Fixed the display date of the calendar items. Created test project for core library, included tests for recurring calendar events.

Wino.Core.Domain/Entities/Calendar/CalendarItem.cs

@@ -27,9 +27,6 @@ public class CalendarItem : ICalendarItem
         }
     }
 
-    public TimeSpan StartDateOffset { get; set; }
-    public TimeSpan EndDateOffset { get; set; }
-
     /// <summary>
     /// IANA timezone identifier for the start time (e.g., "America/New_York", "Europe/London").
     /// If null or empty, UTC is assumed.
@@ -180,8 +177,6 @@ public class CalendarItem : ICalendarItem
             Status = Status,
             CustomEventColorHex = CustomEventColorHex,
             HtmlLink = HtmlLink,
-            StartDateOffset = StartDateOffset,
-            EndDateOffset = EndDateOffset,
             StartTimeZone = StartTimeZone,
             EndTimeZone = EndTimeZone,
             RemoteEventId = RemoteEventId,
@@ -194,7 +189,7 @@ public class CalendarItem : ICalendarItem
     /// <summary>
     /// Gets the start date as a DateTimeOffset with the correct timezone.
     /// If StartTimeZone is available, uses it to calculate the offset.
-    /// Otherwise, uses the stored StartDateOffset or assumes UTC.
+    /// Otherwise, assumes UTC (StartDate is stored as UTC in database).
     /// </summary>
     [Ignore]
     public DateTimeOffset StartDateTimeOffset
@@ -206,24 +201,27 @@ public class CalendarItem : ICalendarItem
                 try
                 {
                     var timeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById(StartTimeZone);
-                    var offset = timeZoneInfo.GetUtcOffset(StartDate);
-                    return new DateTimeOffset(StartDate, offset);
+                    // StartDate is stored in UTC, convert to the specified timezone
+                    var utcDateTime = DateTime.SpecifyKind(StartDate, DateTimeKind.Utc);
+                    var zonedDateTime = TimeZoneInfo.ConvertTimeFromUtc(utcDateTime, timeZoneInfo);
+                    var offset = timeZoneInfo.GetUtcOffset(zonedDateTime);
+                    return new DateTimeOffset(zonedDateTime, offset);
                 }
                 catch
                 {
-                    // If timezone lookup fails, fall back to stored offset
+                    // If timezone lookup fails, assume UTC
                 }
             }
 
-            // Fall back to stored offset, or UTC if offset is zero
-            return new DateTimeOffset(StartDate, StartDateOffset);
+            // Assume UTC (StartDate is stored as UTC in database)
+            return new DateTimeOffset(StartDate, TimeSpan.Zero);
         }
     }
 
     /// <summary>
     /// Gets the end date as a DateTimeOffset with the correct timezone.
     /// If EndTimeZone is available, uses it to calculate the offset.
-    /// Otherwise, uses the stored EndDateOffset or assumes UTC.
+    /// Otherwise, assumes UTC (EndDate is stored as UTC in database).
     /// </summary>
     [Ignore]
     public DateTimeOffset EndDateTimeOffset
@@ -235,17 +233,20 @@ public class CalendarItem : ICalendarItem
                 try
                 {
                     var timeZoneInfo = TimeZoneInfo.FindSystemTimeZoneById(EndTimeZone);
-                    var offset = timeZoneInfo.GetUtcOffset(EndDate);
-                    return new DateTimeOffset(EndDate, offset);
+                    // EndDate is stored in UTC, convert to the specified timezone
+                    var utcDateTime = DateTime.SpecifyKind(EndDate, DateTimeKind.Utc);
+                    var zonedDateTime = TimeZoneInfo.ConvertTimeFromUtc(utcDateTime, timeZoneInfo);
+                    var offset = timeZoneInfo.GetUtcOffset(zonedDateTime);
+                    return new DateTimeOffset(zonedDateTime, offset);
                 }
                 catch
                 {
-                    // If timezone lookup fails, fall back to stored offset
+                    // If timezone lookup fails, assume UTC
                 }
             }
 
-            // Fall back to stored offset, or UTC if offset is zero
-            return new DateTimeOffset(EndDate, EndDateOffset);
+            // Assume UTC (EndDate is stored as UTC in database)
+            return new DateTimeOffset(EndDate, TimeSpan.Zero);
         }
     }
 }

Wino.Core.Domain/Interfaces/ICalendarService.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Threading.Tasks;
+using Itenso.TimePeriod;
 using Wino.Core.Domain.Entities.Calendar;
 using Wino.Core.Domain.Models.Calendar;
 
@@ -16,7 +17,15 @@ public interface ICalendarService
     Task InsertAccountCalendarAsync(AccountCalendar accountCalendar);
     Task UpdateAccountCalendarAsync(AccountCalendar accountCalendar);
     Task CreateNewCalendarItemAsync(CalendarItem calendarItem, List<CalendarEventAttendee> attendees);
-    Task<List<CalendarItem>> GetCalendarEventsAsync(IAccountCalendar calendar, DayRangeRenderModel dayRangeRenderModel);
+    
+    /// <summary>
+    /// Retrieves calendar events for a given calendar within the specified time period.
+    /// </summary>
+    /// <param name="calendar">The calendar to retrieve events from.</param>
+    /// <param name="period">The time period to query events for.</param>
+    /// <returns>List of calendar items including regular events and recurring event occurrences.</returns>
+    Task<List<CalendarItem>> GetCalendarEventsAsync(IAccountCalendar calendar, ITimePeriod period);
+    
     Task<CalendarItem> GetCalendarItemAsync(Guid accountCalendarId, string remoteEventId);
     Task UpdateCalendarDeltaSynchronizationToken(Guid calendarId, string deltaToken);
 

Wino.Core.Domain/Interfaces/IStatePersistenceService.cs

@@ -28,6 +28,16 @@ public interface IStatePersistanceService : INotifyPropertyChanged
     /// </summary>
     bool IsBackButtonVisible { get; }
 
+    /// <summary>
+    /// Current application mode (Mail or Calendar).
+    /// Not persisted to configuration, only kept in memory.
+    /// </summary>
+    WinoApplicationMode ApplicationMode { get; set; }
+
+    /// <summary>
+    /// Whether event details page is visible in Calendar mode.
+    /// </summary>
+    bool IsEventDetailsVisible { get; set; }
 
     /// <summary>
     /// Setting: Opened pane length for the navigation view.

Wino.Core.Domain/Interfaces/IWinoNavigationService.cs

@@ -12,6 +12,6 @@ public interface INavigationService
                          NavigationTransitionType transition = NavigationTransitionType.None);
 
     Type GetPageType(WinoPage winoPage);
-    void GoBack();
     bool ChangeApplicationMode(WinoApplicationMode mode);
+    void GoBack();
 }

Wino.Core.Domain/Models/Calendar/DayRangeRenderModel.cs

@@ -18,6 +18,8 @@ public class DayRangeRenderModel
     public List<DayHeaderRenderModel> DayHeaders { get; } = [];
     public CalendarRenderOptions CalendarRenderOptions { get; }
 
+    public int TotalDays => CalendarRenderOptions.TotalDayCount;
+
     public DayRangeRenderModel(CalendarRenderOptions calendarRenderOptions)
     {
         CalendarRenderOptions = calendarRenderOptions;