Remove commented code.

Wino.Authentication/Office365Authenticator.cs

@@ -1,16 +0,0 @@
-using Wino.Core.Domain.Enums;
-using Wino.Core.Domain.Interfaces;
-
-namespace Wino.Authentication
-{
-    public class Office365Authenticator : OutlookAuthenticator
-    {
-        public Office365Authenticator(INativeAppService nativeAppService,
-                                      IApplicationConfiguration applicationConfiguration,
-                                      IAuthenticatorConfig authenticatorConfig) : base(nativeAppService, applicationConfiguration, authenticatorConfig)
-        {
-        }
-
-        public override MailProviderType ProviderType => MailProviderType.Office365;
-    }
-}

Wino.Calendar.Packaging/Wino.Calendar.Packaging.wapproj

@@ -20,14 +20,6 @@
       <Configuration>Release</Configuration>
       <Platform>x64</Platform>
     </ProjectConfiguration>
-    <ProjectConfiguration Include="Debug|ARM">
-      <Configuration>Debug</Configuration>
-      <Platform>ARM</Platform>
-    </ProjectConfiguration>
-    <ProjectConfiguration Include="Release|ARM">
-      <Configuration>Release</Configuration>
-      <Platform>ARM</Platform>
-    </ProjectConfiguration>
     <ProjectConfiguration Include="Debug|ARM64">
       <Configuration>Debug</Configuration>
       <Platform>ARM64</Platform>
@@ -76,7 +68,6 @@
   </ItemGroup>
   <Import Project="$(WapProjPath)\Microsoft.DesktopBridge.targets" />
   <ItemGroup>
-    <PackageReference Include="Microsoft.Identity.Client" Version="4.66.2" />
     <PackageReference Include="Microsoft.Windows.SDK.BuildTools" Version="10.0.26100.1742" PrivateAssets="all" />
   </ItemGroup>
   <ItemGroup>

Wino.Calendar.ViewModels/AccountManagementViewModel.cs

@@ -81,7 +81,7 @@ namespace Wino.Calendar.ViewModels
             if (accountCreationDialogResult == null) return;
 
             var accountCreationCancellationTokenSource = new CancellationTokenSource();
-            var accountCreationDialog = CalendarDialogService.GetAccountCreationDialog(accountCreationDialogResult.ProviderType);
+            var accountCreationDialog = CalendarDialogService.GetAccountCreationDialog(accountCreationDialogResult);
 
             accountCreationDialog.ShowDialog(accountCreationCancellationTokenSource);
             accountCreationDialog.State = AccountCreationDialogState.SigningIn;
@@ -92,7 +92,6 @@ namespace Wino.Calendar.ViewModels
             {
                 ProviderType = accountCreationDialogResult.ProviderType,
                 Name = accountCreationDialogResult.AccountName,
-                AccountColorHex = accountCreationDialogResult.AccountColorHex,
                 Id = Guid.NewGuid()
             };
 
@@ -104,13 +103,8 @@ namespace Wino.Calendar.ViewModels
             if (accountCreationDialog.State == AccountCreationDialogState.Canceled)
                 throw new AccountSetupCanceledException();
 
-
             tokenInformationResponse.ThrowIfFailed();
 
-            //var tokenInformation = tokenInformationResponse.Data;
-            //createdAccount.Address = tokenInformation.Address;
-            //tokenInformation.AccountId = createdAccount.Id;
-
             await AccountService.CreateAccountAsync(createdAccount, null);
 
             // Sync profile information if supported.

Wino.Calendar.ViewModels/Wino.Calendar.ViewModels.csproj

@@ -9,7 +9,6 @@
 	</PropertyGroup>
 
 	<ItemGroup>
-	  <PackageReference Include="Microsoft.Identity.Client" Version="4.66.2" />
 	  <PackageReference Include="TimePeriodLibrary.NET" Version="2.1.5" />
 	</ItemGroup>
 

Wino.Calendar/Services/ProviderService.cs

@@ -27,7 +27,7 @@ namespace Wino.Calendar.Services
 
             foreach (var type in providers)
             {
-                providerList.Add(new ProviderDetail(type));
+                providerList.Add(new ProviderDetail(type, SpecialImapProvider.None));
             }
 
             return providerList;

Wino.Calendar/Wino.Calendar.csproj

@@ -60,29 +60,6 @@
     <Prefer32Bit>true</Prefer32Bit>
     <UseDotNetNativeToolchain>true</UseDotNetNativeToolchain>
   </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|ARM'">
-    <DebugSymbols>true</DebugSymbols>
-    <OutputPath>bin\ARM\Debug\</OutputPath>
-    <DefineConstants>DEBUG;TRACE;NETFX_CORE;WINDOWS_UWP</DefineConstants>
-    <NoWarn>;2008</NoWarn>
-    <DebugType>full</DebugType>
-    <PlatformTarget>ARM</PlatformTarget>
-    <UseVSHostingProcess>false</UseVSHostingProcess>
-    <ErrorReport>prompt</ErrorReport>
-    <Prefer32Bit>true</Prefer32Bit>
-  </PropertyGroup>
-  <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Release|ARM'">
-    <OutputPath>bin\ARM\Release\</OutputPath>
-    <DefineConstants>TRACE;NETFX_CORE;WINDOWS_UWP</DefineConstants>
-    <Optimize>true</Optimize>
-    <NoWarn>;2008</NoWarn>
-    <DebugType>pdbonly</DebugType>
-    <PlatformTarget>ARM</PlatformTarget>
-    <UseVSHostingProcess>false</UseVSHostingProcess>
-    <ErrorReport>prompt</ErrorReport>
-    <Prefer32Bit>true</Prefer32Bit>
-    <UseDotNetNativeToolchain>true</UseDotNetNativeToolchain>
-  </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|ARM64'">
     <DebugSymbols>true</DebugSymbols>
     <OutputPath>bin\ARM64\Debug\</OutputPath>
@@ -334,7 +311,7 @@
       <Version>6.2.14</Version>
     </PackageReference>
     <PackageReference Include="Win2D.uwp">
-      <Version>1.28.0</Version>
+      <Version>1.28.1</Version>
     </PackageReference>
   </ItemGroup>
   <ItemGroup>

Wino.Core.Domain/Entities/Shared/MailAccount.cs

@@ -72,6 +72,12 @@ namespace Wino.Core.Domain.Entities.Shared
         /// </summary>
         public Guid? MergedInboxId { get; set; }
 
+        /// <summary>
+        /// Gets or sets the additional IMAP provider assignment for the account.
+        /// Providers that use IMAP as a synchronizer but have special requirements.
+        /// </summary>
+        public SpecialImapProvider SpecialImapProvider { get; set; }
+
         /// <summary>
         /// Contains the merged inbox this account belongs to.
         /// Ignored for all SQLite operations.
@@ -95,7 +101,7 @@ namespace Wino.Core.Domain.Entities.Shared
         /// <summary>
         /// Gets whether the account can perform ProfileInformation sync type.
         /// </summary>
-        public bool IsProfileInfoSyncSupported => ProviderType == MailProviderType.Outlook || ProviderType == MailProviderType.Office365 || ProviderType == MailProviderType.Gmail;
+        public bool IsProfileInfoSyncSupported => ProviderType == MailProviderType.Outlook || ProviderType == MailProviderType.Gmail;
 
         /// <summary>
         /// Gets whether the account can perform AliasInformation sync type.

Wino.Core.Domain/Enums/MailProviderType.cs

@@ -4,8 +4,6 @@
     {
         Outlook,
         Gmail,
-        Office365,
-        Yahoo,
-        IMAP4
+        IMAP4 = 4 // 2-3 were removed after release. Don't change for backward compatibility.
     }
 }

Wino.Core.Domain/Enums/MailSynchronizationType.cs

@@ -2,13 +2,13 @@
 {
     public enum MailSynchronizationType
     {
-        // Shared
         UpdateProfile, // Only update profile information
         ExecuteRequests, // Run the queued requests, and then synchronize if needed.
         FoldersOnly, // Only synchronize folder metadata.
-        InboxOnly, // Only Inbox, Sent and Draft folders.
+        InboxOnly, // Only Inbox, Sent, Draft and Deleted folders.
         CustomFolders, // Only sync folders that are specified in the options.
         FullFolders, // Synchronize all folders. This won't update profile or alias information.
         Alias, // Only update alias information
+        IMAPIdle // Idle client triggered synchronization.
     }
 }

Wino.Core.Domain/Enums/SpecialImapProvider.cs

@@ -0,0 +1,9 @@
+namespace Wino.Core.Domain.Enums
+{
+    public enum SpecialImapProvider
+    {
+        None,
+        iCloud,
+        Yahoo
+    }
+}

Wino.Core.Domain/Exceptions/ImapSynchronizerStrategyException.cs

@@ -0,0 +1,10 @@
+namespace Wino.Core.Domain.Exceptions
+{
+    public class ImapSynchronizerStrategyException : System.Exception
+    {
+        public ImapSynchronizerStrategyException(string message) : base(message)
+        {
+
+        }
+    }
+}

Wino.Core.Domain/Interfaces/IAccountCreationDialog.cs

@@ -1,11 +1,12 @@
 using System.Threading;
+using System.Threading.Tasks;
 using Wino.Core.Domain.Enums;
 
 namespace Wino.Core.Domain.Interfaces
 {
     public interface IAccountCreationDialog
     {
-        void ShowDialog(CancellationTokenSource cancellationTokenSource);
+        Task ShowDialogAsync(CancellationTokenSource cancellationTokenSource);
         void Complete(bool cancel);
         AccountCreationDialogState State { get; set; }
     }

Wino.Core.Domain/Interfaces/IBaseSynchronizer.cs

@@ -23,12 +23,6 @@ namespace Wino.Core.Domain.Interfaces
         /// <param name="request">Request to queue.</param>
         void QueueRequest(IRequestBase request);
 
-        /// <summary>
-        /// TODO
-        /// </summary>
-        /// <returns>Whether active synchronization is stopped or not.</returns>
-        bool CancelActiveSynchronization();
-
         /// <summary>
         /// Synchronizes profile information with the server.
         /// Sender name and Profile picture are updated.

Wino.Core.Domain/Interfaces/ICustomFolderSynchronizationRequest.cs

@@ -13,5 +13,10 @@ namespace Wino.Core.Domain.Interfaces
         /// Which folders to sync after this operation?
         /// </summary>
         List<Guid> SynchronizationFolderIds { get; }
+
+        /// <summary>
+        /// If true, additional folders like Sent, Drafts and Deleted will not be synchronized
+        /// </summary>
+        bool ExcludeMustHaveFolders { get; }
     }
 }

Wino.Core.Domain/Interfaces/IDialogServiceBase.cs

@@ -27,7 +27,7 @@ namespace Wino.Core.Domain.Interfaces
                                             string dontAskAgainConfigurationKey = "");
         Task<bool> ShowCustomThemeBuilderDialogAsync();
         Task<AccountCreationDialogResult> ShowAccountProviderSelectionDialogAsync(List<IProviderDetail> availableProviders);
-        IAccountCreationDialog GetAccountCreationDialog(MailProviderType type);
+        IAccountCreationDialog GetAccountCreationDialog(AccountCreationDialogResult accountCreationDialogResult);
         Task<List<SharedFile>> PickFilesAsync(params object[] typeFilters);
         Task<string> PickFilePathAsync(string saveFileName);
     }

Wino.Core.Domain/Interfaces/IImapAccountCreationDialog.cs

@@ -3,7 +3,7 @@ using Wino.Core.Domain.Entities.Shared;
 
 namespace Wino.Core.Domain.Interfaces
 {
-    public interface ICustomServerAccountCreationDialog : IAccountCreationDialog
+    public interface IImapAccountCreationDialog : IAccountCreationDialog
     {
         /// <summary>
         /// Returns the custom server information from the dialog..

Wino.Core.Domain/Interfaces/IImapSynchronizationStrategyProvider.cs

@@ -0,0 +1,12 @@
+using MailKit.Net.Imap;
+
+namespace Wino.Core.Domain.Interfaces
+{
+    /// <summary>
+    /// Provides a synchronization strategy for synchronizing IMAP folders based on the server capabilities.
+    /// </summary>
+    public interface IImapSynchronizationStrategyProvider
+    {
+        IImapSynchronizerStrategy GetSynchronizationStrategy(IImapClient client);
+    }
+}

Wino.Core.Domain/Interfaces/IImapSynchronizer.cs

@@ -0,0 +1,17 @@
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Models.MailItem;
+
+namespace Wino.Core.Domain.Interfaces
+{
+    public interface IImapSynchronizer
+    {
+        uint InitialMessageDownloadCountPerFolder { get; }
+
+        Task<List<NewMailItemPackage>> CreateNewMailPackagesAsync(ImapMessageCreationPackage message, MailItemFolder assignedFolder, CancellationToken cancellationToken = default);
+        Task StartIdleClientAsync();
+        Task StopIdleClientAsync();
+    }
+}

Wino.Core.Domain/Interfaces/IImapSynchronizerStrategy.cs

@@ -0,0 +1,22 @@
+using System.Collections.Generic;
+using System.Threading;
+using System.Threading.Tasks;
+using MailKit.Net.Imap;
+using Wino.Core.Domain.Entities.Mail;
+
+namespace Wino.Core.Domain.Interfaces
+{
+    public interface IImapSynchronizerStrategy
+    {
+        /// <summary>
+        /// Synchronizes given folder with the ImapClient client from the client pool.
+        /// </summary>
+        /// <param name="client">Client to perform sync with. I love Mira and Jasminka</param>
+        /// <param name="folder">Folder to synchronize.</param>
+        /// <param name="synchronizer">Imap synchronizer that downloads messages.</param>
+        /// <param name="cancellationToken">Cancellation token.</param>
+        /// <returns>List of new downloaded message ids that don't exist locally.</returns>
+        Task<List<string>> HandleSynchronizationAsync(IImapClient client, MailItemFolder folder, IImapSynchronizer synchronizer, CancellationToken cancellationToken = default);
+    }
+}
+

Wino.Core.Domain/Interfaces/IMailService.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
+using MailKit;
 using Wino.Core.Domain.Entities.Mail;
 using Wino.Core.Domain.Entities.Shared;
 using Wino.Core.Domain.Models.MailItem;
@@ -108,5 +109,13 @@ namespace Wino.Core.Domain.Interfaces
         /// <param name="draftCreationOptions">Options like new email/forward/draft.</param>
         /// <returns>Draft MailCopy and Draft MimeMessage as base64.</returns>
         Task<(MailCopy draftMailCopy, string draftBase64MimeMessage)> CreateDraftAsync(Guid accountId, DraftCreationOptions draftCreationOptions);
+
+        /// <summary>
+        /// Returns ids 
+        /// </summary>
+        /// <param name="folderId"></param>
+        /// <param name="uniqueIds"></param>
+        /// <returns></returns>
+        Task<List<MailCopy>> GetExistingMailsAsync(Guid folderId, IEnumerable<UniqueId> uniqueIds);
     }
 }

Wino.Core.Domain/Interfaces/IProviderDetail.cs

@@ -5,6 +5,7 @@ namespace Wino.Core.Domain.Interfaces
     public interface IProviderDetail
     {
         MailProviderType Type { get; }
+        SpecialImapProvider SpecialImapProvider { get; }
         string Name { get; }
         string Description { get; }
         string ProviderImage { get; }

Wino.Core.Domain/Interfaces/ISpecialImapProviderConfigResolver.cs

@@ -0,0 +1,10 @@
+using Wino.Core.Domain.Entities.Shared;
+using Wino.Core.Domain.Models.Accounts;
+
+namespace Wino.Core.Domain.Interfaces
+{
+    public interface ISpecialImapProviderConfigResolver
+    {
+        CustomServerInformation GetServerInformation(MailAccount account, AccountCreationDialogResult dialogResult);
+    }
+}

Wino.Core.Domain/Interfaces/ISynchronizerFactory.cs

@@ -7,5 +7,6 @@ namespace Wino.Core.Domain.Interfaces
     {
         Task<IWinoSynchronizerBase> GetAccountSynchronizerAsync(Guid accountId);
         Task InitializeAsync();
+        Task DeleteSynchronizerAsync(Guid accountId);
     }
 }

Wino.Core.Domain/Interfaces/IWinoSynchronizerBase.cs

@@ -28,5 +28,12 @@ namespace Wino.Core.Domain.Interfaces
         /// <param name="transferProgress">Optional progress reporting for download operation.</param>
         /// <param name="cancellationToken">Cancellation token.</param>
         Task DownloadMissingMimeMessageAsync(IMailItem mailItem, ITransferProgress transferProgress, CancellationToken cancellationToken = default);
+
+        /// <summary>
+        /// 1. Cancel active synchronization.
+        /// 2. Stop all running tasks.
+        /// 3. Dispose all resources.
+        /// </summary>
+        Task KillSynchronizerAsync();
     }
 }

Wino.Core.Domain/Models/Accounts/AccountCreationDialogResult.cs

@@ -2,5 +2,5 @@
 
 namespace Wino.Core.Domain.Models.Accounts
 {
-    public record AccountCreationDialogResult(MailProviderType ProviderType, string AccountName, string AccountColorHex = "");
+    public record AccountCreationDialogResult(MailProviderType ProviderType, string AccountName, SpecialImapProviderDetails SpecialImapProviderDetails);
 }

Wino.Core.Domain/Models/Accounts/ProviderDetail.cs

@@ -6,18 +6,32 @@ namespace Wino.Core.Domain.Models.Accounts
     public class ProviderDetail : IProviderDetail
     {
         public MailProviderType Type { get; }
-
+        public SpecialImapProvider SpecialImapProvider { get; }
         public string Name { get; }
 
         public string Description { get; }
 
-        public string ProviderImage => $"ms-appx:///Wino.Core.UWP/Assets/Providers/{Type}.png";
+        public string ProviderImage
+        {
+            get
+            {
+                if (SpecialImapProvider == SpecialImapProvider.None)
+                {
+                    return $"ms-appx:///Wino.Core.UWP/Assets/Providers/{Type}.png";
+                }
+                else
+                {
+                    return $"ms-appx:///Wino.Core.UWP/Assets/Providers/{SpecialImapProvider}.png";
+                }
+            }
+        }
 
         public bool IsSupported => Type == MailProviderType.Outlook || Type == MailProviderType.Gmail || Type == MailProviderType.IMAP4;
 
-        public ProviderDetail(MailProviderType type)
+        public ProviderDetail(MailProviderType type, SpecialImapProvider specialImapProvider)
         {
             Type = type;
+            SpecialImapProvider = specialImapProvider;
 
             switch (Type)
             {
@@ -25,21 +39,29 @@ namespace Wino.Core.Domain.Models.Accounts
                     Name = "Outlook";
                     Description = "Outlook.com, Live.com, Hotmail, MSN";
                     break;
-                case MailProviderType.Office365:
-                    Name = "Office 365";
-                    Description = "Office 365, Exchange";
-                    break;
                 case MailProviderType.Gmail:
                     Name = "Gmail";
                     Description = Translator.ProviderDetail_Gmail_Description;
                     break;
-                case MailProviderType.Yahoo:
-                    Name = "Yahoo";
-                    Description = "Yahoo Mail";
-                    break;
                 case MailProviderType.IMAP4:
-                    Name = Translator.ProviderDetail_IMAP_Title;
-                    Description = Translator.ProviderDetail_IMAP_Description;
+                    switch (specialImapProvider)
+                    {
+                        case SpecialImapProvider.None:
+                            Name = Translator.ProviderDetail_IMAP_Title;
+                            Description = Translator.ProviderDetail_IMAP_Description;
+                            break;
+                        case SpecialImapProvider.iCloud:
+                            Name = Translator.ProviderDetail_iCloud_Title;
+                            Description = Translator.ProviderDetail_iCloud_Description;
+                            break;
+                        case SpecialImapProvider.Yahoo:
+                            Name = Translator.ProviderDetail_Yahoo_Title;
+                            Description = Translator.ProviderDetail_Yahoo_Description;
+                            break;
+                        default:
+                            break;
+                    }
+
                     break;
             }
         }

Wino.Core.Domain/Models/Accounts/SpecialImapProviderDetails.cs

@@ -0,0 +1,6 @@
+using Wino.Core.Domain.Enums;
+
+namespace Wino.Core.Domain.Models.Accounts
+{
+    public record SpecialImapProviderDetails(string Address, string Password, string SenderName, SpecialImapProvider SpecialImapProvider);
+}

Wino.Core.Domain/Models/MailItem/ImapMessageCreationPackage.cs

@@ -0,0 +1,20 @@
+using MailKit;
+using MimeKit;
+
+namespace Wino.Core.Domain.Models.MailItem
+{
+    /// <summary>
+    /// Encapsulates all required information to create a MimeMessage for IMAP synchronizer.
+    /// </summary>
+    public class ImapMessageCreationPackage
+    {
+        public IMessageSummary MessageSummary { get; }
+        public MimeMessage MimeMessage { get; }
+
+        public ImapMessageCreationPackage(IMessageSummary messageSummary, MimeMessage mimeMessage)
+        {
+            MessageSummary = messageSummary;
+            MimeMessage = mimeMessage;
+        }
+    }
+}

Wino.Core.Domain/Models/Synchronization/MailSynchronizationOptions.cs

@@ -26,6 +26,12 @@ namespace Wino.Core.Domain.Models.Synchronization
         /// </summary>
         public List<Guid> SynchronizationFolderIds { get; set; }
 
+        /// <summary>
+        /// If true, additional folders like Sent,Drafts and Deleted will not be synchronized
+        /// with InboxOnly and CustomFolders sync type.
+        /// </summary>
+        public bool ExcludeMustHaveFolders { get; set; }
+
         /// <summary>
         /// When doing a linked inbox synchronization, we must ignore reporting completion to the caller for each folder.
         /// This Id will help tracking that. Id is unique, but this one can be the same for all sync requests
@@ -33,6 +39,6 @@ namespace Wino.Core.Domain.Models.Synchronization
         /// </summary>
         public Guid? GroupedSynchronizationTrackingId { get; set; }
 
-        public override string ToString() => $"Type: {Type}, Folders: {(SynchronizationFolderIds == null ? "All" : string.Join(",", SynchronizationFolderIds))}";
+        public override string ToString() => $"Type: {Type}";
     }
 }

Wino.Core.Domain/Translations/en_US/resources.json

@@ -403,6 +403,10 @@
     "ProviderDetail_Gmail_Description": "Google Account",
     "ProviderDetail_IMAP_Description": "Custom IMAP/SMTP server",
     "ProviderDetail_IMAP_Title": "IMAP Server",
+    "ProviderDetail_Yahoo_Title": "Yahoo Mail",
+    "ProviderDetail_Yahoo_Description": "Yahoo Account",
+    "ProviderDetail_iCloud_Title": "iCloud",
+    "ProviderDetail_iCloud_Description": "Apple iCloud Account",
     "ProtocolLogAvailable_Message": "Protocol logs are available for diagnostics.",
     "Results": "Results",
     "Right": "Right",

Wino.Core.Domain/Wino.Core.Domain.csproj

@@ -66,10 +66,10 @@
 		  <PrivateAssets>all</PrivateAssets>
 		  <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
 		</PackageReference>
-		<PackageReference Include="MimeKit" Version="4.9.0" />
-		<PackageReference Include="MailKit" Version="4.9.0" />
+		<PackageReference Include="MimeKit" Version="4.10.0" />
+		<PackageReference Include="MailKit" Version="4.10.0" />
 		<PackageReference Include="sqlite-net-pcl" Version="1.9.172" />
-		<PackageReference Include="System.Text.Json" Version="8.0.5" />
+		<PackageReference Include="System.Text.Json" Version="9.0.1" />
 		<PackageReference Include="TimePeriodLibrary.NET" Version="2.1.5" />
 	</ItemGroup>
 	<ItemGroup>

Wino.Core.UWP/Controls/AccountCreationDialogControl.xaml.cs

@@ -0,0 +1,76 @@
+using System;
+using System.Threading.Tasks;
+using CommunityToolkit.Mvvm.Messaging;
+using Microsoft.Extensions.DependencyInjection;
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Controls;
+using Wino.Core.Domain.Enums;
+using Wino.Core.Domain.Interfaces;
+using Wino.Messaging.UI;
+
+
+namespace Wino.Core.UWP.Controls
+{
+    public sealed partial class AccountCreationDialogControl : UserControl, IRecipient<CopyAuthURLRequested>
+    {
+        private string copyClipboardURL;
+
+        public event EventHandler CancelClicked;
+
+        public AccountCreationDialogState State
+        {
+            get { return (AccountCreationDialogState)GetValue(StateProperty); }
+            set { SetValue(StateProperty, value); }
+        }
+
+        public static readonly DependencyProperty StateProperty = DependencyProperty.Register(nameof(State), typeof(AccountCreationDialogState), typeof(AccountCreationDialogControl), new PropertyMetadata(AccountCreationDialogState.Idle, new PropertyChangedCallback(OnStateChanged)));
+
+        public AccountCreationDialogControl()
+        {
+            InitializeComponent();
+        }
+
+        private static void OnStateChanged(DependencyObject obj, DependencyPropertyChangedEventArgs args)
+        {
+            if (obj is AccountCreationDialogControl dialog)
+            {
+                dialog.UpdateVisualStates();
+            }
+        }
+
+        private void UpdateVisualStates() => VisualStateManager.GoToState(this, State.ToString(), false);
+
+        public async void Receive(CopyAuthURLRequested message)
+        {
+            copyClipboardURL = message.AuthURL;
+
+            await Task.Delay(2000);
+
+            await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
+            {
+                AuthHelpDialogButton.Visibility = Windows.UI.Xaml.Visibility.Visible;
+            });
+        }
+
+        private void ControlLoaded(object sender, Windows.UI.Xaml.RoutedEventArgs e)
+        {
+            WeakReferenceMessenger.Default.Register(this);
+        }
+
+        private void ControlUnloaded(object sender, Windows.UI.Xaml.RoutedEventArgs e)
+        {
+            WeakReferenceMessenger.Default.UnregisterAll(this);
+        }
+
+        private async void CopyClicked(object sender, Windows.UI.Xaml.RoutedEventArgs e)
+        {
+            if (string.IsNullOrEmpty(copyClipboardURL)) return;
+
+            var clipboardService = WinoApplication.Current.Services.GetService<IClipboardService>();
+            await clipboardService.CopyClipboardAsync(copyClipboardURL);
+        }
+
+
+        private void CancelButtonClicked(object sender, Windows.UI.Xaml.RoutedEventArgs e) => CancelClicked?.Invoke(this, null);
+    }
+}

Wino.Core.UWP/Controls/ControlConstants.cs

@@ -98,7 +98,9 @@ namespace Wino.Core.UWP.Controls
             { WinoIconGlyph.EventRespond, "\uE924" },
             { WinoIconGlyph.EventReminder, "\uE923" },
             { WinoIconGlyph.EventJoinOnline, "\uE926" },
-            { WinoIconGlyph.ViewMessageSource, "\uE943" }
+            { WinoIconGlyph.ViewMessageSource, "\uE943" },
+            { WinoIconGlyph.Apple, "\uE92B" },
+            { WinoIconGlyph.Yahoo, "\uE92C" }
         };
     }
 }

Wino.Core.UWP/Controls/WinoFontIcon.cs

@@ -100,6 +100,8 @@ namespace Wino.Core.UWP.Controls
         EventEditSeries,
         EventJoinOnline,
         ViewMessageSource,
+        Apple,
+        Yahoo
     }
 
     public class WinoFontIcon : FontIcon

Wino.Core.UWP/Dialogs/AccountCreationDialog.xaml.cs

@@ -1,50 +1,73 @@
-using System;
+using System.Threading;
 using System.Threading.Tasks;
-using CommunityToolkit.Mvvm.Messaging;
-using Microsoft.Extensions.DependencyInjection;
 using Windows.UI.Xaml;
+using Windows.UI.Xaml.Controls;
 using Wino.Core.Domain.Enums;
 using Wino.Core.Domain.Interfaces;
-using Wino.Core.UWP;
-using Wino.Messaging.UI;
 
 namespace Wino.Dialogs
 {
-    public sealed partial class AccountCreationDialog : BaseAccountCreationDialog, IRecipient<CopyAuthURLRequested>
+    public sealed partial class AccountCreationDialog : ContentDialog, IAccountCreationDialog
     {
-        private string copyClipboardURL;
+        private TaskCompletionSource<bool> dialogOpened = new TaskCompletionSource<bool>();
+        public CancellationTokenSource CancellationTokenSource { get; private set; }
+
+        public AccountCreationDialogState State
+        {
+            get { return (AccountCreationDialogState)GetValue(StateProperty); }
+            set { SetValue(StateProperty, value); }
+        }
+
+        public static readonly DependencyProperty StateProperty = DependencyProperty.Register(nameof(State), typeof(AccountCreationDialogState), typeof(AccountCreationDialog), new PropertyMetadata(AccountCreationDialogState.Idle));
+
         public AccountCreationDialog()
         {
             InitializeComponent();
-
-            WeakReferenceMessenger.Default.Register(this);
         }
 
-        public override void OnStateChanged(AccountCreationDialogState state)
+        // Prevent users from dismissing it by ESC key.
+        public void DialogClosing(ContentDialog sender, ContentDialogClosingEventArgs args)
         {
-            var tt = VisualStateManager.GoToState(this, state.ToString(), true);
-        }
-
-        public async void Receive(CopyAuthURLRequested message)
-        {
-            copyClipboardURL = message.AuthURL;
-
-            await Task.Delay(2000);
-
-            await Dispatcher.RunAsync(Windows.UI.Core.CoreDispatcherPriority.Normal, () =>
+            if (args.Result == ContentDialogResult.None)
             {
-                AuthHelpDialogButton.Visibility = Windows.UI.Xaml.Visibility.Visible;
-            });
+                args.Cancel = true;
+            }
         }
 
-        private void CancelClicked(object sender, Windows.UI.Xaml.RoutedEventArgs e) => Complete(true);
-
-        private async void CopyClicked(object sender, Windows.UI.Xaml.RoutedEventArgs e)
+        public void Complete(bool cancel)
         {
-            if (string.IsNullOrEmpty(copyClipboardURL)) return;
+            State = cancel ? AccountCreationDialogState.Canceled : AccountCreationDialogState.Completed;
 
-            var clipboardService = WinoApplication.Current.Services.GetService<IClipboardService>();
-            await clipboardService.CopyClipboardAsync(copyClipboardURL);
+            // Unregister from closing event.
+            Closing -= DialogClosing;
+
+            if (cancel && !CancellationTokenSource.IsCancellationRequested)
+            {
+                CancellationTokenSource.Cancel();
+            }
+
+            Hide();
+        }
+
+        private void CancelClicked(object sender, System.EventArgs e) => Complete(true);
+
+        public async Task ShowDialogAsync(CancellationTokenSource cancellationTokenSource)
+        {
+            var tcs =
+
+            CancellationTokenSource = cancellationTokenSource;
+
+            Opened += DialogOpened;
+            _ = ShowAsync();
+
+            await dialogOpened.Task;
+        }
+
+        private void DialogOpened(ContentDialog sender, ContentDialogOpenedEventArgs args)
+        {
+            Opened -= DialogOpened;
+
+            dialogOpened?.SetResult(true);
         }
     }
 }

Wino.Core.UWP/Dialogs/BaseAccountCreationDialog.cs

@@ -1,60 +0,0 @@
-using System.Threading;
-using Windows.UI.Xaml;
-using Windows.UI.Xaml.Controls;
-using Wino.Core.Domain.Enums;
-using Wino.Core.Domain.Interfaces;
-
-namespace Wino.Dialogs
-{
-    public abstract class BaseAccountCreationDialog : ContentDialog, IAccountCreationDialog
-    {
-        public AccountCreationDialogState State
-        {
-            get { return (AccountCreationDialogState)GetValue(StateProperty); }
-            set { SetValue(StateProperty, value); }
-        }
-
-        public CancellationTokenSource CancellationTokenSource { get; private set; }
-
-        public static readonly DependencyProperty StateProperty = DependencyProperty.Register(nameof(State), typeof(AccountCreationDialogState), typeof(BaseAccountCreationDialog), new PropertyMetadata(AccountCreationDialogState.Idle, OnStateChanged));
-
-        private static void OnStateChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
-        {
-            var dialog = d as BaseAccountCreationDialog;
-            dialog.OnStateChanged((AccountCreationDialogState)e.NewValue);
-        }
-
-        public abstract void OnStateChanged(AccountCreationDialogState state);
-
-        // Prevent users from dismissing it by ESC key.
-        public void DialogClosing(ContentDialog sender, ContentDialogClosingEventArgs args)
-        {
-            if (args.Result == ContentDialogResult.None)
-            {
-                args.Cancel = true;
-            }
-        }
-
-        public void ShowDialog(CancellationTokenSource cancellationTokenSource)
-        {
-            CancellationTokenSource = cancellationTokenSource;
-
-            _ = ShowAsync();
-        }
-
-        public void Complete(bool cancel)
-        {
-            State = cancel ? AccountCreationDialogState.Canceled : AccountCreationDialogState.Completed;
-
-            // Unregister from closing event.
-            Closing -= DialogClosing;
-
-            if (cancel && !CancellationTokenSource.IsCancellationRequested)
-            {
-                CancellationTokenSource.Cancel();
-            }
-
-            Hide();
-        }
-    }
-}

Wino.Core.UWP/Dialogs/NewAccountDialog.xaml

@@ -43,38 +43,91 @@
     </ContentDialog.Resources>
 
     <Grid MinWidth="400" RowSpacing="12">
-        <Grid.RowDefinitions>
-            <RowDefinition Height="Auto" />
-            <RowDefinition Height="Auto" />
-            <RowDefinition Height="*" />
-        </Grid.RowDefinitions>
+        <Grid Visibility="{x:Bind IsProviderSelectionVisible, Mode=OneWay}">
+            <Grid.RowDefinitions>
+                <RowDefinition Height="Auto" />
+                <RowDefinition Height="Auto" />
+                <RowDefinition Height="*" />
+            </Grid.RowDefinitions>
 
-        <!--  Account Name  -->
-        <TextBox
-            x:Name="AccountNameTextbox"
-            Header="{x:Bind domain:Translator.NewAccountDialog_AccountName}"
-            PlaceholderText="{x:Bind domain:Translator.NewAccountDialog_AccountNamePlaceholder}"
-            TextChanged="AccountNameChanged" />
+            <!--  Account Name  -->
+            <TextBox
+                x:Name="AccountNameTextbox"
+                Header="{x:Bind domain:Translator.NewAccountDialog_AccountName}"
+                PlaceholderText="{x:Bind domain:Translator.NewAccountDialog_AccountNamePlaceholder}"
+                TextChanged="InputChanged" />
 
-        <!--
-            TODO: Move Name, Sender Name and Color Picker to another Frame.
-            Provider selection should be first, then account details.
-        -->
-        <!--<Grid Grid.Row="1">
-            <Grid.ColumnDefinitions>
-                <ColumnDefinition Width="Auto" />
-                <ColumnDefinition Width="*" />
-            </Grid.ColumnDefinitions>
-            <TextBlock Text="Color" />
-            <muxc:ColorPicker x:Name="AccountColorPicker" Grid.Column="1" />
-        </Grid>-->
+            <!--
+                TODO: Move Name, Sender Name and Color Picker to another Frame.
+                Provider selection should be first, then account details.
+            -->
+            <!--<Grid Grid.Row="1">
+    <Grid.ColumnDefinitions>
+        <ColumnDefinition Width="Auto" />
+        <ColumnDefinition Width="*" />
+    </Grid.ColumnDefinitions>
+    <TextBlock Text="Color" />
+    <muxc:ColorPicker x:Name="AccountColorPicker" Grid.Column="1" />
+</Grid>-->
 
-        <ListView
-            Grid.Row="2"
-            Padding="0"
-            ItemTemplate="{StaticResource NewMailProviderTemplate}"
-            ItemsSource="{x:Bind Providers}"
-            SelectedItem="{x:Bind SelectedMailProvider, Mode=TwoWay}"
-            SelectionMode="Single" />
+            <ListView
+                Grid.Row="2"
+                Padding="0"
+                ItemTemplate="{StaticResource NewMailProviderTemplate}"
+                ItemsSource="{x:Bind Providers}"
+                SelectedItem="{x:Bind SelectedMailProvider, Mode=TwoWay}"
+                SelectionMode="Single" />
+        </Grid>
+
+        <!--  Known special IMAP login details.  -->
+        <Grid RowSpacing="12" Visibility="{x:Bind IsSpecialImapServerPartVisible, Mode=OneWay}">
+            <Grid.RowDefinitions>
+                <RowDefinition Height="Auto" />
+                <RowDefinition Height="Auto" />
+                <RowDefinition Height="Auto" />
+                <RowDefinition Height="Auto" />
+                <RowDefinition Height="*" />
+            </Grid.RowDefinitions>
+
+            <Button Click="BackClicked">
+                <Button.Content>
+                    <Viewbox Width="16">
+                        <PathIcon Data="F1 M 20 9.375 C 20 9.544271 19.93815 9.690756 19.814453 9.814453 C 19.690754 9.938151 19.54427 10 19.375 10 L 2.138672 10 L 9.814453 17.685547 C 9.93815 17.809244 10 17.955729 10 18.125 C 10 18.294271 9.93815 18.440756 9.814453 18.564453 C 9.690755 18.68815 9.544271 18.75 9.375 18.75 C 9.205729 18.75 9.059244 18.68815 8.935547 18.564453 L 0.214844 9.84375 C 0.143229 9.772136 0.089518 9.700521 0.053711 9.628906 C 0.017904 9.557292 0 9.472656 0 9.375 C 0 9.277344 0.017904 9.192709 0.053711 9.121094 C 0.089518 9.049479 0.143229 8.977865 0.214844 8.90625 L 8.935547 0.185547 C 9.059244 0.06185 9.205729 0 9.375 0 C 9.544271 0 9.690755 0.06185 9.814453 0.185547 C 9.93815 0.309246 10 0.45573 10 0.625 C 10 0.794271 9.93815 0.940756 9.814453 1.064453 L 2.138672 8.75 L 19.375 8.75 C 19.54427 8.75 19.690754 8.81185 19.814453 8.935547 C 19.93815 9.059245 20 9.205729 20 9.375 Z " />
+                    </Viewbox>
+                </Button.Content>
+            </Button>
+
+            <Image
+                Width="150"
+                Height="50"
+                HorizontalAlignment="Center"
+                Source="{x:Bind SelectedMailProvider.ProviderImage, Mode=OneWay}" />
+
+            <TextBox
+                x:Name="DisplayNameTextBox"
+                Grid.Row="1"
+                Header="Display Name"
+                PlaceholderText="eg. John Doe"
+                TextChanged="InputChanged" />
+
+            <TextBox
+                x:Name="SpecialImapAddress"
+                Grid.Row="2"
+                Header="E-mail Address"
+                PlaceholderText="eg. johndoe@testmail.com"
+                TextChanged="InputChanged" />
+
+            <PasswordBox
+                x:Name="AppSpecificPassword"
+                Grid.Row="3"
+                Header="App-Specific Password"
+                PasswordChanged="ImapPasswordChanged" />
+
+            <HyperlinkButton
+                Grid.Row="4"
+                HorizontalAlignment="Right"
+                Click="AppSpecificHelpButtonClicked"
+                Content="How do I get app-specific password?" />
+        </Grid>
     </Grid>
 </ContentDialog>

Wino.Core.UWP/Dialogs/NewAccountDialog.xaml.cs

@@ -1,6 +1,9 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
+using Windows.System;
 using Windows.UI.Xaml;
 using Windows.UI.Xaml.Controls;
+using Wino.Core.Domain.Enums;
 using Wino.Core.Domain.Interfaces;
 using Wino.Core.Domain.Models.Accounts;
 
@@ -8,6 +11,17 @@ namespace Wino.Core.UWP.Dialogs
 {
     public sealed partial class NewAccountDialog : ContentDialog
     {
+        private Dictionary<SpecialImapProvider, string> helpingLinks = new Dictionary<SpecialImapProvider, string>()
+        {
+            { SpecialImapProvider.iCloud, "https://support.apple.com/en-us/102654" },
+            { SpecialImapProvider.Yahoo, "http://help.yahoo.com/kb/SLN15241.html" },
+        };
+
+        public static readonly DependencyProperty IsProviderSelectionVisibleProperty = DependencyProperty.Register(nameof(IsProviderSelectionVisible), typeof(bool), typeof(NewAccountDialog), new PropertyMetadata(true));
+        public static readonly DependencyProperty IsSpecialImapServerPartVisibleProperty = DependencyProperty.Register(nameof(IsSpecialImapServerPartVisible), typeof(bool), typeof(NewAccountDialog), new PropertyMetadata(false));
+        public static readonly DependencyProperty SelectedMailProviderProperty = DependencyProperty.Register(nameof(SelectedMailProvider), typeof(ProviderDetail), typeof(NewAccountDialog), new PropertyMetadata(null, new PropertyChangedCallback(OnSelectedProviderChanged)));
+
+
         /// <summary>
         /// Gets or sets current selected mail provider in the dialog.
         /// </summary>
@@ -17,7 +31,18 @@ namespace Wino.Core.UWP.Dialogs
             set { SetValue(SelectedMailProviderProperty, value); }
         }
 
-        public static readonly DependencyProperty SelectedMailProviderProperty = DependencyProperty.Register(nameof(SelectedMailProvider), typeof(ProviderDetail), typeof(NewAccountDialog), new PropertyMetadata(null, new PropertyChangedCallback(OnSelectedProviderChanged)));
+
+        public bool IsProviderSelectionVisible
+        {
+            get { return (bool)GetValue(IsProviderSelectionVisibleProperty); }
+            set { SetValue(IsProviderSelectionVisibleProperty, value); }
+        }
+
+        public bool IsSpecialImapServerPartVisible
+        {
+            get { return (bool)GetValue(IsSpecialImapServerPartVisibleProperty); }
+            set { SetValue(IsSpecialImapServerPartVisibleProperty, value); }
+        }
 
         // List of available mail providers for now.
 
@@ -45,16 +70,40 @@ namespace Wino.Core.UWP.Dialogs
 
         private void CreateClicked(ContentDialog sender, ContentDialogButtonClickEventArgs args)
         {
+            if (IsSpecialImapServerPartVisible)
+            {
+                // Special imap detail input.
+
+                var details = new SpecialImapProviderDetails(SpecialImapAddress.Text.Trim(), AppSpecificPassword.Password.Trim(), DisplayNameTextBox.Text.Trim(), SelectedMailProvider.SpecialImapProvider);
+                Result = new AccountCreationDialogResult(SelectedMailProvider.Type, AccountNameTextbox.Text.Trim(), details);
+                Hide();
+
+                return;
+            }
+
             Validate();
 
             if (IsSecondaryButtonEnabled)
             {
-                Result = new AccountCreationDialogResult(SelectedMailProvider.Type, AccountNameTextbox.Text.Trim());
-                Hide();
+                if (SelectedMailProvider.SpecialImapProvider != SpecialImapProvider.None)
+                {
+                    // This step requires app-sepcific password login for some providers.
+                    args.Cancel = true;
+
+                    IsProviderSelectionVisible = false;
+                    IsSpecialImapServerPartVisible = true;
+
+                    Validate();
+                }
+                else
+                {
+                    Result = new AccountCreationDialogResult(SelectedMailProvider.Type, AccountNameTextbox.Text.Trim(), null);
+                    Hide();
+                }
             }
         }
 
-        private void AccountNameChanged(object sender, TextChangedEventArgs e) => Validate();
+        private void InputChanged(object sender, TextChangedEventArgs e) => Validate();
         private void SenderNameChanged(object sender, TextChangedEventArgs e) => Validate();
 
         private void Validate()
@@ -68,7 +117,10 @@ namespace Wino.Core.UWP.Dialogs
         {
             bool shouldEnable = SelectedMailProvider != null
                 && SelectedMailProvider.IsSupported
-                && !string.IsNullOrEmpty(AccountNameTextbox.Text);
+                && !string.IsNullOrEmpty(AccountNameTextbox.Text)
+                && (IsSpecialImapServerPartVisible ? (!string.IsNullOrEmpty(AppSpecificPassword.Password)
+                && !string.IsNullOrEmpty(DisplayNameTextBox.Text)
+                && EmailValidation.EmailValidator.Validate(SpecialImapAddress.Text)) : true);
 
             IsPrimaryButtonEnabled = shouldEnable;
         }
@@ -79,5 +131,22 @@ namespace Wino.Core.UWP.Dialogs
         }
 
         private void DialogOpened(ContentDialog sender, ContentDialogOpenedEventArgs args) => Validate();
+
+        private void BackClicked(object sender, RoutedEventArgs e)
+        {
+            IsSpecialImapServerPartVisible = false;
+            IsProviderSelectionVisible = true;
+
+            Validate();
+        }
+
+        private void ImapPasswordChanged(object sender, RoutedEventArgs e) => Validate();
+
+        private async void AppSpecificHelpButtonClicked(object sender, RoutedEventArgs e)
+        {
+            var helpUrl = helpingLinks[SelectedMailProvider.SpecialImapProvider];
+
+            await Launcher.LaunchUriAsync(new Uri(helpUrl));
+        }
     }
 }

Wino.Core.UWP/Helpers/XamlHelpers.cs

@@ -11,6 +11,7 @@ using Windows.UI.Xaml.Controls.Primitives;
 using Windows.UI.Xaml.Markup;
 using Windows.UI.Xaml.Media;
 using Wino.Core.Domain;
+using Wino.Core.Domain.Entities.Shared;
 using Wino.Core.Domain.Enums;
 using Wino.Core.Domain.Models.MailItem;
 using Wino.Core.UWP.Controls;
@@ -262,17 +263,31 @@ namespace Wino.Helpers
             };
         }
 
-        public static WinoIconGlyph GetProviderIcon(MailProviderType providerType)
+
+        public static WinoIconGlyph GetProviderIcon(MailProviderType providerType, SpecialImapProvider specialImapProvider)
         {
-            return providerType switch
+            if (specialImapProvider == SpecialImapProvider.None)
             {
-                MailProviderType.Outlook => WinoIconGlyph.Microsoft,
-                MailProviderType.Gmail => WinoIconGlyph.Google,
-                MailProviderType.Office365 => WinoIconGlyph.Microsoft,
-                MailProviderType.IMAP4 => WinoIconGlyph.IMAP,
-                _ => WinoIconGlyph.None,
-            };
+                return providerType switch
+                {
+                    MailProviderType.Outlook => WinoIconGlyph.Microsoft,
+                    MailProviderType.Gmail => WinoIconGlyph.Google,
+                    MailProviderType.IMAP4 => WinoIconGlyph.IMAP,
+                    _ => WinoIconGlyph.None,
+                };
+            }
+            else
+            {
+                return specialImapProvider switch
+                {
+                    SpecialImapProvider.iCloud => WinoIconGlyph.Apple,
+                    SpecialImapProvider.Yahoo => WinoIconGlyph.Yahoo,
+                    _ => WinoIconGlyph.None,
+                };
+            }
         }
+        public static WinoIconGlyph GetProviderIcon(MailAccount account)
+            => GetProviderIcon(account.ProviderType, account.SpecialImapProvider);
 
         public static Geometry GetPathGeometry(string pathMarkup)
         {

Wino.Core.UWP/Services/DialogServiceBase.cs

@@ -132,7 +132,7 @@ namespace Wino.Core.UWP.Services
             return file;
         }
 
-        public virtual IAccountCreationDialog GetAccountCreationDialog(MailProviderType type)
+        public virtual IAccountCreationDialog GetAccountCreationDialog(AccountCreationDialogResult accountCreationDialogResult)
         {
             return new AccountCreationDialog
             {

Wino.Core.UWP/Services/WinoServerConnectionManager.cs

@@ -18,6 +18,7 @@ using Wino.Core.Integration.Json;
 using Wino.Messaging;
 using Wino.Messaging.Client.Connection;
 using Wino.Messaging.Enums;
+using Wino.Messaging.Server;
 using Wino.Messaging.UI;
 
 namespace Wino.Core.UWP.Services
@@ -256,6 +257,9 @@ namespace Wino.Core.UWP.Services
                 case nameof(CopyAuthURLRequested):
                     WeakReferenceMessenger.Default.Send(JsonSerializer.Deserialize<CopyAuthURLRequested>(messageJson));
                     break;
+                case nameof(NewMailSynchronizationRequested):
+                    WeakReferenceMessenger.Default.Send(JsonSerializer.Deserialize<NewMailSynchronizationRequested>(messageJson));
+                    break;
                 default:
                     throw new Exception("Invalid data type name passed to client.");
             }

Wino.Core.UWP/Styles/DataTemplates.xaml

@@ -29,7 +29,7 @@
             Header="{x:Bind Account.Name}"
             IsClickEnabled="True">
             <winuiControls:SettingsCard.HeaderIcon>
-                <coreControls:WinoFontIcon FontSize="64" Icon="{x:Bind helpers:XamlHelpers.GetProviderIcon(ProviderDetail.Type)}" />
+                <coreControls:WinoFontIcon FontSize="64" Icon="{x:Bind helpers:XamlHelpers.GetProviderIcon(Account)}" />
             </winuiControls:SettingsCard.HeaderIcon>
         </winuiControls:SettingsCard>
     </DataTemplate>

Wino.Core.UWP/Wino.Core.UWP.csproj

@@ -84,6 +84,9 @@
   <ItemGroup>
     <Compile Include="Activation\ActivationHandler.cs" />
     <Compile Include="BasePage.cs" />
+    <Compile Include="Controls\AccountCreationDialogControl.xaml.cs">
+      <DependentUpon>AccountCreationDialogControl.xaml</DependentUpon>
+    </Compile>
     <Compile Include="Controls\ControlConstants.cs" />
     <Compile Include="Controls\CustomWrapPanel.cs" />
     <Compile Include="Controls\EqualGridPanel.cs" />
@@ -115,7 +118,6 @@
     <Compile Include="Dialogs\AccountPickerDialog.xaml.cs">
       <DependentUpon>AccountPickerDialog.xaml</DependentUpon>
     </Compile>
-    <Compile Include="Dialogs\BaseAccountCreationDialog.cs" />
     <Compile Include="Dialogs\CustomMessageDialogInformationContainer.cs" />
     <Compile Include="Dialogs\CustomThemeBuilderDialog.xaml.cs">
       <DependentUpon>CustomThemeBuilderDialog.xaml</DependentUpon>
@@ -185,7 +187,7 @@
   </ItemGroup>
   <ItemGroup>
     <PackageReference Include="CommunityToolkit.Common">
-      <Version>8.3.2</Version>
+      <Version>8.4.0</Version>
     </PackageReference>
     <PackageReference Include="CommunityToolkit.Diagnostics">
       <Version>8.3.2</Version>
@@ -215,6 +217,9 @@
     <PackageReference Include="CommunityToolkit.Uwp.Controls.TabbedCommandBar">
       <Version>8.1.240916</Version>
     </PackageReference>
+    <PackageReference Include="EmailValidation">
+      <Version>1.2.0</Version>
+    </PackageReference>
     <PackageReference Include="Microsoft.AppCenter.Analytics">
       <Version>5.0.6</Version>
     </PackageReference>
@@ -231,7 +236,7 @@
       <Version>2.8.6</Version>
     </PackageReference>
     <PackageReference Include="Win2D.uwp">
-      <Version>1.28.0</Version>
+      <Version>1.28.1</Version>
     </PackageReference>
   </ItemGroup>
   <ItemGroup>
@@ -262,6 +267,7 @@
     </SDKReference>
   </ItemGroup>
   <ItemGroup>
+    <Content Include="Assets\Providers\iCloud.png" />
     <Content Include="Assets\WinoIcons.ttf" />
   </ItemGroup>
   <ItemGroup>
@@ -337,6 +343,10 @@
     </Content>
   </ItemGroup>
   <ItemGroup>
+    <Page Include="Controls\AccountCreationDialogControl.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:Compile</Generator>
+    </Page>
     <Page Include="Controls\WinoAppTitleBar.xaml">
       <Generator>MSBuild:Compile</Generator>
       <SubType>Designer</SubType>

Wino.Core.ViewModels/AboutPageViewModel.cs

@@ -19,7 +19,7 @@ namespace Wino.Core.ViewModels
         public string VersionName => _nativeAppService.GetFullAppVersion();
         public string DiscordChannelUrl => "https://discord.gg/windows-apps-hub-714581497222398064";
         public string GitHubUrl => "https://github.com/bkaankose/Wino-Mail/";
-        public string PrivacyPolicyUrl => "https://www.winomail.app/privacy_policy.html";
+        public string PrivacyPolicyUrl => "https://www.winomail.app/support/privacy";
         public string PaypalUrl => "https://paypal.me/bkaankose?country.x=PL&locale.x=en_US";
 
         public IPreferencesService PreferencesService { get; }

Wino.Core.ViewModels/Wino.Core.ViewModels.csproj

@@ -14,7 +14,6 @@
 			<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
 		</PackageReference>
 		<PackageReference Include="Microsoft.AppCenter.Crashes" Version="5.0.6" />
-		<PackageReference Include="Microsoft.Identity.Client" Version="4.66.2" />
 		<PackageReference Include="System.Reactive" Version="6.0.1" />
 	</ItemGroup>
 

Wino.Core/CoreContainerSetup.cs

@@ -4,6 +4,7 @@ using Wino.Authentication;
 using Wino.Core.Domain.Interfaces;
 using Wino.Core.Integration.Processors;
 using Wino.Core.Services;
+using Wino.Core.Synchronizers.ImapSync;
 
 namespace Wino.Core
 {
@@ -28,6 +29,11 @@ namespace Wino.Core
             services.AddTransient<IUnsubscriptionService, UnsubscriptionService>();
             services.AddTransient<IOutlookAuthenticator, OutlookAuthenticator>();
             services.AddTransient<IGmailAuthenticator, GmailAuthenticator>();
+
+            services.AddTransient<IImapSynchronizationStrategyProvider, ImapSynchronizationStrategyProvider>();
+            services.AddTransient<CondstoreSynchronizer>();
+            services.AddTransient<QResyncSynchronizer>();
+            services.AddTransient<UidBasedSynchronizer>();
         }
     }
 }

Wino.Core/Integration/ImapClientPool.cs

@@ -25,8 +25,6 @@ namespace Wino.Core.Integration
     /// Provides a pooling mechanism for ImapClient.
     /// Makes sure that we don't have too many connections to the server.
     /// Rents a connected & authenticated client from the pool all the time.
-    /// TODO: Keeps the clients alive by sending NOOP command periodically.
-    /// TODO: Listens to the Inbox folder for new messages.
     /// </summary>
     /// <param name="customServerInformation">Connection/Authentication info to be used to configure ImapClient.</param>
     public class ImapClientPool : IDisposable
@@ -48,14 +46,16 @@ namespace Wino.Core.Integration
 
         public bool ThrowOnSSLHandshakeCallback { get; set; }
         public ImapClientPoolOptions ImapClientPoolOptions { get; }
+        internal WinoImapClient IdleClient { get; set; }
 
         private readonly int MinimumPoolSize = 5;
 
-        private readonly ConcurrentStack<ImapClient> _clients = [];
+        private readonly ConcurrentStack<IImapClient> _clients = [];
         private readonly SemaphoreSlim _semaphore;
         private readonly CustomServerInformation _customServerInformation;
         private readonly Stream _protocolLogStream;
         private readonly ILogger _logger = Log.ForContext<ImapClientPool>();
+        private bool _disposedValue;
 
         public ImapClientPool(ImapClientPoolOptions imapClientPoolOptions)
         {
@@ -74,7 +74,7 @@ namespace Wino.Core.Integration
         /// Reconnects and reauthenticates if necessary.
         /// </summary>
         /// <param name="isCreatedNew">Whether the client has been newly created.</param>
-        private async Task EnsureCapabilitiesAsync(ImapClient client, bool isCreatedNew)
+        private async Task EnsureCapabilitiesAsync(IImapClient client, bool isCreatedNew)
         {
             try
             {
@@ -84,6 +84,9 @@ namespace Wino.Core.Integration
 
                 if ((isCreatedNew || isReconnected) && client.IsConnected)
                 {
+                    if (client.Capabilities.HasFlag(ImapCapabilities.Compress))
+                        await client.CompressAsync();
+
                     // Identify if the server supports ID extension.
                     // Some servers require it pre-authentication, some post-authentication.
                     // We'll observe the response here and do it after authentication if needed.
@@ -113,10 +116,11 @@ namespace Wino.Core.Integration
 
                     // Activate post-auth capabilities.
                     if (client.Capabilities.HasFlag(ImapCapabilities.QuickResync))
-                        await client.EnableQuickResyncAsync();
+                    {
+                        await client.EnableQuickResyncAsync().ConfigureAwait(false);
 
-                    if (client.Capabilities.HasFlag(ImapCapabilities.Compress))
-                        await client.CompressAsync();
+                        if (client is WinoImapClient winoImapClient) winoImapClient.IsQResyncEnabled = true;
+                    }
                 }
             }
             catch (Exception ex)
@@ -145,11 +149,11 @@ namespace Wino.Core.Integration
             return reader.ReadToEnd();
         }
 
-        public async Task<ImapClient> GetClientAsync()
+        public async Task<IImapClient> GetClientAsync()
         {
             await _semaphore.WaitAsync();
 
-            if (_clients.TryPop(out ImapClient item))
+            if (_clients.TryPop(out IImapClient item))
             {
                 await EnsureCapabilitiesAsync(item, false);
 
@@ -163,20 +167,24 @@ namespace Wino.Core.Integration
             return client;
         }
 
-        public void Release(ImapClient item, bool destroyClient = false)
+        public void Release(IImapClient item, bool destroyClient = false)
         {
             if (item != null)
             {
                 if (destroyClient)
                 {
-                    lock (item.SyncRoot)
+                    if (item.IsConnected)
                     {
-                        item.Disconnect(true);
+                        lock (item.SyncRoot)
+                        {
+                            item.Disconnect(quit: true);
+                        }
                     }
 
+                    _clients.TryPop(out _);
                     item.Dispose();
                 }
-                else
+                else if (!_disposedValue)
                 {
                     _clients.Push(item);
                 }
@@ -185,23 +193,15 @@ namespace Wino.Core.Integration
             }
         }
 
-        public void DestroyClient(ImapClient client)
+        private IImapClient CreateNewClient()
         {
-            if (client == null) return;
-
-            client.Disconnect(true);
-            client.Dispose();
-        }
-
-        private ImapClient CreateNewClient()
-        {
-            ImapClient client = null;
+            WinoImapClient client = null;
 
             // Make sure to create a ImapClient with a protocol logger if enabled.
 
             client = _protocolLogStream != null
-                ? new ImapClient(new ProtocolLogger(_protocolLogStream))
-                : new ImapClient();
+                ? new WinoImapClient(new ProtocolLogger(_protocolLogStream))
+                : new WinoImapClient();
 
             HttpProxyClient proxyClient = null;
 
@@ -213,7 +213,7 @@ namespace Wino.Core.Integration
 
             client.ProxyClient = proxyClient;
 
-            _logger.Debug("Created new ImapClient. Current clients: {Count}", _clients.Count);
+            _logger.Debug("Creating new ImapClient. Current clients: {Count}", _clients.Count);
 
             return client;
         }
@@ -229,7 +229,7 @@ namespace Wino.Core.Integration
             };
 
         /// <returns>True if the connection is newly established.</returns>
-        public async Task<bool> EnsureConnectedAsync(ImapClient client)
+        public async Task<bool> EnsureConnectedAsync(IImapClient client)
         {
             if (client.IsConnected) return false;
 
@@ -263,8 +263,20 @@ namespace Wino.Core.Integration
         {
             if (_protocolLogStream == null) return;
 
-            var messageBytes = Encoding.UTF8.GetBytes($"W: {message}\n");
-            _protocolLogStream.Write(messageBytes, 0, messageBytes.Length);
+            try
+            {
+                var messageBytes = Encoding.UTF8.GetBytes($"W: {message}\n");
+                _protocolLogStream.Write(messageBytes, 0, messageBytes.Length);
+            }
+            catch (ObjectDisposedException)
+            {
+                Log.Warning($"Protocol log stream is disposed. Cannot write to it.");
+            }
+            catch (Exception)
+            {
+
+                throw;
+            }
         }
 
         bool MyServerCertificateValidationCallback(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
@@ -281,7 +293,7 @@ namespace Wino.Core.Integration
             return true;
         }
 
-        public async Task EnsureAuthenticatedAsync(ImapClient client)
+        public async Task EnsureAuthenticatedAsync(IImapClient client)
         {
             if (client.IsAuthenticated) return;
 
@@ -319,27 +331,38 @@ namespace Wino.Core.Integration
             };
         }
 
+        protected virtual void Dispose(bool disposing)
+        {
+            if (!_disposedValue)
+            {
+                if (disposing)
+                {
+                    _clients.ForEach(client =>
+                    {
+                        lock (client.SyncRoot)
+                        {
+                            client.Disconnect(true);
+                        }
+                    });
+
+                    _clients.ForEach(client =>
+                    {
+                        client.Dispose();
+                    });
+
+                    _clients.Clear();
+
+                    _protocolLogStream?.Dispose();
+                }
+
+                _disposedValue = true;
+            }
+        }
+
         public void Dispose()
         {
-            _clients.ForEach(client =>
-            {
-                lock (client.SyncRoot)
-                {
-                    client.Disconnect(true);
-                }
-            });
-
-            _clients.ForEach(client =>
-            {
-                client.Dispose();
-            });
-
-            _clients.Clear();
-
-            if (_protocolLogStream != null)
-            {
-                _protocolLogStream.Dispose();
-            }
+            Dispose(disposing: true);
+            GC.SuppressFinalize(this);
         }
     }
 }

Wino.Core/Integration/WinoImapClient.cs

@@ -0,0 +1,60 @@
+using MailKit;
+using MailKit.Net.Imap;
+using Serilog;
+
+namespace Wino.Core.Integration
+{
+    /// <summary>
+    /// Extended class for ImapClient that is used in Wino.
+    /// </summary>
+    internal class WinoImapClient : ImapClient
+    {
+        /// <summary>
+        /// Gets or internally sets whether the QRESYNC extension is enabled.
+        /// It is set by ImapClientPool immidiately after the authentication.
+        /// </summary>
+        public bool IsQResyncEnabled { get; internal set; }
+
+        public WinoImapClient()
+        {
+            HookEvents();
+        }
+
+        public WinoImapClient(IProtocolLogger protocolLogger) : base(protocolLogger)
+        {
+            HookEvents();
+        }
+
+        private void HookEvents()
+        {
+            Disconnected += ClientDisconnected;
+        }
+
+        private void UnhookEvents()
+        {
+            Disconnected -= ClientDisconnected;
+        }
+
+        private void ClientDisconnected(object sender, DisconnectedEventArgs e)
+        {
+            if (e.IsRequested)
+            {
+                Log.Debug("Imap client is disconnected on request.");
+            }
+            else
+            {
+                Log.Debug("Imap client connection is dropped by server.");
+            }
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            base.Dispose(disposing);
+
+            if (disposing)
+            {
+                UnhookEvents();
+            }
+        }
+    }
+}

Wino.Core/Mime/ImapMessageCreationPackage.cs

@@ -1,9 +0,0 @@
-using MailKit;
-
-namespace Wino.Core.Mime
-{
-    /// <summary>
-    /// Encapsulates all required information to create a MimeMessage for IMAP synchronizer.
-    /// </summary>
-    public record ImapMessageCreationPackage(IMessageSummary MessageSummary, IMailFolder MailFolder);
-}

Wino.Core/Requests/Bundles/TaskRequestBundle.cs

@@ -7,10 +7,10 @@ namespace Wino.Core.Requests.Bundles
 {
     public class ImapRequest
     {
-        public Func<ImapClient, IRequestBase, Task> IntegratorTask { get; }
+        public Func<IImapClient, IRequestBase, Task> IntegratorTask { get; }
         public IRequestBase Request { get; }
 
-        public ImapRequest(Func<ImapClient, IRequestBase, Task> integratorTask, IRequestBase request)
+        public ImapRequest(Func<IImapClient, IRequestBase, Task> integratorTask, IRequestBase request)
         {
             IntegratorTask = integratorTask;
             Request = request;
@@ -19,7 +19,7 @@ namespace Wino.Core.Requests.Bundles
 
     public class ImapRequest<TRequestBaseType> : ImapRequest where TRequestBaseType : IRequestBase
     {
-        public ImapRequest(Func<ImapClient, TRequestBaseType, Task> integratorTask, TRequestBaseType request)
+        public ImapRequest(Func<IImapClient, TRequestBaseType, Task> integratorTask, TRequestBaseType request)
             : base((client, request) => integratorTask(client, (TRequestBaseType)request), request)
         {
         }

Wino.Core/Requests/Folder/EmptyFolderRequest.cs

@@ -11,6 +11,7 @@ namespace Wino.Core.Requests.Folder
 {
     public record EmptyFolderRequest(MailItemFolder Folder, List<MailCopy> MailsToDelete) : FolderRequestBase(Folder, FolderSynchronizerOperation.EmptyFolder), ICustomFolderSynchronizationRequest
     {
+        public bool ExcludeMustHaveFolders => false;
         public override void ApplyUIChanges()
         {
             foreach (var item in MailsToDelete)

Wino.Core/Requests/Folder/MarkFolderAsReadRequest.cs

@@ -32,5 +32,7 @@ namespace Wino.Core.Requests.Folder
         }
 
         public List<Guid> SynchronizationFolderIds => [Folder.Id];
+
+        public bool ExcludeMustHaveFolders => true;
     }
 }

Wino.Core/Requests/Mail/ArchiveRequest.cs

@@ -21,6 +21,7 @@ namespace Wino.Core.Requests.Mail
     public record ArchiveRequest(bool IsArchiving, MailCopy Item, MailItemFolder FromFolder, MailItemFolder ToFolder = null)
         : MailRequestBase(Item), ICustomFolderSynchronizationRequest
     {
+        public bool ExcludeMustHaveFolders => false;
         public List<Guid> SynchronizationFolderIds
         {
             get

Wino.Core/Requests/Mail/ChangeFlagRequest.cs

@@ -14,6 +14,8 @@ namespace Wino.Core.Requests.Mail
     {
         public List<Guid> SynchronizationFolderIds => [Item.FolderId];
 
+        public bool ExcludeMustHaveFolders => true;
+
         public override MailSynchronizerOperation Operation => MailSynchronizerOperation.ChangeFlag;
 
         public override void ApplyUIChanges()

Wino.Core/Requests/Mail/CreateDraftRequest.cs

@@ -13,6 +13,8 @@ namespace Wino.Core.Requests.Mail
         : MailRequestBase(DraftPreperationRequest.CreatedLocalDraftCopy),
         ICustomFolderSynchronizationRequest
     {
+        public bool ExcludeMustHaveFolders => false;
+
         public List<Guid> SynchronizationFolderIds =>
         [
             DraftPreperationRequest.CreatedLocalDraftCopy.AssignedFolder.Id

Wino.Core/Requests/Mail/DeleteRequest.cs

@@ -17,7 +17,7 @@ namespace Wino.Core.Requests.Mail
         ICustomFolderSynchronizationRequest
     {
         public List<Guid> SynchronizationFolderIds => [Item.FolderId];
-
+        public bool ExcludeMustHaveFolders => false;
         public override MailSynchronizerOperation Operation => MailSynchronizerOperation.Delete;
 
         public override void ApplyUIChanges()

Wino.Core/Requests/Mail/MarkReadRequest.cs

@@ -15,6 +15,8 @@ namespace Wino.Core.Requests.Mail
 
         public override MailSynchronizerOperation Operation => MailSynchronizerOperation.MarkRead;
 
+        public bool ExcludeMustHaveFolders => true;
+
         public override void ApplyUIChanges()
         {
             Item.IsRead = IsRead;

Wino.Core/Requests/Mail/MoveRequest.cs

@@ -13,7 +13,7 @@ namespace Wino.Core.Requests.Mail
         : MailRequestBase(Item), ICustomFolderSynchronizationRequest
     {
         public List<Guid> SynchronizationFolderIds => new() { FromFolder.Id, ToFolder.Id };
-
+        public bool ExcludeMustHaveFolders => false;
         public override MailSynchronizerOperation Operation => MailSynchronizerOperation.Move;
 
         public override void ApplyUIChanges()

Wino.Core/Requests/Mail/SendDraftRequest.cs

@@ -28,6 +28,8 @@ namespace Wino.Core.Requests.Mail
             }
         }
 
+        public bool ExcludeMustHaveFolders => false;
+
         public override MailSynchronizerOperation Operation => MailSynchronizerOperation.Send;
 
         public override void ApplyUIChanges()

Wino.Core/Services/AuthenticationProvider.cs

@@ -28,7 +28,6 @@ namespace Wino.Core.Services
             return providerType switch
             {
                 MailProviderType.Outlook => new OutlookAuthenticator(_nativeAppService, _applicationConfiguration, _authenticatorConfig),
-                MailProviderType.Office365 => new Office365Authenticator(_nativeAppService, _applicationConfiguration, _authenticatorConfig),
                 MailProviderType.Gmail => new GmailAuthenticator(_authenticatorConfig),
                 _ => throw new ArgumentException(Translator.Exception_UnsupportedProvider),
             };

Wino.Core/Services/SynchronizerFactory.cs

@@ -13,6 +13,7 @@ namespace Wino.Core.Services
         private bool isInitialized = false;
 
         private readonly IAccountService _accountService;
+        private readonly IImapSynchronizationStrategyProvider _imapSynchronizationStrategyProvider;
         private readonly IApplicationConfiguration _applicationConfiguration;
         private readonly IOutlookChangeProcessor _outlookChangeProcessor;
         private readonly IGmailChangeProcessor _gmailChangeProcessor;
@@ -28,6 +29,7 @@ namespace Wino.Core.Services
                                    IOutlookAuthenticator outlookAuthenticator,
                                    IGmailAuthenticator gmailAuthenticator,
                                    IAccountService accountService,
+                                   IImapSynchronizationStrategyProvider imapSynchronizationStrategyProvider,
                                    IApplicationConfiguration applicationConfiguration)
         {
             _outlookChangeProcessor = outlookChangeProcessor;
@@ -36,6 +38,7 @@ namespace Wino.Core.Services
             _outlookAuthenticator = outlookAuthenticator;
             _gmailAuthenticator = gmailAuthenticator;
             _accountService = accountService;
+            _imapSynchronizationStrategyProvider = imapSynchronizationStrategyProvider;
             _applicationConfiguration = applicationConfiguration;
         }
 
@@ -51,6 +54,7 @@ namespace Wino.Core.Services
                 {
                     synchronizer = CreateNewSynchronizer(account);
 
+
                     return await GetAccountSynchronizerAsync(accountId);
                 }
             }
@@ -65,12 +69,11 @@ namespace Wino.Core.Services
             switch (providerType)
             {
                 case Domain.Enums.MailProviderType.Outlook:
-                case Domain.Enums.MailProviderType.Office365:
                     return new OutlookSynchronizer(mailAccount, _outlookAuthenticator, _outlookChangeProcessor);
                 case Domain.Enums.MailProviderType.Gmail:
                     return new GmailSynchronizer(mailAccount, _gmailAuthenticator, _gmailChangeProcessor);
                 case Domain.Enums.MailProviderType.IMAP4:
-                    return new ImapSynchronizer(mailAccount, _imapChangeProcessor, _applicationConfiguration);
+                    return new ImapSynchronizer(mailAccount, _imapChangeProcessor, _imapSynchronizationStrategyProvider, _applicationConfiguration);
                 default:
                     break;
             }
@@ -82,6 +85,12 @@ namespace Wino.Core.Services
         {
             var synchronizer = CreateIntegratorWithDefaultProcessor(account);
 
+            if (synchronizer is IImapSynchronizer imapSynchronizer)
+            {
+                // Start the idle client for IMAP synchronizer.
+                _ = imapSynchronizer.StartIdleClientAsync();
+            }
+
             synchronizerCache.Add(synchronizer);
 
             return synchronizer;
@@ -100,5 +109,18 @@ namespace Wino.Core.Services
 
             isInitialized = true;
         }
+
+        public async Task DeleteSynchronizerAsync(Guid accountId)
+        {
+            var synchronizer = synchronizerCache.Find(a => a.Account.Id == accountId);
+
+            if (synchronizer != null)
+            {
+                // Stop the current synchronization.
+                await synchronizer.KillSynchronizerAsync();
+
+                synchronizerCache.Remove(synchronizer);
+            }
+        }
     }
 }

Wino.Core/Services/ThreadingStrategyProvider.cs

@@ -23,7 +23,7 @@ namespace Wino.Core.Services
         {
             return mailProviderType switch
             {
-                MailProviderType.Outlook or MailProviderType.Office365 => _outlookThreadingStrategy,
+                MailProviderType.Outlook => _outlookThreadingStrategy,
                 MailProviderType.Gmail => _gmailThreadingStrategy,
                 _ => _imapThreadStrategy,
             };

Wino.Core/Services/WinoRequestProcessor.cs

@@ -163,8 +163,7 @@ namespace Wino.Core.Services
                 MailItemFolder archiveFolder = null;
 
                 bool shouldRequireArchiveFolder = mailItem.AssignedAccount.ProviderType == MailProviderType.Outlook
-                                                  || mailItem.AssignedAccount.ProviderType == MailProviderType.IMAP4
-                                                  || mailItem.AssignedAccount.ProviderType == MailProviderType.Office365;
+                                                  || mailItem.AssignedAccount.ProviderType == MailProviderType.IMAP4;
 
                 if (shouldRequireArchiveFolder)
                 {

Wino.Core/Synchronizers/BaseSynchronizer.cs

@@ -51,9 +51,6 @@ namespace Wino.Core.Synchronizers
         /// <param name="cancellationToken">Cancellation token</param>
         public abstract Task ExecuteNativeRequestsAsync(List<IRequestBundle<TBaseRequest>> batchedRequests, CancellationToken cancellationToken = default);
 
-        // TODO: What if account is deleted during synchronization?
-        public bool CancelActiveSynchronization() => true;
-
         /// <summary>
         /// Refreshes remote mail account profile if possible.
         /// Profile picture, sender name and mailbox settings (todo) will be handled in this step.

Wino.Core/Synchronizers/GmailSynchronizer.cs

@@ -1193,5 +1193,15 @@ namespace Wino.Core.Synchronizers.Mail
         }
 
         #endregion
+
+        public override async Task KillSynchronizerAsync()
+        {
+            await base.KillSynchronizerAsync();
+
+            _gmailService.Dispose();
+            _peopleService.Dispose();
+            _calendarService.Dispose();
+            _googleHttpClient.Dispose();
+        }
     }
 }

Wino.Core/Synchronizers/ImapSync/CondstoreSynchronizer.cs

@@ -0,0 +1,131 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using MailKit;
+using MailKit.Net.Imap;
+using MailKit.Search;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Exceptions;
+using Wino.Core.Domain.Interfaces;
+using Wino.Core.Integration;
+using IMailService = Wino.Core.Domain.Interfaces.IMailService;
+
+namespace Wino.Core.Synchronizers.ImapSync
+{
+    /// <summary>
+    /// RFC 4551 CONDSTORE IMAP Synchronization strategy.
+    /// </summary>
+    internal class CondstoreSynchronizer : ImapSynchronizationStrategyBase
+    {
+        public CondstoreSynchronizer(IFolderService folderService, IMailService mailService) : base(folderService, mailService)
+        {
+        }
+
+        public async override Task<List<string>> HandleSynchronizationAsync(IImapClient client,
+                                                                              MailItemFolder folder,
+                                                                              IImapSynchronizer synchronizer,
+                                                                              CancellationToken cancellationToken = default)
+        {
+            if (client is not WinoImapClient winoClient)
+                throw new ArgumentException("Client must be of type WinoImapClient.", nameof(client));
+
+            if (!client.Capabilities.HasFlag(ImapCapabilities.CondStore))
+                throw new ImapSynchronizerStrategyException("Server does not support CONDSTORE.");
+
+            IMailFolder remoteFolder = null;
+
+            var downloadedMessageIds = new List<string>();
+
+            try
+            {
+                remoteFolder = await winoClient.GetFolderAsync(folder.RemoteFolderId, cancellationToken).ConfigureAwait(false);
+
+                await remoteFolder.OpenAsync(FolderAccess.ReadOnly, cancellationToken).ConfigureAwait(false);
+
+                var localHighestModSeq = (ulong)folder.HighestModeSeq;
+
+                bool isInitialSynchronization = localHighestModSeq == 0;
+
+                // There are some changes on new messages or flag changes.
+                // Deletions are tracked separately because some servers do not increase
+                // the MODSEQ value for deleted messages.
+                if (remoteFolder.HighestModSeq > localHighestModSeq)
+                {
+                    var changedUids = await GetChangedUidsAsync(client, folder, remoteFolder, synchronizer, cancellationToken).ConfigureAwait(false);
+
+                    // Get locally exists mails for the returned UIDs.
+                    downloadedMessageIds = await HandleChangedUIdsAsync(folder, synchronizer, remoteFolder, changedUids, cancellationToken).ConfigureAwait(false);
+
+                    folder.HighestModeSeq = unchecked((long)remoteFolder.HighestModSeq);
+
+                    await FolderService.UpdateFolderAsync(folder).ConfigureAwait(false);
+                }
+
+                await ManageUUIdBasedDeletedMessagesAsync(folder, remoteFolder, cancellationToken).ConfigureAwait(false);
+
+                return downloadedMessageIds;
+            }
+            catch (FolderNotFoundException)
+            {
+                await FolderService.DeleteFolderAsync(folder.MailAccountId, folder.RemoteFolderId).ConfigureAwait(false);
+
+                return default;
+            }
+            catch (Exception)
+            {
+                throw;
+            }
+            finally
+            {
+                if (!cancellationToken.IsCancellationRequested)
+                {
+                    if (remoteFolder != null)
+                    {
+                        if (remoteFolder.IsOpen)
+                        {
+                            await remoteFolder.CloseAsync(cancellationToken: cancellationToken).ConfigureAwait(false);
+                        }
+                    }
+                }
+            }
+        }
+
+        internal override async Task<IList<UniqueId>> GetChangedUidsAsync(IImapClient winoClient, MailItemFolder localFolder, IMailFolder remoteFolder, IImapSynchronizer synchronizer, CancellationToken cancellationToken = default)
+        {
+            var localHighestModSeq = (ulong)localFolder.HighestModeSeq;
+            var remoteHighestModSeq = remoteFolder.HighestModSeq;
+
+            // Search for emails with a MODSEQ greater than the last known value.
+            // Use SORT extension if server supports.
+
+            IList<UniqueId> changedUids = null;
+
+            if (winoClient.Capabilities.HasFlag(ImapCapabilities.Sort))
+            {
+                // Highest mod seq must be greater than 0 for SORT.
+                changedUids = await remoteFolder.SortAsync(SearchQuery.ChangedSince(Math.Max(localHighestModSeq, 1)), [OrderBy.ReverseDate], cancellationToken).ConfigureAwait(false);
+            }
+            else
+            {
+                changedUids = await remoteFolder.SearchAsync(SearchQuery.ChangedSince(localHighestModSeq), cancellationToken).ConfigureAwait(false);
+            }
+
+            changedUids = await remoteFolder.SearchAsync(SearchQuery.ChangedSince(localHighestModSeq), cancellationToken).ConfigureAwait(false);
+
+            // For initial synchronizations, take the first allowed number of items.
+            // For consequtive synchronizations, take all the items. We don't want to miss any changes.
+            // Smaller uid means newer message. For initial sync, we need start taking items from the top.
+
+            bool isInitialSynchronization = localHighestModSeq == 0;
+
+            if (isInitialSynchronization)
+            {
+                changedUids = changedUids.OrderByDescending(a => a.Id).Take((int)synchronizer.InitialMessageDownloadCountPerFolder).ToList();
+            }
+
+            return changedUids;
+        }
+    }
+}

Wino.Core/Synchronizers/ImapSync/ImapSynchronizationStrategyBase.cs

@@ -0,0 +1,178 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using MailKit;
+using MailKit.Net.Imap;
+using MailKit.Search;
+using MoreLinq;
+using Serilog;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Interfaces;
+using Wino.Core.Domain.Models.MailItem;
+using Wino.Services.Extensions;
+using IMailService = Wino.Core.Domain.Interfaces.IMailService;
+
+namespace Wino.Core.Synchronizers.ImapSync
+{
+    public abstract class ImapSynchronizationStrategyBase : IImapSynchronizerStrategy
+    {
+        // Minimum summary items to Fetch for mail synchronization from IMAP.
+        protected readonly MessageSummaryItems MailSynchronizationFlags =
+            MessageSummaryItems.Flags |
+            MessageSummaryItems.UniqueId |
+            MessageSummaryItems.ThreadId |
+            MessageSummaryItems.EmailId |
+            MessageSummaryItems.Headers |
+            MessageSummaryItems.PreviewText |
+            MessageSummaryItems.GMailThreadId |
+            MessageSummaryItems.References |
+            MessageSummaryItems.ModSeq;
+
+        protected IFolderService FolderService { get; }
+        protected IMailService MailService { get; }
+
+        protected ImapSynchronizationStrategyBase(IFolderService folderService, IMailService mailService)
+        {
+            FolderService = folderService;
+            MailService = mailService;
+        }
+
+        public abstract Task<List<string>> HandleSynchronizationAsync(IImapClient client, MailItemFolder folder, IImapSynchronizer synchronizer, CancellationToken cancellationToken = default);
+        internal abstract Task<IList<UniqueId>> GetChangedUidsAsync(IImapClient client, MailItemFolder localFolder, IMailFolder remoteFolder, IImapSynchronizer synchronizer, CancellationToken cancellationToken = default);
+
+        protected async Task<List<string>> HandleChangedUIdsAsync(MailItemFolder folder, IImapSynchronizer synchronizer, IMailFolder remoteFolder, IList<UniqueId> changedUids, CancellationToken cancellationToken)
+        {
+            List<string> downloadedMessageIds = new();
+
+            var existingMails = await MailService.GetExistingMailsAsync(folder.Id, changedUids).ConfigureAwait(false);
+            var existingMailUids = existingMails.Select(m => MailkitClientExtensions.ResolveUidStruct(m.Id)).ToArray();
+
+            // These are the non-existing mails. They will be downloaded + processed.
+            var newMessageIds = changedUids.Except(existingMailUids).ToList();
+            var deletedMessageIds = existingMailUids.Except(changedUids).ToList();
+
+            // Fetch minimum data for the existing mails in one query.
+            var existingFlagData = await remoteFolder.FetchAsync(existingMailUids, MessageSummaryItems.Flags | MessageSummaryItems.UniqueId).ConfigureAwait(false);
+
+            foreach (var update in existingFlagData)
+            {
+                if (update.UniqueId == null)
+                {
+                    Log.Warning($"Couldn't fetch UniqueId for the mail. FetchAsync failed.");
+                    continue;
+                }
+
+                if (update.Flags == null)
+                {
+                    Log.Warning($"Couldn't fetch flags for the mail with UID {update.UniqueId.Id}. FetchAsync failed.");
+                    continue;
+                }
+
+                var existingMail = existingMails.FirstOrDefault(m => MailkitClientExtensions.ResolveUidStruct(m.Id).Id == update.UniqueId.Id);
+
+                if (existingMail == null)
+                {
+                    Log.Warning($"Couldn't find the mail with UID {update.UniqueId.Id} in the local database. Flag update is ignored.");
+                    continue;
+                }
+
+                await HandleMessageFlagsChangeAsync(existingMail, update.Flags.Value).ConfigureAwait(false);
+            }
+
+            // Fetch the new mails in batch.
+
+            var batchedMessageIds = newMessageIds.Batch(50);
+
+            foreach (var group in batchedMessageIds)
+            {
+                var summaries = await remoteFolder.FetchAsync(group, MailSynchronizationFlags, cancellationToken).ConfigureAwait(false);
+
+                foreach (var summary in summaries)
+                {
+                    var mimeMessage = await remoteFolder.GetMessageAsync(summary.UniqueId, cancellationToken).ConfigureAwait(false);
+
+                    var creationPackage = new ImapMessageCreationPackage(summary, mimeMessage);
+
+                    var mailPackages = await synchronizer.CreateNewMailPackagesAsync(creationPackage, folder, cancellationToken).ConfigureAwait(false);
+
+                    if (mailPackages != null)
+                    {
+                        foreach (var package in mailPackages)
+                        {
+                            // Local draft is mapped. We don't need to create a new mail copy.
+                            if (package == null) continue;
+
+                            bool isCreatedNew = await MailService.CreateMailAsync(folder.MailAccountId, package).ConfigureAwait(false);
+
+                            // This is upsert. We are not interested in updated mails.
+                            if (isCreatedNew) downloadedMessageIds.Add(package.Copy.Id);
+                        }
+                    }
+                }
+            }
+
+
+            return downloadedMessageIds;
+        }
+
+        protected async Task HandleMessageFlagsChangeAsync(MailItemFolder folder, UniqueId? uniqueId, MessageFlags flags)
+        {
+            if (folder == null) return;
+            if (uniqueId == null) return;
+
+            var localMailCopyId = MailkitClientExtensions.CreateUid(folder.Id, uniqueId.Value.Id);
+
+            var isFlagged = MailkitClientExtensions.GetIsFlagged(flags);
+            var isRead = MailkitClientExtensions.GetIsRead(flags);
+
+            await MailService.ChangeReadStatusAsync(localMailCopyId, isRead).ConfigureAwait(false);
+            await MailService.ChangeFlagStatusAsync(localMailCopyId, isFlagged).ConfigureAwait(false);
+        }
+
+        protected async Task HandleMessageFlagsChangeAsync(MailCopy mailCopy, MessageFlags flags)
+        {
+            if (mailCopy == null) return;
+
+            var isFlagged = MailkitClientExtensions.GetIsFlagged(flags);
+            var isRead = MailkitClientExtensions.GetIsRead(flags);
+
+            if (isFlagged != mailCopy.IsFlagged)
+            {
+                await MailService.ChangeFlagStatusAsync(mailCopy.Id, isFlagged).ConfigureAwait(false);
+            }
+
+            if (isRead != mailCopy.IsRead)
+            {
+                await MailService.ChangeReadStatusAsync(mailCopy.Id, isRead).ConfigureAwait(false);
+            }
+        }
+
+        protected async Task HandleMessageDeletedAsync(MailItemFolder folder, IList<UniqueId> uniqueIds)
+        {
+            if (folder == null) return;
+            if (uniqueIds == null || uniqueIds.Count == 0) return;
+
+            foreach (var uniqueId in uniqueIds)
+            {
+                if (uniqueId == null) continue;
+                var localMailCopyId = MailkitClientExtensions.CreateUid(folder.Id, uniqueId.Id);
+
+                await MailService.DeleteMailAsync(folder.MailAccountId, localMailCopyId).ConfigureAwait(false);
+            }
+        }
+
+        protected async Task ManageUUIdBasedDeletedMessagesAsync(MailItemFolder localFolder, IMailFolder remoteFolder, CancellationToken cancellationToken = default)
+        {
+            var allUids = (await FolderService.GetKnownUidsForFolderAsync(localFolder.Id)).Select(a => new UniqueId(a)).ToList();
+
+            if (allUids.Count > 0)
+            {
+                var remoteAllUids = await remoteFolder.SearchAsync(SearchQuery.All, cancellationToken);
+                var deletedUids = allUids.Except(remoteAllUids).ToList();
+
+                await HandleMessageDeletedAsync(localFolder, deletedUids).ConfigureAwait(false);
+            }
+        }
+    }
+}

Wino.Core/Synchronizers/ImapSync/ImapSynchronizationStrategyProvider.cs

@@ -0,0 +1,31 @@
+using MailKit.Net.Imap;
+using Wino.Core.Domain.Interfaces;
+using Wino.Core.Integration;
+
+namespace Wino.Core.Synchronizers.ImapSync
+{
+    internal class ImapSynchronizationStrategyProvider : IImapSynchronizationStrategyProvider
+    {
+        private readonly QResyncSynchronizer _qResyncSynchronizer;
+        private readonly CondstoreSynchronizer _condstoreSynchronizer;
+        private readonly UidBasedSynchronizer _uidBasedSynchronizer;
+
+        public ImapSynchronizationStrategyProvider(QResyncSynchronizer qResyncSynchronizer, CondstoreSynchronizer condstoreSynchronizer, UidBasedSynchronizer uidBasedSynchronizer)
+        {
+            _qResyncSynchronizer = qResyncSynchronizer;
+            _condstoreSynchronizer = condstoreSynchronizer;
+            _uidBasedSynchronizer = uidBasedSynchronizer;
+        }
+
+        public IImapSynchronizerStrategy GetSynchronizationStrategy(IImapClient client)
+        {
+            if (client is not WinoImapClient winoImapClient)
+                throw new System.ArgumentException("Client must be of type WinoImapClient.", nameof(client));
+
+            if (client.Capabilities.HasFlag(ImapCapabilities.QuickResync) && winoImapClient.IsQResyncEnabled) return _qResyncSynchronizer;
+            if (client.Capabilities.HasFlag(ImapCapabilities.CondStore)) return _condstoreSynchronizer;
+
+            return _uidBasedSynchronizer;
+        }
+    }
+}

Wino.Core/Synchronizers/ImapSync/QResyncSynchronizer.cs

@@ -0,0 +1,119 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using MailKit;
+using MailKit.Net.Imap;
+using MailKit.Search;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Exceptions;
+using Wino.Core.Domain.Interfaces;
+using Wino.Core.Integration;
+using IMailService = Wino.Core.Domain.Interfaces.IMailService;
+
+namespace Wino.Core.Synchronizers.ImapSync
+{
+    /// <summary>
+    /// RFC 5162 QRESYNC IMAP Synchronization strategy.
+    /// </summary>
+    internal class QResyncSynchronizer : ImapSynchronizationStrategyBase
+    {
+        public QResyncSynchronizer(IFolderService folderService, IMailService mailService) : base(folderService, mailService)
+        {
+        }
+
+        public override async Task<List<string>> HandleSynchronizationAsync(IImapClient client,
+                                                                                                MailItemFolder folder,
+                                                                                                IImapSynchronizer synchronizer,
+                                                                                                CancellationToken cancellationToken = default)
+        {
+            var downloadedMessageIds = new List<string>();
+
+            if (client is not WinoImapClient winoClient)
+                throw new ImapSynchronizerStrategyException("Client must be of type WinoImapClient.");
+
+            if (!client.Capabilities.HasFlag(ImapCapabilities.QuickResync))
+                throw new ImapSynchronizerStrategyException("Server does not support QRESYNC.");
+
+            if (!winoClient.IsQResyncEnabled)
+                throw new ImapSynchronizerStrategyException("QRESYNC is not enabled for WinoImapClient.");
+
+            // Ready to implement QRESYNC synchronization.
+
+            IMailFolder remoteFolder = null;
+
+            try
+            {
+                remoteFolder = await client.GetFolderAsync(folder.RemoteFolderId, cancellationToken).ConfigureAwait(false);
+
+                // Check the Uid validity first.
+                // If they don't match, clear all the local data and perform full-resync.
+
+                bool isCacheValid = remoteFolder.UidValidity == folder.UidValidity;
+
+                if (!isCacheValid)
+                {
+                    // TODO: Remove all local data.
+                }
+
+                // Perform QRESYNC synchronization.
+                var localHighestModSeq = (ulong)folder.HighestModeSeq;
+
+                remoteFolder.MessagesVanished += async (c, r) => await HandleMessageDeletedAsync(folder, r.UniqueIds).ConfigureAwait(false);
+                remoteFolder.MessageFlagsChanged += async (c, r) => await HandleMessageFlagsChangeAsync(folder, r.UniqueId, r.Flags).ConfigureAwait(false);
+
+                var allUids = await FolderService.GetKnownUidsForFolderAsync(folder.Id);
+                var allUniqueIds = allUids.Select(a => new UniqueId(a)).ToList();
+
+                await remoteFolder.OpenAsync(FolderAccess.ReadOnly, folder.UidValidity, localHighestModSeq, allUniqueIds).ConfigureAwait(false);
+
+                var changedUids = await GetChangedUidsAsync(client, folder, remoteFolder, synchronizer, cancellationToken).ConfigureAwait(false);
+
+                downloadedMessageIds = await HandleChangedUIdsAsync(folder, synchronizer, remoteFolder, changedUids, cancellationToken).ConfigureAwait(false);
+
+                // Update the local folder with the new highest mod-seq and validity.
+                folder.HighestModeSeq = unchecked((long)remoteFolder.HighestModSeq);
+                folder.UidValidity = remoteFolder.UidValidity;
+
+                await ManageUUIdBasedDeletedMessagesAsync(folder, remoteFolder, cancellationToken).ConfigureAwait(false);
+
+                await FolderService.UpdateFolderAsync(folder).ConfigureAwait(false);
+            }
+            catch (FolderNotFoundException)
+            {
+                await FolderService.DeleteFolderAsync(folder.MailAccountId, folder.RemoteFolderId).ConfigureAwait(false);
+
+                return default;
+            }
+            catch (Exception)
+            {
+                throw;
+            }
+            finally
+            {
+                if (!cancellationToken.IsCancellationRequested)
+                {
+                    if (remoteFolder != null)
+                    {
+                        remoteFolder.MessagesVanished -= async (c, r) => await HandleMessageDeletedAsync(folder, r.UniqueIds).ConfigureAwait(false);
+                        remoteFolder.MessageFlagsChanged -= async (c, r) => await HandleMessageFlagsChangeAsync(folder, r.UniqueId, r.Flags).ConfigureAwait(false);
+
+                        if (remoteFolder.IsOpen)
+                        {
+                            await remoteFolder.CloseAsync();
+                        }
+                    }
+                }
+            }
+
+            return downloadedMessageIds;
+        }
+
+        internal override async Task<IList<UniqueId>> GetChangedUidsAsync(IImapClient client, MailItemFolder localFolder, IMailFolder remoteFolder, IImapSynchronizer synchronizer, CancellationToken cancellationToken = default)
+        {
+            var localHighestModSeq = (ulong)localFolder.HighestModeSeq;
+            return await remoteFolder.SearchAsync(SearchQuery.ChangedSince(localHighestModSeq), cancellationToken).ConfigureAwait(false);
+        }
+    }
+}

Wino.Core/Synchronizers/ImapSync/UidBasedSynchronizer.cs

@@ -0,0 +1,79 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using MailKit;
+using MailKit.Net.Imap;
+using MailKit.Search;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Interfaces;
+using Wino.Core.Integration;
+
+namespace Wino.Core.Synchronizers.ImapSync
+{
+    /// <summary>
+    /// Uid based IMAP Synchronization strategy.
+    /// </summary>
+    internal class UidBasedSynchronizer : ImapSynchronizationStrategyBase
+    {
+        public UidBasedSynchronizer(IFolderService folderService, Domain.Interfaces.IMailService mailService) : base(folderService, mailService)
+        {
+        }
+
+        public override async Task<List<string>> HandleSynchronizationAsync(IImapClient client, MailItemFolder folder, IImapSynchronizer synchronizer, CancellationToken cancellationToken = default)
+        {
+            if (client is not WinoImapClient winoClient)
+                throw new ArgumentException("Client must be of type WinoImapClient.", nameof(client));
+
+            var downloadedMessageIds = new List<string>();
+            IMailFolder remoteFolder = null;
+
+            try
+            {
+                remoteFolder = await winoClient.GetFolderAsync(folder.RemoteFolderId, cancellationToken).ConfigureAwait(false);
+
+                await remoteFolder.OpenAsync(FolderAccess.ReadOnly, cancellationToken).ConfigureAwait(false);
+
+                // Fetch UIDs from the remote folder
+                var remoteUids = await remoteFolder.SearchAsync(SearchQuery.All, cancellationToken).ConfigureAwait(false);
+
+                remoteUids = remoteUids.OrderByDescending(a => a.Id).Take((int)synchronizer.InitialMessageDownloadCountPerFolder).ToList();
+
+                await HandleChangedUIdsAsync(folder, synchronizer, remoteFolder, remoteUids, cancellationToken).ConfigureAwait(false);
+                await ManageUUIdBasedDeletedMessagesAsync(folder, remoteFolder, cancellationToken).ConfigureAwait(false);
+            }
+            catch (FolderNotFoundException)
+            {
+                await FolderService.DeleteFolderAsync(folder.MailAccountId, folder.RemoteFolderId).ConfigureAwait(false);
+
+                return default;
+            }
+            catch (Exception)
+            {
+
+                throw;
+            }
+            finally
+            {
+                if (!cancellationToken.IsCancellationRequested)
+                {
+                    if (remoteFolder != null)
+                    {
+                        if (remoteFolder.IsOpen)
+                        {
+                            await remoteFolder.CloseAsync(cancellationToken: cancellationToken).ConfigureAwait(false);
+                        }
+                    }
+                }
+            }
+
+            return downloadedMessageIds;
+        }
+
+        internal override Task<IList<UniqueId>> GetChangedUidsAsync(IImapClient client, MailItemFolder localFolder, IMailFolder remoteFolder, IImapSynchronizer synchronizer, CancellationToken cancellationToken = default)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}

Wino.Core/Synchronizers/ImapSynchronizer.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Diagnostics;
 using System.IO;
 using System.Linq;
 using System.Threading;
@@ -7,8 +8,6 @@ using System.Threading.Tasks;
 using CommunityToolkit.Mvvm.Messaging;
 using MailKit;
 using MailKit.Net.Imap;
-using MailKit.Search;
-using MimeKit;
 using MoreLinq;
 using Serilog;
 using Wino.Core.Domain.Entities.Mail;
@@ -22,72 +21,55 @@ using Wino.Core.Domain.Models.Synchronization;
 using Wino.Core.Extensions;
 using Wino.Core.Integration;
 using Wino.Core.Integration.Processors;
-using Wino.Core.Mime;
 using Wino.Core.Requests.Bundles;
 using Wino.Core.Requests.Folder;
 using Wino.Core.Requests.Mail;
+using Wino.Messaging.Server;
 using Wino.Messaging.UI;
 using Wino.Services.Extensions;
 
 namespace Wino.Core.Synchronizers.Mail
 {
-    public class ImapSynchronizer : WinoSynchronizer<ImapRequest, ImapMessageCreationPackage, object>
+    public class ImapSynchronizer : WinoSynchronizer<ImapRequest, ImapMessageCreationPackage, object>, IImapSynchronizer
     {
-        private CancellationTokenSource idleDoneToken;
-        private CancellationTokenSource cancelInboxListeningToken = new CancellationTokenSource();
+        [Obsolete("N/A")]
+        public override uint BatchModificationSize => 1000;
+        public override uint InitialMessageDownloadCountPerFolder => 500;
 
-        private IMailFolder inboxFolder;
+        #region Idle Implementation
+
+        private CancellationTokenSource idleCancellationTokenSource;
+        private CancellationTokenSource idleDoneTokenSource;
+
+        #endregion
 
         private readonly ILogger _logger = Log.ForContext<ImapSynchronizer>();
         private readonly ImapClientPool _clientPool;
         private readonly IImapChangeProcessor _imapChangeProcessor;
+        private readonly IImapSynchronizationStrategyProvider _imapSynchronizationStrategyProvider;
         private readonly IApplicationConfiguration _applicationConfiguration;
 
-        // Minimum summary items to Fetch for mail synchronization from IMAP.
-        private readonly MessageSummaryItems mailSynchronizationFlags =
-            MessageSummaryItems.Flags |
-            MessageSummaryItems.UniqueId |
-            MessageSummaryItems.ThreadId |
-            MessageSummaryItems.EmailId |
-            MessageSummaryItems.Headers |
-            MessageSummaryItems.PreviewText |
-            MessageSummaryItems.GMailThreadId |
-            MessageSummaryItems.References |
-            MessageSummaryItems.ModSeq;
-
-        /// <summary>
-        /// Timer that keeps the <see cref="InboxClient"/> alive for the lifetime of the pool.
-        /// Sends NOOP command to the server periodically.
-        /// </summary>
-        private Timer _noOpTimer;
-
-        /// <summary>
-        /// ImapClient that keeps the Inbox folder opened all the time for listening notifications.
-        /// </summary>
-        private ImapClient _inboxIdleClient;
-
-        public override uint BatchModificationSize => 1000;
-        public override uint InitialMessageDownloadCountPerFolder => 250;
-
         public ImapSynchronizer(MailAccount account,
                                 IImapChangeProcessor imapChangeProcessor,
+                                IImapSynchronizationStrategyProvider imapSynchronizationStrategyProvider,
                                 IApplicationConfiguration applicationConfiguration) : base(account)
         {
             // Create client pool with account protocol log.
             _imapChangeProcessor = imapChangeProcessor;
+            _imapSynchronizationStrategyProvider = imapSynchronizationStrategyProvider;
             _applicationConfiguration = applicationConfiguration;
 
-            var poolOptions = ImapClientPoolOptions.CreateDefault(Account.ServerInformation, CreateAccountProtocolLogFileStream());
+            var protocolLogStream = CreateAccountProtocolLogFileStream();
+            var poolOptions = ImapClientPoolOptions.CreateDefault(Account.ServerInformation, protocolLogStream);
 
             _clientPool = new ImapClientPool(poolOptions);
-            idleDoneToken = new CancellationTokenSource();
         }
 
         private Stream CreateAccountProtocolLogFileStream()
         {
             if (Account == null) throw new ArgumentNullException(nameof(Account));
 
-            var logFile = Path.Combine(_applicationConfiguration.ApplicationDataFolderPath, $"Protocol_{Account.Address}.log");
+            var logFile = Path.Combine(_applicationConfiguration.ApplicationDataFolderPath, $"Protocol_{Account.Address}_{Account.Id}.log");
 
             // Each session should start a new log.
             if (File.Exists(logFile)) File.Delete(logFile);
@@ -95,136 +77,10 @@ namespace Wino.Core.Synchronizers.Mail
             return new FileStream(logFile, FileMode.CreateNew);
         }
 
-        // TODO
-        // private async void NoOpTimerTriggered(object state) => await AwaitInboxIdleAsync();
-
-        private async Task AwaitInboxIdleAsync()
-        {
-            if (_inboxIdleClient == null)
-            {
-                _logger.Warning("InboxClient is null. Cannot send NOOP command.");
-                return;
-            }
-
-            await _clientPool.EnsureConnectedAsync(_inboxIdleClient);
-            await _clientPool.EnsureAuthenticatedAsync(_inboxIdleClient);
-
-            try
-            {
-                if (inboxFolder == null)
-                {
-                    inboxFolder = _inboxIdleClient.Inbox;
-                    await inboxFolder.OpenAsync(FolderAccess.ReadOnly, cancelInboxListeningToken.Token);
-                }
-
-                idleDoneToken = new CancellationTokenSource();
-
-                await _inboxIdleClient.IdleAsync(idleDoneToken.Token, cancelInboxListeningToken.Token);
-            }
-            finally
-            {
-                idleDoneToken.Dispose();
-                idleDoneToken = null;
-            }
-        }
-
-        private async Task StopInboxListeningAsync()
-        {
-            if (inboxFolder != null)
-            {
-                inboxFolder.CountChanged -= InboxFolderCountChanged;
-                inboxFolder.MessageExpunged -= InboxFolderMessageExpunged;
-                inboxFolder.MessageFlagsChanged -= InboxFolderMessageFlagsChanged;
-            }
-
-            if (_noOpTimer != null)
-            {
-                _noOpTimer.Dispose();
-                _noOpTimer = null;
-            }
-
-            if (idleDoneToken != null)
-            {
-                idleDoneToken.Cancel();
-                idleDoneToken.Dispose();
-                idleDoneToken = null;
-            }
-
-            if (_inboxIdleClient != null)
-            {
-                await _inboxIdleClient.DisconnectAsync(true);
-                _inboxIdleClient.Dispose();
-                _inboxIdleClient = null;
-            }
-        }
-
-        /// <summary>
-        /// Tries to connect & authenticate with the given credentials.
-        /// Prepares synchronizer for active listening of Inbox folder.
-        /// </summary>
-        public async Task StartInboxListeningAsync()
-        {
-            _inboxIdleClient = await _clientPool.GetClientAsync();
-
-            // Run it every 8 minutes after 1 minute delay.
-            // _noOpTimer = new Timer(NoOpTimerTriggered, null, 60000, 8 * 60 * 1000);
-
-            await _clientPool.EnsureConnectedAsync(_inboxIdleClient);
-            await _clientPool.EnsureAuthenticatedAsync(_inboxIdleClient);
-
-            if (!_inboxIdleClient.Capabilities.HasFlag(ImapCapabilities.Idle))
-            {
-                _logger.Information("Imap server does not support IDLE command. Listening live changes is not supported for {Name}", Account.Name);
-                return;
-            }
-
-            inboxFolder = _inboxIdleClient.Inbox;
-
-            if (inboxFolder == null)
-            {
-                _logger.Information("Inbox folder is null. Cannot listen for changes.");
-                return;
-            }
-
-            inboxFolder.CountChanged += InboxFolderCountChanged;
-            inboxFolder.MessageExpunged += InboxFolderMessageExpunged;
-            inboxFolder.MessageFlagsChanged += InboxFolderMessageFlagsChanged;
-
-            while (!cancelInboxListeningToken.IsCancellationRequested)
-            {
-                await AwaitInboxIdleAsync();
-            }
-
-            await StopInboxListeningAsync();
-        }
-
-        private void InboxFolderMessageFlagsChanged(object sender, MessageFlagsChangedEventArgs e)
-        {
-            Console.WriteLine("Flags have changed for message #{0} ({1}).", e.Index, e.Flags);
-        }
-
-        private void InboxFolderMessageExpunged(object sender, MessageEventArgs e)
-        {
-            _logger.Information("Inbox folder message expunged");
-        }
-
-        private void InboxFolderCountChanged(object sender, EventArgs e)
-        {
-            _logger.Information("Inbox folder count changed.");
-        }
-
-        /// <summary>
-        /// Parses List of string of mail copy ids and return valid uIds.
-        /// Follow the rules for creating arbitrary unique id for mail copies.
-        /// </summary>
-        private UniqueIdSet GetUniqueIds(IEnumerable<string> mailCopyIds)
-            => new(mailCopyIds.Select(a => new UniqueId(MailkitClientExtensions.ResolveUid(a))));
-
         /// <summary>
         /// Returns UniqueId for the given mail copy id.
         /// </summary>
-        private UniqueId GetUniqueId(string mailCopyId)
-            => new(MailkitClientExtensions.ResolveUid(mailCopyId));
+        private UniqueId GetUniqueId(string mailCopyId) => new(MailkitClientExtensions.ResolveUid(mailCopyId));
 
         #region Mail Integrations
 
@@ -319,8 +175,6 @@ namespace Wino.Core.Synchronizers.Mail
 
                 var singleRequest = request.Request;
 
-                singleRequest.Mime.Prepare(EncodingConstraint.None);
-
                 using var smtpClient = new MailKit.Net.Smtp.SmtpClient();
 
                 if (smtpClient.IsConnected && client.IsAuthenticated) return;
@@ -400,22 +254,19 @@ namespace Wino.Core.Synchronizers.Mail
 
         public override async Task<List<NewMailItemPackage>> CreateNewMailPackagesAsync(ImapMessageCreationPackage message, MailItemFolder assignedFolder, CancellationToken cancellationToken = default)
         {
-            var imapFolder = message.MailFolder;
-            var summary = message.MessageSummary;
-
-            var mimeMessage = await imapFolder.GetMessageAsync(summary.UniqueId, cancellationToken).ConfigureAwait(false);
-            var mailCopy = summary.GetMailDetails(assignedFolder, mimeMessage);
+            var mailCopy = message.MessageSummary.GetMailDetails(assignedFolder, message.MimeMessage);
 
             // Draft folder message updates must be updated as IsDraft.
-            // I couldn't find it in MimeMessage...
+            // I couldn't find it in MimeMesssage...
 
             mailCopy.IsDraft = assignedFolder.SpecialFolderType == SpecialFolderType.Draft;
 
             // Check draft mapping.
             // This is the same implementation as in the OutlookSynchronizer.
 
-            if (mimeMessage.Headers.Contains(Domain.Constants.WinoLocalDraftHeader)
-                && Guid.TryParse(mimeMessage.Headers[Domain.Constants.WinoLocalDraftHeader], out Guid localDraftCopyUniqueId))
+            if (message.MimeMessage != null &&
+                message.MimeMessage.Headers.Contains(Domain.Constants.WinoLocalDraftHeader) &&
+                Guid.TryParse(message.MimeMessage.Headers[Domain.Constants.WinoLocalDraftHeader], out Guid localDraftCopyUniqueId))
             {
                 // This message belongs to existing local draft copy.
                 // We don't need to create a new mail copy for this message, just update the existing one.
@@ -427,7 +278,7 @@ namespace Wino.Core.Synchronizers.Mail
                 // Local copy doesn't exists. Continue execution to insert mail copy.
             }
 
-            var package = new NewMailItemPackage(mailCopy, mimeMessage, assignedFolder.RemoteFolderId);
+            var package = new NewMailItemPackage(mailCopy, message.MimeMessage, assignedFolder.RemoteFolderId);
 
             return
             [
@@ -463,7 +314,13 @@ namespace Wino.Core.Synchronizers.Mail
                     PublishSynchronizationProgress(progress);
 
                     var folderDownloadedMessageIds = await SynchronizeFolderInternalAsync(folder, cancellationToken).ConfigureAwait(false);
-                    downloadedMessageIds.AddRange(folderDownloadedMessageIds);
+
+                    if (cancellationToken.IsCancellationRequested) return MailSynchronizationResult.Canceled;
+
+                    if (folderDownloadedMessageIds != null)
+                    {
+                        downloadedMessageIds.AddRange(folderDownloadedMessageIds);
+                    }
                 }
             }
 
@@ -497,7 +354,7 @@ namespace Wino.Core.Synchronizers.Mail
                 // At this point this client is ready to execute async commands.
                 // Each task bundle will await and execution will continue in case of error.
 
-                ImapClient executorClient = null;
+                IImapClient executorClient = null;
 
                 bool isCrashed = false;
 
@@ -550,7 +407,7 @@ namespace Wino.Core.Synchronizers.Mail
         /// <param name="executorClient">ImapClient from the pool</param>
         /// <param name="remoteFolder">Assigning remote folder.</param>
         /// <param name="localFolder">Assigning local folder.</param>
-        private void AssignSpecialFolderType(ImapClient executorClient, IMailFolder remoteFolder, MailItemFolder localFolder)
+        private void AssignSpecialFolderType(IImapClient executorClient, IMailFolder remoteFolder, MailItemFolder localFolder)
         {
             // Inbox is awlawys available. Don't miss it for assignment even though XList or SpecialUser is not supported.
             if (executorClient.Inbox == remoteFolder)
@@ -592,7 +449,7 @@ namespace Wino.Core.Synchronizers.Mail
 
             var localFolders = await _imapChangeProcessor.GetLocalFoldersAsync(Account.Id).ConfigureAwait(false);
 
-            ImapClient executorClient = null;
+            IImapClient executorClient = null;
 
             try
             {
@@ -674,6 +531,11 @@ namespace Wino.Core.Synchronizers.Mail
                     if (remoteFolder.IsNamespace && !remoteFolder.Attributes.HasFlag(FolderAttributes.Inbox) || !remoteFolder.Exists)
                         continue;
 
+                    // Check for NoSelect folders. These are not selectable folders.
+                    // TODO: With new MailKit version 'CanOpen' will be implemented for ease of use. Use that one.
+                    if (remoteFolder.Attributes.HasFlag(FolderAttributes.NoSelect))
+                        continue;
+
                     var existingLocalFolder = localFolders.FirstOrDefault(a => a.RemoteFolderId == remoteFolder.FullName);
 
                     if (existingLocalFolder == null)
@@ -768,264 +630,42 @@ namespace Wino.Core.Synchronizers.Mail
             }
         }
 
-
-
         private async Task<IEnumerable<string>> SynchronizeFolderInternalAsync(MailItemFolder folder, CancellationToken cancellationToken = default)
         {
             if (!folder.IsSynchronizationEnabled) return default;
 
-            var downloadedMessageIds = new List<string>();
-
-            // STEP1: Ask for flag changes for older mails.
-            // STEP2: Get new mail changes.
-            // https://www.rfc-editor.org/rfc/rfc4549 - Section 4.3
-
-            var _synchronizationClient = await _clientPool.GetClientAsync();
-
-            IMailFolder imapFolder = null;
-
-            var knownMailIds = new UniqueIdSet();
-            var locallyKnownMailUids = await _imapChangeProcessor.GetKnownUidsForFolderAsync(folder.Id);
-            knownMailIds.AddRange(locallyKnownMailUids.Select(a => new UniqueId(a)));
-
-            var highestUniqueId = Math.Max(0, locallyKnownMailUids.Count == 0 ? 0 : locallyKnownMailUids.Max());
-
-            var missingMailIds = new UniqueIdSet();
-
-            var uidValidity = folder.UidValidity;
-            var highestModeSeq = folder.HighestModeSeq;
-
-            var logger = Log.ForContext("FolderName", folder.FolderName);
-
-            logger.Verbose("HighestModeSeq: {HighestModeSeq}, HighestUniqueId: {HighestUniqueId}, UIDValidity: {UIDValidity}", highestModeSeq, highestUniqueId, uidValidity);
-
-            // Event handlers are placed here to handle existing MailItemFolder and IIMailFolder from MailKit.
-            // MailKit doesn't expose folder data when these events are emitted.
-
-            // Use local folder's UidValidty because cache might've been expired for remote IMAP folder.
-            // That will make our mail copy id invalid.
-
-            EventHandler<MessagesVanishedEventArgs> MessageVanishedHandler = async (s, e) =>
-            {
-                if (imapFolder == null) return;
-
-                foreach (var uniqueId in e.UniqueIds)
-                {
-                    var localMailCopyId = MailkitClientExtensions.CreateUid(folder.Id, uniqueId.Id);
-
-                    await _imapChangeProcessor.DeleteMailAsync(Account.Id, localMailCopyId);
-                }
-            };
-
-            EventHandler<MessageFlagsChangedEventArgs> MessageFlagsChangedHandler = async (s, e) =>
-            {
-                if (imapFolder == null) return;
-                if (e.UniqueId == null) return;
-
-                var localMailCopyId = MailkitClientExtensions.CreateUid(folder.Id, e.UniqueId.Value.Id);
-
-                var isFlagged = MailkitClientExtensions.GetIsFlagged(e.Flags);
-                var isRead = MailkitClientExtensions.GetIsRead(e.Flags);
-
-                await _imapChangeProcessor.ChangeMailReadStatusAsync(localMailCopyId, isRead);
-                await _imapChangeProcessor.ChangeFlagStatusAsync(localMailCopyId, isFlagged);
-            };
-
-            EventHandler<MessageEventArgs> MessageExpungedHandler = async (s, e) =>
-            {
-                if (imapFolder == null) return;
-                if (e.UniqueId == null) return;
-
-                var localMailCopyId = MailkitClientExtensions.CreateUid(folder.Id, e.UniqueId.Value.Id);
-                await _imapChangeProcessor.DeleteMailAsync(Account.Id, localMailCopyId);
-            };
+            IImapClient availableClient = null;
 
+        retry:
             try
             {
-                imapFolder = await _synchronizationClient.GetFolderAsync(folder.RemoteFolderId, cancellationToken);
 
-                imapFolder.MessageFlagsChanged += MessageFlagsChangedHandler;
+                availableClient = await _clientPool.GetClientAsync().ConfigureAwait(false);
 
-                // TODO: Bug: Enabling quick re-sync actually doesn't enable it.
-
-                var qsyncEnabled = false; // _synchronizationClient.Capabilities.HasFlag(ImapCapabilities.QuickResync);
-                var condStoreEnabled = _synchronizationClient.Capabilities.HasFlag(ImapCapabilities.CondStore);
-
-                if (qsyncEnabled)
-                {
-
-                    imapFolder.MessagesVanished += MessageVanishedHandler;
-
-                    await imapFolder.OpenAsync(FolderAccess.ReadWrite, uidValidity, (ulong)highestModeSeq, knownMailIds, cancellationToken);
-
-                    // Check the folder validity.
-                    // We'll delete our existing cache if it's not.
-
-                    // Get all messages after the last successful synchronization date.
-                    // This is fine for Wino synchronization because we're not really looking to
-                    // synchronize all folder.
-
-                    var allMessageIds = await imapFolder.SearchAsync(SearchQuery.All, cancellationToken);
-
-                    if (uidValidity != imapFolder.UidValidity)
-                    {
-                        // TODO: Cache is invalid. Delete all local cache.
-                        //await ChangeProcessor.FolderService.ClearImapFolderCacheAsync(folder.Id);
-
-                        folder.UidValidity = imapFolder.UidValidity;
-                        missingMailIds.AddRange(allMessageIds);
-                    }
-                    else
-                    {
-                        // Cache is valid.
-                        // Add missing mails only.
-
-                        missingMailIds.AddRange(allMessageIds.Except(knownMailIds).Where(a => a.Id > highestUniqueId));
-                    }
-                }
-                else
-                {
-                    // QSYNC extension is not enabled for the server.
-                    // We rely on ConditionalStore.
-
-                    imapFolder.MessageExpunged += MessageExpungedHandler;
-                    await imapFolder.OpenAsync(FolderAccess.ReadWrite, cancellationToken);
-
-                    // Get all messages after the last succesful synchronization date.
-                    // This is fine for Wino synchronization because we're not really looking to
-                    // synchronize all folder.
-
-                    var allMessageIds = await imapFolder.SearchAsync(SearchQuery.All, cancellationToken);
-
-                    if (uidValidity != imapFolder.UidValidity)
-                    {
-                        // TODO: Cache is invalid. Delete all local cache.
-                        // await ChangeProcessor.FolderService.ClearImapFolderCacheAsync(folder.Id);
-
-                        folder.UidValidity = imapFolder.UidValidity;
-                        missingMailIds.AddRange(allMessageIds);
-                    }
-                    else
-                    {
-                        // Cache is valid.
-
-                        var purgedMessages = knownMailIds.Except(allMessageIds);
-
-                        foreach (var purgedMessage in purgedMessages)
-                        {
-                            var mailId = MailkitClientExtensions.CreateUid(folder.Id, purgedMessage.Id);
-
-                            await _imapChangeProcessor.DeleteMailAsync(Account.Id, mailId);
-                        }
-
-                        IList<IMessageSummary> changed;
-
-                        if (knownMailIds.Count > 0)
-                        {
-                            // CONDSTORE enabled. Fetch items with highest mode seq for known items
-                            // to track flag changes. Otherwise just get changes without the mode seq.
-
-                            if (condStoreEnabled)
-                                changed = await imapFolder.FetchAsync(knownMailIds, (ulong)highestModeSeq, MessageSummaryItems.Flags | MessageSummaryItems.ModSeq | MessageSummaryItems.UniqueId);
-                            else
-                                changed = await imapFolder.FetchAsync(knownMailIds, MessageSummaryItems.Flags | MessageSummaryItems.UniqueId);
-
-                            foreach (var changedItem in changed)
-                            {
-                                var localMailCopyId = MailkitClientExtensions.CreateUid(folder.Id, changedItem.UniqueId.Id);
-
-                                var isFlagged = changedItem.Flags.GetIsFlagged();
-                                var isRead = changedItem.Flags.GetIsRead();
-
-                                await _imapChangeProcessor.ChangeMailReadStatusAsync(localMailCopyId, isRead);
-                                await _imapChangeProcessor.ChangeFlagStatusAsync(localMailCopyId, isFlagged);
-                            }
-                        }
-
-                        // We're only interested in items that has highier known uid than we fetched before.
-                        // Others are just older messages.
-
-                        missingMailIds.AddRange(allMessageIds.Except(knownMailIds).Where(a => a.Id > highestUniqueId));
-                    }
-                }
-
-                // Fetch completely missing new items in the end.
-
-                // Limit check.
-                if (missingMailIds.Count > InitialMessageDownloadCountPerFolder)
-                {
-                    missingMailIds = new UniqueIdSet(missingMailIds.TakeLast((int)InitialMessageDownloadCountPerFolder));
-                }
-
-                // In case of the high input, we'll batch them by 50 to reflect changes quickly.
-                var batchedMissingMailIds = missingMailIds.Batch(50).Select(a => new UniqueIdSet(a, SortOrder.Ascending));
-
-                foreach (var batchMissingMailIds in batchedMissingMailIds)
-                {
-                    var summaries = await imapFolder.FetchAsync(batchMissingMailIds, mailSynchronizationFlags, cancellationToken).ConfigureAwait(false);
-
-                    foreach (var summary in summaries)
-                    {
-                        // We pass the opened folder and summary to retrieve raw MimeMessage.
-
-                        var creationPackage = new ImapMessageCreationPackage(summary, imapFolder);
-                        var createdMailPackages = await CreateNewMailPackagesAsync(creationPackage, folder, cancellationToken).ConfigureAwait(false);
-
-                        // Local draft is mapped. We don't need to create a new mail copy.
-                        if (createdMailPackages == null)
-                            continue;
-
-                        foreach (var mailPackage in createdMailPackages)
-                        {
-                            bool isCreated = await _imapChangeProcessor.CreateMailAsync(Account.Id, mailPackage).ConfigureAwait(false);
-
-                            if (isCreated)
-                            {
-                                downloadedMessageIds.Add(mailPackage.Copy.Id);
-                            }
-                        }
-                    }
-                }
-
-                if (folder.HighestModeSeq != (long)imapFolder.HighestModSeq)
-                {
-                    folder.HighestModeSeq = (long)imapFolder.HighestModSeq;
-
-                    await _imapChangeProcessor.UpdateFolderAsync(folder).ConfigureAwait(false);
-                }
-
-                // Update last synchronization date for the folder..
-
-                await _imapChangeProcessor.UpdateFolderLastSyncDateAsync(folder.Id).ConfigureAwait(false);
-
-                return downloadedMessageIds;
+                var strategy = _imapSynchronizationStrategyProvider.GetSynchronizationStrategy(availableClient);
+                return await strategy.HandleSynchronizationAsync(availableClient, folder, this, cancellationToken).ConfigureAwait(false);
             }
-            catch (FolderNotFoundException)
+            catch (IOException)
             {
-                await _imapChangeProcessor.DeleteFolderAsync(Account.Id, folder.RemoteFolderId).ConfigureAwait(false);
+                _clientPool.Release(availableClient, false);
 
-                return default;
+                goto retry;
+            }
+            catch (OperationCanceledException)
+            {
+                // Ignore cancellations.
             }
             catch (Exception)
             {
-                throw;
+
             }
             finally
             {
-                if (imapFolder != null)
-                {
-                    imapFolder.MessageFlagsChanged -= MessageFlagsChangedHandler;
-                    imapFolder.MessageExpunged -= MessageExpungedHandler;
-                    imapFolder.MessagesVanished -= MessageVanishedHandler;
-
-                    if (imapFolder.IsOpen)
-                        await imapFolder.CloseAsync();
-                }
-
-                _clientPool.Release(_synchronizationClient);
+                _clientPool.Release(availableClient, false);
             }
-        }
 
+            return new List<string>();
+        }
 
         /// <summary>
         /// Whether the local folder should be updated with the remote folder.
@@ -1037,8 +677,141 @@ namespace Wino.Core.Synchronizers.Mail
             => !localFolder.FolderName.Equals(remoteFolder.Name, StringComparison.OrdinalIgnoreCase);
 
         protected override Task<CalendarSynchronizationResult> SynchronizeCalendarEventsInternalAsync(CalendarSynchronizationOptions options, CancellationToken cancellationToken = default)
+            => throw new NotImplementedException();
+
+        public async Task StartIdleClientAsync()
         {
-            throw new NotImplementedException();
+            IImapClient idleClient = null;
+            IMailFolder inboxFolder = null;
+
+            bool? reconnect = null;
+
+            try
+            {
+                var client = await _clientPool.GetClientAsync().ConfigureAwait(false);
+
+                if (!client.Capabilities.HasFlag(ImapCapabilities.Idle))
+                {
+                    Log.Debug($"{Account.Name} does not support Idle command. Ignored.");
+                    return;
+                }
+
+                if (client.Inbox == null)
+                {
+                    Log.Warning($"{Account.Name} does not have an Inbox folder for idle client to track. Ignored.");
+                    return;
+                }
+
+                // Setup idle client.
+                idleClient = client;
+
+                idleDoneTokenSource ??= new CancellationTokenSource();
+                idleCancellationTokenSource ??= new CancellationTokenSource();
+
+                inboxFolder = client.Inbox;
+
+                await inboxFolder.OpenAsync(FolderAccess.ReadOnly, idleCancellationTokenSource.Token);
+
+                inboxFolder.CountChanged += IdleNotificationTriggered;
+                inboxFolder.MessageFlagsChanged += IdleNotificationTriggered;
+                inboxFolder.MessageExpunged += IdleNotificationTriggered;
+                inboxFolder.MessagesVanished += IdleNotificationTriggered;
+
+                Log.Debug("Starting an idle client for {Name}", Account.Name);
+
+                await client.IdleAsync(idleDoneTokenSource.Token, idleCancellationTokenSource.Token);
+            }
+            catch (ImapProtocolException protocolException)
+            {
+                Log.Warning(protocolException, "Idle client received protocol exception.");
+                reconnect = true;
+            }
+            catch (IOException ioException)
+            {
+                Log.Warning(ioException, "Idle client received IO exception.");
+                reconnect = true;
+            }
+            catch (OperationCanceledException)
+            {
+                reconnect = !IsDisposing;
+            }
+            catch (Exception ex)
+            {
+                Log.Warning(ex, "Idle client failed to start.");
+                reconnect = false;
+            }
+            finally
+            {
+                if (inboxFolder != null)
+                {
+                    inboxFolder.CountChanged -= IdleNotificationTriggered;
+                    inboxFolder.MessageFlagsChanged -= IdleNotificationTriggered;
+                    inboxFolder.MessageExpunged -= IdleNotificationTriggered;
+                    inboxFolder.MessagesVanished -= IdleNotificationTriggered;
+                }
+
+                if (idleDoneTokenSource != null)
+                {
+                    idleDoneTokenSource.Dispose();
+                    idleDoneTokenSource = null;
+                }
+
+                if (idleClient != null)
+                {
+                    // Killing the client is not necessary. We can re-use it later.
+                    _clientPool.Release(idleClient, destroyClient: false);
+
+                    idleClient = null;
+                }
+
+                if (reconnect == true)
+                {
+                    Log.Information("Idle client is reconnecting.");
+
+                    _ = StartIdleClientAsync();
+                }
+                else if (reconnect == false)
+                {
+                    Log.Information("Finalized idle client.");
+                }
+            }
+        }
+
+        private void RequestIdleChangeSynchronization()
+        {
+            Debug.WriteLine("Detected idle change.");
+
+            // We don't really need to act on the count change in detail.
+            // Our synchronization should be enough to handle the changes with on-demand sync.
+            // We can just trigger a sync here IMAPIdle type.
+
+            var options = new MailSynchronizationOptions()
+            {
+                AccountId = Account.Id,
+                Type = MailSynchronizationType.IMAPIdle
+            };
+
+            WeakReferenceMessenger.Default.Send(new NewMailSynchronizationRequested(options, SynchronizationSource.Client));
+        }
+
+        private void IdleNotificationTriggered(object sender, EventArgs e)
+            => RequestIdleChangeSynchronization();
+
+        public Task StopIdleClientAsync()
+        {
+            idleDoneTokenSource?.Cancel();
+            idleCancellationTokenSource?.Cancel();
+
+            return Task.CompletedTask;
+        }
+
+        public override async Task KillSynchronizerAsync()
+        {
+            await base.KillSynchronizerAsync();
+            await StopIdleClientAsync();
+
+            // Make sure the client pool safely disconnects all ImapClients.
+            _clientPool.Dispose();
         }
     }
 }

Wino.Core/Synchronizers/OutlookSynchronizer.cs

@@ -1163,5 +1163,12 @@ namespace Wino.Core.Synchronizers.Mail
 
             return !localCalendarName.Equals(remoteCalendarName, StringComparison.OrdinalIgnoreCase);
         }
+
+        public override async Task KillSynchronizerAsync()
+        {
+            await base.KillSynchronizerAsync();
+
+            _graphClient.Dispose();
+        }
     }
 }

Wino.Core/Synchronizers/WinoSynchronizer.cs

@@ -25,11 +25,13 @@ namespace Wino.Core.Synchronizers
 {
     public abstract class WinoSynchronizer<TBaseRequest, TMessageType, TCalendarEventType> : BaseSynchronizer<TBaseRequest>, IWinoSynchronizerBase
     {
+        protected bool IsDisposing { get; private set; }
+
+        protected Dictionary<MailSynchronizationOptions, CancellationTokenSource> PendingSynchronizationRequest = new();
+
         protected ILogger Logger = Log.ForContext<WinoSynchronizer<TBaseRequest, TMessageType, TCalendarEventType>>();
 
-        protected WinoSynchronizer(MailAccount account) : base(account)
-        {
-        }
+        protected WinoSynchronizer(MailAccount account) : base(account) { }
 
         /// <summary>
         /// How many items per single HTTP call can be modified.
@@ -83,94 +85,129 @@ namespace Wino.Core.Synchronizers
         {
             try
             {
-                activeSynchronizationCancellationToken = cancellationToken;
-
-                State = AccountSynchronizerState.ExecutingRequests;
-
-                List<IRequestBundle<TBaseRequest>> nativeRequests = new();
-
-                List<IRequestBase> requestCopies = new(changeRequestQueue);
-
-                var keys = changeRequestQueue.GroupBy(a => a.GroupingKey());
-
-                foreach (var group in keys)
+                if (!ShouldQueueMailSynchronization(options))
                 {
-                    var key = group.Key;
-
-                    if (key is MailSynchronizerOperation mailSynchronizerOperation)
-                    {
-                        switch (mailSynchronizerOperation)
-                        {
-                            case MailSynchronizerOperation.MarkRead:
-                                nativeRequests.AddRange(MarkRead(new BatchMarkReadRequest(group.Cast<MarkReadRequest>())));
-                                break;
-                            case MailSynchronizerOperation.Move:
-                                nativeRequests.AddRange(Move(new BatchMoveRequest(group.Cast<MoveRequest>())));
-                                break;
-                            case MailSynchronizerOperation.Delete:
-                                nativeRequests.AddRange(Delete(new BatchDeleteRequest(group.Cast<DeleteRequest>())));
-                                break;
-                            case MailSynchronizerOperation.CreateDraft:
-                                nativeRequests.AddRange(CreateDraft(group.ElementAt(0) as CreateDraftRequest));
-                                break;
-                            case MailSynchronizerOperation.Send:
-                                nativeRequests.AddRange(SendDraft(group.ElementAt(0) as SendDraftRequest));
-                                break;
-                            case MailSynchronizerOperation.ChangeFlag:
-                                nativeRequests.AddRange(ChangeFlag(new BatchChangeFlagRequest(group.Cast<ChangeFlagRequest>())));
-                                break;
-                            case MailSynchronizerOperation.AlwaysMoveTo:
-                                nativeRequests.AddRange(AlwaysMoveTo(new BatchAlwaysMoveToRequest(group.Cast<AlwaysMoveToRequest>())));
-                                break;
-                            case MailSynchronizerOperation.MoveToFocused:
-                                nativeRequests.AddRange(MoveToFocused(new BatchMoveToFocusedRequest(group.Cast<MoveToFocusedRequest>())));
-                                break;
-                            case MailSynchronizerOperation.Archive:
-                                nativeRequests.AddRange(Archive(new BatchArchiveRequest(group.Cast<ArchiveRequest>())));
-                                break;
-                            default:
-                                break;
-                        }
-                    }
-                    else if (key is FolderSynchronizerOperation folderSynchronizerOperation)
-                    {
-                        switch (folderSynchronizerOperation)
-                        {
-                            case FolderSynchronizerOperation.RenameFolder:
-                                nativeRequests.AddRange(RenameFolder(group.ElementAt(0) as RenameFolderRequest));
-                                break;
-                            case FolderSynchronizerOperation.EmptyFolder:
-                                nativeRequests.AddRange(EmptyFolder(group.ElementAt(0) as EmptyFolderRequest));
-                                break;
-                            case FolderSynchronizerOperation.MarkFolderRead:
-                                nativeRequests.AddRange(MarkFolderAsRead(group.ElementAt(0) as MarkFolderAsReadRequest));
-                                break;
-                            default:
-                                break;
-                        }
-                    }
+                    Log.Debug($"{options.Type} synchronization is ignored.");
+                    return MailSynchronizationResult.Canceled;
                 }
 
-                changeRequestQueue.Clear();
+                var newCancellationTokenSource = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken);
 
-                Console.WriteLine($"Prepared {nativeRequests.Count()} native requests");
+                PendingSynchronizationRequest.Add(options, newCancellationTokenSource);
+                activeSynchronizationCancellationToken = newCancellationTokenSource.Token;
+
+                await synchronizationSemaphore.WaitAsync(activeSynchronizationCancellationToken);
 
                 PublishSynchronizationProgress(1);
 
-                await ExecuteNativeRequestsAsync(nativeRequests, activeSynchronizationCancellationToken);
+                // ImapSynchronizer will send this type when an Idle client receives a notification of changes.
+                // We should not execute requests in this case.
+                bool shouldExecuteRequests = options.Type != MailSynchronizationType.IMAPIdle;
 
-                PublishUnreadItemChanges();
+                bool shouldDelayExecution = false;
+                int maxExecutionDelay = 0;
 
-                // Execute request sync options should be re-calculated after execution.
-                // This is the part we decide which individual folders must be synchronized
-                // after the batch request execution.
-                if (options.Type == MailSynchronizationType.ExecuteRequests)
-                    options = GetSynchronizationOptionsAfterRequestExecution(requestCopies);
+                if (shouldExecuteRequests && changeRequestQueue.Any())
+                {
+                    State = AccountSynchronizerState.ExecutingRequests;
+
+                    List<IRequestBundle<TBaseRequest>> nativeRequests = new();
+
+                    List<IRequestBase> requestCopies = new(changeRequestQueue);
+
+                    var keys = changeRequestQueue.GroupBy(a => a.GroupingKey());
+
+                    foreach (var group in keys)
+                    {
+                        var key = group.Key;
+
+                        if (key is MailSynchronizerOperation mailSynchronizerOperation)
+                        {
+                            switch (mailSynchronizerOperation)
+                            {
+                                case MailSynchronizerOperation.MarkRead:
+                                    nativeRequests.AddRange(MarkRead(new BatchMarkReadRequest(group.Cast<MarkReadRequest>())));
+                                    break;
+                                case MailSynchronizerOperation.Move:
+                                    nativeRequests.AddRange(Move(new BatchMoveRequest(group.Cast<MoveRequest>())));
+                                    break;
+                                case MailSynchronizerOperation.Delete:
+                                    nativeRequests.AddRange(Delete(new BatchDeleteRequest(group.Cast<DeleteRequest>())));
+                                    break;
+                                case MailSynchronizerOperation.CreateDraft:
+                                    nativeRequests.AddRange(CreateDraft(group.ElementAt(0) as CreateDraftRequest));
+                                    break;
+                                case MailSynchronizerOperation.Send:
+                                    nativeRequests.AddRange(SendDraft(group.ElementAt(0) as SendDraftRequest));
+                                    break;
+                                case MailSynchronizerOperation.ChangeFlag:
+                                    nativeRequests.AddRange(ChangeFlag(new BatchChangeFlagRequest(group.Cast<ChangeFlagRequest>())));
+                                    break;
+                                case MailSynchronizerOperation.AlwaysMoveTo:
+                                    nativeRequests.AddRange(AlwaysMoveTo(new BatchAlwaysMoveToRequest(group.Cast<AlwaysMoveToRequest>())));
+                                    break;
+                                case MailSynchronizerOperation.MoveToFocused:
+                                    nativeRequests.AddRange(MoveToFocused(new BatchMoveToFocusedRequest(group.Cast<MoveToFocusedRequest>())));
+                                    break;
+                                case MailSynchronizerOperation.Archive:
+                                    nativeRequests.AddRange(Archive(new BatchArchiveRequest(group.Cast<ArchiveRequest>())));
+                                    break;
+                                default:
+                                    break;
+                            }
+                        }
+                        else if (key is FolderSynchronizerOperation folderSynchronizerOperation)
+                        {
+                            switch (folderSynchronizerOperation)
+                            {
+                                case FolderSynchronizerOperation.RenameFolder:
+                                    nativeRequests.AddRange(RenameFolder(group.ElementAt(0) as RenameFolderRequest));
+                                    break;
+                                case FolderSynchronizerOperation.EmptyFolder:
+                                    nativeRequests.AddRange(EmptyFolder(group.ElementAt(0) as EmptyFolderRequest));
+                                    break;
+                                case FolderSynchronizerOperation.MarkFolderRead:
+                                    nativeRequests.AddRange(MarkFolderAsRead(group.ElementAt(0) as MarkFolderAsReadRequest));
+                                    break;
+                                default:
+                                    break;
+                            }
+                        }
+                    }
+
+                    changeRequestQueue.Clear();
+
+                    Console.WriteLine($"Prepared {nativeRequests.Count()} native requests");
+
+                    await ExecuteNativeRequestsAsync(nativeRequests, activeSynchronizationCancellationToken).ConfigureAwait(false);
+
+                    PublishUnreadItemChanges();
+
+                    // Execute request sync options should be re-calculated after execution.
+                    // This is the part we decide which individual folders must be synchronized
+                    // after the batch request execution.
+                    if (options.Type == MailSynchronizationType.ExecuteRequests)
+                        options = GetSynchronizationOptionsAfterRequestExecution(requestCopies);
+
+                    // Let servers to finish their job. Sometimes the servers doesn't respond immediately.
+                    // Bug: if Outlook can't create the message in Sent Items folder before this delay,
+                    // message will not appear in user's inbox since it's not in the Sent Items folder.
+
+                    shouldDelayExecution =
+                        (Account.ProviderType == MailProviderType.Outlook)
+                        && requestCopies.Any(a => a.ResynchronizationDelay > 0);
+
+                    if (shouldDelayExecution)
+                    {
+                        maxExecutionDelay = requestCopies.Aggregate(0, (max, next) => Math.Max(max, next.ResynchronizationDelay));
+                    }
+
+                    // In terms of flag/read changes, there is no point of synchronizing must have folders.
+                    options.ExcludeMustHaveFolders = requestCopies.All(a => a is ICustomFolderSynchronizationRequest request && request.ExcludeMustHaveFolders);
+                }
 
                 State = AccountSynchronizerState.Synchronizing;
 
-                await synchronizationSemaphore.WaitAsync(activeSynchronizationCancellationToken);
-
                 // Handle special synchronization types.
 
                 // Profile information sync.
@@ -213,19 +250,9 @@ namespace Wino.Core.Synchronizers
                     }
                 }
 
-                // Let servers to finish their job. Sometimes the servers doesn't respond immediately.
-                // Bug: if Outlook can't create the message in Sent Items folder before this delay,
-                // message will not appear in user's inbox since it's not in the Sent Items folder.
-
-                bool shouldDelayExecution =
-                    (Account.ProviderType == MailProviderType.Outlook || Account.ProviderType == MailProviderType.Office365)
-                    && requestCopies.Any(a => a.ResynchronizationDelay > 0);
-
                 if (shouldDelayExecution)
                 {
-                    var maxDelay = requestCopies.Aggregate(0, (max, next) => Math.Max(max, next.ResynchronizationDelay));
-
-                    await Task.Delay(maxDelay);
+                    await Task.Delay(maxExecutionDelay);
                 }
 
                 // Start the internal synchronization.
@@ -249,6 +276,8 @@ namespace Wino.Core.Synchronizers
             }
             finally
             {
+                PendingSynchronizationRequest.Remove(options);
+
                 // Reset account progress to hide the progress.
                 PublishSynchronizationProgress(0);
 
@@ -317,6 +346,23 @@ namespace Wino.Core.Synchronizers
             return options;
         }
 
+        /// <summary>
+        /// Checks if the mail synchronization should be queued or not.
+        /// </summary>
+        /// <param name="options">New mail sync request.</param>
+        /// <returns>Whether sync should be queued or not.</returns>
+        private bool ShouldQueueMailSynchronization(MailSynchronizationOptions options)
+        {
+            // Multiple IMAPIdle requests are ignored.
+            if (options.Type == MailSynchronizationType.IMAPIdle &&
+                PendingSynchronizationRequest.Any(a => a.Key.Type == MailSynchronizationType.IMAPIdle))
+            {
+                return false;
+            }
+
+            return true;
+        }
+
         #region Mail/Folder Operations
 
         public virtual bool DelaySendOperationSynchronization() => false;
@@ -349,12 +395,12 @@ namespace Wino.Core.Synchronizers
         /// <param name="cancellationToken">Cancellation token.</param>
         public virtual Task DownloadMissingMimeMessageAsync(IMailItem mailItem, ITransferProgress transferProgress = null, CancellationToken cancellationToken = default) => throw new NotSupportedException(string.Format(Translator.Exception_UnsupportedSynchronizerOperation, this.GetType()));
 
-        public List<IRequestBundle<ImapRequest>> CreateSingleTaskBundle(Func<ImapClient, IRequestBase, Task> action, IRequestBase request, IUIChangeRequest uIChangeRequest)
+        public List<IRequestBundle<ImapRequest>> CreateSingleTaskBundle(Func<IImapClient, IRequestBase, Task> action, IRequestBase request, IUIChangeRequest uIChangeRequest)
         {
             return [new ImapRequestBundle(new ImapRequest(action, request), request, uIChangeRequest)];
         }
 
-        public List<IRequestBundle<ImapRequest>> CreateTaskBundle<TSingeRequestType>(Func<ImapClient, TSingeRequestType, Task> value,
+        public List<IRequestBundle<ImapRequest>> CreateTaskBundle<TSingeRequestType>(Func<IImapClient, TSingeRequestType, Task> value,
             List<TSingeRequestType> requests)
             where TSingeRequestType : IRequestBase, IUIChangeRequest
         {
@@ -368,6 +414,20 @@ namespace Wino.Core.Synchronizers
             return ret;
         }
 
+        public virtual Task KillSynchronizerAsync()
+        {
+            IsDisposing = true;
+            CancelAllSynchronizations();
 
+            return Task.CompletedTask;
+        }
+
+        protected void CancelAllSynchronizations()
+        {
+            foreach (var request in PendingSynchronizationRequest)
+            {
+                request.Value.Cancel();
+            }
+        }
     }
 }

Wino.Core/Wino.Core.csproj

@@ -16,34 +16,34 @@
 
 
    <ItemGroup>
-     <PackageReference Include="CommunityToolkit.Diagnostics" Version="8.3.2" />
-     <PackageReference Include="CommunityToolkit.Mvvm" Version="8.3.2" />
-     <PackageReference Include="Google.Apis.Calendar.v3" Version="1.68.0.3592" />
-     <PackageReference Include="Google.Apis.Gmail.v1" Version="1.68.0.3427" />
-     <PackageReference Include="Google.Apis.PeopleService.v1" Version="1.68.0.3359" />
-     <PackageReference Include="HtmlAgilityPack" Version="1.11.70" />
-     <PackageReference Include="HtmlKit" Version="1.1.0" />
-     <PackageReference Include="IsExternalInit" Version="1.0.3">
-       <PrivateAssets>all</PrivateAssets>
-       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
-     </PackageReference>
-     <PackageReference Include="MailKit" Version="4.9.0" />
-     <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="8.0.1" />
-     <PackageReference Include="Microsoft.Graph" Version="5.67.0" />
-     <PackageReference Include="Microsoft.Identity.Client" Version="4.66.2" />
-     <PackageReference Include="Microsoft.Identity.Client.Broker" Version="4.66.2" />
-     <PackageReference Include="Microsoft.Identity.Client.Extensions.Msal" Version="4.66.2" />
-     <PackageReference Include="MimeKit" Version="4.9.0" />
-     <PackageReference Include="morelinq" Version="4.3.0" />
-     <PackageReference Include="Nito.AsyncEx.Tasks" Version="5.1.2" />
-     <PackageReference Include="NodaTime" Version="3.2.0" />
-     <PackageReference Include="Serilog" Version="4.1.0" />
-     <PackageReference Include="Serilog.Exceptions" Version="8.4.0" />
-     <PackageReference Include="Serilog.Sinks.Debug" Version="3.0.0" />
-     <PackageReference Include="Serilog.Sinks.File" Version="6.0.0" />
-     <PackageReference Include="SkiaSharp" Version="2.88.9" />
-     <PackageReference Include="SqlKata" Version="2.4.0" />
-     <PackageReference Include="System.Text.Encoding.CodePages" Version="8.0.0" />
+		<PackageReference Include="CommunityToolkit.Diagnostics" Version="8.3.2" />
+		<PackageReference Include="CommunityToolkit.Mvvm" Version="8.3.2" />
+		<PackageReference Include="Google.Apis.Calendar.v3" Version="1.68.0.3592" />
+		<PackageReference Include="Google.Apis.Gmail.v1" Version="1.68.0.3427" />
+		<PackageReference Include="Google.Apis.PeopleService.v1" Version="1.68.0.3359" />
+		<PackageReference Include="HtmlAgilityPack" Version="1.11.70" />
+		<PackageReference Include="HtmlKit" Version="1.1.0" />
+		<PackageReference Include="IsExternalInit" Version="1.0.3">
+			<PrivateAssets>all</PrivateAssets>
+			<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
+		</PackageReference>
+		<PackageReference Include="MailKit" Version="4.10.0" />
+		<PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="8.0.1" />
+		<PackageReference Include="Microsoft.Graph" Version="5.67.0" />
+		<PackageReference Include="Microsoft.Identity.Client" Version="4.66.2" />
+		<PackageReference Include="Microsoft.Identity.Client.Broker" Version="4.66.2" />
+		<PackageReference Include="Microsoft.Identity.Client.Extensions.Msal" Version="4.66.2" />
+		<PackageReference Include="MimeKit" Version="4.10.0" />
+		<PackageReference Include="morelinq" Version="4.3.0" />
+		<PackageReference Include="Nito.AsyncEx.Tasks" Version="5.1.2" />
+		<PackageReference Include="NodaTime" Version="3.2.0" />
+		<PackageReference Include="Serilog" Version="4.2.0" />
+		<PackageReference Include="Serilog.Exceptions" Version="8.4.0" />
+		<PackageReference Include="Serilog.Sinks.Debug" Version="3.0.0" />
+		<PackageReference Include="Serilog.Sinks.File" Version="6.0.0" />
+		<PackageReference Include="SkiaSharp" Version="2.88.9" />
+		<PackageReference Include="SqlKata" Version="2.4.0" />
+		<PackageReference Include="System.Text.Encoding.CodePages" Version="8.0.0" />
    </ItemGroup>
 
    <ItemGroup>
@@ -52,4 +52,8 @@
      <ProjectReference Include="..\Wino.Messages\Wino.Messaging.csproj" />
      <ProjectReference Include="..\Wino.Services\Wino.Services.csproj" />
    </ItemGroup>
+
+   <ItemGroup>
+     <Folder Include="Mime\" />
+   </ItemGroup>
 </Project>

Wino.Mail.ViewModels/AccountDetailsPageViewModel.cs

@@ -12,6 +12,7 @@ using Wino.Core.Domain.Interfaces;
 using Wino.Core.Domain.Models.Folders;
 using Wino.Core.Domain.Models.Navigation;
 using Wino.Messaging.Client.Navigation;
+using Wino.Messaging.Server;
 using Wino.Messaging.UI;
 
 namespace Wino.Mail.ViewModels
@@ -20,6 +21,7 @@ namespace Wino.Mail.ViewModels
     {
         private readonly IMailDialogService _dialogService;
         private readonly IAccountService _accountService;
+        private readonly IWinoServerConnectionManager _serverConnectionManager;
         private readonly IFolderService _folderService;
 
         public MailAccount Account { get; set; }
@@ -48,10 +50,12 @@ namespace Wino.Mail.ViewModels
 
         public AccountDetailsPageViewModel(IMailDialogService dialogService,
             IAccountService accountService,
+            IWinoServerConnectionManager serverConnectionManager,
             IFolderService folderService)
         {
             _dialogService = dialogService;
             _accountService = accountService;
+            _serverConnectionManager = serverConnectionManager;
             _folderService = folderService;
         }
 
@@ -102,13 +106,17 @@ namespace Wino.Mail.ViewModels
             if (!confirmation)
                 return;
 
-            await _accountService.DeleteAccountAsync(Account);
 
-            // TODO: Server: Cancel ongoing calls from server for this account.
+            var isSynchronizerKilledResponse = await _serverConnectionManager.GetResponseAsync<bool, KillAccountSynchronizerRequested>(new KillAccountSynchronizerRequested(Account.Id));
 
-            _dialogService.InfoBarMessage(Translator.Info_AccountDeletedTitle, string.Format(Translator.Info_AccountDeletedMessage, Account.Name), InfoBarMessageType.Success);
+            if (isSynchronizerKilledResponse.IsSuccess)
+            {
+                await _accountService.DeleteAccountAsync(Account);
 
-            Messenger.Send(new BackBreadcrumNavigationRequested());
+                _dialogService.InfoBarMessage(Translator.Info_AccountDeletedTitle, string.Format(Translator.Info_AccountDeletedMessage, Account.Name), InfoBarMessageType.Success);
+
+                Messenger.Send(new BackBreadcrumNavigationRequested());
+            }
         }
 
         public override async void OnNavigatedTo(NavigationMode mode, object parameters)

Wino.Mail.ViewModels/AccountManagementViewModel.cs

@@ -28,18 +28,25 @@ namespace Wino.Mail.ViewModels
 {
     public partial class AccountManagementViewModel : AccountManagementPageViewModelBase
     {
+        private readonly ISpecialImapProviderConfigResolver _specialImapProviderConfigResolver;
+        private readonly IImapTestService _imapTestService;
+
         public IMailDialogService MailDialogService { get; }
 
         public AccountManagementViewModel(IMailDialogService dialogService,
                                           IWinoServerConnectionManager winoServerConnectionManager,
                                           INavigationService navigationService,
                                           IAccountService accountService,
+                                          ISpecialImapProviderConfigResolver specialImapProviderConfigResolver,
                                           IProviderService providerService,
+                                          IImapTestService imapTestService,
                                           IStoreManagementService storeManagementService,
                                           IAuthenticationProvider authenticationProvider,
                                           IPreferencesService preferencesService) : base(dialogService, winoServerConnectionManager, navigationService, accountService, providerService, storeManagementService, authenticationProvider, preferencesService)
         {
             MailDialogService = dialogService;
+            _specialImapProviderConfigResolver = specialImapProviderConfigResolver;
+            _imapTestService = imapTestService;
         }
 
         [RelayCommand]
@@ -93,7 +100,7 @@ namespace Wino.Mail.ViewModels
 
                 if (accountCreationDialogResult != null)
                 {
-                    creationDialog = MailDialogService.GetAccountCreationDialog(accountCreationDialogResult.ProviderType);
+                    creationDialog = MailDialogService.GetAccountCreationDialog(accountCreationDialogResult);
 
                     CustomServerInformation customServerInformation = null;
 
@@ -101,17 +108,17 @@ namespace Wino.Mail.ViewModels
                     {
                         ProviderType = accountCreationDialogResult.ProviderType,
                         Name = accountCreationDialogResult.AccountName,
-                        AccountColorHex = accountCreationDialogResult.AccountColorHex,
+                        SpecialImapProvider = accountCreationDialogResult.SpecialImapProviderDetails?.SpecialImapProvider ?? SpecialImapProvider.None,
                         Id = Guid.NewGuid()
                     };
 
-                    creationDialog.ShowDialog(accountCreationCancellationTokenSource);
+                    await creationDialog.ShowDialogAsync(accountCreationCancellationTokenSource);
                     creationDialog.State = AccountCreationDialogState.SigningIn;
 
                     string tokenInformation = string.Empty;
 
                     // Custom server implementation requires more async waiting.
-                    if (creationDialog is ICustomServerAccountCreationDialog customServerDialog)
+                    if (creationDialog is IImapAccountCreationDialog customServerDialog)
                     {
                         // Pass along the account properties and perform initial navigation on the imap frame.
                         customServerDialog.StartImapConnectionSetup(createdAccount);
@@ -130,20 +137,39 @@ namespace Wino.Mail.ViewModels
                     }
                     else
                     {
-                        // OAuth authentication is handled here.
-                        // Server authenticates, returns the token info here.
+                        // Hanle special imap providers like iCloud and Yahoo.
+                        if (accountCreationDialogResult.SpecialImapProviderDetails != null)
+                        {
+                            // Special imap provider testing dialog. This is only available for iCloud and Yahoo.
+                            customServerInformation = _specialImapProviderConfigResolver.GetServerInformation(createdAccount, accountCreationDialogResult);
+                            customServerInformation.Id = Guid.NewGuid();
+                            customServerInformation.AccountId = createdAccount.Id;
 
-                        var tokenInformationResponse = await WinoServerConnectionManager
-                            .GetResponseAsync<TokenInformationEx, AuthorizationRequested>(new AuthorizationRequested(accountCreationDialogResult.ProviderType,
-                                                                                                                   createdAccount,
-                                                                                                                   createdAccount.ProviderType == MailProviderType.Gmail), accountCreationCancellationTokenSource.Token);
+                            createdAccount.SenderName = accountCreationDialogResult.SpecialImapProviderDetails.SenderName;
+                            createdAccount.Address = customServerInformation.Address;
 
-                        if (creationDialog.State == AccountCreationDialogState.Canceled)
-                            throw new AccountSetupCanceledException();
+                            await _imapTestService.TestImapConnectionAsync(customServerInformation, true);
+                        }
+                        else
+                        {
+                            // OAuth authentication is handled here.
+                            // Server authenticates, returns the token info here.
 
-                        createdAccount.Address = tokenInformationResponse.Data.AccountAddress;
+                            var tokenInformationResponse = await WinoServerConnectionManager
+                                .GetResponseAsync<TokenInformationEx, AuthorizationRequested>(new AuthorizationRequested(accountCreationDialogResult.ProviderType,
+                                                                                                                       createdAccount,
+                                                                                                                       createdAccount.ProviderType == MailProviderType.Gmail), accountCreationCancellationTokenSource.Token);
 
-                        tokenInformationResponse.ThrowIfFailed();
+                            if (creationDialog.State == AccountCreationDialogState.Canceled)
+                                throw new AccountSetupCanceledException();
+
+                            if (!tokenInformationResponse.IsSuccess)
+                                throw new Exception(tokenInformationResponse.Message);
+
+                            createdAccount.Address = tokenInformationResponse.Data.AccountAddress;
+
+                            tokenInformationResponse.ThrowIfFailed();
+                        }
                     }
 
                     // Address is still doesn't have a value for API synchronizers.
@@ -183,7 +209,7 @@ namespace Wino.Mail.ViewModels
                         await AccountService.UpdateProfileInformationAsync(createdAccount.Id, profileSynchronizationResult.ProfileInformation);
                     }
 
-                    if (creationDialog is ICustomServerAccountCreationDialog customServerAccountCreationDialog)
+                    if (creationDialog is IImapAccountCreationDialog customServerAccountCreationDialog)
                         customServerAccountCreationDialog.ShowPreparingFolders();
                     else
                         creationDialog.State = AccountCreationDialogState.PreparingFolders;
@@ -227,14 +253,6 @@ namespace Wino.Mail.ViewModels
                         await AccountService.CreateRootAliasAsync(createdAccount.Id, createdAccount.Address);
                     }
 
-                    // TODO: Temporary disabled. Is this even needed? Users can configure special folders manually later on if discovery fails.
-                    // Check if Inbox folder is available for the account after synchronization.
-
-                    //var isInboxAvailable = await _folderService.IsInboxAvailableForAccountAsync(createdAccount.Id);
-
-                    //if (!isInboxAvailable)
-                    //    throw new Exception(Translator.Exception_InboxNotAvailable);
-
                     // Send changes to listeners.
                     ReportUIChange(new AccountCreatedMessage(createdAccount));
 
@@ -250,6 +268,10 @@ namespace Wino.Mail.ViewModels
             {
                 // Ignore
             }
+            catch (ImapClientPoolException clientPoolException)
+            {
+                DialogService.InfoBarMessage(Translator.Info_AccountCreationFailedTitle, clientPoolException.InnerException.Message, InfoBarMessageType.Error);
+            }
             catch (Exception ex)
             {
                 Log.Error(ex, WinoErrors.AccountCreation);

Wino.Mail.ViewModels/AppShellViewModel.cs

@@ -243,7 +243,9 @@ namespace Wino.Mail.ViewModels
             await RecreateMenuItemsAsync();
             await ProcessLaunchOptionsAsync();
 
+#if !DEBUG
             await ForceAllAccountSynchronizationsAsync();
+#endif
             await MakeSureEnableStartupLaunchAsync();
             await ConfigureBackgroundTasksAsync();
         }

Wino.Mail.ViewModels/Wino.Mail.ViewModels.csproj

@@ -16,7 +16,6 @@
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
     </PackageReference>
     <PackageReference Include="Microsoft.AppCenter.Crashes" Version="5.0.6" />
-    <PackageReference Include="Microsoft.Identity.Client" Version="4.66.2" />
     <PackageReference Include="System.Reactive" Version="6.0.1" />
   </ItemGroup>
 

Wino.Mail/App.xaml.cs

@@ -233,6 +233,7 @@ namespace Wino
             }
             catch (WinoServerException serverException)
             {
+                // TODO: Exception context is lost.
                 var dialogService = Services.GetService<IMailDialogService>();
 
                 dialogService.InfoBarMessage(Translator.Info_SyncFailedTitle, serverException.Message, InfoBarMessageType.Error);

Wino.Mail/AppShell.xaml

@@ -41,7 +41,7 @@
                     </TransitionCollection>
                 </coreControls:WinoNavigationViewItem.ContentTransitions>
                 <muxc:NavigationViewItem.Icon>
-                    <coreControls:WinoFontIcon FontSize="12" Icon="{x:Bind helpers:XamlHelpers.GetProviderIcon(Parameter.ProviderType)}" />
+                    <coreControls:WinoFontIcon FontSize="12" Icon="{x:Bind helpers:XamlHelpers.GetProviderIcon(Parameter)}" />
                 </muxc:NavigationViewItem.Icon>
                 <muxc:NavigationViewItem.InfoBadge>
                     <muxc:InfoBadge

Wino.Mail/Dialogs/AccountReorderDialog.xaml

@@ -34,7 +34,7 @@
                     Grid.RowSpan="2"
                     VerticalAlignment="Center"
                     FontSize="24"
-                    Icon="{x:Bind helpers:XamlHelpers.GetProviderIcon(ProviderDetail.Type)}" />
+                    Icon="{x:Bind helpers:XamlHelpers.GetProviderIcon(ProviderDetail.Type, ProviderDetail.SpecialImapProvider)}" />
                 <TextBlock
                     Grid.Column="1"
                     FontWeight="SemiBold"

Wino.Mail/Dialogs/NewImapSetupDialog.xaml.cs

@@ -7,6 +7,7 @@ using Windows.UI.Xaml.Media.Animation;
 using Wino.Core.Domain.Entities.Shared;
 using Wino.Core.Domain.Enums;
 using Wino.Core.Domain.Interfaces;
+using Wino.Core.Domain.Models.Accounts;
 using Wino.Messaging.Client.Mails;
 using Wino.Views.ImapSetup;
 
@@ -24,7 +25,7 @@ namespace Wino.Dialogs
         IRecipient<ImapSetupNavigationRequested>,
         IRecipient<ImapSetupBackNavigationRequested>,
         IRecipient<ImapSetupDismissRequested>,
-        ICustomServerAccountCreationDialog
+        IImapAccountCreationDialog
     {
         private TaskCompletionSource<CustomServerInformation> _getServerInfoTaskCompletionSource = new TaskCompletionSource<CustomServerInformation>();
 
@@ -77,8 +78,17 @@ namespace Wino.Dialogs
 
         public void Receive(ImapSetupDismissRequested message) => _getServerInfoTaskCompletionSource.TrySetResult(message.CompletedServerInformation);
 
-        public void ShowDialog(CancellationTokenSource cancellationTokenSource)
-            => _ = ShowAsync();
+        public async Task ShowDialogAsync(CancellationTokenSource cancellationTokenSource)
+        {
+            var tcs = new TaskCompletionSource<bool>();
+
+            _ = ShowAsync().AsTask().ContinueWith((t) =>
+            {
+                tcs.TrySetResult(true);
+            });
+
+            await tcs.Task;
+        }
 
         public void ShowPreparingFolders()
         {
@@ -86,7 +96,7 @@ namespace Wino.Dialogs
         }
 
         public void StartImapConnectionSetup(MailAccount account) => ImapFrame.Navigate(typeof(WelcomeImapSetupPage), account, new DrillInNavigationTransitionInfo());
-
+        public void StartImapConnectionSetup(AccountCreationDialogResult accountCreationDialogResult) => ImapFrame.Navigate(typeof(WelcomeImapSetupPage), accountCreationDialogResult, new DrillInNavigationTransitionInfo());
 
         private void ImapSetupDialogClosed(ContentDialog sender, ContentDialogClosedEventArgs args) => WeakReferenceMessenger.Default.UnregisterAll(this);
 

Wino.Mail/MenuFlyouts/AccountSelectorFlyout.cs

@@ -3,7 +3,6 @@ using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
 using Windows.UI.Xaml.Controls;
-using Wino.Controls;
 using Wino.Core.Domain.Entities.Shared;
 using Wino.Core.UWP.Controls;
 using Wino.Helpers;
@@ -22,7 +21,7 @@ namespace Wino.MenuFlyouts
 
             foreach (var account in _accounts)
             {
-                var pathData = new WinoFontIcon() { Icon = XamlHelpers.GetProviderIcon(account.ProviderType) };
+                var pathData = new WinoFontIcon() { Icon = XamlHelpers.GetProviderIcon(account) };
                 var menuItem = new MenuFlyoutItem() { Tag = account.Address, Icon = pathData, Text = $"{account.Name} ({account.Address})", MinHeight = 55 };
 
                 menuItem.Click += AccountClicked;

Wino.Mail/Services/DialogService.cs

@@ -10,6 +10,7 @@ using Wino.Core.Domain.Entities.Mail;
 using Wino.Core.Domain.Entities.Shared;
 using Wino.Core.Domain.Enums;
 using Wino.Core.Domain.Interfaces;
+using Wino.Core.Domain.Models.Accounts;
 using Wino.Core.Domain.Models.Folders;
 using Wino.Core.Domain.Models.Synchronization;
 using Wino.Core.UWP.Extensions;
@@ -30,18 +31,27 @@ namespace Wino.Services
 
         }
 
-        public override IAccountCreationDialog GetAccountCreationDialog(MailProviderType type)
+        public override IAccountCreationDialog GetAccountCreationDialog(AccountCreationDialogResult accountCreationDialogResult)
         {
-            if (type == MailProviderType.IMAP4)
+            if (accountCreationDialogResult.SpecialImapProviderDetails == null)
             {
-                return new NewImapSetupDialog
+                if (accountCreationDialogResult.ProviderType == MailProviderType.IMAP4)
                 {
-                    RequestedTheme = ThemeService.RootTheme.ToWindowsElementTheme()
-                };
+                    return new NewImapSetupDialog
+                    {
+                        RequestedTheme = ThemeService.RootTheme.ToWindowsElementTheme()
+                    };
+                }
+                else
+                {
+                    return base.GetAccountCreationDialog(accountCreationDialogResult);
+                }
             }
             else
             {
-                return base.GetAccountCreationDialog(type);
+                // Special IMAP provider like iCloud or Yahoo.
+
+                return base.GetAccountCreationDialog(accountCreationDialogResult);
             }
         }
 

Wino.Mail/Services/ProviderService.cs

@@ -20,20 +20,15 @@ namespace Wino.Mail.Services
 
         public List<IProviderDetail> GetAvailableProviders()
         {
-            var providerList = new List<IProviderDetail>();
-
-            var providers = new MailProviderType[]
+            var providerList = new List<IProviderDetail>
             {
-                MailProviderType.Outlook,
-                MailProviderType.Gmail,
-                MailProviderType.IMAP4
+                new ProviderDetail(MailProviderType.Outlook, SpecialImapProvider.None),
+                new ProviderDetail(MailProviderType.Gmail, SpecialImapProvider.None),
+                new ProviderDetail(MailProviderType.IMAP4, SpecialImapProvider.iCloud),
+                new ProviderDetail(MailProviderType.IMAP4, SpecialImapProvider.Yahoo),
+                new ProviderDetail(MailProviderType.IMAP4, SpecialImapProvider.None)
             };
 
-            foreach (var type in providers)
-            {
-                providerList.Add(new ProviderDetail(type));
-            }
-
             return providerList;
         }
     }

Wino.Mail/Views/Account/MergedAccountDetailsPage.xaml

@@ -24,7 +24,7 @@
                 Header="{x:Bind Account.Name}"
                 IsClickEnabled="True">
                 <controls:SettingsCard.HeaderIcon>
-                    <coreControls:WinoFontIcon FontSize="64" Icon="{x:Bind helpers:XamlHelpers.GetProviderIcon(ProviderDetail.Type)}" />
+                    <coreControls:WinoFontIcon FontSize="64" Icon="{x:Bind helpers:XamlHelpers.GetProviderIcon(Account)}" />
                 </controls:SettingsCard.HeaderIcon>
                 <controls:SettingsCard.ActionIcon>
                     <PathIcon
@@ -45,7 +45,7 @@
                 Header="{x:Bind Account.Name}"
                 IsClickEnabled="True">
                 <controls:SettingsCard.HeaderIcon>
-                    <coreControls:WinoFontIcon FontSize="64" Icon="{x:Bind helpers:XamlHelpers.GetProviderIcon(ProviderDetail.Type)}" />
+                    <coreControls:WinoFontIcon FontSize="64" Icon="{x:Bind helpers:XamlHelpers.GetProviderIcon(Account)}" />
                 </controls:SettingsCard.HeaderIcon>
 
                 <controls:SettingsCard.ActionIcon>

Wino.Mail/Views/ImapSetup/WelcomeImapSetupPage.xaml.cs

@@ -9,6 +9,7 @@ using Wino.Core.Domain;
 using Wino.Core.Domain.Entities.Shared;
 using Wino.Core.Domain.Exceptions;
 using Wino.Core.Domain.Interfaces;
+using Wino.Core.Domain.Models.Accounts;
 using Wino.Core.Domain.Models.AutoDiscovery;
 using Wino.Messaging.Client.Mails;
 
@@ -35,6 +36,10 @@ namespace Wino.Views.ImapSetup
             {
                 DisplayNameBox.Text = accountProperties.Name;
             }
+            else if (e.Parameter is AccountCreationDialogResult creationDialogResult)
+            {
+                WeakReferenceMessenger.Default.Send(new ImapSetupNavigationRequested(typeof(TestingImapConnectionPage), creationDialogResult));
+            }
         }
 
         private async void SignInClicked(object sender, RoutedEventArgs e)

Wino.Mail/Views/MailListPage.xaml

@@ -423,6 +423,7 @@
                 <!--  Mail Items  -->
                 <muxc:RefreshContainer
                     Grid.Row="2"
+                    Margin="-4,0"
                     RefreshRequested="PullToRefreshRequested"
                     Visibility="{x:Bind ViewModel.IsEmpty, Converter={StaticResource ReverseBooleanToVisibilityConverter}, Mode=OneWay}">
                     <SemanticZoom x:Name="SemanticZoomContainer" CanChangeViews="{x:Bind ViewModel.PreferencesService.IsSemanticZoomEnabled, Mode=OneWay}">
@@ -445,7 +446,7 @@
                                 </ListView.ItemContainerTransitions>
                                 <ListView.ItemsPanel>
                                     <ItemsPanelTemplate>
-                                        <ItemsStackPanel AreStickyGroupHeadersEnabled="True" />
+                                        <ItemsStackPanel Margin="8,0,12,0" AreStickyGroupHeadersEnabled="True" />
                                     </ItemsPanelTemplate>
                                 </ListView.ItemsPanel>
                                 <ListView.Resources>
@@ -467,13 +468,13 @@
                                     <Style TargetType="ListViewItem">
                                         <Setter Property="HorizontalContentAlignment" Value="Stretch" />
                                         <Setter Property="VerticalContentAlignment" Value="Stretch" />
-                                        <Setter Property="Margin" Value="0,12" />
+                                        <Setter Property="Margin" Value="12" />
                                         <Setter Property="Padding" Value="0" />
                                     </Style>
                                 </ListView.Resources>
                                 <ListView.ItemTemplate>
                                     <DataTemplate x:DataType="ICollectionViewGroup">
-                                        <Grid Background="{ThemeResource MailListHeaderBackgroundColor}" CornerRadius="4">
+                                        <Grid Background="{ThemeResource MailListHeaderBackgroundColor}" CornerRadius="6">
                                             <TextBlock
                                                 Margin="12,0"
                                                 HorizontalAlignment="Center"

Wino.Mail/Wino.Mail.csproj

@@ -128,7 +128,7 @@
       <Version>1.0.0</Version>
     </PackageReference>
     <PackageReference Include="CommunityToolkit.Common">
-      <Version>8.3.2</Version>
+      <Version>8.4.0</Version>
     </PackageReference>
     <PackageReference Include="CommunityToolkit.Diagnostics">
       <Version>8.3.2</Version>
@@ -196,7 +196,7 @@
       <Version>5.1.2</Version>
     </PackageReference>
     <PackageReference Include="Serilog">
-      <Version>4.1.0</Version>
+      <Version>4.2.0</Version>
     </PackageReference>
     <PackageReference Include="Serilog.Exceptions">
       <Version>8.4.0</Version>
@@ -205,7 +205,7 @@
       <Version>1.9.172</Version>
     </PackageReference>
     <PackageReference Include="Win2D.uwp">
-      <Version>1.28.0</Version>
+      <Version>1.28.1</Version>
     </PackageReference>
   </ItemGroup>
   <ItemGroup>

Wino.Messages/Server/KillAccountSynchronizerRequested.cs

@@ -0,0 +1,11 @@
+using System;
+using Wino.Core.Domain.Interfaces;
+
+namespace Wino.Messaging.Server
+{
+    /// <summary>
+    /// Client message that requests to kill the account synchronizer.
+    /// </summary>
+    /// <param name="AccountId">Account id to kill synchronizer for.</param>
+    public record KillAccountSynchronizerRequested(Guid AccountId) : IClientMessage;
+}

Wino.Messages/Server/NewSynchronizationRequested.cs

@@ -8,7 +8,7 @@ namespace Wino.Messaging.Server
     /// Triggers a new mail synchronization if possible.
     /// </summary>
     /// <param name="Options">Options for synchronization.</param>
-    public record NewMailSynchronizationRequested(MailSynchronizationOptions Options, SynchronizationSource Source) : IClientMessage;
+    public record NewMailSynchronizationRequested(MailSynchronizationOptions Options, SynchronizationSource Source) : IClientMessage, IUIMessage;
 
     /// <summary>
     /// Triggers a new calendar synchronization if possible.

Wino.Messages/Wino.Messaging.csproj

@@ -18,7 +18,7 @@
 			<PrivateAssets>all</PrivateAssets>
 			<IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
 		</PackageReference>
-		<PackageReference Include="System.Text.Json" Version="8.0.5" />
+		<PackageReference Include="System.Text.Json" Version="9.0.1" />
 	</ItemGroup>
 
 </Project>

Wino.Packaging/Package.appxmanifest

@@ -11,7 +11,7 @@
 	<Identity
 	  Name="58272BurakKSE.WinoMailPreview"
 	  Publisher="CN=51FBDAF3-E212-4149-89A2-A2636B3BC911"
-	  Version="1.9.43.0" />
+	  Version="1.9.50.0" />
 	
 	<Extensions>
 		<!-- Publisher Cache Folders -->

Wino.Packaging/Wino.Packaging.wapproj

@@ -43,12 +43,13 @@
     <EntryPointProjectUniqueName>..\Wino.Mail\Wino.Mail.csproj</EntryPointProjectUniqueName>
     <GenerateAppInstallerFile>False</GenerateAppInstallerFile>
     <AppxPackageSigningTimestampDigestAlgorithm>SHA256</AppxPackageSigningTimestampDigestAlgorithm>
-    <AppxAutoIncrementPackageRevision>False</AppxAutoIncrementPackageRevision>
+    <AppxAutoIncrementPackageRevision>True</AppxAutoIncrementPackageRevision>
     <AppxPackageDir>$(USERPROFILE)\Desktop\Packages\</AppxPackageDir>
     <GenerateTestArtifacts>True</GenerateTestArtifacts>
-    <AppxBundlePlatforms>x86|x64|arm64</AppxBundlePlatforms>
+    <AppxBundlePlatforms>x64</AppxBundlePlatforms>
     <GenerateTemporaryStoreCertificate>True</GenerateTemporaryStoreCertificate>
     <HoursBetweenUpdateChecks>0</HoursBetweenUpdateChecks>
+    <AppxSymbolPackageEnabled>True</AppxSymbolPackageEnabled>
   </PropertyGroup>
   <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
     <AppxBundle>Always</AppxBundle>
@@ -132,7 +133,4 @@
     <ProjectReference Include="..\Wino.Mail\Wino.Mail.csproj" />
     <ProjectReference Include="..\Wino.Server\Wino.Server.csproj" />
   </ItemGroup>
-  <ItemGroup>
-    <PackageReference Include="Microsoft.Identity.Client" Version="4.66.2" />
-  </ItemGroup>
 </Project>

Wino.Server/App.xaml.cs

@@ -8,6 +8,7 @@ using System.Threading.Tasks;
 using System.Windows;
 using H.NotifyIcon;
 using Microsoft.Extensions.DependencyInjection;
+using Serilog;
 using Windows.Storage;
 using Wino.Calendar.Services;
 using Wino.Core;
@@ -188,6 +189,9 @@ namespace Wino.Server
 
             if (isCreatedNew)
             {
+                AppDomain.CurrentDomain.UnhandledException += ServerCrashed;
+                Application.Current.DispatcherUnhandledException += UIThreadCrash;
+                TaskScheduler.UnobservedTaskException += TaskCrashed;
                 // Ensure proper encodings are available for MimeKit
                 System.Text.Encoding.RegisterProvider(System.Text.CodePagesEncodingProvider.Instance);
 
@@ -237,6 +241,12 @@ namespace Wino.Server
             }
         }
 
+        private void TaskCrashed(object sender, UnobservedTaskExceptionEventArgs e) => Log.Error(e.Exception, "Task crashed.");
+
+        private void UIThreadCrash(object sender, System.Windows.Threading.DispatcherUnhandledExceptionEventArgs e) => Log.Error(e.Exception, "UI thread crashed.");
+
+        private void ServerCrashed(object sender, UnhandledExceptionEventArgs e) => Log.Error((Exception)e.ExceptionObject, "Server crashed.");
+
         protected override void OnExit(ExitEventArgs e)
         {
             notifyIcon?.Dispose();