From ba7ffaff92aa9c1d7840d7d171b7e4dbc8626706 Mon Sep 17 00:00:00 2001
From: sb <sb@MacBook-Pro.local>
Date: Tue, 7 Jul 2026 23:42:33 +0900
Subject: [PATCH] =?UTF-8?q?fix(entry):=20=EB=8C=80=EC=B6=9C=20=EC=83=81?=
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- 가계부에서 원리금균등 대출 선택 시 최초원금 PMT 추정값(옛 방식) 대신
  저장된 월 상환금을 그대로 사용 → 은행/상환표와 일치
- 잔액이 작은 마지막 회차는 원금을 잔액까지만(초과 상환 방지)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---
 src/views/account/AccountView.vue | 24 +++++++++++++++++-------
 1 file changed, 17 insertions(+), 7 deletions(-)

diff --git a/src/views/account/AccountView.vue b/src/views/account/AccountView.vue
index 137574c..6641711 100644
--- a/src/views/account/AccountView.vue
+++ b/src/views/account/AccountView.vue
@@ -173,13 +173,23 @@ const loanAutoResult = computed(() => {
     const principal = Math.round(Number(loan.loanAmount) / loan.loanMonths)
     return { interest, principal, total: principal + interest, needsInput: false }
   }
-  if (loan.loanMethod === 'EQUAL_PAYMENT' && loan.loanAmount && loan.loanMonths && loan.loanRate) {
-    // PMT 공식: M = P × r(1+r)^n / ((1+r)^n − 1)
-    const r = Number(loan.loanRate) / 100 / 12
-    const n = loan.loanMonths
-    const M = Math.round(Number(loan.loanAmount) * r * Math.pow(1 + r, n) / (Math.pow(1 + r, n) - 1))
-    const principal = Math.max(0, M - interest)
-    return { interest, principal, total: M, needsInput: false }
+  if (loan.loanMethod === 'EQUAL_PAYMENT') {
+    // 월 상환금이 저장돼 있으면 그대로 사용(은행과 일치) → 없으면 원금·개월수로 PMT 추정
+    let M = null
+    if (loan.loanPayment) {
+      M = Number(loan.loanPayment)
+    } else if (loan.loanAmount && loan.loanMonths && loan.loanRate) {
+      // PMT 공식: M = P × r(1+r)^n / ((1+r)^n − 1)
+      const r = Number(loan.loanRate) / 100 / 12
+      const n = loan.loanMonths
+      M = Math.round(Number(loan.loanAmount) * r * Math.pow(1 + r, n) / (Math.pow(1 + r, n) - 1))
+    }
+    if (M != null) {
+      // 마지막 회차 등 잔액이 작을 땐 원금을 잔액까지만(초과 상환 방지)
+      const bal = Math.abs(Number(loan.balance) || 0)
+      const principal = Math.min(Math.max(0, M - interest), bal)
+      return { interest, principal, total: principal + interest, needsInput: false }
+    }
   }
   return { interest: null, principal: null, total: null, needsInput: true }
 })