Encapsulation of grouped account selection events and collective events.

Wino.Calendar.ViewModels/Data/AccountCalendarViewModel.cs

@@ -8,8 +8,6 @@ namespace Wino.Calendar.ViewModels.Data
 {
     public partial class AccountCalendarViewModel : ObservableObject, IAccountCalendar
     {
-        public event EventHandler<AccountCalendarViewModel> CalendarSelectionStateChanged;
-
         public MailAccount Account { get; }
         public AccountCalendar AccountCalendar { get; }
 
@@ -24,11 +22,7 @@ namespace Wino.Calendar.ViewModels.Data
         [ObservableProperty]
         private bool _isChecked;
 
-        partial void OnIsCheckedChanged(bool value)
-        {
-            IsExtended = value;
-            CalendarSelectionStateChanged?.Invoke(this, this);
-        }
+        partial void OnIsCheckedChanged(bool value) => IsExtended = value;
 
         public string Name
         {
@@ -71,5 +65,6 @@ namespace Wino.Calendar.ViewModels.Data
             get => AccountCalendar.RemoteCalendarId;
             set => SetProperty(AccountCalendar.RemoteCalendarId, value, AccountCalendar, (u, r) => u.RemoteCalendarId = r);
         }
+        public Guid Id { get => ((IAccountCalendar)AccountCalendar).Id; set => ((IAccountCalendar)AccountCalendar).Id = value; }
     }
 }

Wino.Calendar.ViewModels/Data/CalendarItemViewModel.cs

@@ -1,13 +1,14 @@
 using System;
 using CommunityToolkit.Mvvm.ComponentModel;
 using Itenso.TimePeriod;
+using Wino.Core.Domain.Entities.Calendar;
 using Wino.Core.Domain.Interfaces;
 
 namespace Wino.Calendar.ViewModels.Data
 {
-    public partial class CalendarItemViewModel : ObservableObject, ICalendarItem
+    public partial class CalendarItemViewModel : ObservableObject, ICalendarItem, ICalendarItemViewModel
     {
-        public ICalendarItem CalendarItem { get; }
+        public CalendarItem CalendarItem { get; }
 
         public string Title => CalendarItem.Title;
 
@@ -19,7 +20,9 @@ namespace Wino.Calendar.ViewModels.Data
 
         public TimeRange Period => CalendarItem.Period;
 
-        public CalendarItemViewModel(ICalendarItem calendarItem)
+        public IAccountCalendar AssignedCalendar => ((ICalendarItem)CalendarItem).AssignedCalendar;
+
+        public CalendarItemViewModel(CalendarItem calendarItem)
         {
             CalendarItem = calendarItem;
         }

Wino.Calendar.ViewModels/Data/GroupedAccountCalendarViewModel.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Collections.ObjectModel;
 using System.Collections.Specialized;
 using System.Linq;
@@ -9,6 +10,9 @@ namespace Wino.Calendar.ViewModels.Data
 {
     public partial class GroupedAccountCalendarViewModel : ObservableObject
     {
+        public event EventHandler CollectiveSelectionStateChanged;
+        public event EventHandler<AccountCalendarViewModel> CalendarSelectionStateChanged;
+
         public MailAccount Account { get; }
         public ObservableCollection<AccountCalendarViewModel> AccountCalendars { get; }
 
@@ -59,6 +63,7 @@ namespace Wino.Calendar.ViewModels.Data
                 if (e.PropertyName == nameof(AccountCalendarViewModel.IsChecked))
                 {
                     ManageIsCheckedState();
+                    UpdateCalendarCheckedState(viewModel, viewModel.IsChecked, true);
                 }
             }
         }
@@ -73,6 +78,8 @@ namespace Wino.Calendar.ViewModels.Data
 
         private void ManageIsCheckedState()
         {
+            if (_isExternalPropChangeBlocked) return;
+
             _isExternalPropChangeBlocked = true;
 
             if (AccountCalendars.All(c => c.IsChecked))
@@ -95,22 +102,45 @@ namespace Wino.Calendar.ViewModels.Data
         {
             if (_isExternalPropChangeBlocked) return;
 
+            // Update is triggered by user on the three-state checkbox.
+            // We should not report all changes one by one.
+
+            _isExternalPropChangeBlocked = true;
+
             if (newValue == null)
             {
                 // Only primary calendars must be checked.
 
                 foreach (var calendar in AccountCalendars)
                 {
-                    calendar.IsChecked = calendar.IsPrimary;
+                    UpdateCalendarCheckedState(calendar, calendar.IsPrimary);
                 }
             }
             else
             {
                 foreach (var calendar in AccountCalendars)
                 {
-                    calendar.IsChecked = newValue.GetValueOrDefault();
+                    UpdateCalendarCheckedState(calendar, newValue.GetValueOrDefault());
                 }
             }
+
+            _isExternalPropChangeBlocked = false;
+
+            CollectiveSelectionStateChanged?.Invoke(this, EventArgs.Empty);
+        }
+
+        private void UpdateCalendarCheckedState(AccountCalendarViewModel accountCalendarViewModel, bool newValue, bool ignoreValueCheck = false)
+        {
+            var currentValue = accountCalendarViewModel.IsChecked;
+
+            if (currentValue == newValue && !ignoreValueCheck) return;
+
+            accountCalendarViewModel.IsChecked = newValue;
+
+            // No need to report.
+            if (_isExternalPropChangeBlocked == true) return;
+
+            CalendarSelectionStateChanged?.Invoke(this, accountCalendarViewModel);
         }
     }
 }