From 40f1583796d9abe01dd48b9a1b630592a3ad78fb Mon Sep 17 00:00:00 2001
From: "kihong.kim" <kihong.kim@yanolja.com>
Date: Sun, 1 Feb 2026 01:14:31 +0900
Subject: [PATCH] Fix: Update getDayRange to use Korea Standard Time (KST) for
 correct timezone handling

---
 backend/routes/todos.js | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/backend/routes/todos.js b/backend/routes/todos.js
index b0e422e..71cc11b 100644
--- a/backend/routes/todos.js
+++ b/backend/routes/todos.js
@@ -3,11 +3,26 @@ const Todo = require("../models/Todo");
 
 const router = express.Router();
 
-const getDayRange = (date = new Date()) => {
-  const start = new Date(date);
-  start.setHours(0, 0, 0, 0);
-  const end = new Date(date);
-  end.setHours(23, 59, 59, 999);
+// Get day range in Korea Standard Time (UTC+9)
+const getDayRange = () => {
+  const now = new Date();
+  // Get current time in KST (UTC+9)
+  const kstOffset = 9 * 60; // minutes
+  const utcTime = now.getTime() + (now.getTimezoneOffset() * 60000);
+  const kstTime = new Date(utcTime + (kstOffset * 60000));
+
+  // Start of day in KST
+  const startKst = new Date(kstTime);
+  startKst.setHours(0, 0, 0, 0);
+
+  // End of day in KST
+  const endKst = new Date(kstTime);
+  endKst.setHours(23, 59, 59, 999);
+
+  // Convert back to UTC for MongoDB query
+  const start = new Date(startKst.getTime() - (kstOffset * 60000));
+  const end = new Date(endKst.getTime() - (kstOffset * 60000));
+
   return { start, end };
 };