feat: track future cashflows per asset

Fixes #196

schema.graphql

@@ -341,6 +341,15 @@ type AssetTransaction @entity {
   realizedProfitFifo: BigInt
 }
 
+type AssetCashflow @entity {
+  id: ID! # pool id - asset id - cf timestamp
+  asset: Asset! @index
+
+  timestamp: Date!
+  principal: BigInt!
+  interest: BigInt!
+}
+
 type OracleTransaction @entity {
   id: ID! # extrinsic hash - timestamp - oracle key
   timestamp: Date!

src/chaintypes.ts

@@ -36,6 +36,11 @@ const latestTypes = {
     bucket: 'CfgTraitsFeePoolFeeBucket',
     fees: 'Vec<CfgTypesPoolsPoolFee>',
   },
+  CashflowPayment: {
+    when: 'Seconds',
+    principal: 'Balance',
+    interest: 'Balance',
+  },
 }
 
 const definitions: OverrideBundleDefinition = {
@@ -73,6 +78,20 @@ const definitions: OverrideBundleDefinition = {
             ],
             type: 'Option<PalletLoansEntitiesLoansActiveLoan>',
           },
+          expected_cashflows: {
+            description: 'Retrieve expected cashflows',
+            params: [
+              {
+                name: 'pool_id',
+                type: 'u64',
+              },
+              {
+                name: 'loan_id',
+                type: 'u64',
+              },
+            ],
+            type: 'Vec<CashflowPayment>',
+          },
         },
         version: 2,
       },

src/helpers/types.ts

@@ -265,7 +265,7 @@ export interface LoanPricing extends Enum {
   asExternal: {
     priceId: OracleKey
     maxBorrowAmount: LoanExternalPricingMaxBorrowAmount
-    notional: u128,
+    notional: u128
     maxPriceVariation: u128
   }
 }
@@ -403,30 +403,36 @@ export interface PoolFee extends Struct {
 }
 
 export interface OracleKey extends Enum {
-  readonly isIsin: boolean;
-    readonly asIsin: U8aFixed;
-    readonly isConversionRatio: boolean;
-    readonly asConversionRatio: ITuple<[TokensCurrencyId, TokensCurrencyId]>;
-    readonly isPoolLoanId: boolean;
-    readonly asPoolLoanId: ITuple<[u64, u64]>;
-    readonly type: 'Isin' | 'ConversionRatio' | 'PoolLoanId';
+  readonly isIsin: boolean
+  readonly asIsin: U8aFixed
+  readonly isConversionRatio: boolean
+  readonly asConversionRatio: ITuple<[TokensCurrencyId, TokensCurrencyId]>
+  readonly isPoolLoanId: boolean
+  readonly asPoolLoanId: ITuple<[u64, u64]>
+  readonly type: 'Isin' | 'ConversionRatio' | 'PoolLoanId'
 }
 
 interface DevelopmentRuntimeOriginCaller extends Enum {
-  readonly isSystem: boolean;
-  readonly asSystem: unknown//FrameSupportDispatchRawOrigin;
-  readonly isVoid: boolean;
-  readonly isCouncil: boolean;
+  readonly isSystem: boolean
+  readonly asSystem: unknown //FrameSupportDispatchRawOrigin;
+  readonly isVoid: boolean
+  readonly isCouncil: boolean
   readonly asCouncil: unknown //PalletCollectiveRawOrigin;
-  readonly isLiquidityPoolsGateway: boolean;
+  readonly isLiquidityPoolsGateway: boolean
   readonly asLiquidityPoolsGateway: unknown //PalletLiquidityPoolsGatewayOriginGatewayOrigin;
-  readonly isPolkadotXcm: boolean;
-  readonly asPolkadotXcm: unknown//PalletXcmOrigin;
-  readonly isCumulusXcm: boolean;
+  readonly isPolkadotXcm: boolean
+  readonly asPolkadotXcm: unknown //PalletXcmOrigin;
+  readonly isCumulusXcm: boolean
   readonly asCumulusXcm: unknown //CumulusPalletXcmOrigin;
-  readonly isEthereum: boolean;
+  readonly isEthereum: boolean
   readonly asEthereum: unknown //PalletEthereumRawOrigin;
-  readonly type: 'System' | 'Void' | 'Council' | 'LiquidityPoolsGateway' | 'PolkadotXcm' | 'CumulusXcm' | 'Ethereum';
+  readonly type: 'System' | 'Void' | 'Council' | 'LiquidityPoolsGateway' | 'PolkadotXcm' | 'CumulusXcm' | 'Ethereum'
+}
+
+export interface CashflowPayment extends Struct {
+  when: u64
+  principal: Balance
+  interest: Balance
 }
 
 export type LoanAsset = ITuple<[collectionId: u64, itemId: u128]>
@@ -492,6 +498,7 @@ export type ExtendedRpc = typeof api.rpc & {
 export type ExtendedCall = typeof api.call & {
   loansApi: {
     portfolio: AugmentedCall<'promise', (poolId: string) => Observable<Vec<ITuple<[u64, LoanInfoActivePortfolio]>>>>
+    expectedCashflows: AugmentedCall<'promise', (poolId: string, loanId: string) => Observable<Vec<CashflowPayment>>>
   }
   poolsApi: {
     nav: AugmentedCall<'promise', (poolId: string) => Observable<Option<PoolNav>>>

src/mappings/handlers/loansHandlers.ts

@@ -18,6 +18,7 @@ import { AssetType, AssetValuationMethod } from '../../types'
 import { bnToBn, nToBigInt } from '@polkadot/util'
 import { WAD } from '../../config'
 import { AssetPositionService } from '../services/assetPositionService'
+import { AssetCashflowService } from '../services/assetCashflowService'
 
 export const handleLoanCreated = errorHandler(_handleLoanCreated)
 async function _handleLoanCreated(event: SubstrateEvent<LoanCreatedEvent>) {
@@ -96,6 +97,9 @@ async function _handleLoanCreated(event: SubstrateEvent<LoanCreatedEvent>) {
   // Update pool info
   await pool.increaseNumberOfAssets()
   await pool.save()
+
+  // Record cashflows
+  await AssetCashflowService.recordAssetCashflows(pool.id, asset.id)
 }
 
 export const handleLoanBorrowed = errorHandler(_handleLoanBorrowed)
@@ -168,6 +172,9 @@ async function _handleLoanBorrowed(event: SubstrateEvent<LoanBorrowedEvent>): Pr
     await epoch.save()
   }
   await asset.save()
+
+  // Record cashflows
+  await AssetCashflowService.recordAssetCashflows(pool.id, asset.id)
 }
 
 export const handleLoanRepaid = errorHandler(_handleLoanRepaid)
@@ -245,22 +252,28 @@ async function _handleLoanRepaid(event: SubstrateEvent<LoanRepaidEvent>) {
   }
 
   await asset.save()
+
+  // Record cashflows
+  await AssetCashflowService.recordAssetCashflows(pool.id, asset.id)
 }
 
 export const handleLoanWrittenOff = errorHandler(_handleLoanWrittenOff)
 async function _handleLoanWrittenOff(event: SubstrateEvent<LoanWrittenOffEvent>) {
   const [poolId, loanId, status] = event.event.data
   logger.info(`Loan writtenoff event for pool: ${poolId.toString()} loanId: ${loanId.toString()}`)
   const { percentage, penalty } = status
-  const loan = await AssetService.getById(poolId.toString(), loanId.toString())
-  await loan.writeOff(percentage.toBigInt(), penalty.toBigInt())
-  await loan.save()
+  const asset = await AssetService.getById(poolId.toString(), loanId.toString())
+  await asset.writeOff(percentage.toBigInt(), penalty.toBigInt())
+  await asset.save()
 
   const pool = await PoolService.getById(poolId.toString())
   if (pool === undefined) throw missingPool
 
-  await pool.increaseWriteOff(loan.writtenOffAmountByPeriod)
+  await pool.increaseWriteOff(asset.writtenOffAmountByPeriod)
   await pool.save()
+
+  // Record cashflows
+  await AssetCashflowService.recordAssetCashflows(pool.id, asset.id)
 }
 
 export const handleLoanClosed = errorHandler(_handleLoanClosed)
@@ -273,9 +286,9 @@ async function _handleLoanClosed(event: SubstrateEvent<LoanClosedEvent>) {
 
   const account = await AccountService.getOrInit(event.extrinsic.extrinsic.signer.toHex())
 
-  const loan = await AssetService.getById(poolId.toString(), loanId.toString())
-  await loan.close()
-  await loan.save()
+  const asset = await AssetService.getById(poolId.toString(), loanId.toString())
+  await asset.close()
+  await asset.save()
 
   const epoch = await EpochService.getById(pool.id, pool.currentEpoch)
   if (!epoch) throw new Error('Epoch not found!')
@@ -289,6 +302,9 @@ async function _handleLoanClosed(event: SubstrateEvent<LoanClosedEvent>) {
     timestamp: event.block.timestamp,
   })
   await at.save()
+
+  // Record cashflows
+  await AssetCashflowService.recordAssetCashflows(pool.id, asset.id)
 }
 
 export const handleLoanDebtTransferred = errorHandler(_handleLoanDebtTransferred)

src/mappings/services/assetCashflowService.ts

@@ -0,0 +1,29 @@
+import { ExtendedCall } from '../../helpers/types'
+import { AssetCashflow } from '../../types/models/AssetCashflow'
+
+export class AssetCashflowService extends AssetCashflow {
+  static init(poolId: string, assetId: string, timestamp: Date, principal: bigint, interest: bigint) {
+    logger.info(`Initialising new AssetCashflow with Id ${chainId}`)
+    return new this(
+      `${poolId}-${assetId}-${timestamp}`,
+      assetId,
+      timestamp,
+      principal,
+      interest
+    )
+  }
+
+  static async recordAssetCashflows(poolId: string, assetId: string) {
+    const specVersion = api.runtimeVersion.specVersion.toNumber()
+    if(specVersion < 1103) return
+    const apiCall = api.call as ExtendedCall
+    const response = await apiCall.loansApi.expectedCashflows(poolId, assetId)
+    const saves = response.map( ( cf ) => {
+      const { when, principal, interest } = cf
+      const timestamp = new Date(when.toNumber() * 1000)
+      const cashflow = this.init(poolId, assetId, timestamp, principal.toBigInt(), interest.toBigInt())
+      return cashflow.save()
+    })
+    return Promise.all(saves)
+  }
+}