New change request abstractions.

Wino.Core/Requests/Mail/ChangeFlagRequest.cs

@@ -0,0 +1,40 @@
+using System;
+using System.Collections.Generic;
+using CommunityToolkit.Mvvm.Messaging;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Enums;
+using Wino.Core.Domain.Interfaces;
+using Wino.Core.Domain.Models.Requests;
+using Wino.Messaging.UI;
+
+namespace Wino.Core.Requests.Mail
+{
+    public record ChangeFlagRequest(MailCopy Item, bool IsFlagged) : MailRequestBase(Item),
+        ICustomFolderSynchronizationRequest
+    {
+        public List<Guid> SynchronizationFolderIds => [Item.FolderId];
+
+        public override MailSynchronizerOperation Operation => MailSynchronizerOperation.ChangeFlag;
+
+        public override void ApplyUIChanges()
+        {
+            Item.IsFlagged = IsFlagged;
+
+            WeakReferenceMessenger.Default.Send(new MailUpdatedMessage(Item));
+        }
+
+        public override void RevertUIChanges()
+        {
+            Item.IsFlagged = !IsFlagged;
+
+            WeakReferenceMessenger.Default.Send(new MailUpdatedMessage(Item));
+        }
+    }
+
+    public class BatchChangeFlagRequest : BatchCollection<ChangeFlagRequest>
+    {
+        public BatchChangeFlagRequest(IEnumerable<ChangeFlagRequest> collection) : base(collection)
+        {
+        }
+    }
+}