From 8498888a589df9c685514bf728aad90bd56eb243 Mon Sep 17 00:00:00 2001
From: Kannan <kannans02001@gmail.com>
Date: Wed, 24 Jun 2026 11:21:52 +0530
Subject: [PATCH] fix: display booking times in IST instead of UTC in emails
 and notifications

- Replace hardcoded timeZone: UTC with Asia/Kolkata in
  sendBookingConfirmation and sendBookingCancelled (email.service.ts)
- Replace bare date-fns format() calls (server-local timezone) with
  Intl toLocaleString IST-aware formatting in mentor-booking.service.ts
- Append IST label to all user-facing date strings for clarity
- Remove unused `format` import from date-fns

Fixes booking confirmation and cancellation emails showing wrong time
(e.g. 3:30 AM instead of 9:00 AM IST for IST-scheduled sessions)
---
 .../src/infrastructure/email/email.service.ts | 32 +++++++++++--------
 .../services/mentor/mentor-booking.service.ts | 14 ++++++--
 2 files changed, 29 insertions(+), 17 deletions(-)

diff --git a/backend/src/infrastructure/email/email.service.ts b/backend/src/infrastructure/email/email.service.ts
index 5fca0f6..83f744f 100644
--- a/backend/src/infrastructure/email/email.service.ts
+++ b/backend/src/infrastructure/email/email.service.ts
@@ -96,15 +96,16 @@ export class EmailService implements IEmailService {
   }
 
   async sendBookingConfirmation(data: BookingConfirmationEmailData): Promise<void> {
-    const startFormatted = data.startTime.toLocaleString('en-US', {
-      timeZone: 'UTC',
-      weekday: 'long', year: 'numeric', month: 'long', day: 'numeric',
-      hour: '2-digit', minute: '2-digit',
-    });
-    const endFormatted = data.endTime.toLocaleString('en-US', {
-      timeZone: 'UTC',
-      hour: '2-digit', minute: '2-digit',
-    });
+    const formatIST = (date: Date, opts: Intl.DateTimeFormatOptions): string =>
+      date.toLocaleString('en-IN', { timeZone: 'Asia/Kolkata', ...opts });
+
+    const startFormatted =
+      formatIST(data.startTime, {
+        weekday: 'long', year: 'numeric', month: 'long', day: 'numeric',
+        hour: '2-digit', minute: '2-digit',
+      }) + ' IST';
+    const endFormatted =
+      formatIST(data.endTime, { hour: '2-digit', minute: '2-digit' }) + ' IST';
 
     try {
       await this._transporter.sendMail({
@@ -134,11 +135,14 @@ export class EmailService implements IEmailService {
   }
 
   async sendBookingCancelled(data: BookingCancelledEmailData): Promise<void> {
-    const startFormatted = data.startTime.toLocaleString('en-US', {
-      timeZone: 'UTC',
-      weekday: 'long', year: 'numeric', month: 'long', day: 'numeric',
-      hour: '2-digit', minute: '2-digit',
-    });
+    const formatIST = (date: Date, opts: Intl.DateTimeFormatOptions): string =>
+      date.toLocaleString('en-IN', { timeZone: 'Asia/Kolkata', ...opts });
+
+    const startFormatted =
+      formatIST(data.startTime, {
+        weekday: 'long', year: 'numeric', month: 'long', day: 'numeric',
+        hour: '2-digit', minute: '2-digit',
+      }) + ' IST';
 
     try {
       await this._transporter.sendMail({
diff --git a/backend/src/services/mentor/mentor-booking.service.ts b/backend/src/services/mentor/mentor-booking.service.ts
index f49574c..f4ac2f3 100644
--- a/backend/src/services/mentor/mentor-booking.service.ts
+++ b/backend/src/services/mentor/mentor-booking.service.ts
@@ -1,4 +1,4 @@
-import { isAfter, differenceInHours, format } from 'date-fns';
+import { isAfter, differenceInHours } from 'date-fns';
 import { IMentorBookingService, MentorDashboardStats } from '../../interfaces/service-interfaces/mentor/IMentorBookingService';
 import { Types } from 'mongoose';
 import { IMentorBookingRepository } from '../../interfaces/repository-interfaces/mentor/IMentorBookingRepository';
@@ -130,7 +130,11 @@ export class MentorBookingService implements IMentorBookingService {
       }
 
       const bookingId    = (booking._id as { toString(): string }).toString();
-      const formattedTime = format(startTime, 'MMM d, yyyy \'at\' h:mm a');
+      const formattedTime = startTime.toLocaleString('en-IN', {
+        timeZone: 'Asia/Kolkata',
+        month: 'short', day: 'numeric', year: 'numeric',
+        hour: 'numeric', minute: '2-digit',
+      }) + ' IST';
 
       // Candidate: "Your session is confirmed"
       void this.notificationService.create({
@@ -192,7 +196,11 @@ export class MentorBookingService implements IMentorBookingService {
         return;
       }
 
-      const formattedTime    = format(booking.startTime, 'MMM d, yyyy \'at\' h:mm a');
+      const formattedTime = booking.startTime.toLocaleString('en-IN', {
+        timeZone: 'Asia/Kolkata',
+        month: 'short', day: 'numeric', year: 'numeric',
+        hour: 'numeric', minute: '2-digit',
+      }) + ' IST';
       const cancelledByName  = cancelledBy.fullName;
 
       const sharedData = {