feat: Enhance date handling by implementing timezone utilities for consistent IST management across components and services

Author: codevoid048

client-test/src/components/Admin/datepicker.tsx

@@ -4,6 +4,7 @@ import { motion, AnimatePresence } from "framer-motion";
 import { Calendar as CalendarIcon, ChevronLeft, ChevronRight } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Label } from "@/components/ui/label";
+import { isPastDateIST, istToUTC } from "@/lib/timezone";
 
 interface DatePickerProps {
   selectedDate: Date;
@@ -52,12 +53,7 @@ const DatePicker: React.FC<DatePickerProps> = ({ selectedDate, onChange, label,
 
   // Check if date is in the past (comparing against IST midnight)
   const isPastDate = (date: Date) => {
-    const today = new Date();
-    // Get current IST date by adding offset
-    const istOffset = 5.5 * 60 * 60 * 1000; // 5.5 hours in milliseconds
-    const istDate = new Date(today.getTime() + istOffset);
-    istDate.setUTCHours(18, 30, 0, 0); // Set to previous day 18:30 UTC (00:00 IST)
-    return date < istDate;
+    return isPastDateIST(date);
   };
 
   // Navigate to previous month
@@ -73,11 +69,14 @@ const DatePicker: React.FC<DatePickerProps> = ({ selectedDate, onChange, label,
   // Handle date selection and set to midnight IST (UTC+5:30)
   const selectDate = (day: number) => {
     // Create date at midnight IST
-    const newDate = new Date(currentMonth.getFullYear(), currentMonth.getMonth(), day);
-    // Set to midnight IST by adjusting for UTC offset
-    // First, set to previous day 18:30 UTC (equivalent to 00:00 IST next day)
-    newDate.setUTCHours(18, 30, 0, 0);
-    onChange(newDate);
+    const istDate = new Date(currentMonth.getFullYear(), currentMonth.getMonth(), day);
+    istDate.setHours(0, 0, 0, 0); // Set to midnight IST
+
+    // Convert IST date to UTC for storage
+    const utcDate = istToUTC(istDate);
+    if (utcDate) {
+      onChange(utcDate);
+    }
     setShowCalendar(false);
   };
 

client-test/src/components/ProfilePage/index.tsx

@@ -0,0 +1,78 @@
+/**
+ * Client-side timezone utility for consistent IST (Indian Standard Time) handling
+ * All business logic uses IST dates, database stores UTC
+ */
+
+const IST_OFFSET_MS = 5.5 * 60 * 60 * 1000; // IST is UTC+5:30
+
+/**
+ * Get current date/time in IST
+ */
+export const getISTNow = () => {
+  return new Date(Date.now() + IST_OFFSET_MS);
+};
+
+/**
+ * Convert UTC date to IST date
+ */
+export const utcToIST = (utcDate: Date) => {
+  if (!utcDate) return null;
+  return new Date(utcDate.getTime() + IST_OFFSET_MS);
+};
+
+/**
+ * Convert IST date to UTC date
+ */
+export const istToUTC = (istDate: Date) => {
+  if (!istDate) return null;
+  return new Date(istDate.getTime() - IST_OFFSET_MS);
+};
+
+/**
+ * Get IST date boundaries for a given date (defaults to today)
+ * Returns UTC dates that correspond to IST day boundaries
+ */
+export const getISTDateBounds = (date: Date | null = null) => {
+  const referenceDate = date || getISTNow();
+
+  // Create IST date boundaries
+  const istDate = new Date(referenceDate);
+  istDate.setHours(0, 0, 0, 0);
+
+  const istTomorrow = new Date(istDate);
+  istTomorrow.setDate(istTomorrow.getDate() + 1);
+
+  // Convert back to UTC for database queries
+  return {
+    start: istToUTC(istDate),
+    end: istToUTC(istTomorrow)
+  };
+};
+
+/**
+ * Format date to IST date string (YYYY-MM-DD)
+ */
+export const formatISTDateString = (date: Date | null = null) => {
+  const istDate = date ? utcToIST(date) : getISTNow();
+  if (!istDate) return '';
+  return istDate.toISOString().split('T')[0];
+};
+
+/**
+ * Check if date is in the past compared to current IST date
+ */
+export const isPastDateIST = (date: Date) => {
+  const todayIST = getISTNow();
+  const dateIST = utcToIST(date);
+
+  if (!dateIST) return false;
+
+  // Compare dates by setting both to start of day
+  const todayStart = new Date(todayIST);
+  todayStart.setHours(0, 0, 0, 0);
+
+  const dateStart = new Date(dateIST);
+  dateStart.setHours(0, 0, 0, 0);
+
+  return dateStart < todayStart;
+};

client-test/src/lib/timezone.ts

@@ -4,6 +4,7 @@ import { Solution } from "../models/Solution.js";
 import { Category } from '../models/Category.js';
 import { ensureCategoriesExist } from "../utils/categoryHelper.js";
 import auditService from "../services/auditService.js";
+import { getISTDateBounds, istToUTC } from "../utils/timezone.js";
 
 export const getUsers = async (req, res) => {
     try {
@@ -98,33 +99,26 @@ export const addChallenge = async (req, res) => {
             solution,
         } = req.body;
 
-        // Convert createdAt to midnight IST (18:30 UTC of previous day)
         let scheduleDate;
         if (createdAt) {
-            const date = new Date(createdAt);
-            // Set to 18:30:00 UTC of the previous day (00:00 IST of selected day)
-            date.setUTCHours(18, 30, 0, 0);
-            scheduleDate = date;
+            const istDate = new Date(createdAt);
+            istDate.setHours(0, 0, 0, 0);
+            scheduleDate = istToUTC(istDate);
         } else {
-            // If no date provided, use next day midnight IST
-            const now = new Date();
-            const tomorrow = new Date(now);
-            tomorrow.setDate(tomorrow.getDate() + 1);
-            tomorrow.setUTCHours(18, 30, 0, 0);
-            scheduleDate = tomorrow;
+            const tomorrowIST = new Date();
+            tomorrowIST.setDate(tomorrowIST.getDate() + 1);
+            tomorrowIST.setHours(0, 0, 0, 0);
+            scheduleDate = istToUTC(tomorrowIST);
         }
 
-        // Validate required fields
         if (!title || !description || !category || !difficulty || !points || !problemLink || !platform) {
             return res.status(400).json({ success: false, message: "All fields are required" });
         }
 
-        // Ensure category is an array of strings
         if (!Array.isArray(category)) {
             return res.status(400).json({ success: false, message: "Category must be an array of strings" });
         }
 
-        // Ensure categories exist in database (create if they don't)
         await ensureCategoriesExist(category);
 
         const newChallenge = new Challenge({
@@ -142,7 +136,6 @@ export const addChallenge = async (req, res) => {
 
         let savedSolution = null;
         if (solution) {
-            // Create solution with all fields, including explanation
             const newSolution = new Solution({
                 explanation: solution.explanation || "No explanation provided",
                 cpp: solution.cpp || "",
@@ -188,13 +181,11 @@ export const updateChallenge = async (req, res) => {
             solution,
         } = req.body;
 
-        // Convert createdAt to midnight IST if provided
         let scheduleDate;
         if (createdAt) {
-            const date = new Date(createdAt);
-            // Set to 18:30:00 UTC of the previous day (00:00 IST of selected day)
-            date.setUTCHours(18, 30, 0, 0);
-            scheduleDate = date;
+            const istDate = new Date(createdAt);
+            istDate.setHours(0, 0, 0, 0);
+            scheduleDate = istToUTC(istDate);
         }
         if (!challengeId) {
             return res.status(400).json({ success: false, message: "Challenge ID is required" });
@@ -203,11 +194,10 @@ export const updateChallenge = async (req, res) => {
         if (!challenge) {
             return res.status(404).json({ success: false, message: "Challenge not found" });
         }
-        // Update challenge fields if provided
+
         if (title) challenge.title = title;
         if (description) challenge.description = description;
         if (category) {
-            // Ensure new categories exist (create if they don't)
             await ensureCategoriesExist(category);
             challenge.category = category;
         }
@@ -268,26 +258,12 @@ export const updateChallenge = async (req, res) => {
 // Example: GET /admin/getchallenge
 export const getTodayChallenge = async (req, res) => {
     try {
-        // Get current time in UTC
-        const now = new Date();
-
-        // Calculate today's and tomorrow's midnight in IST (18:30 UTC of previous day)
-        const todayIST = new Date(now);
-        todayIST.setUTCHours(18, 30, 0, 0);
-        if (now < todayIST) {
-            // If current time is before today's IST midnight, adjust to previous day
-            todayIST.setDate(todayIST.getDate() - 1);
-        }
-
-        const tomorrowIST = new Date(todayIST);
-        tomorrowIST.setDate(tomorrowIST.getDate() + 1);
+        const { start: todayUTC, end: tomorrowUTC } = getISTDateBounds();
 
-        // Find today's challenge using createdAt
-        // The dates are already in UTC since we set them using setUTCHours
         const challenge = await Challenge.findOne({
             createdAt: {
-                $gte: todayIST,
-                $lt: tomorrowIST
+                $gte: todayUTC,
+                $lt: tomorrowUTC
             }
         }).sort({ createdAt: -1 });
 
@@ -298,7 +274,6 @@ export const getTodayChallenge = async (req, res) => {
             });
         }
 
-        // Manually fetch related solution (since challenge schema has no `solution` field)
         const solution = await Solution.findOne({ challenge: challenge._id });
 
         return res.status(200).json({

server/controllers/adminControllers.js

@@ -8,26 +8,25 @@ import mongoose from "mongoose";
 // import { client } from "../utils/typesenseClient.js";
 import { warmupLeaderboardCache } from "../utils/leaderBoardCache.js";
 import auditService from "../services/auditService.js";
+import { getISTNow } from "../utils/timezone.js";
 import dotenv from "dotenv";
 
 dotenv.config();
 
 
 const setAuthCookies = (res, user, token) => {
-  // Store JWT in HTTP-only cookie
   res.cookie("jwt", token, {
     httpOnly: true,
     secure: process.env.NODE_ENV === "production",
     sameSite: process.env.NODE_ENV === "production" ? "Strict" : "Lax",
-    maxAge: 24 * 60 * 60 * 1000, // 1 day
+    maxAge: 24 * 60 * 60 * 1000,
   });
 
-  // Store user ID and email in HTTP-only cookie
   res.cookie("user", JSON.stringify({ id: user._id, email: user.email }), {
-    httpOnly: true, // Prevent JavaScript access
+    httpOnly: true,
     secure: process.env.NODE_ENV === "production",
     sameSite: process.env.NODE_ENV === "production" ? "Strict" : "Lax",
-    maxAge: 24 * 60 * 60 * 1000, // 1 day
+    maxAge: 24 * 60 * 60 * 1000,
   });
 };
 
@@ -116,8 +115,7 @@ export const registerUser = async (req, res) => {
 
       // Generate a 6-digit OTP
       const otp = crypto.randomInt(100000, 999999).toString();
-      const nowIST = new Date(new Date().toLocaleString('en-US', { timeZone: 'Asia/Kolkata' }));
-      const otpExpires = nowIST.getTime() + 5 * 60 * 1000; // OTP expires in 5 minutes
+      const otpExpires = getISTNow().getTime() + 5 * 60 * 1000;
 
       // Use upsert with atomic operation to prevent race conditions
       await User.findOneAndUpdate(
@@ -245,8 +243,7 @@ export const verifyEmail = async (req, res) => {
       return res.status(400).json({ error: "Email already verified, Please login" });
     }
 
-    const nowIST = new Date(new Date().toLocaleString('en-US', { timeZone: 'Asia/Kolkata' }));
-    if (user.otpExpires < nowIST.getTime()) {
+    if (user.otpExpires < getISTNow().getTime()) {
       auditService.authEvent('verification_failed', {
         requestId: req.auditContext?.requestId,
         email,
@@ -463,8 +460,7 @@ export const forgotPassword = async (req, res) => {
 
     // Save Token & Expiry in DB
     user.resetPasswordToken = resetToken;
-    const nowIST = new Date(new Date().toLocaleString('en-US', { timeZone: 'Asia/Kolkata' }));
-    user.resetPasswordExpires = nowIST.getTime() + 15 * 60 * 1000;
+    user.resetPasswordExpires = getISTNow().getTime() + 15 * 60 * 1000;
     await user.save();
 
     // Send Reset Link via Email
@@ -487,7 +483,7 @@ export const resetPassword = async (req, res) => {
     const decoded = jwt.verify(token, process.env.JWT_SECRET);
     const user = await User.findById(decoded.id);
 
-    const nowIST = new Date(new Date().toLocaleString('en-US', { timeZone: 'Asia/Kolkata' }));
+    const nowIST = getISTNow();
     if (!user || user.resetPasswordToken !== token || user.resetPasswordExpires < nowIST.getTime()) {
       return res.status(400).json({ message: "Invalid or expired token" });
     }

server/controllers/authController.js

@@ -1,5 +1,6 @@
 import cacheService from "../services/cacheService.js";
 import auditService from "../services/auditService.js";
+import { formatISTDateString } from "../utils/timezone.js";
 
 const CACHE_NAMESPACE = 'challenges';
 const CHALLENGE_TTL = 3600; // 1 hour
@@ -10,7 +11,7 @@ class ChallengeCacheService {
     // Cache today's challenge (POTD)
     async cacheTodaysChallenge(challengeData) {
         try {
-            const today = new Date().toISOString().split('T')[0];
+            const today = formatISTDateString();
             await cacheService.set(CACHE_NAMESPACE, `potd_${today}`, challengeData, POTD_TTL);
             await cacheService.set(CACHE_NAMESPACE, 'potd_latest', challengeData, POTD_TTL);
             auditService.cacheEvent('potd_cached', { date: today });
@@ -22,7 +23,7 @@ class ChallengeCacheService {
     // Get cached today's challenge
     async getCachedTodaysChallenge() {
         try {
-            const today = new Date().toISOString().split('T')[0];
+            const today = formatISTDateString();
             let potd = await cacheService.get(CACHE_NAMESPACE, `potd_${today}`);
 
             if (!potd) {

server/services/challengeCacheService.js

@@ -1,6 +1,7 @@
 import cron from 'node-cron';
 import { User } from '../models/User.js';
 import auditService from '../services/auditService.js';
+import { getISTNow, formatISTDateString } from './timezone.js';
 
 const getLastSolvedDate = (challenges = []) => {
     if (!challenges.length) return null;
@@ -23,13 +24,11 @@ const resetUserStreaks = async () => {
 
   try {
     // Use IST timezone for consistent date calculation
-    const now = new Date();
-    const istOffset = 5.5 * 60 * 60 * 1000;
-    const istNow = new Date(now.getTime() + istOffset);
+    const istNow = getISTNow();
 
     const yesterday = new Date(istNow);
     yesterday.setDate(istNow.getDate() - 1);
-    const yesterStr = yesterday.toISOString().split("T")[0];
+    const yesterStr = formatISTDateString(yesterday);
 
     auditService.systemEvent('streak_reset_started', { 
       targetDate: yesterStr,