From d284c6e940964fa96a54a8c049294ca32451bbb7 Mon Sep 17 00:00:00 2001
From: Zakhar Timoshenko <vp1984tanki@gmail.com>
Date: Thu, 17 Sep 2026 18:57:55 +0300
Subject: [PATCH] feat: update alert timestamps to use Minsk timezone for
 accurate display and input handling

---
 frontend/src/pages/AlertsPage.jsx | 34 ++++++++++++++++++++++++-------
 1 file changed, 27 insertions(+), 7 deletions(-)

diff --git a/frontend/src/pages/AlertsPage.jsx b/frontend/src/pages/AlertsPage.jsx
index 6eb3d57..725df3f 100644
--- a/frontend/src/pages/AlertsPage.jsx
+++ b/frontend/src/pages/AlertsPage.jsx
@@ -380,16 +380,16 @@ function AlertCard({ alert, index, onEdit, onDelete }) {
             <div className="text-xs text-gray-500">
               {alert.start_time && (
                 <div>
-                  Начало: {new Date(alert.start_time).toLocaleString('ru-RU')}
+                  Начало: {new Date(alert.start_time).toLocaleString('ru-RU', { timeZone: MINSK_TIME_ZONE })}
                 </div>
               )}
               {alert.end_time && (
                 <div>
-                  Конец: {new Date(alert.end_time).toLocaleString('ru-RU')}
+                  Конец: {new Date(alert.end_time).toLocaleString('ru-RU', { timeZone: MINSK_TIME_ZONE })}
                 </div>
               )}
               {status === 'scheduled' && <div className="mt-1 text-blue-700">Push будет отправлен в момент начала</div>}
-              {alert.notification_sent_at && <div className="mt-1 text-green-700">Push отправлен: {new Date(alert.notification_sent_at).toLocaleString('ru-RU')}</div>}
+              {alert.notification_sent_at && <div className="mt-1 text-green-700">Push отправлен: {new Date(alert.notification_sent_at).toLocaleString('ru-RU', { timeZone: MINSK_TIME_ZONE })}</div>}
             </div>
 
             <div className="flex gap-2">
@@ -416,11 +416,30 @@ function createAlertIdempotencyKey() {
   return `alert-${Date.now()}-${Math.random().toString(36).slice(2)}`;
 }
 
+const MINSK_TIME_ZONE = 'Europe/Minsk';
+const MINSK_OFFSET = '+03:00';
+
 function toDateTimeInput(value = new Date()) {
   const date = new Date(value);
   if (Number.isNaN(date.getTime())) return '';
-  const local = new Date(date.getTime() - date.getTimezoneOffset() * 60_000);
-  return local.toISOString().slice(0, 16);
+  const parts = new Intl.DateTimeFormat('en-CA', {
+    timeZone: MINSK_TIME_ZONE,
+    year: 'numeric', month: '2-digit', day: '2-digit',
+    hour: '2-digit', minute: '2-digit', hourCycle: 'h23'
+  }).formatToParts(date).reduce((result, part) => ({ ...result, [part.type]: part.value }), {});
+  return `${parts.year}-${parts.month}-${parts.day}T${parts.hour}:${parts.minute}`;
+}
+
+// PostgreSQL currently stores alert timestamps without a timezone. Keep UTC
+// values there, while the operator always sees and enters Polotsk time.
+function toApiDateTime(value) {
+  if (!value) return null;
+  const date = new Date(`${value}:00${MINSK_OFFSET}`);
+  return Number.isNaN(date.getTime()) ? value : date.toISOString().slice(0, 19);
+}
+
+function toMinskDate(value) {
+  return new Date(`${value}:00${MINSK_OFFSET}`);
 }
 
 function AlertForm({ alert, routes, templates, onSubmit, onCancel }) {
@@ -443,7 +462,8 @@ function AlertForm({ alert, routes, templates, onSubmit, onCancel }) {
     const data = {
       ...formData,
       route_id: formData.route_id || null,
-      end_time: formData.end_time || null
+      start_time: toApiDateTime(formData.start_time),
+      end_time: toApiDateTime(formData.end_time)
     };
 
     setSubmitting(true);
@@ -472,7 +492,7 @@ function AlertForm({ alert, routes, templates, onSubmit, onCancel }) {
     }));
   };
 
-  const startDate = new Date(formData.start_time);
+  const startDate = toMinskDate(formData.start_time);
   const isScheduled = formData.is_active && !Number.isNaN(startDate.getTime()) && startDate > new Date();
   const saveLabel = alert ? 'Сохранить' : !formData.is_active ? 'Сохранить черновик' : isScheduled ? 'Запланировать' : 'Опубликовать';