From 466b755a3da64900c4da800b1d88875af8b644cf Mon Sep 17 00:00:00 2001
From: Moriz Wahl <moriz.wahl@gmx.de>
Date: Mon, 3 Apr 2023 15:55:15 +0200
Subject: [PATCH] middleware to ensure best possible decay displayed

---
 .../graphql/resolver/TransactionResolver.ts   |  4 +++-
 backend/src/middleware/fixDecayCalculation.ts | 24 +++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)
 create mode 100644 backend/src/middleware/fixDecayCalculation.ts

diff --git a/backend/src/graphql/resolver/TransactionResolver.ts b/backend/src/graphql/resolver/TransactionResolver.ts
index d855a0701..a968a9ebb 100644
--- a/backend/src/graphql/resolver/TransactionResolver.ts
+++ b/backend/src/graphql/resolver/TransactionResolver.ts
@@ -7,7 +7,7 @@ import { Transaction as dbTransaction } from '@entity/Transaction'
 import { TransactionLink as dbTransactionLink } from '@entity/TransactionLink'
 import { User as dbUser } from '@entity/User'
 import { Decimal } from 'decimal.js-light'
-import { Resolver, Query, Args, Authorized, Ctx, Mutation } from 'type-graphql'
+import { Resolver, Query, Args, Authorized, Ctx, Mutation, UseMiddleware } from 'type-graphql'
 
 import Paginated from '@arg/Paginated'
 import TransactionSendArgs from '@arg/TransactionSendArgs'
@@ -25,6 +25,7 @@ import {
   sendTransactionReceivedEmail,
 } from '@/emails/sendEmailVariants'
 import { EVENT_TRANSACTION_RECEIVE, EVENT_TRANSACTION_SEND } from '@/event/Event'
+import { fixDecayCalculation } from '@/middleware/fixDecayCalculation'
 import { Context, getUser } from '@/server/context'
 import LogError from '@/server/LogError'
 import { backendLogger as logger } from '@/server/logger'
@@ -184,6 +185,7 @@ export const executeTransaction = async (
 export class TransactionResolver {
   @Authorized([RIGHTS.TRANSACTION_LIST])
   @Query(() => TransactionList)
+  @UseMiddleware(fixDecayCalculation)
   async transactionList(
     @Args()
     { currentPage = 1, pageSize = 25, order = Order.DESC }: Paginated,
diff --git a/backend/src/middleware/fixDecayCalculation.ts b/backend/src/middleware/fixDecayCalculation.ts
new file mode 100644
index 000000000..7d25b7484
--- /dev/null
+++ b/backend/src/middleware/fixDecayCalculation.ts
@@ -0,0 +1,24 @@
+import { Decimal } from 'decimal.js-light'
+import { MiddlewareFn } from 'type-graphql'
+
+import { TransactionTypeId } from '@enum/TransactionTypeId'
+import { Transaction } from '@model/Transaction'
+import { TransactionList } from '@model/TransactionList'
+
+export const fixDecayCalculation: MiddlewareFn = async (
+  /* eslint-disable-next-line @typescript-eslint/no-unused-vars */
+  { root, args, context, info },
+  next,
+) => {
+  const result: TransactionList = (await next()) as TransactionList
+  const { transactions } = result
+  transactions.forEach((transaction: Transaction) => {
+    if (transaction.typeId !== TransactionTypeId.DECAY) {
+      const { balance, previousBalance, amount } = transaction
+      transaction.decay.decay = new Decimal(
+        Number(balance) - Number(amount) - Number(previousBalance),
+      ).toDecimalPlaces(2, Decimal.ROUND_HALF_UP)
+    }
+  })
+  return result
+}