Fix timezone handling for calendar events

Events with explicit timezones (e.g., India Standard Time) were being displayed in the wrong time. The issue was that ical.js Time objects contain the correct time components but toJSDate() interprets them as local time.

Added convertIcalTimeToDate() method that:
- Extracts time components directly from ICAL Time objects
- Creates DateTime objects in the specified timezone
- Properly converts to local timezone for display

Also updated Time type definitions to include year, month, day, hour, minute, second properties.

src/services/CalendarService.ts

@@ -415,18 +415,18 @@ export class CalendarService {
     let next: Time | null;
 
     while ((next = iterator.next())) {
-      const occurStart = next.toJSDate();
-      const occurEnd = this.calculateEndDate(next, event.duration);
-
-      const startDate = this.convertTimezone(occurStart, tzid);
-      const endDate = this.convertTimezone(occurEnd, tzid);
+      // Use the ICAL Time object directly for proper timezone handling
+      const startDate = this.convertIcalTimeToDate(next, tzid);
+      const endTime = next.clone();
+      endTime.addDuration(event.duration);
+      const endDate = this.convertIcalTimeToDate(endTime, tzid);
 
       if (startDate > periodEnd) break;
 
-      const dateStr = occurStart.toISOString().substring(0, 10);
+      const dateStr = next.toJSDate().toISOString().substring(0, 10);
       const recKey = `${event.uid}-${dateStr}`;
 
-      if (this.shouldSkipOccurrence(occurStart, excludedDates, recurrenceExceptions, recKey)) {
+      if (this.shouldSkipOccurrence(next.toJSDate(), excludedDates, recurrenceExceptions, recKey)) {
         const exception = this.processException(
           recurrenceExceptions.get(recKey),
           source,
@@ -459,8 +459,8 @@ export class CalendarService {
     source: CalendarSource,
     tzid: string | null
   ): CalendarEvent[] {
-    const startDate = this.convertTimezone(event.startDate.toJSDate(), tzid);
-    const endDate = this.convertTimezone(event.endDate.toJSDate(), tzid);
+    const startDate = this.convertIcalTimeToDate(event.startDate, tzid);
+    const endDate = this.convertIcalTimeToDate(event.endDate, tzid);
 
     return [{
       id: event.uid,
@@ -555,21 +555,80 @@ export class CalendarService {
     return paramTzid || defaultTzid;
   }
 
-  private convertTimezone(date: Date, tzid: string | null): Date {
+  private convertIcalTimeToDate(icalTime: Time, tzid: string | null): Date {
     try {
-      const zone = tzid 
-        ? (CalendarService.TIMEZONE_MAP[tzid] || tzid)
-        : "UTC";
+      // Get the time components from the ICAL Time object
+      const year = icalTime.year;
+      const month = icalTime.month;
+      const day = icalTime.day;
+      const hour = icalTime.hour;
+      const minute = icalTime.minute;
+      const second = icalTime.second;
 
-      let dt = DateTime.fromJSDate(date, { zone });
-
-      if (!dt.isValid) {
-        dt = DateTime.fromJSDate(date, { zone: "UTC" });
+      // If no timezone specified, create date in local timezone
+      if (!tzid) {
+        return new Date(year, month - 1, day, hour, minute, second);
       }
 
+      // Map Windows timezone names to IANA timezone identifiers
+      const zone = CalendarService.TIMEZONE_MAP[tzid] || tzid;
+
+      // Create a DateTime object in the specified timezone
+      let dt = DateTime.fromObject(
+        { year, month, day, hour, minute, second },
+        { zone }
+      );
+
+      if (!dt.isValid) {
+        console.warn(`Invalid timezone conversion for zone: ${zone}, falling back to local time`);
+        return new Date(year, month - 1, day, hour, minute, second);
+      }
+
+      // Convert to local timezone
       return dt.toLocal().toJSDate();
     } catch (error) {
-      console.error("Failed to convert timezone:", error);
+      console.error("Failed to convert ICAL time:", error, { icalTime, tzid });
+      // Fallback to simple date creation
+      return new Date(icalTime.year, icalTime.month - 1, icalTime.day, 
+                      icalTime.hour, icalTime.minute, icalTime.second);
+    }
+  }
+
+  private convertTimezone(date: Date, tzid: string | null): Date {
+    try {
+      // If no timezone specified, assume the date is already in local time
+      if (!tzid) {
+        return date;
+      }
+
+      // Map Windows timezone names to IANA timezone identifiers
+      const zone = CalendarService.TIMEZONE_MAP[tzid] || tzid;
+
+      // The date from ical.js is parsed as if it were in UTC, but it's actually
+      // in the timezone specified by tzid. We need to interpret it correctly.
+      // First, get the date components as if they were in the target timezone
+      const year = date.getUTCFullYear();
+      const month = date.getUTCMonth() + 1;
+      const day = date.getUTCDate();
+      const hour = date.getUTCHours();
+      const minute = date.getUTCMinutes();
+      const second = date.getUTCSeconds();
+
+      // Create a DateTime object in the specified timezone
+      let dt = DateTime.fromObject(
+        { year, month, day, hour, minute, second },
+        { zone }
+      );
+
+      if (!dt.isValid) {
+        console.warn(`Invalid timezone conversion for zone: ${zone}, using original date`);
+        return date;
+      }
+
+      // Convert to local timezone
+      return dt.toLocal().toJSDate();
+    } catch (error) {
+      console.error("Failed to convert timezone:", error, { date, tzid });
       return date;
     }
   }

src/types/ical.d.ts

@@ -29,6 +29,14 @@ declare module "ical.js" {
 
   export class Time {
     constructor();
+    year: number;
+    month: number;
+    day: number;
+    hour: number;
+    minute: number;
+    second: number;
+    isDate: boolean;
+    timezone: string;
     toJSDate(): Date;
     fromJSDate(date: Date): void;
     clone(): Time;