Fix incorrect shift assignments due to timezone conversion errors

Address timezone discrepancies by implementing a function to calculate the correct offset for Europe/Rome, ensuring accurate conversion of shift start and end times from local time to UTC for assignment processing.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: e0b5b11c-5b75-4389-8ea9-5f3cd9332f88
Replit-Commit-Checkpoint-Type: intermediate_checkpoint
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/6d543d2c-20b9-4ea6-93fe-70fe9b1d9f80/e0b5b11c-5b75-4389-8ea9-5f3cd9332f88/7VmWFMu

.replit

@@ -47,6 +47,10 @@ externalPort = 5000
 localPort = 43267
 externalPort = 3003
 
+[[ports]]
+localPort = 44369
+externalPort = 6000
+
 [env]
 PORT = "5000"
 

server/routes.ts

@@ -10,6 +10,31 @@ import { differenceInDays, differenceInHours, differenceInMinutes, startOfWeek,
 import { z } from "zod";
 import { fromZodError } from "zod-validation-error";
 
+/**
+ * Calcola l'offset di Europe/Rome rispetto a UTC per una data specifica.
+ * Italy: UTC+1 (ora solare inverno) / UTC+2 (ora legale estate)
+ * L'ora legale va dall'ultima domenica di marzo all'ultima domenica di ottobre
+ * @returns offset in ore (1 o 2)
+ */
+function getItalyTimezoneOffsetHours(date: Date): number {
+  const year = date.getFullYear();
+  
+  // Calcola ultima domenica di marzo (inizio ora legale)
+  const marchLastSunday = new Date(year, 2, 31);  // 31 marzo
+  marchLastSunday.setDate(31 - marchLastSunday.getDay()); // torna indietro alla domenica
+  
+  // Calcola ultima domenica di ottobre (fine ora legale)
+  const octoberLastSunday = new Date(year, 9, 31);  // 31 ottobre
+  octoberLastSunday.setDate(31 - octoberLastSunday.getDay()); // torna indietro alla domenica
+  
+  // L'ora legale inizia alle 02:00 UTC dell'ultima domenica di marzo
+  // e termina alle 03:00 UTC dell'ultima domenica di ottobre
+  const isDST = date >= marchLastSunday && date < octoberLastSunday;
+  
+  // UTC+1 (inverno) o UTC+2 (estate)
+  return isDST ? 2 : 1;
+}
+
 // Determina quale sistema auth usare basandosi sull'ambiente
 const USE_LOCAL_AUTH = process.env.DOMAIN === "vt.alfacom.it" || !process.env.REPLIT_DOMAINS;
 
@@ -1283,6 +1308,15 @@ export async function registerRoutes(app: Express): Promise<Server> {
     try {
       const { siteId, date, guardId, startTime, durationHours, consecutiveDays = 1, vehicleId, force = false } = req.body;
       
+      // DEBUG: Log per capire il problema timezone
+      console.log("🔍 DEBUG assign-guard - Input ricevuto:", {
+        date,
+        startTime,
+        durationHours,
+        serverTimezone: Intl.DateTimeFormat().resolvedOptions().timeZone,
+        serverOffset: new Date().getTimezoneOffset()
+      });
+      
       if (!siteId || !date || !guardId || !startTime || !durationHours) {
         return res.status(400).json({ 
           message: "Missing required fields: siteId, date, guardId, startTime, durationHours" 
@@ -1312,6 +1346,16 @@ export async function registerRoutes(app: Express): Promise<Server> {
       }
       const [hours, minutes] = startTime.split(":").map(Number);
       
+      // CRITICAL: Gli orari dal frontend sono in fuso orario Europe/Rome (UTC+1 o UTC+2)
+      // Calcola offset corretto per convertire a UTC
+      const italyOffsetHours = getItalyTimezoneOffsetHours(new Date(year, month - 1, day));
+      console.log("🕐 DEBUG Timezone setup:", { 
+        inputDate: date,
+        inputTime: `${String(hours).padStart(2,'0')}:${String(minutes).padStart(2,'0')}`,
+        italyOffsetHours,
+        isDST: italyOffsetHours === 2
+      });
+      
       // Atomic transaction: create assignments for all consecutive days
       const result = await db.transaction(async (tx) => {
         const createdAssignments = [];
@@ -1342,9 +1386,20 @@ export async function registerRoutes(app: Express): Promise<Server> {
             }
           }
           
-          // Calculate planned start and end times in LOCAL timezone
+          // Calculate planned start and end times converting from Europe/Rome to UTC
-          const plannedStart = new Date(actualYear, actualMonth, actualDay, hours, minutes, 0, 0);
+          // IMPORTANTE: l'utente inserisce orari in fuso orario Italia (Europe/Rome)
-          const plannedEnd = new Date(actualYear, actualMonth, actualDay, hours + durationHours, minutes, 0, 0);
+          // Il server è in UTC, quindi dobbiamo convertire Italy time → UTC
+          // Formula: UTC time = Italy time - offset
+          // Esempio: 09:00 Italy (UTC+2) = 07:00 UTC
+          const plannedStart = new Date(Date.UTC(actualYear, actualMonth, actualDay, hours - italyOffsetHours, minutes, 0, 0));
+          const plannedEnd = new Date(Date.UTC(actualYear, actualMonth, actualDay, hours + durationHours - italyOffsetHours, minutes, 0, 0));
+          
+          console.log("🕐 DEBUG Timestamp conversion:", {
+            inputTime: `${String(hours).padStart(2,'0')}:${String(minutes).padStart(2,'0')}`,
+            italyOffset: `UTC+${italyOffsetHours}`,
+            plannedStartUTC: plannedStart.toISOString(),
+            plannedEndUTC: plannedEnd.toISOString()
+          });
           
           // Find or create shift for this site/date (full day boundaries in LOCAL timezone)
           const dayStart = new Date(actualYear, actualMonth, actualDay, 0, 0, 0, 0);