From 55ff0ee96437bb60fb495520c243c264c9ed47e8 Mon Sep 17 00:00:00 2001
From: Moriz Wahl <moriz.wahl@gmx.de>
Date: Tue, 12 Apr 2022 22:52:51 +0200
Subject: [PATCH] add roundedDecay field to Decay Model. This is used to
 calibrate the decay since the last transaction

---
 backend/src/graphql/model/Decay.ts       | 5 +++++
 backend/src/graphql/model/Transaction.ts | 3 +++
 backend/src/util/decay.ts                | 5 +++++
 backend/src/util/virtualTransactions.ts  | 4 ++--
 4 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/backend/src/graphql/model/Decay.ts b/backend/src/graphql/model/Decay.ts
index 4416a738f..591294df5 100644
--- a/backend/src/graphql/model/Decay.ts
+++ b/backend/src/graphql/model/Decay.ts
@@ -4,6 +4,7 @@ import Decimal from 'decimal.js-light'
 interface DecayInterface {
   balance: Decimal
   decay: Decimal
+  roundedDecay: Decimal
   start: Date | null
   end: Date | null
   duration: number | null
@@ -14,6 +15,7 @@ export class Decay {
   constructor(data: DecayInterface) {
     this.balance = data.balance
     this.decay = data.decay
+    this.roundedDecay = data.roundedDecay
     this.start = data.start
     this.end = data.end
     this.duration = data.duration
@@ -25,6 +27,9 @@ export class Decay {
   @Field(() => Decimal)
   decay: Decimal
 
+  @Field(() => Decimal)
+  roundedDecay: Decimal
+
   @Field(() => Date, { nullable: true })
   start: Date | null
 
diff --git a/backend/src/graphql/model/Transaction.ts b/backend/src/graphql/model/Transaction.ts
index 523ca06bc..b6f75f745 100644
--- a/backend/src/graphql/model/Transaction.ts
+++ b/backend/src/graphql/model/Transaction.ts
@@ -20,6 +20,7 @@ export class Transaction {
       this.decay = new Decay({
         balance: transaction.balance.toDecimalPlaces(2, Decimal.ROUND_DOWN),
         decay: new Decimal(0),
+        roundedDecay: new Decimal(0),
         start: null,
         end: null,
         duration: null,
@@ -28,6 +29,8 @@ export class Transaction {
       this.decay = new Decay({
         balance: transaction.balance.toDecimalPlaces(2, Decimal.ROUND_DOWN),
         decay: transaction.decay.toDecimalPlaces(2, Decimal.ROUND_FLOOR),
+        // TODO
+        roundedDecay: new Decimal(0),
         start: transaction.decayStart,
         end: transaction.balanceDate,
         duration: Math.round(
diff --git a/backend/src/util/decay.ts b/backend/src/util/decay.ts
index 36f83f23f..48674dc50 100644
--- a/backend/src/util/decay.ts
+++ b/backend/src/util/decay.ts
@@ -29,6 +29,7 @@ function calculateDecay(
   const decay: Decay = {
     balance: amount,
     decay: new Decimal(0),
+    roundedDecay: new Decimal(0),
     start: null,
     end: null,
     duration: null,
@@ -52,6 +53,10 @@ function calculateDecay(
   decay.end = to
   decay.balance = decayFormula(amount, decay.duration)
   decay.decay = decay.balance.minus(amount)
+  decay.roundedDecay = amount
+    .toDecimalPlaces(2, Decimal.ROUND_DOWN)
+    .minus(decay.balance.toDecimalPlaces(2, Decimal.ROUND_DOWN).toString())
+    .mul(-1)
   return decay
 }
 
diff --git a/backend/src/util/virtualTransactions.ts b/backend/src/util/virtualTransactions.ts
index 920fc4201..2f37ad188 100644
--- a/backend/src/util/virtualTransactions.ts
+++ b/backend/src/util/virtualTransactions.ts
@@ -68,12 +68,12 @@ const virtualDecayTransaction = (
     userId: -1,
     previous: -1,
     typeId: TransactionTypeId.DECAY,
-    amount: decay.decay ? decay.decay.toDecimalPlaces(2, Decimal.ROUND_FLOOR) : new Decimal(0), // new Decimal(0), // this kinda is wrong, but helps with the frontend query
+    amount: decay.decay ? decay.roundedDecay : new Decimal(0), // this kinda is wrong, but helps with the frontend query
     balance: decay.balance
       .minus(holdAvailabeAmount.toString())
       .toDecimalPlaces(2, Decimal.ROUND_DOWN),
     balanceDate: time,
-    decay: decay.decay ? decay.decay.toDecimalPlaces(2, Decimal.ROUND_FLOOR) : new Decimal(0),
+    decay: decay.decay ? decay.roundedDecay : new Decimal(0),
     decayStart: decay.start,
     memo: '',
     creationDate: null,