriod: BigInt
+  sumInterestAccruedByPeriod: BigInt
 
   sumChargedAmountByPeriod: BigInt
   sumAccruedAmountByPeriod: BigInt
@@ -102,6 +103,7 @@ type PoolSnapshot @entity {
   sumDebtOverdue: BigInt
   sumDebtWrittenOffByPeriod: BigInt
   deltaPortfolioValuationByPeriod: BigInt
+  sumInterestAccruedByPeriod: BigInt
 
   sumChargedAmountByPeriod: BigInt
   sumAccruedAmountByPeriod: BigInt
@@ -390,6 +392,8 @@ type Asset @entity {
   borrowedAmountByPeriod: BigInt
   repaidAmountByPeriod: BigInt
 
+  interestAccruedByPeriod: BigInt
+
   writeOffIndex: Int
   writtenOffPercentageByPeriod: BigInt
   writtenOffAmountByPeriod: BigInt
@@ -421,6 +425,8 @@ type AssetSnapshot @entity {
   borrowedAmountByPeriod: BigInt
   repaidAmountByPeriod: BigInt
 
+  interestAccruedByPeriod: BigInt
+
   writtenOffPercentageByPeriod: BigInt
   writtenOffAmountByPeriod: BigInt
   penaltyInterestRatePerSec: BigInt
diff --git a/src/mappings/handlers/blockHandlers.ts b/src/mappings/handlers/blockHandlers.ts
index 908d505d..aa401510 100644
--- a/src/mappings/handlers/blockHandlers.ts
+++ b/src/mappings/handlers/blockHandlers.ts
@@ -65,8 +65,8 @@ async function _handleBlock(block: SubstrateBlock): Promise<void> {
       for (const loanId in activeLoanData) {
         const loan = await AssetService.getById(pool.id, loanId)
         await loan.updateActiveAssetData(activeLoanData[loanId])
+        await pool.increaseInterestAccrued(loan.interestAccruedByPeriod)
         await loan.save()
-
         if (loan.actualMaturityDate < block.timestamp) pool.increaseDebtOverdue(loan.outstandingDebt)
       }
 
diff --git a/src/mappings/services/assetService.ts b/src/mappings/services/assetService.ts
index 51e7f441..d9973a5d 100644
--- a/src/mappings/services/assetService.ts
+++ b/src/mappings/services/assetService.ts
@@ -48,6 +48,7 @@ export class AssetService extends Asset {
     asset.repaidAmountByPeriod = BigInt(0)
     asset.writtenOffPercentageByPeriod = BigInt(0)
     asset.writtenOffAmountByPeriod = BigInt(0)
+    asset.interestAccruedByPeriod = BigInt(0)
 
     return asset
   }
@@ -98,8 +99,12 @@ export class AssetService extends Asset {
   }
 
   public async updateActiveAssetData(activeAssetData: ActiveLoanData[keyof ActiveLoanData]) {
+    const oldOutstaidingInterest = this.outstandingInterest
+    const oldTotalRepaidInterest = this.totalRepaidInterest
     Object.assign(this, activeAssetData)
-    logger.info(`Updating outstanding debt for asset: ${this.id} to ${this.outstandingDebt.toString()}`)
+    const deltaRepaidInterestAmount = this.totalRepaid - oldTotalRepaidInterest
+    this.interestAccruedByPeriod = this.outstandingInterest - oldOutstaidingInterest + deltaRepaidInterestAmount
+    logger.info(`Updated outstanding debt for asset: ${this.id} to ${this.outstandingDebt.toString()}`)
   }
 
   public async updateItemMetadata() {
diff --git a/src/mappings/services/poolService.ts b/src/mappings/services/poolService.ts
index da002251..a7538004 100644
--- a/src/mappings/services/poolService.ts
+++ b/src/mappings/services/poolService.ts
@@ -69,6 +69,7 @@ export class PoolService extends Pool {
     this.sumAccruedAmountByPeriod = BigInt(0)
     this.sumPaidAmountByPeriod = BigInt(0)
     this.deltaPortfolioValuationByPeriod = BigInt(0)
+    this.sumInterestAccruedByPeriod = BigInt(0)
 
     this.sumBorrowedAmount = BigInt(0)
     this.sumRepaidAmount = BigInt(0)
@@ -261,6 +262,11 @@ export class PoolService extends Pool {
     this.sumDebtWrittenOffByPeriod += amount
   }
 
+  public increaseInterestAccrued(amount: bigint) {
+    logger.info(`Increasing interestAccrued by ${amount}`)
+    this.sumInterestAccruedByPeriod += amount
+  }
+
   public async getTranches() {
     const poolResponse = await api.query.poolSystem.pool<Option<PoolDetails>>(this.id)
     logger.info(`Fetching tranches for pool: ${this.id}`)