Single isntances and some updates shit.

Wino.Core.Domain/Interfaces/ICalendarItemViewModel.cs

@@ -1,4 +1,8 @@
-namespace Wino.Core.Domain.Interfaces;
+using Itenso.TimePeriod;
+using Wino.Core.Domain.Entities.Calendar;
+using Wino.Core.Domain.Models.Calendar;
+
+namespace Wino.Core.Domain.Interfaces;
 
 /// <summary>
 /// Temporarily to enforce CalendarItemViewModel. Used in CalendarEventCollection.
@@ -6,4 +10,21 @@
 public interface ICalendarItemViewModel
 {
     bool IsSelected { get; set; }
+
+    /// <summary>
+    /// The period of the day where this item is currently being displayed.
+    /// </summary>
+    ITimePeriod DisplayingPeriod { get; set; }
+
+    /// <summary>
+    /// Calendar settings for time formatting.
+    /// </summary>
+    CalendarSettings CalendarSettings { get; set; }
+
+    /// <summary>
+    /// Updates the view model's underlying CalendarItem from new data.
+    /// This allows in-place updates without removing and re-adding items.
+    /// </summary>
+    /// <param name="calendarItem">The updated calendar item data.</param>
+    void UpdateFrom(CalendarItem calendarItem);
 }