Bump 2.0.2 + changelog for beta.

.github/workflows/beta-release.yml

@@ -0,0 +1,187 @@
+name: Manual Beta Release
+
+on:
+  workflow_dispatch:
+    inputs:
+      release_title:
+        description: Optional GitHub release title override
+        required: false
+        type: string
+
+permissions:
+  contents: write
+  packages: read
+
+jobs:
+  release-beta:
+    name: Build and publish beta release
+    runs-on: windows-latest
+    env:
+      PROJECT_PATH: Wino.Mail.WinUI/Wino.Mail.WinUI.csproj
+      MANIFEST_PATH: Wino.Mail.WinUI/Package.appxmanifest
+      CHANGELOG_PATH: CHANGELOG.md
+      NUGET_CONFIG_PATH: ${{ github.workspace }}\nuget.config
+      PACKAGE_OUTPUT_DIR: ${{ github.workspace }}\artifacts\package
+      RELEASE_OUTPUT_DIR: ${{ github.workspace }}\artifacts\release
+      CERTIFICATE_PFX_PATH: ${{ github.workspace }}\artifacts\signing\beta-signing-cert.pfx
+      CERTIFICATE_CER_PATH: ${{ github.workspace }}\artifacts\release\Wino-Mail-Beta.cer
+    steps:
+      - name: Checkout selected branch
+        uses: actions/checkout@v4
+        with:
+          ref: ${{ github.ref }}
+          fetch-depth: 0
+
+      - name: Fetch tags from origin
+        shell: pwsh
+        run: git fetch origin --force --tags
+
+      - name: Validate release secrets
+        shell: pwsh
+        env:
+          BETA_SIGNING_CERT_PFX_BASE64: ${{ secrets.BETA_SIGNING_CERT_PFX_BASE64 }}
+        run: |
+          if ([string]::IsNullOrWhiteSpace($env:BETA_SIGNING_CERT_PFX_BASE64)) {
+            throw "Missing required secret: BETA_SIGNING_CERT_PFX_BASE64"
+          }
+
+      - name: Setup .NET SDK
+        uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: 10.0.x
+        env:
+          NUGET_AUTH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Compute beta version and release metadata
+        id: metadata
+        shell: pwsh
+        env:
+          RELEASE_TITLE_INPUT: ${{ github.event.inputs.release_title }}
+        run: |
+          $manifestPath = Join-Path $env:GITHUB_WORKSPACE $env:MANIFEST_PATH
+          if (-not (Test-Path $manifestPath)) {
+            throw "Package manifest not found: $manifestPath"
+          }
+
+          $changelogPath = Join-Path $env:GITHUB_WORKSPACE $env:CHANGELOG_PATH
+          if (-not (Test-Path $changelogPath)) {
+            throw "Release notes file not found: $changelogPath"
+          }
+
+          [xml]$manifest = Get-Content -LiteralPath $manifestPath
+          $identityNode = $manifest.Package.Identity
+          if (-not $identityNode) {
+            throw "Could not locate the Package/Identity node in $manifestPath"
+          }
+
+          $currentVersionText = [string]$identityNode.Version
+          if ($currentVersionText -notmatch '^(?<major>\d+)\.(?<minor>\d+)\.(?<patch>\d+)\.(?<revision>\d+)$') {
+            throw "Manifest version '$currentVersionText' is not a four-part numeric version."
+          }
+
+          $packageVersion = $currentVersionText
+          $releaseTag = "v$packageVersion"
+          $releaseTitleInput = $env:RELEASE_TITLE_INPUT
+          $releaseTitle = if ([string]::IsNullOrWhiteSpace($releaseTitleInput)) { $releaseTag } else { $releaseTitleInput.Trim() }
+
+          $headSha = (git rev-parse HEAD).Trim()
+          if ([string]::IsNullOrWhiteSpace($headSha)) {
+            throw "Failed to resolve the checked out commit SHA."
+          }
+
+          $notesInput = Get-Content -LiteralPath $changelogPath -Raw
+          if ([string]::IsNullOrWhiteSpace($notesInput)) {
+            throw "Release notes file is empty: $changelogPath"
+          }
+
+          $notesInput = $notesInput.Trim()
+          New-Item -ItemType Directory -Path $env:RELEASE_OUTPUT_DIR -Force | Out-Null
+          $releaseNotesPath = Join-Path $env:RELEASE_OUTPUT_DIR 'beta-release-notes.md'
+          $notesInput | Set-Content -LiteralPath $releaseNotesPath -Encoding utf8
+
+          "package_version=$packageVersion" >> $env:GITHUB_OUTPUT
+          "release_tag=$releaseTag" >> $env:GITHUB_OUTPUT
+          "release_title=$releaseTitle" >> $env:GITHUB_OUTPUT
+          "release_notes_path=$releaseNotesPath" >> $env:GITHUB_OUTPUT
+          "head_sha=$headSha" >> $env:GITHUB_OUTPUT
+
+      - name: Materialize signing certificate
+        shell: pwsh
+        env:
+          BETA_SIGNING_CERT_PFX_BASE64: ${{ secrets.BETA_SIGNING_CERT_PFX_BASE64 }}
+        run: |
+          $signingDir = Split-Path -Parent $env:CERTIFICATE_PFX_PATH
+          New-Item -ItemType Directory -Path $signingDir -Force | Out-Null
+          [IO.File]::WriteAllBytes($env:CERTIFICATE_PFX_PATH, [Convert]::FromBase64String($env:BETA_SIGNING_CERT_PFX_BASE64))
+
+          $certificate = New-Object System.Security.Cryptography.X509Certificates.X509Certificate2($env:CERTIFICATE_PFX_PATH, $null, [System.Security.Cryptography.X509Certificates.X509KeyStorageFlags]::Exportable)
+
+          New-Item -ItemType Directory -Path (Split-Path -Parent $env:CERTIFICATE_CER_PATH) -Force | Out-Null
+          [IO.File]::WriteAllBytes($env:CERTIFICATE_CER_PATH, $certificate.Export([System.Security.Cryptography.X509Certificates.X509ContentType]::Cert))
+
+      - name: Restore WinUI project dependencies
+        shell: pwsh
+        run: |
+          if (-not (Test-Path $env:NUGET_CONFIG_PATH)) {
+            throw "NuGet config file not found: $env:NUGET_CONFIG_PATH"
+          }
+
+          dotnet restore $env:PROJECT_PATH `
+            --configfile $env:NUGET_CONFIG_PATH `
+            -p:Platform=x64 `
+            /p:RestoreConfigFile="$env:NUGET_CONFIG_PATH"
+
+      - name: Build MSIX bundle
+        shell: pwsh
+        run: |
+          New-Item -ItemType Directory -Path $env:PACKAGE_OUTPUT_DIR -Force | Out-Null
+
+          dotnet build $env:PROJECT_PATH `
+            --configuration Release `
+            --no-restore `
+            --configfile $env:NUGET_CONFIG_PATH `
+            /p:Platform=x64 `
+            /p:RestoreConfigFile="$env:NUGET_CONFIG_PATH" `
+            /p:GenerateAppxPackageOnBuild=true `
+            /p:UapAppxPackageBuildMode=SideloadOnly `
+            /p:AppxBundle=Always `
+            /p:AppxBundlePlatforms="x86|x64|arm64" `
+            /p:AppxPackageDir="$env:PACKAGE_OUTPUT_DIR\\" `
+            /p:AppxPackageVersion=${{ steps.metadata.outputs.package_version }} `
+            /p:PackageCertificateKeyFile="$env:CERTIFICATE_PFX_PATH" `
+            /p:PackageCertificatePassword= `
+            /p:PackageCertificateThumbprint= `
+            /p:AppxPackageSigningEnabled=true
+
+      - name: Collect packaged artifacts
+        id: package
+        shell: pwsh
+        run: |
+          $bundle = Get-ChildItem -Path $env:PACKAGE_OUTPUT_DIR -Recurse -Filter *.msixbundle | Select-Object -First 1
+          if (-not $bundle) {
+            throw "No .msixbundle file was generated under $env:PACKAGE_OUTPUT_DIR"
+          }
+
+          $releaseAssetPath = Join-Path $env:RELEASE_OUTPUT_DIR "Wino_${{ steps.metadata.outputs.package_version }}.zip"
+          if (Test-Path $releaseAssetPath) {
+            Remove-Item -LiteralPath $releaseAssetPath -Force
+          }
+
+          Compress-Archive -LiteralPath @($bundle.FullName, $env:CERTIFICATE_CER_PATH) -DestinationPath $releaseAssetPath -Force
+
+          "bundle_path=$($bundle.FullName)" >> $env:GITHUB_OUTPUT
+          "bundle_name=$($bundle.Name)" >> $env:GITHUB_OUTPUT
+          "release_asset_path=$releaseAssetPath" >> $env:GITHUB_OUTPUT
+
+      - name: Create GitHub prerelease
+        shell: pwsh
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          gh release create "${{ steps.metadata.outputs.release_tag }}" `
+            "${{ steps.package.outputs.release_asset_path }}" `
+            --repo "${{ github.repository }}" `
+            --target "${{ steps.metadata.outputs.head_sha }}" `
+            --title "${{ steps.metadata.outputs.release_title }}" `
+            --notes-file "${{ steps.metadata.outputs.release_notes_path }}" `
+            --prerelease

CHANGELOG.md

@@ -0,0 +1,7 @@
+Released on April 15. Second bugfix/improvements update for v2 beta testing.
+
+-  [Ability to delete custom themes](https://github.com/bkaankose/Wino-Mail/issues/844)
+-  [[Proposal] Reply/Reply all sets focus to the "To" line versus Body](https://github.com/bkaankose/Wino-Mail/issues/844274)
+- Email categories. Online sync for Outlook, offline use for IMAP/Gmail.
+- Handling of read-only calendars.
+- Implemented a new Github action workflow to trigger beta releases on demand.

Wino.Calendar.ViewModels/CalendarAppShellViewModel.cs

@@ -178,18 +178,6 @@ public partial class CalendarAppShellViewModel : CalendarBaseViewModel,
         await InitializeAccountCalendarsAsync();
         ValidateConfiguredNewEventCalendar();
 
-        if (activationContext?.Parameter is CalendarItemTarget calendarItemTarget)
-        {
-            NavigationService.Navigate(WinoPage.EventDetailsPage, calendarItemTarget);
-            return;
-        }
-
-        if (activationContext?.Parameter is CalendarPageNavigationArgs calendarPageNavigationArgs)
-        {
-            NavigationService.Navigate(WinoPage.CalendarPage, calendarPageNavigationArgs);
-            return;
-        }
-
         TodayClicked();
     }
 

Wino.Calendar.ViewModels/CalendarPageViewModel.cs

@@ -86,6 +86,7 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
         get
         {
             if (SelectedQuickEventAccountCalendar == null ||
+                SelectedQuickEventAccountCalendar.IsReadOnly ||
                 SelectedQuickEventDate == null ||
                 string.IsNullOrWhiteSpace(EventName) ||
                 string.IsNullOrWhiteSpace(SelectedStartTimeString) ||
@@ -204,6 +205,12 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
         if (DisplayDetailsCalendarItemViewModel?.CalendarItem == null)
             return;
 
+        if (DisplayDetailsCalendarItemViewModel.AssignedCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
+
         if (DisplayDetailsCalendarItemViewModel.CalendarItem.IsRecurringParent)
         {
             var confirmed = await _dialogService.ShowConfirmationDialogAsync(
@@ -460,6 +467,12 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
     [RelayCommand(AllowConcurrentExecutions = false, CanExecute = nameof(CanSaveQuickEvent))]
     private async Task SaveQuickEventAsync()
     {
+        if (SelectedQuickEventAccountCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
+
         var startDate = IsAllDay ? SelectedQuickEventDate.Value.Date : QuickEventStartTime;
         var endDate = IsAllDay ? SelectedQuickEventDate.Value.Date.AddDays(1) : QuickEventEndTime;
         var composeResult = new CalendarEventComposeResult
@@ -553,6 +566,12 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
             return;
         }
 
+        if (calendarItem.AssignedCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
+
         var normalizedTargetStart = calendarItem.IsAllDayEvent
             ? targetStart.Date
             : targetStart;
@@ -1195,6 +1214,12 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
         if (targetItem == null)
             return;
 
+        if (targetItem.AssignedCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
+
         if (targetItem.IsRecurringParent)
         {
             var confirmed = await _dialogService.ShowConfirmationDialogAsync(
@@ -1221,6 +1246,12 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
         if (targetItem == null || targetItem.ShowAs == showAs)
             return;
 
+        if (targetItem.AssignedCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
+
         var originalItem = await _calendarService.GetCalendarItemAsync(targetItem.Id).ConfigureAwait(false);
         var attendees = await _calendarService.GetAttendeesAsync(targetItem.Id).ConfigureAwait(false);
 
@@ -1245,6 +1276,12 @@ public partial class CalendarPageViewModel : CalendarBaseViewModel,
         if (targetItem == null)
             return;
 
+        if (targetItem.AssignedCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
+
         var operation = responseStatus switch
         {
             CalendarItemStatus.Accepted => CalendarSynchronizerOperation.AcceptEvent,

Wino.Calendar.ViewModels/Data/AccountCalendarViewModel.cs

@@ -55,6 +55,12 @@ public partial class AccountCalendarViewModel : ObservableObject, IAccountCalend
         set => SetProperty(AccountCalendar.IsPrimary, value, AccountCalendar, (u, i) => u.IsPrimary = i);
     }
 
+    public bool IsReadOnly
+    {
+        get => AccountCalendar.IsReadOnly;
+        set => SetProperty(AccountCalendar.IsReadOnly, value, AccountCalendar, (u, i) => u.IsReadOnly = i);
+    }
+
     public bool IsSynchronizationEnabled
     {
         get => AccountCalendar.IsSynchronizationEnabled;

Wino.Calendar.ViewModels/EventDetailsPageViewModel.cs

@@ -440,6 +440,11 @@ public partial class EventDetailsPageViewModel : CalendarBaseViewModel
     private async Task SaveAsync()
     {
         if (CurrentEvent == null) return;
+        if (CurrentEvent.AssignedCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
 
         try
         {
@@ -506,6 +511,11 @@ public partial class EventDetailsPageViewModel : CalendarBaseViewModel
     private async Task DeleteAsync()
     {
         if (CurrentEvent == null) return;
+        if (CurrentEvent.AssignedCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
 
         // If the event is a master recurring event, ask for confirmation
         if (CurrentEvent.IsRecurringParent)
@@ -610,6 +620,11 @@ public partial class EventDetailsPageViewModel : CalendarBaseViewModel
     private async Task SendRsvpResponse(AttendeeStatus status)
     {
         if (CurrentEvent == null) return;
+        if (CurrentEvent.AssignedCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
 
         try
         {

Wino.Core.Domain/Constants.cs

@@ -21,7 +21,6 @@ public static class Constants
     public const string ToastCalendarJoinOnlineAction = nameof(ToastCalendarJoinOnlineAction);
     public const string ToastCalendarSnoozeAction = nameof(ToastCalendarSnoozeAction);
     public const string ToastCalendarSnoozeDurationInputId = nameof(ToastCalendarSnoozeDurationInputId);
-    public const string ToastCalendarSnoozeDurationMinutesKey = nameof(ToastCalendarSnoozeDurationMinutesKey);
     public const string ToastModeKey = nameof(ToastModeKey);
     public const string ToastModeMail = nameof(ToastModeMail);
     public const string ToastModeCalendar = nameof(ToastModeCalendar);

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

@@ -16,6 +16,7 @@ public class AccountCalendar : IAccountCalendar
     public string SynchronizationDeltaToken { get; set; }
     public string Name { get; set; }
     public bool IsPrimary { get; set; }
+    public bool IsReadOnly { get; set; }
     public bool IsSynchronizationEnabled { get; set; } = true;
     public bool IsExtended { get; set; } = true;
     public CalendarItemShowAs DefaultShowAs { get; set; } = CalendarItemShowAs.Busy;

Wino.Core.Domain/Entities/Mail/MailCategory.cs

@@ -0,0 +1,25 @@
+using System;
+using SQLite;
+using Wino.Core.Domain.Enums;
+
+namespace Wino.Core.Domain.Entities.Mail;
+
+public class MailCategory
+{
+    [PrimaryKey]
+    public Guid Id { get; set; }
+
+    public Guid MailAccountId { get; set; }
+
+    public string RemoteId { get; set; }
+
+    public string Name { get; set; }
+
+    public bool IsFavorite { get; set; }
+
+    public string BackgroundColorHex { get; set; }
+
+    public string TextColorHex { get; set; }
+
+    public MailCategorySource Source { get; set; } = MailCategorySource.Local;
+}

Wino.Core.Domain/Entities/Mail/MailCategoryAssignment.cs

@@ -0,0 +1,14 @@
+using System;
+using SQLite;
+
+namespace Wino.Core.Domain.Entities.Mail;
+
+public class MailCategoryAssignment
+{
+    [PrimaryKey]
+    public Guid Id { get; set; }
+
+    public Guid MailCategoryId { get; set; }
+
+    public Guid MailCopyUniqueId { get; set; }
+}

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

@@ -132,5 +132,10 @@ public class MailAccount
     /// </summary>
     public bool IsAliasSyncSupported => ProviderType == MailProviderType.Gmail || ProviderType == MailProviderType.Outlook;
 
+    /// <summary>
+    /// Gets whether the account can perform category definition sync type.
+    /// </summary>
+    public bool IsCategorySyncSupported => ProviderType == MailProviderType.Outlook;
+
     public override string ToString() => Name;
 }

Wino.Core.Domain/Enums/MailCategorySource.cs

@@ -0,0 +1,7 @@
+namespace Wino.Core.Domain.Enums;
+
+public enum MailCategorySource
+{
+    Local,
+    Outlook
+}

Wino.Core.Domain/Enums/MailOperation.cs

@@ -13,6 +13,7 @@ public enum MailSynchronizerOperation
     AlwaysMoveTo,
     MoveToFocused,
     Archive,
+    UpdateCategories,
 }
 
 public enum FolderSynchronizerOperation
@@ -35,6 +36,13 @@ public enum CalendarSynchronizerOperation
     TentativeEvent,
 }
 
+public enum CategorySynchronizerOperation
+{
+    CreateCategory,
+    UpdateCategory,
+    DeleteCategory,
+}
+
 // UI requests
 public enum MailOperation
 {

Wino.Core.Domain/Enums/MailSynchronizationType.cs

@@ -3,6 +3,7 @@
 public enum MailSynchronizationType
 {
     UpdateProfile, // Only update profile information
+    Categories, // Only update mail categories
     ExecuteRequests, // Run the queued requests, and then synchronize if needed.
     FoldersOnly, // Only synchronize folder metadata.
     InboxOnly, // Only Inbox, Sent, Draft and Deleted folders.

Wino.Core.Domain/Enums/WinoPage.cs

@@ -24,6 +24,7 @@ public enum WinoPage
     AppPreferencesPage,
     SettingOptionsPage,
     AliasManagementPage,
+    MailCategoryManagementPage,
     ImapCalDavSettingsPage,
     KeyboardShortcutsPage,
     CalendarPage,

Wino.Core.Domain/Interfaces/IAccountCalendar.cs

@@ -10,6 +10,7 @@ public interface IAccountCalendar
     string TextColorHex { get; set; }
     string BackgroundColorHex { get; set; }
     bool IsPrimary { get; set; }
+    bool IsReadOnly { get; set; }
     bool IsSynchronizationEnabled { get; set; }
     Guid AccountId { get; set; }
     string RemoteCalendarId { get; set; }

Wino.Core.Domain/Interfaces/IFolderMenuItem.cs

@@ -14,6 +14,22 @@ public interface IFolderMenuItem : IBaseFolderMenuItem
 
 public interface IMergedAccountFolderMenuItem : IBaseFolderMenuItem { }
 
+public interface IMailCategoryMenuItem : IBaseFolderMenuItem
+{
+    Entities.Mail.MailCategory MailCategory { get; }
+    string TextColorHex { get; }
+    string BackgroundColorHex { get; }
+    bool HasTextColor { get; }
+}
+
+public interface IMergedMailCategoryMenuItem : IBaseFolderMenuItem
+{
+    IReadOnlyList<Entities.Mail.MailCategory> Categories { get; }
+    string TextColorHex { get; }
+    string BackgroundColorHex { get; }
+    bool HasTextColor { get; }
+}
+
 public interface IBaseFolderMenuItem : IMenuItem
 {
     string FolderName { get; }

Wino.Core.Domain/Interfaces/IMailCategoryService.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Models.Accounts;
+
+namespace Wino.Core.Domain.Interfaces;
+
+public interface IMailCategoryService
+{
+    Task<List<MailCategory>> GetCategoriesAsync(Guid accountId);
+    Task<List<MailCategory>> GetFavoriteCategoriesAsync(Guid accountId);
+    Task<MailCategory> GetCategoryAsync(Guid categoryId);
+    Task<bool> CategoryNameExistsAsync(Guid accountId, string name, Guid? excludedCategoryId = null);
+    Task<MailCategory> CreateCategoryAsync(MailCategory category);
+    Task UpdateCategoryAsync(MailCategory category);
+    Task DeleteCategoryAsync(Guid categoryId);
+    Task DeleteCategoriesAsync(Guid accountId);
+    Task ToggleFavoriteAsync(Guid categoryId, bool isFavorite);
+    Task UpdateRemoteIdAsync(Guid categoryId, string remoteId);
+    Task ReplaceCategoriesAsync(Guid accountId, IEnumerable<MailCategory> categories);
+    Task ReplaceMailAssignmentsAsync(Guid accountId, Guid mailCopyUniqueId, IEnumerable<string> categoryNames);
+    Task AssignCategoryAsync(Guid categoryId, IEnumerable<Guid> mailCopyUniqueIds);
+    Task UnassignCategoryAsync(Guid categoryId, IEnumerable<Guid> mailCopyUniqueIds);
+    Task<List<MailCategory>> GetCategoriesForMailAsync(Guid accountId, IEnumerable<Guid> mailCopyUniqueIds);
+    Task<List<Guid>> GetAssignedCategoryIdsForAllAsync(IEnumerable<Guid> mailCopyUniqueIds);
+    Task<List<string>> GetCategoryNamesForMailAsync(Guid mailCopyUniqueId);
+    Task<List<MailCopy>> GetMailCopiesForCategoryAsync(Guid categoryId);
+    Task<List<UnreadCategoryCountResult>> GetUnreadCategoryCountResultsAsync(IEnumerable<Guid> accountIds);
+}

Wino.Core.Domain/Interfaces/IMailDialogService.cs

@@ -11,11 +11,13 @@ using Wino.Core.Domain.Models;
 using Wino.Core.Domain.Models.Accounts;
 using Wino.Core.Domain.Models.Calendar;
 using Wino.Core.Domain.Models.Folders;
+using Wino.Core.Domain.Models.MailItem;
 
 namespace Wino.Core.Domain.Interfaces;
 
 public interface IMailDialogService : IDialogServiceBase
 {
+    void ShowReadOnlyCalendarMessage();
     Task<bool> ShowHardDeleteConfirmationAsync();
     Task HandleSystemFolderConfigurationDialogAsync(Guid accountId, IFolderService folderService);
 
@@ -51,6 +53,13 @@ public interface IMailDialogService : IDialogServiceBase
     /// <returns>Created alias model if not canceled.</returns>
     Task<ICreateAccountAliasDialog> ShowCreateAccountAliasDialogAsync();
 
+    /// <summary>
+    /// Presents a dialog to the user for mail category creation/modification.
+    /// </summary>
+#pragma warning disable CS8625
+    Task<MailCategoryDialogResult> ShowEditMailCategoryDialogAsync(MailCategory category = null);
+#pragma warning restore CS8625
+
     /// <summary>
     /// Presents a dialog to the user to show email source.
     /// </summary>

Wino.Core.Domain/Interfaces/IRequestBundle.cs

@@ -72,3 +72,9 @@ public interface ICalendarActionRequest : IRequestBase
     Guid? LocalCalendarItemId { get; }
     CalendarSynchronizerOperation Operation { get; }
 }
+
+public interface ICategoryActionRequest : IRequestBase
+{
+    Guid AccountId { get; }
+    CategorySynchronizerOperation Operation { get; }
+}

Wino.Core.Domain/Interfaces/ISynchronizationManager.cs

@@ -63,6 +63,12 @@ public interface ISynchronizationManager
     Task<MailSynchronizationResult> SynchronizeAliasesAsync(Guid accountId,
                                                             CancellationToken cancellationToken = default);
 
+    /// <summary>
+    /// Handles category synchronization for the given account.
+    /// </summary>
+    Task<MailSynchronizationResult> SynchronizeCategoriesAsync(Guid accountId,
+                                                               CancellationToken cancellationToken = default);
+
     /// <summary>
     /// Handles profile synchronization for the given account.
     /// </summary>

Wino.Core.Domain/Interfaces/IWinoRequestDelegator.cs

@@ -1,4 +1,6 @@
-using System.Threading.Tasks;
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
 using Wino.Core.Domain.Models.Calendar;
 using Wino.Core.Domain.Models.Folders;
 using Wino.Core.Domain.Models.MailItem;
@@ -36,4 +38,9 @@ public interface IWinoRequestDelegator
     /// </summary>
     /// <param name="calendarOperationPreparationRequest">Calendar preparation request.</param>
     Task ExecuteAsync(CalendarOperationPreparationRequest calendarOperationPreparationRequest);
+
+    /// <summary>
+    /// Queues pre-built requests for a single account and triggers synchronization.
+    /// </summary>
+    Task ExecuteAsync(Guid accountId, IEnumerable<IRequestBase> requests);
 }

Wino.Core.Domain/MenuItems/MailCategoryMenuItem.cs

@@ -0,0 +1,48 @@
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Linq;
+using CommunityToolkit.Mvvm.ComponentModel;
+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.Folders;
+
+namespace Wino.Core.Domain.MenuItems;
+
+public partial class MailCategoryMenuItem : MenuItemBase<MailCategory, IMenuItem>, IFolderMenuItem, IMailCategoryMenuItem
+{
+    private IReadOnlyList<IMailItemFolder> _handlingFolders;
+
+    [ObservableProperty]
+    private int unreadItemCount;
+
+    public MailCategoryMenuItem(MailCategory category, MailAccount parentAccount, IEnumerable<IMailItemFolder> handlingFolders, IMenuItem parentMenuItem)
+        : base(category, category.Id, parentMenuItem)
+    {
+        ParentAccount = parentAccount;
+        _handlingFolders = handlingFolders?.ToList() ?? [];
+    }
+
+    public string FolderName => Parameter.Name;
+    public bool IsSynchronizationEnabled => false;
+    public SpecialFolderType SpecialFolderType => SpecialFolderType.Other;
+    public IEnumerable<IMailItemFolder> HandlingFolders => _handlingFolders;
+    public new ObservableCollection<IMenuItem> SubMenuItems { get; } = [];
+    public bool IsMoveTarget => true;
+    public bool IsSticky => false;
+    public bool IsSystemFolder => false;
+    public bool ShowUnreadCount => true;
+    public string AssignedAccountName => ParentAccount?.Name;
+    public MailAccount ParentAccount { get; private set; }
+    public string TextColorHex => Parameter.TextColorHex;
+    public string BackgroundColorHex => Parameter.BackgroundColorHex;
+    public bool HasTextColor => !string.IsNullOrWhiteSpace(Parameter.TextColorHex);
+    public MailCategory MailCategory => Parameter;
+
+    public void UpdateFolder(IMailItemFolder folder)
+    {
+    }
+
+    public void UpdateParentAccounnt(MailAccount account) => ParentAccount = account;
+}

Wino.Core.Domain/MenuItems/MenuItemCollection.cs

@@ -22,11 +22,13 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
 
     public IEnumerable<IAccountMenuItem> GetAllAccountMenuItems()
     {
-        foreach (var item in this)
+        var rootItems = this.ToList();
+
+        foreach (var item in rootItems)
         {
             if (item is MergedAccountMenuItem mergedAccountMenuItem)
             {
-                foreach (var singleItem in mergedAccountMenuItem.SubMenuItems.OfType<IAccountMenuItem>())
+                foreach (var singleItem in mergedAccountMenuItem.SubMenuItems.OfType<IAccountMenuItem>().ToList())
                 {
                     yield return singleItem;
                 }
@@ -40,9 +42,11 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
 
     public IEnumerable<IBaseFolderMenuItem> GetAllFolderMenuItems(Guid folderId)
     {
-        foreach (var item in this)
+        var rootItems = this.ToList();
+
+        foreach (var item in rootItems)
         {
-            if (item is IBaseFolderMenuItem folderMenuItem)
+            if (item is IBaseFolderMenuItem folderMenuItem && item is not IMailCategoryMenuItem && item is not IMergedMailCategoryMenuItem)
             {
                 if (folderMenuItem.HandlingFolders.Any(a => a.Id == folderId))
                 {
@@ -50,7 +54,7 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
                 }
                 else if (folderMenuItem.SubMenuItems.Any())
                 {
-                    foreach (var subItem in folderMenuItem.SubMenuItems.OfType<IBaseFolderMenuItem>())
+                    foreach (var subItem in folderMenuItem.SubMenuItems.OfType<IBaseFolderMenuItem>().ToList())
                     {
                         if (subItem.HandlingFolders.Any(a => a.Id == folderId))
                         {
@@ -65,8 +69,10 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
 
     public bool TryGetAccountMenuItem(Guid accountId, out IAccountMenuItem value)
     {
-        value = this.OfType<AccountMenuItem>().FirstOrDefault(a => a.AccountId == accountId);
+        var rootItems = this.ToList();
-        value ??= this.OfType<MergedAccountMenuItem>().FirstOrDefault(a => a.SubMenuItems.OfType<AccountMenuItem>().Where(b => b.AccountId == accountId) != null);
+
+        value = rootItems.OfType<AccountMenuItem>().FirstOrDefault(a => a.AccountId == accountId);
+        value ??= rootItems.OfType<MergedAccountMenuItem>().FirstOrDefault(a => a.SubMenuItems.OfType<AccountMenuItem>().Any(b => b.AccountId == accountId));
 
         return value != null;
     }
@@ -74,7 +80,9 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
     // Pattern: Look for special folder menu item inside the loaded folders for Windows Mail style menu items.
     public bool TryGetWindowsStyleRootSpecialFolderMenuItem(Guid accountId, SpecialFolderType specialFolderType, out FolderMenuItem value)
     {
-        value = this.OfType<IBaseFolderMenuItem>()
+        var rootItems = this.ToList();
+
+        value = rootItems.OfType<IBaseFolderMenuItem>()
                 .FirstOrDefault(a => a.HandlingFolders.Any(b => b.MailAccountId == accountId && b.SpecialFolderType == specialFolderType)) as FolderMenuItem;
 
         return value != null;
@@ -84,7 +92,9 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
     // This will not look for the folders inside individual account menu items inside merged account menu item.
     public bool TryGetMergedAccountSpecialFolderMenuItem(Guid mergedInboxId, SpecialFolderType specialFolderType, out IBaseFolderMenuItem value)
     {
-        value = this.OfType<MergedAccountFolderMenuItem>()
+        var rootItems = this.ToList();
+
+        value = rootItems.OfType<MergedAccountFolderMenuItem>()
                 .Where(a => a.MergedInbox.Id == mergedInboxId)
                 .FirstOrDefault(a => a.SpecialFolderType == specialFolderType);
 
@@ -93,11 +103,14 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
 
     public bool TryGetFolderMenuItem(Guid folderId, out IBaseFolderMenuItem value)
     {
+        var rootItems = this.ToList();
+
         // Root folders
-        value = this.OfType<IBaseFolderMenuItem>()
+        value = rootItems.OfType<IBaseFolderMenuItem>()
+                .Where(a => a is not IMailCategoryMenuItem && a is not IMergedMailCategoryMenuItem)
                 .FirstOrDefault(a => a.HandlingFolders.Any(b => b.Id == folderId));
 
-        value ??= this.OfType<FolderMenuItem>()
+        value ??= rootItems.OfType<FolderMenuItem>()
             .SelectMany(a => a.SubMenuItems)
                 .OfType<IBaseFolderMenuItem>()
                 .FirstOrDefault(a => a.HandlingFolders.Any(b => b.Id == folderId));
@@ -105,10 +118,23 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
         return value != null;
     }
 
+    public bool TryGetCategoryMenuItem(Guid categoryId, out IBaseFolderMenuItem value)
+    {
+        var rootItems = this.ToList();
+
+        value = rootItems.OfType<IMailCategoryMenuItem>()
+            .FirstOrDefault(a => a.MailCategory.Id == categoryId);
+
+        value ??= rootItems.OfType<IMergedMailCategoryMenuItem>()
+            .FirstOrDefault(a => a.Categories.Any(b => b.Id == categoryId)) as IBaseFolderMenuItem;
+
+        return value != null;
+    }
+
     public void UpdateUnreadItemCountsToZero()
     {
         // Handle the root folders.
-        foreach (var item in this.OfType<IBaseFolderMenuItem>())
+        foreach (var item in this.OfType<IBaseFolderMenuItem>().ToList())
         {
             RecursivelyResetUnreadItemCount(item);
         }
@@ -120,7 +146,7 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
 
         if (baseFolderMenuItem.SubMenuItems == null) return;
 
-        foreach (var subMenuItem in baseFolderMenuItem.SubMenuItems.OfType<IBaseFolderMenuItem>())
+        foreach (var subMenuItem in baseFolderMenuItem.SubMenuItems.OfType<IBaseFolderMenuItem>().ToList())
         {
             RecursivelyResetUnreadItemCount(subMenuItem);
         }
@@ -128,7 +154,9 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
 
     public bool TryGetSpecialFolderMenuItem(Guid accountId, SpecialFolderType specialFolderType, out FolderMenuItem value)
     {
-        value = this.OfType<IBaseFolderMenuItem>()
+        var rootItems = this.ToList();
+
+        value = rootItems.OfType<IBaseFolderMenuItem>()
                 .FirstOrDefault(a => a.HandlingFolders.Any(b => b.MailAccountId == accountId && b.SpecialFolderType == specialFolderType)) as FolderMenuItem;
 
         return value != null;
@@ -142,11 +170,12 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
     public AccountMenuItem GetSpecificAccountMenuItem(Guid accountId)
     {
         AccountMenuItem accountMenuItem = null;
+        var rootItems = this.ToList();
 
-        accountMenuItem = this.OfType<AccountMenuItem>().FirstOrDefault(a => a.HoldingAccounts.Any(b => b.Id == accountId));
+        accountMenuItem = rootItems.OfType<AccountMenuItem>().FirstOrDefault(a => a.HoldingAccounts.Any(b => b.Id == accountId));
 
         // Look for the items inside the merged accounts if regular menu item is not found.
-        accountMenuItem ??= this.OfType<MergedAccountMenuItem>()
+        accountMenuItem ??= rootItems.OfType<MergedAccountMenuItem>()
             .FirstOrDefault(a => a.HoldingAccounts.Any(b => b.Id == accountId))?.SubMenuItems
             .OfType<AccountMenuItem>()
             .FirstOrDefault(a => a.AccountId == accountId);
@@ -167,7 +196,7 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
     /// <param name="isEnabled">Whether menu items should be enabled or disabled.</param>
     public async Task SetAccountMenuItemEnabledStatusAsync(bool isEnabled)
     {
-        var accountItems = this.Where(a => a is IAccountMenuItem).Cast<IAccountMenuItem>();
+        var accountItems = this.Where(a => a is IAccountMenuItem).Cast<IAccountMenuItem>().ToList();
 
         await _dispatcher.ExecuteOnUIThread(() =>
         {
@@ -192,6 +221,7 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
     {
         // Check root-level items.
         var rootItem = this.OfType<IBaseFolderMenuItem>()
+            .Where(a => a is not IMailCategoryMenuItem && a is not IMergedMailCategoryMenuItem)
             .FirstOrDefault(a => a.HandlingFolders.Any(b => b.Id == folderId));
 
         if (rootItem != null)
@@ -201,7 +231,7 @@ public class MenuItemCollection : ObservableRangeCollection<IMenuItem>
         }
 
         // Check sub-items of root folders.
-        foreach (var rootFolder in this.OfType<IBaseFolderMenuItem>())
+        foreach (var rootFolder in this.OfType<IBaseFolderMenuItem>().ToList())
         {
             var subItem = rootFolder.SubMenuItems
                 .OfType<IBaseFolderMenuItem>()

Wino.Core.Domain/MenuItems/MergedMailCategoryMenuItem.cs

@@ -0,0 +1,44 @@
+using System.Collections.Generic;
+using System.Linq;
+using CommunityToolkit.Mvvm.ComponentModel;
+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.Folders;
+
+namespace Wino.Core.Domain.MenuItems;
+
+public partial class MergedMailCategoryMenuItem : MenuItemBase<List<MailCategory>, IMenuItem>, IMergedAccountFolderMenuItem, IMergedMailCategoryMenuItem
+{
+    private readonly IReadOnlyList<IMailItemFolder> _handlingFolders;
+
+    [ObservableProperty]
+    private int unreadItemCount;
+
+    public MergedMailCategoryMenuItem(List<MailCategory> categories, IEnumerable<IMailItemFolder> handlingFolders, MergedInbox mergedInbox)
+        : base(categories, null, null)
+    {
+        _handlingFolders = handlingFolders?.ToList() ?? [];
+        MergedInbox = mergedInbox;
+    }
+
+    public string FolderName => Parameter.FirstOrDefault()?.Name ?? string.Empty;
+    public bool IsSynchronizationEnabled => false;
+    public SpecialFolderType SpecialFolderType => SpecialFolderType.Other;
+    public IEnumerable<IMailItemFolder> HandlingFolders => _handlingFolders;
+    public bool IsMoveTarget => true;
+    public bool IsSticky => false;
+    public bool IsSystemFolder => false;
+    public bool ShowUnreadCount => true;
+    public string AssignedAccountName => MergedInbox?.Name;
+    public MergedInbox MergedInbox { get; }
+    public string TextColorHex => Parameter.FirstOrDefault()?.TextColorHex;
+    public string BackgroundColorHex => Parameter.FirstOrDefault()?.BackgroundColorHex;
+    public bool HasTextColor => !string.IsNullOrWhiteSpace(TextColorHex);
+    public IReadOnlyList<MailCategory> Categories => Parameter;
+
+    public void UpdateFolder(IMailItemFolder folder)
+    {
+    }
+}

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

@@ -0,0 +1,10 @@
+using System;
+
+namespace Wino.Core.Domain.Models.Accounts;
+
+public class UnreadCategoryCountResult
+{
+    public Guid CategoryId { get; set; }
+    public Guid AccountId { get; set; }
+    public int UnreadItemCount { get; set; }
+}

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

@@ -0,0 +1,3 @@
+namespace Wino.Core.Domain.Models.MailItem;
+
+public sealed record MailCategoryColorOption(string BackgroundColorHex, string TextColorHex);

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

@@ -0,0 +1,3 @@
+namespace Wino.Core.Domain.Models.MailItem;
+
+public sealed record MailCategoryDialogResult(string Name, string BackgroundColorHex, string TextColorHex);

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

@@ -0,0 +1,30 @@
+using System.Collections.Generic;
+
+namespace Wino.Core.Domain.Models.MailItem;
+
+public static class MailCategoryPalette
+{
+    public static IReadOnlyList<MailCategoryColorOption> DefaultOptions { get; } =
+    [
+        new("#FEE2E2", "#991B1B"),
+        new("#FECACA", "#7F1D1D"),
+        new("#FFEDD5", "#9A3412"),
+        new("#FED7AA", "#7C2D12"),
+        new("#FEF3C7", "#92400E"),
+        new("#FDE68A", "#78350F"),
+        new("#ECFCCB", "#3F6212"),
+        new("#D9F99D", "#365314"),
+        new("#DCFCE7", "#166534"),
+        new("#BBF7D0", "#14532D"),
+        new("#CCFBF1", "#115E59"),
+        new("#99F6E4", "#134E4A"),
+        new("#CFFAFE", "#155E75"),
+        new("#A5F3FC", "#164E63"),
+        new("#DBEAFE", "#1D4ED8"),
+        new("#BFDBFE", "#1E3A8A"),
+        new("#E0E7FF", "#4338CA"),
+        new("#DDD6FE", "#5B21B6"),
+        new("#F3E8FF", "#7E22CE"),
+        new("#FCE7F3", "#9D174D")
+    ];
+}

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

@@ -9,4 +9,5 @@ public record NewMailItemPackage(
     MailCopy Copy,
     MimeMessage Mime,
     string AssignedRemoteFolderId,
-    IReadOnlyList<AccountContact> ExtractedContacts = null);
+    IReadOnlyList<AccountContact> ExtractedContacts = null,
+    IReadOnlyList<string> CategoryNames = null);

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

@@ -17,4 +17,8 @@ public record MailListInitializationOptions(IEnumerable<IMailItemFolder> Folders
                                             List<MailCopy> PreFetchMailCopies = null,
                                             bool DeduplicateByServerId = false,
                                             int Skip = 0,
-                                            int Take = 0);
+                                            int Take = 0)
+{
+    public IReadOnlyList<Guid> CategoryIds { get; init; }
+    public bool IsCategoryView => CategoryIds?.Count > 0;
+}

Wino.Core.Domain/Models/Requests/RequestBase.cs

@@ -35,6 +35,10 @@ public abstract record CalendarRequestBase(CalendarItem Item) : RequestBase<Cale
     public virtual Guid? LocalCalendarItemId => Item?.Id;
 }
 
+public abstract record CategoryRequestBase(Guid AccountId) : RequestBase<CategorySynchronizerOperation>, ICategoryActionRequest
+{
+}
+
 public class BatchCollection<TRequestType> : List<TRequestType>, IUIChangeRequest where TRequestType : IUIChangeRequest
 {
     public BatchCollection(IEnumerable<TRequestType> collection) : base(collection)

Wino.Core.Domain/Models/Settings/SettingsNavigationItemInfo.cs

@@ -170,6 +170,7 @@ public static class SettingsNavigationInfoProvider
             WinoPage.AccountDetailsPage => WinoPage.ManageAccountsPage,
             WinoPage.MergedAccountDetailsPage => WinoPage.ManageAccountsPage,
             WinoPage.AliasManagementPage => WinoPage.ManageAccountsPage,
+            WinoPage.MailCategoryManagementPage => WinoPage.ManageAccountsPage,
             WinoPage.SignatureManagementPage => WinoPage.ManageAccountsPage,
             WinoPage.ImapCalDavSettingsPage => WinoPage.ManageAccountsPage,
             WinoPage.CreateEmailTemplatePage => WinoPage.EmailTemplatesPage,

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

@@ -67,6 +67,7 @@
     "BasicIMAPSetupDialog_Password": "Password",
     "BasicIMAPSetupDialog_Title": "IMAP Account",
     "Busy": "Busy",
+    "Buttons_Add": "Add",
     "Buttons_AddAccount": "Add Account",
     "Buttons_FixAccount": "Fix Account",
     "Buttons_AddNewAlias": "Add New Alias",
@@ -213,6 +214,8 @@
     "CalendarEventDetails_Organizer": "Organizer",
     "CalendarEventDetails_People": "People",
     "CalendarEventDetails_ReadOnlyEvent": "Read-only event",
+    "CalendarReadOnly_Title": "Read-only calendar",
+    "CalendarReadOnly_Message": "You can't update this calendar or its events. This calendar is read-only.",
     "CalendarContextMenu_Respond": "Respond",
     "CalendarEventDetails_Reminder": "Reminder",
     "CalendarReminder_StartedHoursAgo": "Started {0} hours ago",
@@ -875,10 +878,28 @@
     "SettingsManageAccountSettings_Title": "Manage Accounts",
     "SettingsManageAliases_Description": "See e-mail aliases assigned for this account, update or delete them.",
     "SettingsManageAliases_Title": "Aliases",
+    "SettingsMailCategories_Description": "Manage synchronized and local categories for this account.",
+    "SettingsMailCategories_Title": "Categories",
     "SettingsEditAccountDetails_Title": "Edit Account Details",
     "SettingsEditAccountDetails_Description": "Change account name, sender name and assign a new color if you like.",
     "EditAccountDetailsPage_SaveSuccess_Title": "Changes Saved",
     "EditAccountDetailsPage_SaveSuccess_Message": "Your account details have been updated successfully.",
+    "MailCategoryManagementPage_Title": "Categories",
+    "MailCategoryManagementPage_Description": "Create, edit, delete, and favorite categories for this account.",
+    "MailCategoryManagementPage_Empty": "No categories yet.",
+    "MailCategoryManagementPage_DeleteConfirmationTitle": "Delete Category",
+    "MailCategoryManagementPage_DeleteConfirmationMessage": "Delete category \"{0}\"?",
+    "MailCategoryManagementPage_RefreshConfirmationMessage": "This will delete all your local categories, and re-synchronize everything from the server. Do you want to continue?",
+    "MailCategoryMenuItem": "Category",
+    "MailCategoryDialog_CreateTitle": "Create category",
+    "MailCategoryDialog_EditTitle": "Edit category",
+    "MailCategoryDialog_Name": "Name",
+    "MailCategoryDialog_NamePlaceholder": "Category name",
+    "MailCategoryDialog_Color": "Color",
+    "MailCategoryDialog_InvalidNameTitle": "Category name required",
+    "MailCategoryDialog_InvalidNameMessage": "Enter a category name to continue.",
+    "MailCategoryDialog_DuplicateTitle": "Category already exists",
+    "MailCategoryDialog_DuplicateMessage": "A category with the same name already exists for this account.",
     "SettingsManageLink_Description": "Move items to add new link or remove existing link.",
     "SettingsManageLink_Title": "Manage Link",
     "SettingsMarkAsRead_Description": "Change what should happen to the selected item.",
@@ -1491,11 +1512,13 @@
     "AccountSetup_Step_TestingCalendarAuth": "Testing calendar authentication",
     "AccountSetup_Step_SavingAccount": "Saving account information",
     "AccountSetup_Step_FetchingCalendarMetadata": "Fetching calendar metadata",
+    "AccountSetup_Step_SyncingCategories": "Synchronizing categories",
     "AccountSetup_Step_SyncingAliases": "Synchronizing aliases",
     "AccountSetup_Step_Finalizing": "Finalizing setup",
     "AccountSetup_FailureMessage": "Setup failed. Go back to fix your settings, or try again later.",
     "AccountSetup_SuccessMessage": "Your account has been set up successfully!",
     "AccountSetup_GoBackButton": "Go Back",
     "AccountSetup_TryAgainButton": "Try Again",
+    "Exception_FailedToSynchronizeCategories": "Failed to synchronize categories",
     "ImapCalDavSettings_AutoDiscoveryFailed": "Auto-discovery failed. Please enter settings manually in the Advanced tab."
 }

Wino.Core.Tests/Services/MailFetchingTests.cs

@@ -510,7 +510,8 @@ public class MailFetchingTests : IAsyncLifetime
             preferencesService.Object,
             contactPictureFileService.Object);
 
-        var folderService = new FolderService(db, accountService);
+        var mailCategoryService = new MailCategoryService(db);
+        var folderService = new FolderService(db, accountService, mailCategoryService);
         var contactService = new ContactService(db);
         var sentMailReceiptService = new SentMailReceiptService(db, folderService, accountService);
 
@@ -522,6 +523,7 @@ public class MailFetchingTests : IAsyncLifetime
             signatureService.Object,
             mimeFileService.Object,
             preferencesService.Object,
-            sentMailReceiptService);
+            sentMailReceiptService,
+            mailCategoryService);
     }
 }

Wino.Core.Tests/Services/MailThreadingTests.cs

@@ -269,7 +269,8 @@ public class MailThreadingTests : IAsyncLifetime
             preferencesService.Object,
             contactPictureFileService.Object);
 
-        var folderService = new FolderService(db, accountService);
+        var mailCategoryService = new MailCategoryService(db);
+        var folderService = new FolderService(db, accountService, mailCategoryService);
         var contactService = new ContactService(db);
         var sentMailReceiptService = new SentMailReceiptService(db, folderService, accountService);
 
@@ -281,6 +282,7 @@ public class MailThreadingTests : IAsyncLifetime
             signatureService.Object,
             mimeFileService.Object,
             preferencesService.Object,
-            sentMailReceiptService);
+            sentMailReceiptService,
+            mailCategoryService);
     }
 }

Wino.Core.Tests/Synchronizers/OutlookSynchronizerRequestSuccessTests.cs

@@ -70,8 +70,9 @@ public sealed class OutlookSynchronizerRequestSuccessTests
 
         var authenticator = new Mock<IAuthenticator>(MockBehavior.Loose);
         var errorFactory = new Mock<IOutlookSynchronizerErrorHandlerFactory>(MockBehavior.Loose);
+        var mailCategoryService = new Mock<IMailCategoryService>(MockBehavior.Loose);
 
-        return new OutlookSynchronizer(account, authenticator.Object, changeProcessor, errorFactory.Object);
+        return new OutlookSynchronizer(account, authenticator.Object, changeProcessor, errorFactory.Object, mailCategoryService.Object);
     }
 
     private static MailCopy CreateMailCopy() =>

Wino.Core/Extensions/GoogleIntegratorExtensions.cs

@@ -145,6 +145,8 @@ public static class GoogleIntegratorExtensions
             Id = Guid.NewGuid(),
             TimeZone = calendarListEntry.TimeZone,
             IsPrimary = calendarListEntry.Primary.GetValueOrDefault(),
+            IsReadOnly = !string.Equals(calendarListEntry.AccessRole, "owner", StringComparison.OrdinalIgnoreCase)
+                         && !string.Equals(calendarListEntry.AccessRole, "writer", StringComparison.OrdinalIgnoreCase),
             IsSynchronizationEnabled = true,
         };
 

Wino.Core/Extensions/OutlookIntegratorExtensions.cs

@@ -190,6 +190,7 @@ public static class OutlookIntegratorExtensions
             Id = Guid.NewGuid(),
             RemoteCalendarId = outlookCalendar.Id,
             IsPrimary = outlookCalendar.IsDefaultCalendar.GetValueOrDefault(),
+            IsReadOnly = !outlookCalendar.CanEdit.GetValueOrDefault(true),
             Name = outlookCalendar.Name,
             IsSynchronizationEnabled = true,
             IsExtended = true,

Wino.Core/Requests/Category/MailCategoryCreateRequest.cs

@@ -0,0 +1,10 @@
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Enums;
+using Wino.Core.Domain.Models.Requests;
+
+namespace Wino.Core.Requests.Category;
+
+public record MailCategoryCreateRequest(MailCategory Category) : CategoryRequestBase(Category.MailAccountId)
+{
+    public override CategorySynchronizerOperation Operation => CategorySynchronizerOperation.CreateCategory;
+}

Wino.Core/Requests/Category/MailCategoryDeleteRequest.cs

@@ -0,0 +1,14 @@
+using System.Collections.Generic;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Enums;
+using Wino.Core.Domain.Models.Requests;
+
+namespace Wino.Core.Requests.Category;
+
+public record MailCategoryDeleteRequest(
+    MailCategory Category,
+    string PreviousRemoteId,
+    IReadOnlyList<MailCategoryMessageUpdateTarget> AffectedMessages = null) : CategoryRequestBase(Category.MailAccountId)
+{
+    public override CategorySynchronizerOperation Operation => CategorySynchronizerOperation.DeleteCategory;
+}

Wino.Core/Requests/Category/MailCategoryRequestModels.cs

@@ -0,0 +1,5 @@
+using System.Collections.Generic;
+
+namespace Wino.Core.Requests.Category;
+
+public sealed record MailCategoryMessageUpdateTarget(string MessageId, IReadOnlyList<string> CategoryNames);

Wino.Core/Requests/Category/MailCategoryUpdateRequest.cs

@@ -0,0 +1,15 @@
+using System.Collections.Generic;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Enums;
+using Wino.Core.Domain.Models.Requests;
+
+namespace Wino.Core.Requests.Category;
+
+public record MailCategoryUpdateRequest(
+    MailCategory Category,
+    string PreviousName,
+    string PreviousRemoteId,
+    IReadOnlyList<MailCategoryMessageUpdateTarget> AffectedMessages = null) : CategoryRequestBase(Category.MailAccountId)
+{
+    public override CategorySynchronizerOperation Operation => CategorySynchronizerOperation.UpdateCategory;
+}

Wino.Core/Requests/Mail/MailCategoryAssignmentRequest.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Collections.Generic;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Enums;
+using Wino.Core.Domain.Interfaces;
+using Wino.Core.Domain.Models.Requests;
+
+namespace Wino.Core.Requests.Mail;
+
+public record MailCategoryAssignmentRequest(
+    MailCopy Item,
+    Guid MailCategoryId,
+    string CategoryName,
+    IReadOnlyList<string> CategoryNames,
+    bool IsAssigned) : MailRequestBase(Item), ICustomFolderSynchronizationRequest
+{
+    public override MailSynchronizerOperation Operation => MailSynchronizerOperation.UpdateCategories;
+    public List<Guid> SynchronizationFolderIds => [Item.FolderId];
+    public bool ExcludeMustHaveFolders => true;
+}
+
+public class BatchMailCategoryAssignmentRequest : BatchCollection<MailCategoryAssignmentRequest>
+{
+    public BatchMailCategoryAssignmentRequest(IEnumerable<MailCategoryAssignmentRequest> collection) : base(collection)
+    {
+    }
+}

Wino.Core/Services/SynchronizationManager.cs

@@ -370,6 +370,26 @@ public class SynchronizationManager : ISynchronizationManager, IRecipient<Accoun
         return await SynchronizeMailAsync(options, cancellationToken);
     }
 
+    /// <summary>
+    /// Handles category synchronization for the given account.
+    /// </summary>
+    /// <param name="accountId">Account ID to synchronize categories for</param>
+    /// <param name="cancellationToken">Cancellation token</param>
+    /// <returns>Synchronization result</returns>
+    public async Task<MailSynchronizationResult> SynchronizeCategoriesAsync(Guid accountId,
+                                                                            CancellationToken cancellationToken = default)
+    {
+        EnsureInitialized();
+
+        var options = new MailSynchronizationOptions
+        {
+            AccountId = accountId,
+            Type = MailSynchronizationType.Categories
+        };
+
+        return await SynchronizeMailAsync(options, cancellationToken);
+    }
+
     /// <summary>
     /// Handles profile synchronization for the given account.
     /// </summary>

Wino.Core/Services/SynchronizerFactory.cs

@@ -26,6 +26,7 @@ public class SynchronizerFactory : ISynchronizerFactory
     private readonly ICalDavClient _calDavClient;
     private readonly IAutoDiscoveryService _autoDiscoveryService;
     private readonly ICalendarService _calendarService;
+    private readonly IMailCategoryService _mailCategoryService;
 
     private readonly List<IWinoSynchronizerBase> synchronizerCache = new();
 
@@ -41,7 +42,8 @@ public class SynchronizerFactory : ISynchronizerFactory
                                UnifiedImapSynchronizer unifiedImapSynchronizer,
                                ICalDavClient calDavClient,
                                IAutoDiscoveryService autoDiscoveryService,
-                               ICalendarService calendarService)
+                               ICalendarService calendarService,
+                               IMailCategoryService mailCategoryService)
     {
         _outlookChangeProcessor = outlookChangeProcessor;
         _gmailChangeProcessor = gmailChangeProcessor;
@@ -56,6 +58,7 @@ public class SynchronizerFactory : ISynchronizerFactory
         _calDavClient = calDavClient;
         _autoDiscoveryService = autoDiscoveryService;
         _calendarService = calendarService;
+        _mailCategoryService = mailCategoryService;
     }
 
     public async Task<IWinoSynchronizerBase> GetAccountSynchronizerAsync(Guid accountId)
@@ -86,7 +89,7 @@ public class SynchronizerFactory : ISynchronizerFactory
         {
             case Domain.Enums.MailProviderType.Outlook:
                 var outlookAuthenticator = _authenticationProvider.GetAuthenticator(Domain.Enums.MailProviderType.Outlook) as IOutlookAuthenticator;
-                return new OutlookSynchronizer(mailAccount, outlookAuthenticator, _outlookChangeProcessor, _outlookSynchronizerErrorHandlerFactory);
+                return new OutlookSynchronizer(mailAccount, outlookAuthenticator, _outlookChangeProcessor, _outlookSynchronizerErrorHandlerFactory, _mailCategoryService);
             case Domain.Enums.MailProviderType.Gmail:
                 var gmailAuthenticator = _authenticationProvider.GetAuthenticator(Domain.Enums.MailProviderType.Gmail) as IGmailAuthenticator;
                 return new GmailSynchronizer(mailAccount, gmailAuthenticator, _gmailChangeProcessor, _gmailSynchronizerErrorHandlerFactory);

Wino.Core/Services/WinoRequestDelegator.cs

@@ -165,6 +165,13 @@ public class WinoRequestDelegator : IWinoRequestDelegator
         if (calendarPreparationRequest == null)
             return;
 
+        var resolvedCalendar = await ResolveCalendarAsync(calendarPreparationRequest).ConfigureAwait(false);
+        if (resolvedCalendar?.IsReadOnly == true)
+        {
+            _dialogService.ShowReadOnlyCalendarMessage();
+            return;
+        }
+
         IRequestBase request = calendarPreparationRequest.Operation switch
         {
             CalendarSynchronizerOperation.CreateEvent => await CreateCalendarEventRequestAsync(calendarPreparationRequest).ConfigureAwait(false),
@@ -200,6 +207,21 @@ public class WinoRequestDelegator : IWinoRequestDelegator
         await QueueCalendarSynchronizationAsync(accountId);
     }
 
+    public async Task ExecuteAsync(Guid accountId, IEnumerable<IRequestBase> requests)
+    {
+        var requestList = requests?.Where(a => a != null).ToList() ?? [];
+        if (requestList.Count == 0)
+            return;
+
+        foreach (var request in requestList)
+        {
+            await QueueRequestAsync(request, accountId).ConfigureAwait(false);
+        }
+
+        await SendSyncActionsAddedAsync(requestList, accountId).ConfigureAwait(false);
+        await QueueSynchronizationAsync(accountId).ConfigureAwait(false);
+    }
+
     private async Task<IRequestBase> CreateCalendarEventRequestAsync(CalendarOperationPreparationRequest calendarPreparationRequest)
     {
         var composeResult = calendarPreparationRequest.ComposeResult
@@ -212,6 +234,25 @@ public class WinoRequestDelegator : IWinoRequestDelegator
         return new CreateCalendarEventRequest(composeResult, assignedCalendar);
     }
 
+    private async Task<AccountCalendar> ResolveCalendarAsync(CalendarOperationPreparationRequest calendarPreparationRequest)
+    {
+        if (calendarPreparationRequest.Operation == CalendarSynchronizerOperation.CreateEvent)
+        {
+            var calendarId = calendarPreparationRequest.ComposeResult?.CalendarId ?? Guid.Empty;
+            return calendarId == Guid.Empty
+                ? null
+                : await _calendarService.GetAccountCalendarAsync(calendarId).ConfigureAwait(false);
+        }
+
+        if (calendarPreparationRequest.CalendarItem?.AssignedCalendar is AccountCalendar assignedCalendar)
+            return assignedCalendar;
+
+        var fallbackCalendarId = calendarPreparationRequest.CalendarItem?.CalendarId ?? Guid.Empty;
+        return fallbackCalendarId == Guid.Empty
+            ? null
+            : await _calendarService.GetAccountCalendarAsync(fallbackCalendarId).ConfigureAwait(false);
+    }
+
     private IRequestBase CreateDeclineRequest(CalendarItem calendarItem, string responseMessage)
     {
         // For Outlook accounts, declined events are deleted by the server after synchronization.

Wino.Core/Synchronizers/GmailSynchronizer.cs

@@ -759,6 +759,8 @@ public class GmailSynchronizer : WinoSynchronizer<IClientServiceRequest, Message
                     existingLocalCalendar.BackgroundColorHex = resolvedColor;
                     existingLocalCalendar.TextColorHex = ColorHelpers.GetReadableTextColorHex(existingLocalCalendar.BackgroundColorHex);
                     existingLocalCalendar.IsPrimary = string.Equals(existingLocalCalendar.RemoteCalendarId, remotePrimaryCalendarId, StringComparison.OrdinalIgnoreCase);
+                    existingLocalCalendar.IsReadOnly = !string.Equals(calendar.AccessRole, "owner", StringComparison.OrdinalIgnoreCase)
+                                                      && !string.Equals(calendar.AccessRole, "writer", StringComparison.OrdinalIgnoreCase);
 
                     updatedCalendars.Add(existingLocalCalendar);
                 }
@@ -940,14 +942,17 @@ public class GmailSynchronizer : WinoSynchronizer<IClientServiceRequest, Message
         var remoteBackgroundColor = ResolveSynchronizedCalendarBackgroundColor(GetRemoteGmailCalendarBackgroundColor(calendarListEntry), accountCalendar);
         var remoteTextColor = ColorHelpers.GetReadableTextColorHex(remoteBackgroundColor);
         var remoteIsPrimary = string.Equals(calendarListEntry.Id, remotePrimaryCalendarId, StringComparison.OrdinalIgnoreCase);
+        var remoteIsReadOnly = !string.Equals(calendarListEntry.AccessRole, "owner", StringComparison.OrdinalIgnoreCase)
+                               && !string.Equals(calendarListEntry.AccessRole, "writer", StringComparison.OrdinalIgnoreCase);
 
         bool isNameChanged = !string.Equals(accountCalendar.Name, remoteCalendarName, StringComparison.OrdinalIgnoreCase);
         bool isTimeZoneChanged = !string.Equals(accountCalendar.TimeZone, remoteTimeZone, StringComparison.OrdinalIgnoreCase);
         bool isBackgroundColorChanged = !string.Equals(accountCalendar.BackgroundColorHex, remoteBackgroundColor, StringComparison.OrdinalIgnoreCase);
         bool isTextColorChanged = !string.Equals(accountCalendar.TextColorHex, remoteTextColor, StringComparison.OrdinalIgnoreCase);
         bool isPrimaryChanged = accountCalendar.IsPrimary != remoteIsPrimary;
+        bool isReadOnlyChanged = accountCalendar.IsReadOnly != remoteIsReadOnly;
 
-        return isNameChanged || isTimeZoneChanged || isBackgroundColorChanged || isTextColorChanged || isPrimaryChanged;
+        return isNameChanged || isTimeZoneChanged || isBackgroundColorChanged || isTextColorChanged || isPrimaryChanged || isReadOnlyChanged;
     }
 
     private static string GetRemoteGmailCalendarBackgroundColor(CalendarListEntry calendarListEntry)

Wino.Core/Synchronizers/OutlookSynchronizer.cs

@@ -41,6 +41,7 @@ using Wino.Core.Integration.Processors;
 using Wino.Core.Misc;
 using Wino.Core.Requests.Bundles;
 using Wino.Core.Requests.Calendar;
+using Wino.Core.Requests.Category;
 using Wino.Core.Requests.Folder;
 using Wino.Core.Requests.Mail;
 using Wino.Messaging.UI;
@@ -107,6 +108,7 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
         "ParentFolderId",
         "InternetMessageId",
         "InternetMessageHeaders",
+        "Categories",
     ];
 
     private readonly SemaphoreSlim _handleItemRetrievalSemaphore = new(1);
@@ -116,6 +118,7 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
     private readonly IOutlookChangeProcessor _outlookChangeProcessor;
     private readonly GraphServiceClient _graphClient;
     private readonly IOutlookSynchronizerErrorHandlerFactory _errorHandlingFactory;
+    private readonly IMailCategoryService _mailCategoryService;
     private bool _isFolderStructureChanged;
 
     private readonly SemaphoreSlim _concurrentDownloadSemaphore = new(10); // Limit to 10 concurrent downloads
@@ -123,7 +126,8 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
     public OutlookSynchronizer(MailAccount account,
                                IAuthenticator authenticator,
                                IOutlookChangeProcessor outlookChangeProcessor,
-                               IOutlookSynchronizerErrorHandlerFactory errorHandlingFactory) : base(account, WeakReferenceMessenger.Default)
+                               IOutlookSynchronizerErrorHandlerFactory errorHandlingFactory,
+                               IMailCategoryService mailCategoryService) : base(account, WeakReferenceMessenger.Default)
     {
         var tokenProvider = new MicrosoftTokenProvider(Account, authenticator);
 
@@ -138,6 +142,7 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
 
         _outlookChangeProcessor = outlookChangeProcessor;
         _errorHandlingFactory = errorHandlingFactory;
+        _mailCategoryService = mailCategoryService;
     }
 
     #region MS Graph Handlers
@@ -1152,6 +1157,11 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
                     _logger.Debug("Updating flag status for mail {MessageId}: IsFlagged={IsFlagged}", item.Id, isFlagged);
                     await _outlookChangeProcessor.ChangeFlagStatusAsync(item.Id, isFlagged).ConfigureAwait(false);
                 }
+
+                if (item.Categories != null)
+                {
+                    await ReplaceMailAssignmentsAsync(item.Id, item.Categories).ConfigureAwait(false);
+                }
             }
             else
             {
@@ -1208,6 +1218,43 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
         }
     }
 
+    protected override async Task SynchronizeCategoriesAsync(CancellationToken cancellationToken = default)
+    {
+        var response = await _graphClient.Me.Outlook.MasterCategories
+            .GetAsync(cancellationToken: cancellationToken)
+            .ConfigureAwait(false);
+
+        var categories = response?.Value?
+            .Where(a => !string.IsNullOrWhiteSpace(a?.DisplayName))
+            .Select(a =>
+            {
+                var colorOption = GetMailCategoryColorOption(a.Color);
+
+                return new MailCategory
+                {
+                    MailAccountId = Account.Id,
+                    RemoteId = a.Id,
+                    Name = a.DisplayName,
+                    BackgroundColorHex = colorOption.BackgroundColorHex,
+                    TextColorHex = colorOption.TextColorHex,
+                    Source = MailCategorySource.Outlook
+                };
+            })
+            .ToList() ?? [];
+
+        await _mailCategoryService.ReplaceCategoriesAsync(Account.Id, categories).ConfigureAwait(false);
+    }
+
+    private async Task ReplaceMailAssignmentsAsync(string messageId, IEnumerable<string> categoryNames)
+    {
+        var localMailCopies = await _outlookChangeProcessor.GetMailCopiesAsync([messageId]).ConfigureAwait(false);
+
+        foreach (var localMailCopy in localMailCopies)
+        {
+            await _mailCategoryService.ReplaceMailAssignmentsAsync(Account.Id, localMailCopy.UniqueId, categoryNames ?? []).ConfigureAwait(false);
+        }
+    }
+
     private async Task<OutlookSpecialFolderIdInformation> GetSpecialFolderIdsAsync(CancellationToken cancellationToken)
     {
         var localFolders = await _outlookChangeProcessor.GetLocalFoldersAsync(Account.Id).ConfigureAwait(false);
@@ -1767,6 +1814,87 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
         return Move(batchMoveRequest);
     }
 
+    public override List<IRequestBundle<RequestInformation>> UpdateCategories(BatchMailCategoryAssignmentRequest request)
+        => ForEachRequest(request, item => CreateMessageCategoryPatchRequest(item.Item.Id, item.CategoryNames));
+
+    public override List<IRequestBundle<RequestInformation>> CreateCategory(MailCategoryCreateRequest request)
+    {
+        var outlookCategory = new OutlookCategory
+        {
+            DisplayName = request.Category.Name,
+            Color = GetOutlookCategoryColor(request.Category)
+        };
+
+        var requestInfo = _graphClient.Me.Outlook.MasterCategories.ToPostRequestInformation(outlookCategory);
+        return [new HttpRequestBundle<RequestInformation>(requestInfo, request)];
+    }
+
+    public override List<IRequestBundle<RequestInformation>> UpdateCategory(MailCategoryUpdateRequest request)
+    {
+        if (string.IsNullOrWhiteSpace(request.PreviousRemoteId))
+            return CreateCategory(new MailCategoryCreateRequest(request.Category));
+
+        var hasNameChanged = !string.Equals(request.PreviousName, request.Category.Name, StringComparison.Ordinal);
+        if (!hasNameChanged)
+        {
+            var requestInfo = _graphClient.Me.Outlook.MasterCategories[request.PreviousRemoteId].ToPatchRequestInformation(new OutlookCategory
+            {
+                Color = GetOutlookCategoryColor(request.Category)
+            });
+
+            return [new HttpRequestBundle<RequestInformation>(requestInfo, request)];
+        }
+
+        var bundles = new List<IRequestBundle<RequestInformation>>();
+        var createRequestInfo = _graphClient.Me.Outlook.MasterCategories.ToPostRequestInformation(new OutlookCategory
+        {
+            DisplayName = request.Category.Name,
+            Color = GetOutlookCategoryColor(request.Category)
+        });
+
+        bundles.Add(new HttpRequestBundle<RequestInformation>(createRequestInfo, request));
+
+        foreach (var target in request.AffectedMessages ?? [])
+        {
+            bundles.Add(new HttpRequestBundle<RequestInformation>(
+                CreateMessageCategoryPatchRequest(target.MessageId, target.CategoryNames),
+                request));
+        }
+
+        bundles.Add(new HttpRequestBundle<RequestInformation>(
+            _graphClient.Me.Outlook.MasterCategories[request.PreviousRemoteId].ToDeleteRequestInformation(),
+            request));
+
+        return bundles;
+    }
+
+    public override List<IRequestBundle<RequestInformation>> DeleteCategory(MailCategoryDeleteRequest request)
+    {
+        if (string.IsNullOrWhiteSpace(request.PreviousRemoteId))
+            return [];
+
+        var bundles = new List<IRequestBundle<RequestInformation>>();
+
+        foreach (var target in request.AffectedMessages ?? [])
+        {
+            bundles.Add(new HttpRequestBundle<RequestInformation>(
+                CreateMessageCategoryPatchRequest(target.MessageId, target.CategoryNames),
+                request));
+        }
+
+        bundles.Add(new HttpRequestBundle<RequestInformation>(
+            _graphClient.Me.Outlook.MasterCategories[request.PreviousRemoteId].ToDeleteRequestInformation(),
+            request));
+
+        return bundles;
+    }
+
+    private RequestInformation CreateMessageCategoryPatchRequest(string messageId, IReadOnlyList<string> categoryNames)
+        => _graphClient.Me.Messages[messageId].ToPatchRequestInformation(new Message
+        {
+            Categories = categoryNames?.ToList() ?? []
+        });
+
     public override async Task DownloadMissingMimeMessageAsync(MailCopy mailItem,
                                                            MailKit.ITransferProgress transferProgress = null,
                                                            CancellationToken cancellationToken = default)
@@ -1962,7 +2090,9 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
         for (int i = 0; i < itemCount; i++)
         {
             var bundle = batch.ElementAt(i);
-            requiresSerial |= bundle.UIChangeRequest is SendDraftRequest;
+            requiresSerial |= bundle.UIChangeRequest is SendDraftRequest
+                              or MailCategoryUpdateRequest
+                              or MailCategoryDeleteRequest;
 
             // UI changes are already applied in ExecuteNativeRequestsAsync before batching.
             var batchRequestId = await batchContent.AddBatchRequestStepAsync(bundle.NativeRequest);
@@ -2110,7 +2240,10 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
            || request is ChangeFlagRequest
            || request is MarkReadRequest
            || request is ArchiveRequest
+           || request is MailCategoryAssignmentRequest
            || request is RenameFolderRequest
+           || request is MailCategoryUpdateRequest
+           || request is MailCategoryDeleteRequest
            || request is DeleteFolderRequest
            || request is AcceptEventRequest
            || request is DeclineEventRequest
@@ -2165,6 +2298,26 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
                     return;
 
                 await UploadCalendarEventAttachmentsAsync(createCalendarEventRequest, createdEventId, CancellationToken.None).ConfigureAwait(false);
+                return;
+            }
+
+            if (bundle?.UIChangeRequest is MailCategoryCreateRequest createCategoryRequest)
+            {
+                var createdCategoryId = json?["id"]?.GetValue<string>();
+                if (!string.IsNullOrWhiteSpace(createdCategoryId))
+                {
+                    await _mailCategoryService.UpdateRemoteIdAsync(createCategoryRequest.Category.Id, createdCategoryId).ConfigureAwait(false);
+                }
+                return;
+            }
+
+            if (bundle?.UIChangeRequest is MailCategoryUpdateRequest updateCategoryRequest)
+            {
+                var updatedCategoryId = json?["id"]?.GetValue<string>();
+                if (!string.IsNullOrWhiteSpace(updatedCategoryId))
+                {
+                    await _mailCategoryService.UpdateRemoteIdAsync(updateCategoryRequest.Category.Id, updatedCategoryId).ConfigureAwait(false);
+                }
             }
         }
         catch (Exception ex)
@@ -2367,11 +2520,68 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
         // Outlook messages can only be assigned to 1 folder at a time.
         // Therefore we don't need to create multiple copies of the same message for different folders.
         var contacts = ExtractContactsFromOutlookMessage(message);
-        var package = new NewMailItemPackage(mailCopy, mimeMessage, assignedFolder.RemoteFolderId, contacts);
+        var package = new NewMailItemPackage(mailCopy, mimeMessage, assignedFolder.RemoteFolderId, contacts, message.Categories);
 
         return [package];
     }
 
+    private static MailCategoryColorOption GetMailCategoryColorOption(CategoryColor? color)
+        => color switch
+        {
+            CategoryColor.Preset0 => new("#FEE2E2", "#991B1B"),
+            CategoryColor.Preset1 => new("#FFEDD5", "#9A3412"),
+            CategoryColor.Preset2 => new("#FEF3C7", "#92400E"),
+            CategoryColor.Preset3 => new("#ECFCCB", "#3F6212"),
+            CategoryColor.Preset4 => new("#DCFCE7", "#166534"),
+            CategoryColor.Preset5 => new("#CCFBF1", "#115E59"),
+            CategoryColor.Preset6 => new("#CFFAFE", "#155E75"),
+            CategoryColor.Preset7 => new("#DBEAFE", "#1D4ED8"),
+            CategoryColor.Preset8 => new("#E0E7FF", "#4338CA"),
+            CategoryColor.Preset9 => new("#F3E8FF", "#7E22CE"),
+            CategoryColor.Preset10 => new("#FCE7F3", "#9D174D"),
+            CategoryColor.Preset11 => new("#FECACA", "#7F1D1D"),
+            CategoryColor.Preset12 => new("#FED7AA", "#7C2D12"),
+            CategoryColor.Preset13 => new("#FDE68A", "#78350F"),
+            CategoryColor.Preset14 => new("#D9F99D", "#365314"),
+            CategoryColor.Preset15 => new("#BBF7D0", "#14532D"),
+            CategoryColor.Preset16 => new("#99F6E4", "#134E4A"),
+            CategoryColor.Preset17 => new("#A5F3FC", "#164E63"),
+            CategoryColor.Preset18 => new("#BFDBFE", "#1E3A8A"),
+            CategoryColor.Preset19 => new("#DDD6FE", "#5B21B6"),
+            CategoryColor.Preset20 => new("#E5E7EB", "#374151"),
+            CategoryColor.Preset21 => new("#D1D5DB", "#1F2937"),
+            CategoryColor.Preset22 => new("#F3F4F6", "#111827"),
+            CategoryColor.Preset23 => new("#E2E8F0", "#334155"),
+            CategoryColor.Preset24 => new("#F8FAFC", "#475569"),
+            _ => new("#E5E7EB", "#374151")
+        };
+
+    private static CategoryColor GetOutlookCategoryColor(MailCategory category)
+        => (category.BackgroundColorHex?.ToUpperInvariant(), category.TextColorHex?.ToUpperInvariant()) switch
+        {
+            ("#FEE2E2", "#991B1B") => CategoryColor.Preset0,
+            ("#FFEDD5", "#9A3412") => CategoryColor.Preset1,
+            ("#FEF3C7", "#92400E") => CategoryColor.Preset2,
+            ("#ECFCCB", "#3F6212") => CategoryColor.Preset3,
+            ("#DCFCE7", "#166534") => CategoryColor.Preset4,
+            ("#CCFBF1", "#115E59") => CategoryColor.Preset5,
+            ("#CFFAFE", "#155E75") => CategoryColor.Preset6,
+            ("#DBEAFE", "#1D4ED8") => CategoryColor.Preset7,
+            ("#E0E7FF", "#4338CA") => CategoryColor.Preset8,
+            ("#F3E8FF", "#7E22CE") => CategoryColor.Preset9,
+            ("#FCE7F3", "#9D174D") => CategoryColor.Preset10,
+            ("#FECACA", "#7F1D1D") => CategoryColor.Preset11,
+            ("#FED7AA", "#7C2D12") => CategoryColor.Preset12,
+            ("#FDE68A", "#78350F") => CategoryColor.Preset13,
+            ("#D9F99D", "#365314") => CategoryColor.Preset14,
+            ("#BBF7D0", "#14532D") => CategoryColor.Preset15,
+            ("#99F6E4", "#134E4A") => CategoryColor.Preset16,
+            ("#A5F3FC", "#164E63") => CategoryColor.Preset17,
+            ("#BFDBFE", "#1E3A8A") => CategoryColor.Preset18,
+            ("#DDD6FE", "#5B21B6") => CategoryColor.Preset19,
+            _ => CategoryColor.Preset0
+        };
+
     private async Task TryMapCalendarInvitationAsync(MailCopy mailCopy, MimeMessage mimeMessage, CancellationToken cancellationToken)
     {
         if (mailCopy.ItemType != MailItemType.CalendarInvitation || mimeMessage == null)
@@ -2674,6 +2884,7 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
                 {
                     existingLocalCalendar.Name = calendar.Name;
                     existingLocalCalendar.IsPrimary = string.Equals(existingLocalCalendar.RemoteCalendarId, remotePrimaryCalendarId, StringComparison.OrdinalIgnoreCase);
+                    existingLocalCalendar.IsReadOnly = !calendar.CanEdit.GetValueOrDefault(true);
                     existingLocalCalendar.BackgroundColorHex = resolvedColor;
                     existingLocalCalendar.TextColorHex = ColorHelpers.GetReadableTextColorHex(existingLocalCalendar.BackgroundColorHex);
 
@@ -2712,12 +2923,14 @@ public class OutlookSynchronizer : WinoSynchronizer<RequestInformation, Message,
         var remoteCalendarName = calendar.Name;
         var remoteBackgroundColor = ResolveSynchronizedCalendarBackgroundColor(GetRemoteOutlookCalendarBackgroundColor(calendar), accountCalendar);
         var remoteIsPrimary = string.Equals(calendar.Id, remotePrimaryCalendarId, StringComparison.OrdinalIgnoreCase);
+        var remoteIsReadOnly = !calendar.CanEdit.GetValueOrDefault(true);
 
         bool isNameChanged = !string.Equals(accountCalendar.Name, remoteCalendarName, StringComparison.OrdinalIgnoreCase);
         bool isBackgroundColorChanged = !string.Equals(accountCalendar.BackgroundColorHex, remoteBackgroundColor, StringComparison.OrdinalIgnoreCase);
         bool isPrimaryChanged = accountCalendar.IsPrimary != remoteIsPrimary;
+        bool isReadOnlyChanged = accountCalendar.IsReadOnly != remoteIsReadOnly;
 
-        return isNameChanged || isBackgroundColorChanged || isPrimaryChanged;
+        return isNameChanged || isBackgroundColorChanged || isPrimaryChanged || isReadOnlyChanged;
     }
 
     private static string GetRemoteOutlookCalendarBackgroundColor(Calendar calendar)

Wino.Core/Synchronizers/WinoSynchronizer.cs

@@ -20,6 +20,7 @@ using Wino.Core.Domain.Models.MailItem;
 using Wino.Core.Domain.Models.Synchronization;
 using Wino.Core.Requests.Bundles;
 using Wino.Core.Requests.Calendar;
+using Wino.Core.Requests.Category;
 using Wino.Core.Requests.Folder;
 using Wino.Core.Requests.Mail;
 using Wino.Messaging.UI;
@@ -63,6 +64,7 @@ public abstract class WinoSynchronizer<TBaseRequest, TMessageType, TCalendarEven
     /// Only available for Gmail right now.
     /// </summary>
     protected virtual Task SynchronizeAliasesAsync() => Task.CompletedTask;
+    protected virtual Task SynchronizeCategoriesAsync(CancellationToken cancellationToken = default) => Task.CompletedTask;
 
     /// <summary>
     /// Queues all mail ids for initial synchronization for a specific folder.
@@ -194,6 +196,9 @@ public abstract class WinoSynchronizer<TBaseRequest, TMessageType, TCalendarEven
                             case MailSynchronizerOperation.Archive:
                                 nativeRequests.AddRange(Archive(new BatchArchiveRequest(group.Cast<ArchiveRequest>())));
                                 break;
+                            case MailSynchronizerOperation.UpdateCategories:
+                                nativeRequests.AddRange(UpdateCategories(new BatchMailCategoryAssignmentRequest(group.Cast<MailCategoryAssignmentRequest>())));
+                                break;
                             default:
                                 break;
                         }
@@ -221,6 +226,23 @@ public abstract class WinoSynchronizer<TBaseRequest, TMessageType, TCalendarEven
                                 break;
                         }
                     }
+                    else if (key is CategorySynchronizerOperation categorySynchronizerOperation)
+                    {
+                        switch (categorySynchronizerOperation)
+                        {
+                            case CategorySynchronizerOperation.CreateCategory:
+                                nativeRequests.AddRange(CreateCategory(group.ElementAt(0) as MailCategoryCreateRequest));
+                                break;
+                            case CategorySynchronizerOperation.UpdateCategory:
+                                nativeRequests.AddRange(UpdateCategory(group.ElementAt(0) as MailCategoryUpdateRequest));
+                                break;
+                            case CategorySynchronizerOperation.DeleteCategory:
+                                nativeRequests.AddRange(DeleteCategory(group.ElementAt(0) as MailCategoryDeleteRequest));
+                                break;
+                            default:
+                                break;
+                        }
+                    }
                 }
 
                 changeRequestQueue.Clear();
@@ -322,6 +344,30 @@ public abstract class WinoSynchronizer<TBaseRequest, TMessageType, TCalendarEven
                 }
             }
 
+            // Category definition sync.
+            if (options.Type == MailSynchronizationType.Categories)
+            {
+                if (!Account.IsCategorySyncSupported) return MailSynchronizationResult.Empty;
+
+                try
+                {
+                    await SynchronizeCategoriesAsync(activeSynchronizationCancellationToken);
+
+                    return FinalizeMailResult(MailSynchronizationResult.Empty);
+                }
+                catch (AuthenticationAttentionException)
+                {
+                    throw;
+                }
+                catch (Exception ex)
+                {
+                    Log.Error(ex, "Failed to update categories for {Name}", Account.Name);
+
+                    CaptureSynchronizationIssue(SynchronizationIssue.FromException(ex, "CategorySync"));
+                    return FinalizeMailResult(MailSynchronizationResult.Failed(ex));
+                }
+            }
+
             if (shouldDelayExecution)
             {
                 await Task.Delay(maxExecutionDelay);
@@ -526,6 +572,16 @@ public abstract class WinoSynchronizer<TBaseRequest, TMessageType, TCalendarEven
     /// <returns>New synchronization options with minimal HTTP effort.</returns>
     private MailSynchronizationOptions GetSynchronizationOptionsAfterRequestExecution(List<IRequestBase> requests, Guid existingSynchronizationId)
     {
+        if (requests.All(a => a is ICategoryActionRequest or MailCategoryAssignmentRequest))
+        {
+            return new MailSynchronizationOptions
+            {
+                AccountId = Account.Id,
+                Id = existingSynchronizationId,
+                Type = MailSynchronizationType.FoldersOnly
+            };
+        }
+
         List<Guid> synchronizationFolderIds = requests
                 .Where(a => a is ICustomFolderSynchronizationRequest)
                 .Cast<ICustomFolderSynchronizationRequest>()
@@ -602,6 +658,10 @@ public abstract class WinoSynchronizer<TBaseRequest, TMessageType, TCalendarEven
     public virtual List<IRequestBundle<TBaseRequest>> MarkFolderAsRead(MarkFolderAsReadRequest request) => throw new NotSupportedException(string.Format(Translator.Exception_UnsupportedSynchronizerOperation, this.GetType()));
     public virtual List<IRequestBundle<TBaseRequest>> DeleteFolder(DeleteFolderRequest request) => throw new NotSupportedException(string.Format(Translator.Exception_UnsupportedSynchronizerOperation, this.GetType()));
     public virtual List<IRequestBundle<TBaseRequest>> CreateSubFolder(CreateSubFolderRequest request) => throw new NotSupportedException(string.Format(Translator.Exception_UnsupportedSynchronizerOperation, this.GetType()));
+    public virtual List<IRequestBundle<TBaseRequest>> UpdateCategories(BatchMailCategoryAssignmentRequest request) => throw new NotSupportedException(string.Format(Translator.Exception_UnsupportedSynchronizerOperation, this.GetType()));
+    public virtual List<IRequestBundle<TBaseRequest>> CreateCategory(MailCategoryCreateRequest request) => throw new NotSupportedException(string.Format(Translator.Exception_UnsupportedSynchronizerOperation, this.GetType()));
+    public virtual List<IRequestBundle<TBaseRequest>> UpdateCategory(MailCategoryUpdateRequest request) => throw new NotSupportedException(string.Format(Translator.Exception_UnsupportedSynchronizerOperation, this.GetType()));
+    public virtual List<IRequestBundle<TBaseRequest>> DeleteCategory(MailCategoryDeleteRequest request) => throw new NotSupportedException(string.Format(Translator.Exception_UnsupportedSynchronizerOperation, this.GetType()));
 
     #endregion
 

Wino.Mail.ViewModels/AccountDetailsPageViewModel.cs

@@ -169,6 +169,10 @@ public partial class AccountDetailsPageViewModel : MailBaseViewModel
     private void EditAliases()
         => Messenger.Send(new BreadcrumbNavigationRequested(Translator.SettingsManageAliases_Title, WinoPage.AliasManagementPage, Account.Id));
 
+    [RelayCommand]
+    private void EditCategories()
+        => Messenger.Send(new BreadcrumbNavigationRequested(Translator.MailCategoryManagementPage_Title, WinoPage.MailCategoryManagementPage, Account.Id));
+
     [RelayCommand]
     private void EditImapCalDavSettings()
         => Messenger.Send(new BreadcrumbNavigationRequested(

Wino.Mail.ViewModels/AccountSetupProgressPageViewModel.cs

@@ -81,6 +81,10 @@ public partial class AccountSetupProgressPageViewModel : MailBaseViewModel
             Steps.Add(new AccountSetupStepModel { Title = Translator.AccountSetup_Step_FetchingProfile });
             Steps.Add(new AccountSetupStepModel { Title = Translator.AccountSetup_Step_SavingAccount });
             Steps.Add(new AccountSetupStepModel { Title = Translator.AccountSetup_Step_SyncingFolders });
+            if (WizardContext.SelectedProvider.Type == MailProviderType.Outlook)
+            {
+                Steps.Add(new AccountSetupStepModel { Title = Translator.AccountSetup_Step_SyncingCategories });
+            }
             Steps.Add(new AccountSetupStepModel { Title = Translator.AccountSetup_Step_FetchingCalendarMetadata });
             Steps.Add(new AccountSetupStepModel { Title = Translator.AccountSetup_Step_SyncingAliases });
             Steps.Add(new AccountSetupStepModel { Title = Translator.AccountSetup_Step_Finalizing });
@@ -229,6 +233,16 @@ public partial class AccountSetupProgressPageViewModel : MailBaseViewModel
                     throw new Exception(Translator.Exception_FailedToSynchronizeFolders);
                 SetCurrentStepSucceeded();
 
+                // Step: Categories
+                if (_createdAccount.IsCategorySyncSupported)
+                {
+                    SetStepInProgress(Translator.AccountSetup_Step_SyncingCategories);
+                    var categoryResult = await SynchronizationManager.Instance.SynchronizeCategoriesAsync(_createdAccount.Id);
+                    if (categoryResult.CompletedState != SynchronizationCompletedState.Success)
+                        throw new Exception(Translator.Exception_FailedToSynchronizeCategories);
+                    SetCurrentStepSucceeded();
+                }
+
                 // Step: Calendar metadata
                 SetStepInProgress(Translator.AccountSetup_Step_FetchingCalendarMetadata);
                 if (_createdAccount.IsCalendarAccessGranted)

Wino.Mail.ViewModels/MailAppShellViewModel.cs

@@ -73,6 +73,7 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
     public IMenuItem CreatePrimaryMenuItem => CreateMailMenuItem;
 
     private readonly IFolderService _folderService;
+    private readonly IMailCategoryService _mailCategoryService;
     private readonly IConfigurationService _configurationService;
     private readonly IStartupBehaviorService _startupBehaviorService;
     private readonly IAccountService _accountService;
@@ -99,6 +100,7 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
                              IMimeFileService mimeFileService,
                              INativeAppService nativeAppService,
                              IMailService mailService,
+                             IMailCategoryService mailCategoryService,
                              IAccountService accountService,
                              IContextMenuItemService contextMenuItemService,
                              IStoreRatingService storeRatingService,
@@ -125,6 +127,7 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
         _mimeFileService = mimeFileService;
         _nativeAppService = nativeAppService;
         _mailService = mailService;
+        _mailCategoryService = mailCategoryService;
         _folderService = folderService;
         _accountService = accountService;
         _contextMenuItemService = contextMenuItemService;
@@ -721,7 +724,8 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
         {
             await HandleCreateNewMailAsync();
         }
-        else if (clickedMenuItem is IBaseFolderMenuItem baseFolderMenuItem && baseFolderMenuItem.HandlingFolders.All(a => a.IsMoveTarget))
+        else if (clickedMenuItem is IBaseFolderMenuItem baseFolderMenuItem &&
+                 (clickedMenuItem is IMailCategoryMenuItem or IMergedMailCategoryMenuItem || baseFolderMenuItem.HandlingFolders.All(a => a.IsMoveTarget)))
         {
             // Don't navigate to base folders that contain non-move target folders.
             // Theory: This is a special folder like Categories or More. Don't navigate to it.
@@ -793,11 +797,20 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
     {
         // Get visible account menu items, ordered by merged accounts at the last.
         // We will update the unread counts for all single accounts and trigger UI refresh for merged menu items.
-        var accountMenuItems = MenuItems.GetAllAccountMenuItems().OrderBy(a => a.HoldingAccounts.Count());
+        List<IAccountMenuItem> accountMenuItems = null;
+
+        await ExecuteUIThread(() =>
+        {
+            accountMenuItems = MenuItems
+                .GetAllAccountMenuItems()
+                .OrderBy(a => a.HoldingAccounts.Count())
+                .ToList();
+        });
 
         // Individually get all single accounts' unread counts.
-        var accountIds = accountMenuItems.OfType<AccountMenuItem>().Select(a => a.AccountId);
+        var accountIds = accountMenuItems.OfType<AccountMenuItem>().Select(a => a.AccountId).ToList();
         var unreadCountResult = await _folderService.GetUnreadItemCountResultsAsync(accountIds).ConfigureAwait(false);
+        var unreadCategoryCountResult = await _mailCategoryService.GetUnreadCategoryCountResultsAsync(accountIds).ConfigureAwait(false);
 
         // Recursively update all folders' unread counts to 0.
         // Query above only returns unread counts that exists. We need to reset the rest to 0 first.
@@ -849,6 +862,29 @@ public partial class MailAppShellViewModel : MailBaseViewModel,
             }
         }
 
+        foreach (var unreadCategoryCount in unreadCategoryCountResult)
+        {
+            if (MenuItems.TryGetCategoryMenuItem(unreadCategoryCount.CategoryId, out var categoryMenuItem))
+            {
+                if (categoryMenuItem is IMergedMailCategoryMenuItem mergedCategoryMenuItem)
+                {
+                    await ExecuteUIThread(() =>
+                    {
+                        categoryMenuItem.UnreadItemCount = unreadCategoryCountResult
+                            .Where(a => mergedCategoryMenuItem.Categories.Any(b => b.Id == a.CategoryId))
+                            .Sum(a => a.UnreadItemCount);
+                    });
+                }
+                else
+                {
+                    await ExecuteUIThread(() =>
+                    {
+                        categoryMenuItem.UnreadItemCount = unreadCategoryCount.UnreadItemCount;
+                    });
+                }
+            }
+        }
+
         // Update unread badge after all unread counts are updated.
         await _notificationBuilder.UpdateTaskbarIconBadgeAsync();
     }

Wino.Mail.ViewModels/MailCategoryManagementPageViewModel.cs

@@ -0,0 +1,251 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Linq;
+using System.Threading.Tasks;
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+using Wino.Core.Domain;
+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.MailItem;
+using Wino.Core.Domain.Models.Navigation;
+using Wino.Core.Domain.Models.Synchronization;
+using Wino.Core.Requests.Category;
+using Wino.Core.Services;
+
+namespace Wino.Mail.ViewModels;
+
+public partial class MailCategoryManagementPageViewModel : MailBaseViewModel
+{
+    private readonly IMailCategoryService _mailCategoryService;
+    private readonly IAccountService _accountService;
+    private readonly IMailDialogService _dialogService;
+    private readonly IWinoRequestDelegator _winoRequestDelegator;
+
+    [ObservableProperty]
+    [NotifyPropertyChangedFor(nameof(CanRefresh))]
+    public partial MailAccount Account { get; set; }
+
+    public ObservableCollection<MailCategory> Categories { get; } = [];
+
+    public bool CanRefresh => Account?.ProviderType == MailProviderType.Outlook;
+    public bool HasCategories => Categories.Count > 0;
+
+    public MailCategoryManagementPageViewModel(
+        IMailCategoryService mailCategoryService,
+        IAccountService accountService,
+        IMailDialogService dialogService,
+        IWinoRequestDelegator winoRequestDelegator)
+    {
+        _mailCategoryService = mailCategoryService;
+        _accountService = accountService;
+        _dialogService = dialogService;
+        _winoRequestDelegator = winoRequestDelegator;
+    }
+
+    public override async void OnNavigatedTo(NavigationMode mode, object parameters)
+    {
+        base.OnNavigatedTo(mode, parameters);
+
+        if (parameters is not Guid accountId)
+            return;
+
+        Account = await _accountService.GetAccountAsync(accountId).ConfigureAwait(false);
+
+        if (Account != null)
+        {
+            await LoadCategoriesAsync().ConfigureAwait(false);
+        }
+    }
+
+    [RelayCommand]
+    private Task AddCategoryAsync()
+        => CreateOrUpdateCategoryAsync();
+
+    [RelayCommand]
+    private async Task RefreshCategoriesAsync()
+    {
+        if (!CanRefresh)
+            return;
+
+        var shouldContinue = await _dialogService.ShowConfirmationDialogAsync(
+            Translator.MailCategoryManagementPage_RefreshConfirmationMessage,
+            Translator.Buttons_Refresh,
+            Translator.Buttons_Refresh).ConfigureAwait(false);
+
+        if (!shouldContinue)
+            return;
+
+        await _mailCategoryService.DeleteCategoriesAsync(Account.Id).ConfigureAwait(false);
+        await SynchronizationManager.Instance.SynchronizeCategoriesAsync(Account.Id).ConfigureAwait(false);
+
+        await LoadCategoriesAsync().ConfigureAwait(false);
+    }
+
+    public Task EditCategoryAsync(MailCategory category)
+        => CreateOrUpdateCategoryAsync(category);
+
+    public async Task DeleteCategoryAsync(MailCategory category)
+    {
+        if (category == null)
+            return;
+
+        var shouldDelete = await _dialogService.ShowConfirmationDialogAsync(
+            string.Format(Translator.MailCategoryManagementPage_DeleteConfirmationMessage, category.Name),
+            Translator.MailCategoryManagementPage_DeleteConfirmationTitle,
+            Translator.Buttons_Delete).ConfigureAwait(false);
+
+        if (!shouldDelete)
+            return;
+
+        var deleteRequest = await BuildDeleteCategoryRequestAsync(category).ConfigureAwait(false);
+        await _mailCategoryService.DeleteCategoryAsync(category.Id).ConfigureAwait(false);
+        await QueueOutlookCategoryRequestsAsync(deleteRequest).ConfigureAwait(false);
+        await LoadCategoriesAsync().ConfigureAwait(false);
+    }
+
+    public async Task SetFavoriteAsync(MailCategory category, bool isFavorite)
+    {
+        if (category == null)
+            return;
+
+        await _mailCategoryService.ToggleFavoriteAsync(category.Id, isFavorite).ConfigureAwait(false);
+        await LoadCategoriesAsync().ConfigureAwait(false);
+    }
+
+    private async Task CreateOrUpdateCategoryAsync(MailCategory existingCategory = null)
+    {
+        var dialogResult = await _dialogService.ShowEditMailCategoryDialogAsync(existingCategory).ConfigureAwait(false);
+        if (dialogResult == null)
+            return;
+
+        if (string.IsNullOrWhiteSpace(dialogResult.Name))
+        {
+            await _dialogService.ShowMessageAsync(
+                Translator.MailCategoryDialog_InvalidNameMessage,
+                Translator.MailCategoryDialog_InvalidNameTitle,
+                WinoCustomMessageDialogIcon.Warning).ConfigureAwait(false);
+            return;
+        }
+
+        var normalizedName = dialogResult.Name.Trim();
+        var categoryIdToExclude = existingCategory?.Id;
+        var alreadyExists = await _mailCategoryService.CategoryNameExistsAsync(Account.Id, normalizedName, categoryIdToExclude).ConfigureAwait(false);
+
+        if (alreadyExists)
+        {
+            await _dialogService.ShowMessageAsync(
+                Translator.MailCategoryDialog_DuplicateMessage,
+                Translator.MailCategoryDialog_DuplicateTitle,
+                WinoCustomMessageDialogIcon.Warning).ConfigureAwait(false);
+            return;
+        }
+
+        if (existingCategory == null)
+        {
+            var newCategory = new MailCategory
+            {
+                Id = Guid.NewGuid(),
+                MailAccountId = Account.Id,
+                Name = normalizedName,
+                BackgroundColorHex = dialogResult.BackgroundColorHex,
+                TextColorHex = dialogResult.TextColorHex,
+                Source = Account.ProviderType == MailProviderType.Outlook ? MailCategorySource.Outlook : MailCategorySource.Local
+            };
+
+            await _mailCategoryService.CreateCategoryAsync(newCategory).ConfigureAwait(false);
+
+            if (Account.ProviderType == MailProviderType.Outlook)
+            {
+                await _winoRequestDelegator.ExecuteAsync(Account.Id, [new MailCategoryCreateRequest(newCategory)]).ConfigureAwait(false);
+            }
+        }
+        else
+        {
+            var previousName = existingCategory.Name;
+            var previousRemoteId = existingCategory.RemoteId;
+
+            existingCategory.Name = normalizedName;
+            existingCategory.BackgroundColorHex = dialogResult.BackgroundColorHex;
+            existingCategory.TextColorHex = dialogResult.TextColorHex;
+
+            await _mailCategoryService.UpdateCategoryAsync(existingCategory).ConfigureAwait(false);
+
+            if (Account.ProviderType == MailProviderType.Outlook)
+            {
+                if (string.IsNullOrWhiteSpace(previousRemoteId))
+                {
+                    await _winoRequestDelegator.ExecuteAsync(Account.Id, [new MailCategoryCreateRequest(existingCategory)]).ConfigureAwait(false);
+                }
+                else
+                {
+                    var affectedMessages = await BuildAffectedMessageTargetsAsync(existingCategory.Id).ConfigureAwait(false);
+                    var updateRequest = new MailCategoryUpdateRequest(existingCategory, previousName, previousRemoteId, affectedMessages);
+                    await _winoRequestDelegator.ExecuteAsync(Account.Id, [updateRequest]).ConfigureAwait(false);
+                }
+            }
+        }
+
+        await LoadCategoriesAsync().ConfigureAwait(false);
+    }
+
+    private async Task<MailCategoryDeleteRequest> BuildDeleteCategoryRequestAsync(MailCategory category)
+    {
+        if (category == null || Account?.ProviderType != MailProviderType.Outlook)
+            return null;
+
+        var mailCopies = await _mailCategoryService.GetMailCopiesForCategoryAsync(category.Id).ConfigureAwait(false);
+        var affectedMessages = new List<MailCategoryMessageUpdateTarget>();
+
+        foreach (var mailCopy in mailCopies.Where(a => !string.IsNullOrWhiteSpace(a.Id)))
+        {
+            var remainingNames = await _mailCategoryService.GetCategoryNamesForMailAsync(mailCopy.UniqueId).ConfigureAwait(false);
+            var categoryNames = remainingNames
+                .Where(a => !string.Equals(a, category.Name, StringComparison.OrdinalIgnoreCase))
+                .ToList();
+
+            affectedMessages.Add(new MailCategoryMessageUpdateTarget(mailCopy.Id, categoryNames));
+        }
+
+        return new MailCategoryDeleteRequest(category, category.RemoteId, affectedMessages);
+    }
+
+    private async Task<IReadOnlyList<MailCategoryMessageUpdateTarget>> BuildAffectedMessageTargetsAsync(Guid categoryId)
+    {
+        var mailCopies = await _mailCategoryService.GetMailCopiesForCategoryAsync(categoryId).ConfigureAwait(false);
+        var affectedMessages = new List<MailCategoryMessageUpdateTarget>();
+
+        foreach (var mailCopy in mailCopies.Where(a => !string.IsNullOrWhiteSpace(a.Id)))
+        {
+            var categoryNames = await _mailCategoryService.GetCategoryNamesForMailAsync(mailCopy.UniqueId).ConfigureAwait(false);
+            affectedMessages.Add(new MailCategoryMessageUpdateTarget(mailCopy.Id, categoryNames));
+        }
+
+        return affectedMessages;
+    }
+
+    private Task QueueOutlookCategoryRequestsAsync(params IRequestBase[] requests)
+        => Account?.ProviderType == MailProviderType.Outlook && requests.Any(a => a != null)
+            ? _winoRequestDelegator.ExecuteAsync(Account.Id, requests.Where(a => a != null))
+            : Task.CompletedTask;
+
+    private async Task LoadCategoriesAsync()
+    {
+        var categories = await _mailCategoryService.GetCategoriesAsync(Account.Id).ConfigureAwait(false);
+
+        await ExecuteUIThread(() =>
+        {
+            Categories.Clear();
+
+            foreach (var category in categories)
+            {
+                Categories.Add(category);
+            }
+
+            OnPropertyChanged(nameof(HasCategories));
+        });
+    }
+}

Wino.Mail.ViewModels/MailListPageViewModel.cs

@@ -24,6 +24,7 @@ using Wino.Core.Domain.Models.Menus;
 using Wino.Core.Domain.Models.Navigation;
 using Wino.Core.Domain.Models.Reader;
 using Wino.Core.Domain.Models.Synchronization;
+using Wino.Core.Requests.Mail;
 using Wino.Core.Services;
 using Wino.Mail.ViewModels.Collections;
 using Wino.Mail.ViewModels.Data;
@@ -77,6 +78,7 @@ public partial class MailListPageViewModel : MailBaseViewModel,
     private readonly INotificationBuilder _notificationBuilder;
     private readonly IFolderService _folderService;
     private readonly IContextMenuItemService _contextMenuItemService;
+    private readonly IMailCategoryService _mailCategoryService;
     private readonly IWinoRequestDelegator _winoRequestDelegator;
     private readonly IKeyPressService _keyPressService;
     private readonly IWinoLogger _winoLogger;
@@ -156,6 +158,8 @@ public partial class MailListPageViewModel : MailBaseViewModel,
     [ObservableProperty]
     [NotifyPropertyChangedFor(nameof(CanSynchronize))]
     [NotifyPropertyChangedFor(nameof(IsFolderSynchronizationEnabled))]
+    [NotifyPropertyChangedFor(nameof(IsCategoryView))]
+    [NotifyPropertyChangedFor(nameof(IsSyncButtonVisible))]
     public partial IBaseFolderMenuItem ActiveFolder { get; set; }
 
     [ObservableProperty]
@@ -172,6 +176,7 @@ public partial class MailListPageViewModel : MailBaseViewModel,
                                  INotificationBuilder notificationBuilder,
                                  IFolderService folderService,
                                  IContextMenuItemService contextMenuItemService,
+                                 IMailCategoryService mailCategoryService,
                                  IWinoRequestDelegator winoRequestDelegator,
                                  IKeyPressService keyPressService,
                                  IPreferencesService preferencesService,
@@ -185,6 +190,7 @@ public partial class MailListPageViewModel : MailBaseViewModel,
         _mimeFileService = mimeFileService;
         _folderService = folderService;
         _contextMenuItemService = contextMenuItemService;
+        _mailCategoryService = mailCategoryService;
         _winoRequestDelegator = winoRequestDelegator;
         _keyPressService = keyPressService;
 
@@ -277,9 +283,11 @@ public partial class MailListPageViewModel : MailBaseViewModel,
         }
     }
 
-    public bool CanSynchronize => !IsAccountSynchronizerInSynchronization && IsFolderSynchronizationEnabled;
+    public bool CanSynchronize => !IsCategoryView && !IsAccountSynchronizerInSynchronization && IsFolderSynchronizationEnabled;
     public bool IsFolderSynchronizationEnabled => ActiveFolder?.IsSynchronizationEnabled ?? false;
     public bool IsArchiveSpecialFolder => ActiveFolder?.SpecialFolderType == SpecialFolderType.Archive;
+    public bool IsCategoryView => ActiveFolder is IMailCategoryMenuItem or IMergedMailCategoryMenuItem;
+    public bool IsSyncButtonVisible => !IsCategoryView;
 
     public string SelectedMessageText => IsDragInProgress
         ? string.Format(Translator.MailsDragging, DraggingItemsCount)
@@ -396,9 +404,12 @@ public partial class MailListPageViewModel : MailBaseViewModel,
         }
         else
         {
+            if (IsCategoryView)
+            {
+                PivotFolders.Add(new FolderPivotViewModel(ActiveFolder.FolderName, null));
+            }
             // Merged folders don't support focused feature.
-
+            else if (ActiveFolder is IMergedAccountFolderMenuItem)
-            if (ActiveFolder is IMergedAccountFolderMenuItem)
             {
                 PivotFolders.Add(new FolderPivotViewModel(ActiveFolder.FolderName, null));
             }
@@ -545,7 +556,7 @@ public partial class MailListPageViewModel : MailBaseViewModel,
     [RelayCommand]
     private async Task EnableFolderSynchronizationAsync()
     {
-        if (ActiveFolder == null) return;
+        if (ActiveFolder == null || IsCategoryView) return;
 
         foreach (var folder in ActiveFolder.HandlingFolders)
         {
@@ -561,13 +572,9 @@ public partial class MailListPageViewModel : MailBaseViewModel,
         Debug.WriteLine("Loading more...");
         await ExecuteUIThread(() => { IsInitializingFolder = true; });
 
-        var initializationOptions = new MailListInitializationOptions(ActiveFolder.HandlingFolders,
+        var initializationOptions = CreateInitializationOptions(
-                                                                      SelectedFilterOption.Type,
+            IsInSearchMode ? SearchQuery : string.Empty,
-                                                                      SelectedSortingOption.Type,
+            MailCollection.MailCopyIdHashSet);
-                                                                      PreferencesService.IsThreadingEnabled,
-                                                                      SelectedFolderPivot.IsFocused,
-                                                                      IsInSearchMode ? SearchQuery : string.Empty,
-                                                                      MailCollection.MailCopyIdHashSet);
 
         var items = await _mailService.FetchMailsAsync(initializationOptions).ConfigureAwait(false);
 
@@ -674,6 +681,60 @@ public partial class MailListPageViewModel : MailBaseViewModel,
     public IEnumerable<MailOperationMenuItem> GetAvailableMailActions(IEnumerable<MailItemViewModel> contextMailItems)
         => _contextMenuItemService.GetMailItemContextMenuActions(contextMailItems.Select(a => a.MailCopy));
 
+    public async Task<(IReadOnlyList<MailCategory> Categories, IReadOnlyCollection<Guid> AssignedCategoryIds)> GetAvailableCategoriesAsync(IEnumerable<MailItemViewModel> targetItems)
+    {
+        var targetList = targetItems?.Where(a => a?.MailCopy?.AssignedAccount != null).ToList() ?? [];
+        if (targetList.Count == 0)
+            return ([], []);
+
+        var accountIds = targetList.Select(a => a.MailCopy.AssignedAccount.Id).Distinct().ToList();
+        if (accountIds.Count != 1)
+            return ([], []);
+
+        var accountId = accountIds[0];
+        var uniqueIds = targetList.Select(a => a.MailCopy.UniqueId).Distinct().ToList();
+
+        var categories = await _mailCategoryService.GetCategoriesAsync(accountId).ConfigureAwait(false);
+        var assignedCategoryIds = await _mailCategoryService.GetAssignedCategoryIdsForAllAsync(uniqueIds).ConfigureAwait(false);
+
+        return (categories, assignedCategoryIds);
+    }
+
+    public async Task ToggleCategoryAssignmentAsync(MailCategory category, IEnumerable<MailItemViewModel> targetItems, bool isAssignedToAll)
+    {
+        var targetList = targetItems?.Where(a => a?.MailCopy?.AssignedAccount != null).ToList() ?? [];
+        if (category == null || targetList.Count == 0)
+            return;
+
+        var accountIds = targetList.Select(a => a.MailCopy.AssignedAccount.Id).Distinct().ToList();
+        if (accountIds.Count != 1)
+            return;
+
+        var accountId = accountIds[0];
+        var uniqueIds = targetList.Select(a => a.MailCopy.UniqueId).Distinct().ToList();
+
+        if (isAssignedToAll)
+        {
+            await _mailCategoryService.UnassignCategoryAsync(category.Id, uniqueIds).ConfigureAwait(false);
+        }
+        else
+        {
+            await _mailCategoryService.AssignCategoryAsync(category.Id, uniqueIds).ConfigureAwait(false);
+        }
+
+        if (targetList.First().MailCopy.AssignedAccount.ProviderType != MailProviderType.Outlook)
+            return;
+
+        var requests = new List<IRequestBase>();
+        foreach (var mailItem in targetList.Select(a => a.MailCopy).DistinctBy(a => a.UniqueId))
+        {
+            var categoryNames = await _mailCategoryService.GetCategoryNamesForMailAsync(mailItem.UniqueId).ConfigureAwait(false);
+            requests.Add(new MailCategoryAssignmentRequest(mailItem, category.Id, category.Name, categoryNames, !isAssignedToAll));
+        }
+
+        await _winoRequestDelegator.ExecuteAsync(accountId, requests).ConfigureAwait(false);
+    }
+
     private bool ShouldPreventItemAdd(MailCopy mailItem)
     {
         bool condition = mailItem.IsRead
@@ -691,7 +752,7 @@ public partial class MailListPageViewModel : MailBaseViewModel,
         => ActiveFolder?.SpecialFolderType == SpecialFolderType.Draft;
 
     private bool BelongsToActiveFolder(MailCopy mailItem)
-        => mailItem?.AssignedFolder != null && ActiveFolder?.HandlingFolders?.Any(a => a.Id == mailItem.AssignedFolder.Id) == true;
+        => !IsCategoryView && mailItem?.AssignedFolder != null && ActiveFolder?.HandlingFolders?.Any(a => a.Id == mailItem.AssignedFolder.Id) == true;
 
     private bool ShouldIncludeByThread(MailCopy mailItem)
         => PreferencesService.IsThreadingEnabled
@@ -1069,6 +1130,38 @@ public partial class MailListPageViewModel : MailBaseViewModel,
         }
     }
 
+    private MailListInitializationOptions CreateInitializationOptions(
+        string searchQuery,
+        System.Collections.Concurrent.ConcurrentDictionary<Guid, bool> existingUniqueIds,
+        List<MailCopy> preFetchedMailCopies = null,
+        bool deduplicateByServerId = false)
+    {
+        var options = new MailListInitializationOptions(ActiveFolder.HandlingFolders,
+                                                        SelectedFilterOption.Type,
+                                                        SelectedSortingOption.Type,
+                                                        PreferencesService.IsThreadingEnabled,
+                                                        SelectedFolderPivot.IsFocused,
+                                                        searchQuery,
+                                                        existingUniqueIds,
+                                                        preFetchedMailCopies,
+                                                        DeduplicateByServerId: deduplicateByServerId);
+
+        if (!IsCategoryView)
+            return options;
+
+        var categoryIds = ActiveFolder switch
+        {
+            IMailCategoryMenuItem singleCategoryMenuItem => new List<Guid> { singleCategoryMenuItem.MailCategory.Id },
+            IMergedMailCategoryMenuItem mergedCategoryMenuItem => mergedCategoryMenuItem.Categories.Select(a => a.Id).ToList(),
+            _ => []
+        };
+
+        return options with
+        {
+            CategoryIds = categoryIds
+        };
+    }
+
     [RelayCommand]
     private async Task PerformOnlineSearchAsync()
     {
@@ -1218,15 +1311,11 @@ public partial class MailListPageViewModel : MailBaseViewModel,
                 }
             }
 
-            var initializationOptions = new MailListInitializationOptions(ActiveFolder.HandlingFolders,
+            var initializationOptions = CreateInitializationOptions(
-                                                                          SelectedFilterOption.Type,
+                isDoingOnlineSearch ? string.Empty : SearchQuery,
-                                                                          SelectedSortingOption.Type,
+                MailCollection.MailCopyIdHashSet,
-                                                                          PreferencesService.IsThreadingEnabled,
+                onlineSearchItems,
-                                                                          SelectedFolderPivot.IsFocused,
+                isDoingOnlineSearch);
-                                                                          isDoingOnlineSearch ? string.Empty : SearchQuery,
-                                                                          MailCollection.MailCopyIdHashSet,
-                                                                          onlineSearchItems,
-                                                                          DeduplicateByServerId: isDoingOnlineSearch);
 
             items = await _mailService.FetchMailsAsync(initializationOptions, cancellationToken).ConfigureAwait(false);
 

Wino.Mail.WinUI/Activation/ToastActivationResolver.cs

@@ -1,4 +1,4 @@
-using System;
+using Microsoft.Windows.AppNotifications;
 using Wino.Core.Domain;
 using Wino.Core.Domain.Enums;
 
@@ -49,31 +49,8 @@ internal static class ToastActivationResolver
         return true;
     }
 
-    public static bool TryResolveMode(NotificationArguments toastArguments, out WinoApplicationMode mode)
-    {
-        mode = WinoApplicationMode.Mail;
-
-        if (!toastArguments.TryGetValue(Constants.ToastModeKey, out string toastMode))
-            return false;
-
-        if (string.Equals(toastMode, Constants.ToastModeCalendar, StringComparison.OrdinalIgnoreCase))
-        {
-            mode = WinoApplicationMode.Calendar;
-            return true;
-        }
-
-        if (string.Equals(toastMode, Constants.ToastModeMail, StringComparison.OrdinalIgnoreCase))
-        {
-            mode = WinoApplicationMode.Mail;
-            return true;
-        }
-
-        return false;
-    }
-
     private static bool ContainsKnownToastKey(NotificationArguments toastArguments)
         => toastArguments.TryGetValue(Constants.ToastStoreUpdateActionKey, out string _) ||
-           toastArguments.TryGetValue(Constants.ToastModeKey, out string _) ||
            toastArguments.TryGetValue(Constants.ToastCalendarActionKey, out string _) ||
            toastArguments.TryGetValue(Constants.ToastActionKey, out string _);
 }

Wino.Mail.WinUI/App.xaml.cs

@@ -4,8 +4,8 @@ using System.Collections.Generic;
 using System.IO;
 using System.Linq;
 using System.Text;
-using System.Threading;
 using System.Threading.Tasks;
+using System.Threading;
 using CommunityToolkit.Mvvm.Messaging;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.UI.Dispatching;
@@ -16,6 +16,7 @@ using Microsoft.Windows.AppNotifications;
 using MimeKit.Cryptography;
 using Windows.ApplicationModel.Activation;
 using Windows.ApplicationModel.DataTransfer;
+using Windows.ApplicationModel.DataTransfer.ShareTarget;
 using Windows.Storage;
 using Wino.Calendar.ViewModels;
 using Wino.Calendar.ViewModels.Interfaces;
@@ -363,6 +364,7 @@ public partial class App : WinoApplication,
         services.AddTransient(typeof(StoragePageViewModel));
         services.AddTransient(typeof(WinoAccountManagementPageViewModel));
         services.AddTransient(typeof(AliasManagementPageViewModel));
+        services.AddTransient(typeof(MailCategoryManagementPageViewModel));
         services.AddTransient(typeof(ContactsPageViewModel));
         services.AddTransient(typeof(SignatureAndEncryptionPageViewModel));
         services.AddTransient(typeof(EmailTemplatesPageViewModel));
@@ -542,20 +544,23 @@ public partial class App : WinoApplication,
     {
         var activationArgs = AppInstance.GetCurrent().GetActivatedEventArgs();
 
-        if (activationArgs.Kind == ExtendedActivationKind.Launch &&
+        if (activationArgs.Kind != ExtendedActivationKind.AppNotification ||
-            activationArgs.Data is ILaunchActivatedEventArgs launchArgs &&
+            activationArgs.Data is not AppNotificationActivatedEventArgs toastArgs ||
-            ToastActivationResolver.TryParse(launchArgs.Arguments, out var launchToastArguments) &&
+            !TryMarkInitialNotificationActivationHandled())
-            TryMarkInitialNotificationActivationHandled())
         {
-            LogActivation($"Processing initial toast launch activation from application startup. Arguments: {launchArgs.Arguments}");
+            return;
-
-            await EnsureActivationInfrastructureAsync();
-            await HandleToastActivationAsync(launchToastArguments);
         }
+
+        LogActivation($"Processing initial notification activation from application startup. Arguments: {toastArgs.Argument}");
+
+        await EnsureActivationInfrastructureAsync();
+        await HandleToastActivationAsync(toastArgs.Argument, toastArgs.UserInput);
     }
 
     private void AppNotificationInvoked(AppNotificationManager sender, AppNotificationActivatedEventArgs args)
     {
+        // AppNotification callbacks are not guaranteed to run on the UI thread.
+        // Marshal toast handling to the window dispatcher before touching window APIs.
         if (MainWindow?.DispatcherQueue?.TryEnqueue(() => _ = HandleToastActivationAsync(args.Argument, args.UserInput)) == true)
             return;
 
@@ -565,7 +570,19 @@ public partial class App : WinoApplication,
 
     private void TryRegisterAppNotifications()
     {
-        // Classic targeted toasts use normal launch activation instead of COM toast activators.
+        var notificationManager = AppNotificationManager.Default;
+
+        notificationManager.NotificationInvoked -= AppNotificationInvoked;
+        notificationManager.NotificationInvoked += AppNotificationInvoked;
+
+        try
+        {
+            notificationManager.Register();
+        }
+        catch (Exception ex)
+        {
+            LogActivation($"App notification registration failed: {ex.GetType().Name} - {ex.Message}");
+        }
     }
 
     /// <summary>
@@ -595,7 +612,7 @@ public partial class App : WinoApplication,
 
             if (calendarAction == Constants.ToastCalendarSnoozeAction)
             {
-                await HandleCalendarToastSnoozeAsync(toastArguments, userInput, calendarItemId);
+                await HandleCalendarToastSnoozeAsync(userInput, calendarItemId);
                 return;
             }
 
@@ -640,26 +657,6 @@ public partial class App : WinoApplication,
         return HandleToastActivationAsync(toastArguments, userInput);
     }
 
-    private static int? GetToastSnoozeDurationMinutes(NotificationArguments toastArguments, IDictionary<string, string>? userInput)
-    {
-        if (toastArguments.TryGetValue(Constants.ToastCalendarSnoozeDurationMinutesKey, out var snoozeDurationValue) &&
-            int.TryParse(snoozeDurationValue, out var snoozeDurationMinutes) &&
-            snoozeDurationMinutes > 0)
-        {
-            return snoozeDurationMinutes;
-        }
-
-        if (userInput != null &&
-            userInput.TryGetValue(Constants.ToastCalendarSnoozeDurationInputId, out var selectedValue) &&
-            int.TryParse(selectedValue, out snoozeDurationMinutes) &&
-            snoozeDurationMinutes > 0)
-        {
-            return snoozeDurationMinutes;
-        }
-
-        return null;
-    }
-
     private async Task<bool> HandleShareTargetActivationAsync(AppActivationArguments activationArgs, bool activateWindow)
     {
         if (activationArgs.Kind != ExtendedActivationKind.ShareTarget ||
@@ -814,59 +811,9 @@ public partial class App : WinoApplication,
         navigationService.Navigate(WinoPage.EventDetailsPage, target);
     }
 
-    private async Task<object?> TryCreateToastNavigationParameterAsync(NotificationArguments toastArguments)
+    private async Task HandleCalendarToastSnoozeAsync(IDictionary<string, string>? userInput, Guid calendarItemId)
     {
-        if (toastArguments.TryGetValue(Constants.ToastCalendarActionKey, out string calendarAction) &&
+        if (!TryGetSnoozeDurationMinutes(userInput, out var snoozeDurationMinutes))
-            calendarAction == Constants.ToastCalendarNavigateAction &&
-            toastArguments.TryGetValue(Constants.ToastCalendarItemIdKey, out string calendarItemIdString) &&
-            Guid.TryParse(calendarItemIdString, out Guid calendarItemId))
-        {
-            var calendarService = Services.GetRequiredService<ICalendarService>();
-            var calendarItem = await calendarService.GetCalendarItemAsync(calendarItemId);
-
-            if (calendarItem != null)
-            {
-                return new CalendarItemTarget(calendarItem, CalendarEventTargetType.Single);
-            }
-        }
-
-        return null;
-    }
-
-    private async Task<(WinoApplicationMode Mode, object? Parameter)?> TryResolveToastActivationTargetAsync(AppActivationArguments activationArgs)
-    {
-        NotificationArguments? toastArguments = null;
-
-        if (activationArgs.Kind == ExtendedActivationKind.Launch &&
-            activationArgs.Data is ILaunchActivatedEventArgs launchArgs &&
-            ToastActivationResolver.TryParse(launchArgs.Arguments, out var launchToastArguments))
-        {
-            toastArguments = launchToastArguments;
-        }
-        else if (activationArgs.Kind == ExtendedActivationKind.AppNotification &&
-                 activationArgs.Data is AppNotificationActivatedEventArgs appNotificationArgs &&
-                 ToastActivationResolver.TryParse(appNotificationArgs.Argument, out var appNotificationToastArguments))
-        {
-            toastArguments = appNotificationToastArguments;
-        }
-        else if (activationArgs.Data is ToastNotificationActivatedEventArgs classicToastArgs &&
-                 ToastActivationResolver.TryParse(classicToastArgs.Argument, out var classicToastArguments))
-        {
-            toastArguments = classicToastArguments;
-        }
-
-        if (toastArguments == null ||
-            !ToastActivationResolver.TryResolveMode(toastArguments, out var mode))
-        {
-            return null;
-        }
-
-        return (mode, await TryCreateToastNavigationParameterAsync(toastArguments));
-    }
-
-    private async Task HandleCalendarToastSnoozeAsync(NotificationArguments toastArguments, IDictionary<string, string>? userInput, Guid calendarItemId)
-    {
-        if (!TryGetSnoozeDurationMinutes(toastArguments, userInput, out var snoozeDurationMinutes))
             return;
 
         var calendarService = Services.GetRequiredService<ICalendarService>();
@@ -890,13 +837,20 @@ public partial class App : WinoApplication,
         await nativeAppService.LaunchUriAsync(joinUri);
     }
 
-    private bool TryGetSnoozeDurationMinutes(NotificationArguments toastArguments, IDictionary<string, string>? userInput, out int snoozeDurationMinutes)
+    private bool TryGetSnoozeDurationMinutes(IDictionary<string, string>? userInput, out int snoozeDurationMinutes)
     {
-        snoozeDurationMinutes = GetToastSnoozeDurationMinutes(toastArguments, userInput)
+        snoozeDurationMinutes = _preferencesService?.DefaultSnoozeDurationInMinutes ?? 0;
-                                ?? _preferencesService?.DefaultSnoozeDurationInMinutes
-                                ?? 0;
 
-        return snoozeDurationMinutes > 0;
+        if (userInput == null ||
+            !userInput.TryGetValue(Constants.ToastCalendarSnoozeDurationInputId, out var selectedValue) ||
+            selectedValue == null)
+        {
+            return snoozeDurationMinutes > 0;
+        }
+
+        var selectedText = selectedValue.ToString();
+
+        return int.TryParse(selectedText, out snoozeDurationMinutes) && snoozeDurationMinutes > 0;
     }
 
     /// <summary>
@@ -1368,6 +1322,7 @@ public partial class App : WinoApplication,
         return synchronizationType switch
         {
             MailSynchronizationType.Alias => Translator.Exception_FailedToSynchronizeAliases,
+            MailSynchronizationType.Categories => Translator.Exception_FailedToSynchronizeCategories,
             MailSynchronizationType.UpdateProfile => Translator.Exception_FailedToSynchronizeProfileInformation,
             _ => Translator.Exception_FailedToSynchronizeFolders
         };
@@ -1631,22 +1586,7 @@ public partial class App : WinoApplication,
                     }
                     else if (TryResolveActivationMode(args, _preferencesService?.DefaultApplicationMode ?? WinoApplicationMode.Mail, out var redirectedMode))
                     {
-                        var navigationService = Services.GetRequiredService<INavigationService>();
+                        shellWindow.HandleAppActivation(AppEntryConstants.GetModeLaunchArgument(redirectedMode));
-                        var toastActivationTarget = await TryResolveToastActivationTargetAsync(args);
-
-                        if (toastActivationTarget is { Parameter: CalendarItemTarget calendarTarget })
-                        {
-                            navigationService.ChangeApplicationMode(toastActivationTarget.Value.Mode, new ShellModeActivationContext
-                            {
-                                SuppressStartupFlows = true,
-                                Parameter = calendarTarget
-                            });
-                            navigationService.Navigate(WinoPage.EventDetailsPage, calendarTarget);
-                        }
-                        else
-                        {
-                            shellWindow.HandleAppActivation(AppEntryConstants.GetModeLaunchArgument(redirectedMode));
-                        }
                     }
                 }
 
@@ -1659,6 +1599,7 @@ public partial class App : WinoApplication,
             }
         }
 
+        // Dispatch to UI thread since this is called from Program.OnActivated.
         if (MainWindow?.DispatcherQueue.TryEnqueue(() => _ = HandleRedirectedActivationAsync()) == true)
             return;
 
@@ -1703,13 +1644,6 @@ public partial class App : WinoApplication,
             return true;
         }
 
-        if (activationArgs.Data is ToastNotificationActivatedEventArgs classicToastArgs &&
-            ToastActivationResolver.TryParse(classicToastArgs.Argument, out var classicToastArguments) &&
-            ToastActivationResolver.TryResolveMode(classicToastArguments, out mode))
-        {
-            return true;
-        }
-
         if (activationArgs.Kind == ExtendedActivationKind.File &&
             activationArgs.Data is IFileActivatedEventArgs fileArgs)
         {

Wino.Mail.WinUI/Controls/WebViewEditorControl.cs

@@ -296,12 +296,18 @@ public sealed partial class WebViewEditorControl : Control, IDisposable, IEditor
             return;
         }
 
+        if (focusControlAsWell)
+        {
+            Focus(FocusState.Programmatic);
+            _chromium.Focus(FocusState.Programmatic);
+            _chromium.Focus(FocusState.Keyboard);
+        }
+
         await _chromium.ExecuteScriptSafeAsync("focusEditor();");
 
         if (focusControlAsWell)
         {
             _chromium.Focus(FocusState.Keyboard);
-            _chromium.Focus(FocusState.Programmatic);
         }
     }
 

Wino.Mail.WinUI/Dialogs/EditMailCategoryDialog.xaml

@@ -0,0 +1,60 @@
+<ContentDialog
+    x:Class="Wino.Dialogs.EditMailCategoryDialog"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:domain="using:Wino.Core.Domain"
+    xmlns:helpers="using:Wino.Helpers"
+    xmlns:mailModels="using:Wino.Core.Domain.Models.MailItem"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    DefaultButton="Primary"
+    PrimaryButtonClick="SaveClicked"
+    PrimaryButtonText="{x:Bind domain:Translator.Buttons_Save, Mode=OneTime}"
+    SecondaryButtonClick="CancelClicked"
+    SecondaryButtonText="{x:Bind domain:Translator.Buttons_Cancel, Mode=OneTime}"
+    Style="{StaticResource WinoDialogStyle}"
+    mc:Ignorable="d">
+
+    <ContentDialog.Resources>
+        <x:Double x:Key="ContentDialogMinWidth">520</x:Double>
+        <x:Double x:Key="ContentDialogMaxWidth">520</x:Double>
+    </ContentDialog.Resources>
+
+    <StackPanel Spacing="16">
+        <TextBox
+            x:Name="CategoryNameTextBox"
+            Header="{x:Bind domain:Translator.MailCategoryDialog_Name, Mode=OneTime}"
+            PlaceholderText="{x:Bind domain:Translator.MailCategoryDialog_NamePlaceholder, Mode=OneTime}"
+            Text="{x:Bind CategoryName, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
+            TextChanged="CategoryNameTextChanged" />
+
+        <StackPanel Spacing="8">
+            <TextBlock Style="{StaticResource BodyStrongTextBlockStyle}" Text="{x:Bind domain:Translator.MailCategoryDialog_Color, Mode=OneTime}" />
+
+            <GridView
+                x:Name="ColorsGridView"
+                IsItemClickEnabled="True"
+                ItemClick="ColorOptionClicked"
+                ItemsSource="{x:Bind AvailableColors, Mode=OneWay}"
+                SelectedItem="{x:Bind SelectedColor, Mode=TwoWay}"
+                SelectionMode="Single">
+                <GridView.ItemTemplate>
+                    <DataTemplate x:DataType="mailModels:MailCategoryColorOption">
+                        <Border
+                            Width="100"
+                            Padding="8,6"
+                            Background="{x:Bind helpers:XamlHelpers.GetSolidColorBrushFromHex(BackgroundColorHex), Mode=OneWay}"
+                            BorderBrush="{x:Bind helpers:XamlHelpers.GetSolidColorBrushFromHex(TextColorHex), Mode=OneWay}"
+                            BorderThickness="1"
+                            CornerRadius="10">
+                            <TextBlock
+                                HorizontalAlignment="Center"
+                                Foreground="{x:Bind helpers:XamlHelpers.GetSolidColorBrushFromHex(TextColorHex), Mode=OneWay}"
+                                Text="Preview" />
+                        </Border>
+                    </DataTemplate>
+                </GridView.ItemTemplate>
+            </GridView>
+        </StackPanel>
+    </StackPanel>
+</ContentDialog>

Wino.Mail.WinUI/Dialogs/EditMailCategoryDialog.xaml.cs

@@ -0,0 +1,59 @@
+using System.Linq;
+using Microsoft.UI.Xaml.Controls;
+using Wino.Core.Domain;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Models.MailItem;
+
+namespace Wino.Dialogs;
+
+public sealed partial class EditMailCategoryDialog : ContentDialog
+{
+    public MailCategoryDialogResult? Result { get; private set; }
+    public string CategoryName { get; set; }
+    public MailCategoryColorOption? SelectedColor { get; set; }
+
+    public System.Collections.Generic.IReadOnlyList<MailCategoryColorOption> AvailableColors => MailCategoryPalette.DefaultOptions;
+
+    public EditMailCategoryDialog(MailCategory? category = null)
+    {
+        InitializeComponent();
+
+        Title = category == null ? Translator.MailCategoryDialog_CreateTitle : Translator.MailCategoryDialog_EditTitle;
+        CategoryName = category?.Name ?? string.Empty;
+        SelectedColor = MailCategoryPalette.DefaultOptions.FirstOrDefault(a =>
+            a.BackgroundColorHex == category?.BackgroundColorHex &&
+            a.TextColorHex == category?.TextColorHex) ?? MailCategoryPalette.DefaultOptions.First();
+
+        IsPrimaryButtonEnabled = !string.IsNullOrWhiteSpace(CategoryName);
+    }
+
+    private void CategoryNameTextChanged(object sender, TextChangedEventArgs e)
+        => IsPrimaryButtonEnabled = !string.IsNullOrWhiteSpace(CategoryNameTextBox.Text) && SelectedColor != null;
+
+    private void ColorOptionClicked(object sender, ItemClickEventArgs e)
+    {
+        if (e.ClickedItem is MailCategoryColorOption option)
+        {
+            SelectedColor = option;
+            ColorsGridView.SelectedItem = option;
+            IsPrimaryButtonEnabled = !string.IsNullOrWhiteSpace(CategoryNameTextBox.Text);
+        }
+    }
+
+    private void SaveClicked(ContentDialog sender, ContentDialogButtonClickEventArgs args)
+    {
+        if (SelectedColor == null)
+        {
+            args.Cancel = true;
+            return;
+        }
+
+        Result = new MailCategoryDialogResult(CategoryNameTextBox.Text?.Trim(), SelectedColor.BackgroundColorHex, SelectedColor.TextColorHex);
+        Hide();
+    }
+
+    private void CancelClicked(ContentDialog sender, ContentDialogButtonClickEventArgs args)
+    {
+        Hide();
+    }
+}

Wino.Mail.WinUI/Package.appxmanifest

@@ -6,8 +6,10 @@
   xmlns:uap="http://schemas.microsoft.com/appx/manifest/uap/windows10"
   xmlns:uap5="http://schemas.microsoft.com/appx/manifest/uap/windows10/5"
   xmlns:uap10="http://schemas.microsoft.com/appx/manifest/uap/windows10/10"
+  xmlns:com="http://schemas.microsoft.com/appx/manifest/com/windows10"
+  xmlns:desktop="http://schemas.microsoft.com/appx/manifest/desktop/windows10"
   xmlns:rescap="http://schemas.microsoft.com/appx/manifest/foundation/windows10/restrictedcapabilities"
-  IgnorableNamespaces="uap uap10 rescap">
+  IgnorableNamespaces="uap uap10 rescap com desktop">
 	
 	<!-- Publisher Cache Folders -->
 	<Extensions>
@@ -21,7 +23,7 @@
   <Identity
     Name="58272BurakKSE.WinoMailPreview"
     Publisher="CN=51FBDAF3-E212-4149-89A2-A2636B3BC911"
-    Version="2.0.1.0" />
+    Version="2.0.2.0" />
 
   <mp:PhoneIdentity PhoneProductId="3879fcfb-a561-4599-9103-e0c9b35a271f" PhonePublisherId="00000000-0000-0000-0000-000000000000"/>
 
@@ -45,15 +47,16 @@
       Executable="$targetnametoken$.exe"
       EntryPoint="$targetentrypoint$"
       uap10:Parameters="--wino-mail">
-		<uap:VisualElements
+      <uap:VisualElements
         DisplayName="Wino Mail"
-        Description="Wino Mail"
+        Description="Wino.Mail.WinUI"
         BackgroundColor="transparent"
         Square150x150Logo="Assets\AppEntries\MailAssets\Square150x150Logo.png"
         Square44x44Logo="Assets\AppEntries\MailAssets\Square44x44Logo.png">
         <uap:DefaultTile Wide310x150Logo="Assets\AppEntries\MailAssets\Wide310x150Logo.png"  Square71x71Logo="Assets\AppEntries\MailAssets\SmallTile.png" Square310x310Logo="Assets\AppEntries\MailAssets\LargeTile.png"/>
         <uap:SplashScreen Image="Assets\AppEntries\MailAssets\SplashScreen.png" />
       </uap:VisualElements>
+
 		<Extensions>
 			<uap5:Extension Category="windows.startupTask">
 				<uap5:StartupTask
@@ -62,6 +65,19 @@
 					DisplayName="Wino Startup Service" />
 			</uap5:Extension>
 
+			<!-- App notification activation -->
+			<desktop:Extension Category="windows.toastNotificationActivation">
+				<desktop:ToastNotificationActivation ToastActivatorCLSID="72c6d2d0-2538-44fe-a1b1-499f47bb1181" />
+			</desktop:Extension>
+
+			<com:Extension Category="windows.comServer">
+				<com:ComServer>
+					<com:ExeServer Executable="Wino.Mail.WinUI.exe" Arguments="----AppNotificationActivated:" DisplayName="Toast activator">
+						<com:Class Id="72c6d2d0-2538-44fe-a1b1-499f47bb1181" DisplayName="Toast activator"/>
+					</com:ExeServer>
+				</com:ComServer>
+			</com:Extension>
+			
 			<!-- Protocol activation: mailto -->
 			<uap:Extension Category="windows.protocol">
 				<uap:Protocol Name="mailto" />
@@ -102,43 +118,55 @@
 		</Extensions>
     </Application>
 
-	<Application Id="CalendarApp"
+    <Application Id="CalendarApp"
-		Executable="$targetnametoken$.exe"
+      Executable="$targetnametoken$.exe"
-		EntryPoint="$targetentrypoint$"
+      EntryPoint="$targetentrypoint$"
-		uap10:Parameters="--wino-calendar">
+      uap10:Parameters="--wino-calendar">
-		  <uap:VisualElements
+      <uap:VisualElements
-		  DisplayName="Wino Calendar"
+        DisplayName="Wino Calendar"
-		  Description="Wino Calendar"
+        Description="Wino.Mail.WinUI.Calendar"
-		  BackgroundColor="transparent"
+        BackgroundColor="transparent"
-		  Square150x150Logo="Assets\AppEntries\CalendarAssets\Square150x150Logo.png"
+        Square150x150Logo="Assets\AppEntries\CalendarAssets\Square150x150Logo.png"
-		  Square44x44Logo="Assets\AppEntries\CalendarAssets\Square44x44Logo.png">
+        Square44x44Logo="Assets\AppEntries\CalendarAssets\Square44x44Logo.png">
-			  <uap:DefaultTile Wide310x150Logo="Assets\AppEntries\CalendarAssets\Wide310x150Logo.png"  Square71x71Logo="Assets\AppEntries\CalendarAssets\SmallTile.png" Square310x310Logo="Assets\AppEntries\CalendarAssets\LargeTile.png"/>
+        <uap:DefaultTile Wide310x150Logo="Assets\AppEntries\CalendarAssets\Wide310x150Logo.png"  Square71x71Logo="Assets\AppEntries\CalendarAssets\SmallTile.png" Square310x310Logo="Assets\AppEntries\CalendarAssets\LargeTile.png"/>
-			  <uap:SplashScreen Image="Assets\AppEntries\CalendarAssets\SplashScreen.png" />
+        <uap:SplashScreen Image="Assets\AppEntries\CalendarAssets\SplashScreen.png" />
-		  </uap:VisualElements>
+      </uap:VisualElements>
 
-		  <Extensions>
+      <Extensions>
-			  <uap:Extension Category="windows.protocol">
+        <desktop:Extension Category="windows.toastNotificationActivation">
-				  <uap:Protocol Name="webcal">
+          <desktop:ToastNotificationActivation ToastActivatorCLSID="44c05d2b-aa1d-4e59-9d7d-8b4c8607cb8d" />
-					  <uap:DisplayName>Calendar Protocol</uap:DisplayName>
+        </desktop:Extension>
-				  </uap:Protocol>
-			  </uap:Extension>
 
-			  <uap:Extension Category="windows.protocol">
+        <com:Extension Category="windows.comServer">
-				  <uap:Protocol Name="webcals">
+          <com:ComServer>
-					  <uap:DisplayName>Calendar Protocol (Secure)</uap:DisplayName>
+            <com:ExeServer Executable="Wino.Mail.WinUI.exe" Arguments="----AppNotificationActivated:" DisplayName="Calendar toast activator">
-				  </uap:Protocol>
+              <com:Class Id="44c05d2b-aa1d-4e59-9d7d-8b4c8607cb8d" DisplayName="Calendar toast activator"/>
-			  </uap:Extension>
+            </com:ExeServer>
+          </com:ComServer>
+        </com:Extension>
 
-			  <uap:Extension Category="windows.fileTypeAssociation">
+        <uap:Extension Category="windows.protocol">
-				  <uap:FileTypeAssociation Name="ics">
+          <uap:Protocol Name="webcal">
-					  <uap:Logo>Assets\AppEntries\CalendarAssets\Square44x44Logo.png</uap:Logo>
+            <uap:DisplayName>Calendar Protocol</uap:DisplayName>
-					  <uap:SupportedFileTypes>
+          </uap:Protocol>
-						  <uap:FileType>.ics</uap:FileType>
+        </uap:Extension>
-					  </uap:SupportedFileTypes>
+
-				  </uap:FileTypeAssociation>
+        <uap:Extension Category="windows.protocol">
-			  </uap:Extension>
+          <uap:Protocol Name="webcals">
-		  </Extensions>
+            <uap:DisplayName>Calendar Protocol (Secure)</uap:DisplayName>
-	  </Application>
+          </uap:Protocol>
+        </uap:Extension>
+
+        <uap:Extension Category="windows.fileTypeAssociation">
+          <uap:FileTypeAssociation Name="ics">
+            <uap:Logo>Assets\AppEntries\CalendarAssets\Square44x44Logo.png</uap:Logo>
+            <uap:SupportedFileTypes>
+              <uap:FileType>.ics</uap:FileType>
+            </uap:SupportedFileTypes>
+          </uap:FileTypeAssociation>
+        </uap:Extension>
+      </Extensions>
+    </Application>
   </Applications>
 
   <Capabilities>

Wino.Mail.WinUI/Program.cs

@@ -207,13 +207,6 @@ public class Program
                 : true;
         }
 
-        if (args.Data is Windows.ApplicationModel.Activation.ToastNotificationActivatedEventArgs classicToastArgs)
-        {
-            return ToastActivationResolver.TryParse(classicToastArgs.Argument, out var toastArguments)
-                ? ToastActivationResolver.ShouldBringToForeground(toastArguments)
-                : true;
-        }
-
         if (args.Kind == ExtendedActivationKind.Launch &&
             args.Data is Windows.ApplicationModel.Activation.ILaunchActivatedEventArgs launchArgs &&
             ToastActivationResolver.TryParse(launchArgs.Arguments, out var launchToastArguments))

Wino.Mail.WinUI/Selectors/NavigationMenuTemplateSelector.cs

@@ -26,6 +26,7 @@ public partial class NavigationMenuTemplateSelector : DataTemplateSelector
     public DataTemplate NewMailTemplate { get; set; } = null!;
     public DataTemplate CalendarNewEventTemplate { get; set; } = null!;
     public DataTemplate CategoryItemsTemplate { get; set; } = null!;
+    public DataTemplate MergedCategoryItemsTemplate { get; set; } = null!;
     public DataTemplate FixAuthenticationIssueTemplate { get; set; } = null!;
     public DataTemplate FixMissingFolderConfigTemplate { get; set; } = null!;
 
@@ -58,6 +59,10 @@ public partial class NavigationMenuTemplateSelector : DataTemplateSelector
             return MergedAccountTemplate;
         else if (item is MergedAccountMoreFolderMenuItem)
             return MergedAccountMoreExpansionItemTemplate;
+        else if (item is MailCategoryMenuItem)
+            return CategoryItemsTemplate;
+        else if (item is MergedMailCategoryMenuItem)
+            return MergedCategoryItemsTemplate;
         else if (item is MergedAccountFolderMenuItem)
             return MergedAccountFolderTemplate;
         else if (item is FolderMenuItem)

Wino.Mail.WinUI/Services/DialogService.cs

@@ -6,7 +6,6 @@ using CommunityToolkit.Mvvm.Messaging;
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
 using Wino.Core.Domain;
-using Wino.Core.Domain.Entities.Calendar;
 using Wino.Core.Domain.Entities.Mail;
 using Wino.Core.Domain.Entities.Shared;
 using Wino.Core.Domain.Enums;
@@ -15,11 +14,12 @@ using Wino.Core.Domain.Models;
 using Wino.Core.Domain.Models.Accounts;
 using Wino.Core.Domain.Models.Calendar;
 using Wino.Core.Domain.Models.Folders;
+using Wino.Core.Domain.Models.MailItem;
 using Wino.Core.Domain.Models.Synchronization;
-using Wino.Mail.WinUI.Extensions;
-using Wino.Mail.WinUI.Services;
 using Wino.Dialogs;
 using Wino.Mail.Dialogs;
+using Wino.Mail.WinUI.Extensions;
+using Wino.Mail.WinUI.Services;
 using Wino.Messaging.Server;
 using Wino.Messaging.UI;
 
@@ -40,6 +40,12 @@ public class DialogService : DialogServiceBase, IMailDialogService
         _winoAccountDataSyncService = winoAccountDataSyncService;
     }
 
+    public void ShowReadOnlyCalendarMessage()
+        => InfoBarMessage(
+            Translator.CalendarReadOnly_Title,
+            Translator.CalendarReadOnly_Message,
+            InfoBarMessageType.Warning);
+
     public async Task<ICreateAccountAliasDialog> ShowCreateAccountAliasDialogAsync()
     {
         var createAccountAliasDialog = new CreateAccountAliasDialog()
@@ -52,6 +58,19 @@ public class DialogService : DialogServiceBase, IMailDialogService
         return createAccountAliasDialog;
     }
 
+#pragma warning disable CS8625
+    public async Task<MailCategoryDialogResult> ShowEditMailCategoryDialogAsync(MailCategory category = null)
+#pragma warning restore CS8625
+    {
+        var dialog = new EditMailCategoryDialog(category)
+        {
+            RequestedTheme = ThemeService.RootTheme.ToWindowsElementTheme()
+        };
+
+        await HandleDialogPresentationAsync(dialog);
+        return dialog.Result;
+    }
+
     public async Task HandleSystemFolderConfigurationDialogAsync(Guid accountId, IFolderService folderService)
     {
         try

Wino.Mail.WinUI/Services/NavigationService.cs

@@ -82,6 +82,7 @@ public class NavigationService : NavigationServiceBase, INavigationService
         WinoPage.ReadComposePanePage,
         WinoPage.AppPreferencesPage,
         WinoPage.AliasManagementPage,
+        WinoPage.MailCategoryManagementPage,
         WinoPage.ImapCalDavSettingsPage,
         WinoPage.KeyboardShortcutsPage,
         WinoPage.SignatureAndEncryptionPage,
@@ -150,6 +151,7 @@ public class NavigationService : NavigationServiceBase, INavigationService
             WinoPage.SettingOptionsPage => typeof(SettingOptionsPage),
             WinoPage.AppPreferencesPage => typeof(AppPreferencesPage),
             WinoPage.AliasManagementPage => typeof(AliasManagementPage),
+            WinoPage.MailCategoryManagementPage => typeof(MailCategoryManagementPage),
             WinoPage.ImapCalDavSettingsPage => typeof(ImapCalDavSettingsPage),
             WinoPage.KeyboardShortcutsPage => typeof(KeyboardShortcutsPage),
             WinoPage.ContactsPage => typeof(ContactsPage),

Wino.Mail.WinUI/Services/NotificationBuilder.cs

@@ -5,7 +5,8 @@ using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using CommunityToolkit.Mvvm.Messaging;
-using CommunityToolkit.WinUI.Notifications;
+using Microsoft.Windows.AppNotifications;
+using Microsoft.Windows.AppNotifications.Builder;
 using Serilog;
 using Windows.Data.Xml.Dom;
 using Windows.UI.Notifications;
@@ -75,9 +76,9 @@ public class NotificationBuilder : INotificationBuilder
                 builder.AddText(Translator.Notifications_MultipleNotificationsTitle);
                 builder.AddText(string.Format(Translator.Notifications_MultipleNotificationsMessage, mailCount));
                 builder.AddArgument(Constants.ToastModeKey, Constants.ToastModeMail);
-                builder.AddAudio(new Uri("ms-winsoundevent:Notification.Mail"));
+                builder.SetAudioUri(new Uri("ms-winsoundevent:Notification.Mail"));
 
-                ShowNotification(builder, WinoApplicationMode.Mail);
+                ShowNotification(builder);
             }
             else
             {
@@ -145,9 +146,9 @@ public class NotificationBuilder : INotificationBuilder
     {
         try
         {
-            ToastNotificationManager.History.Remove(mailUniqueId.ToString());
+            AppNotificationManager.Default.RemoveByTagAsync(mailUniqueId.ToString()).AsTask().GetAwaiter().GetResult();
         }
-        catch (Exception ex) when (ex is ArgumentException or InvalidOperationException)
+        catch (ArgumentException)
         {
         }
         catch (Exception ex)
@@ -163,12 +164,11 @@ public class NotificationBuilder : INotificationBuilder
         builder.AddText(string.Format(Translator.Exception_AccountNeedsAttention_Message, account.Name));
         builder.AddArgument(Constants.ToastMailAccountIdKey, account.Id.ToString());
         builder.AddArgument(Constants.ToastModeKey, Constants.ToastModeMail);
-        builder.AddButton(new ToastButton()
+        builder.AddButton(new AppNotificationButton(Translator.Buttons_FixAccount)
-            .SetContent(Translator.Buttons_FixAccount)
             .AddArgument(Constants.ToastMailAccountIdKey, account.Id.ToString())
             .AddArgument(Constants.ToastModeKey, Constants.ToastModeMail));
 
-        ShowNotification(builder, WinoApplicationMode.Mail);
+        ShowNotification(builder);
     }
 
     public void CreateWebView2RuntimeMissingNotification()
@@ -178,7 +178,7 @@ public class NotificationBuilder : INotificationBuilder
         builder.AddText(Translator.Exception_WebView2RuntimeMissing_Message);
         builder.AddArgument(Constants.ToastModeKey, Constants.ToastModeMail);
 
-        ShowNotification(builder, WinoApplicationMode.Mail);
+        ShowNotification(builder);
     }
 
     public void CreateStoreUpdateNotification()
@@ -189,7 +189,7 @@ public class NotificationBuilder : INotificationBuilder
         builder.AddArgument(Constants.ToastStoreUpdateActionKey, Constants.ToastStoreUpdateActionInstall);
         builder.AddArgument(Constants.ToastModeKey, Constants.ToastModeMail);
 
-        ShowNotification(builder, WinoApplicationMode.Mail, "store-update-available");
+        ShowNotification(builder, "store-update-available");
     }
 
     public Task CreateCalendarReminderNotificationAsync(CalendarItem calendarItem, long reminderDurationInSeconds)
@@ -197,7 +197,7 @@ public class NotificationBuilder : INotificationBuilder
         if (calendarItem == null)
             return Task.CompletedTask;
 
-        var builder = CreateBuilder(ToastScenario.Reminder);
+        var builder = CreateBuilder(AppNotificationScenario.Reminder);
         var localStart = calendarItem.GetLocalStartDate();
         var reminderContext = GetCalendarReminderContext(localStart, DateTime.Now);
 
@@ -210,7 +210,7 @@ public class NotificationBuilder : INotificationBuilder
         builder.AddArgument(Constants.ToastCalendarActionKey, Constants.ToastCalendarNavigateAction);
         builder.AddArgument(Constants.ToastCalendarItemIdKey, calendarItem.Id.ToString());
         builder.AddArgument(Constants.ToastModeKey, Constants.ToastModeCalendar);
-        builder.AddAudio(new Uri("ms-winsoundevent:Notification.Reminder"));
+        builder.SetAudioUri(new Uri("ms-winsoundevent:Notification.Reminder"));
 
         var allowedSnoozeMinutes = CalendarReminderSnoozeOptions.GetAllowedSnoozeMinutes(
             reminderDurationInSeconds,
@@ -223,33 +223,40 @@ public class NotificationBuilder : INotificationBuilder
                 ? preferredSnoozeMinutes
                 : allowedSnoozeMinutes[0];
 
-            builder.AddButton(new ToastButton()
+            var selectionBox = new AppNotificationComboBox(Constants.ToastCalendarSnoozeDurationInputId)
-                .SetContent(Translator.CalendarReminder_SnoozeAction)
+                .SetSelectedItem(defaultSnoozeMinutes.ToString());
-                .SetImageUri(GetNotificationIconUri("calendar-snooze"))
+
+            foreach (var snoozeMinutes in allowedSnoozeMinutes)
+            {
+                selectionBox.AddItem(
+                    snoozeMinutes.ToString(),
+                    string.Format(Translator.CalendarReminder_SnoozeMinutesOption, snoozeMinutes));
+            }
+
+            builder.AddComboBox(selectionBox);
+            builder.AddButton(new AppNotificationButton(Translator.CalendarReminder_SnoozeAction)
+                .SetIcon(GetNotificationIconUri("calendar-snooze"))
                 .AddArgument(Constants.ToastCalendarActionKey, Constants.ToastCalendarSnoozeAction)
                 .AddArgument(Constants.ToastCalendarItemIdKey, calendarItem.Id.ToString())
-                .AddArgument(Constants.ToastCalendarSnoozeDurationMinutesKey, defaultSnoozeMinutes.ToString())
                 .AddArgument(Constants.ToastModeKey, Constants.ToastModeCalendar));
         }
 
-        builder.AddButton(new ToastButton()
+        builder.AddButton(new AppNotificationButton(Translator.Buttons_Open)
-            .SetContent(Translator.Buttons_Open)
             .AddArgument(Constants.ToastCalendarActionKey, Constants.ToastCalendarNavigateAction)
             .AddArgument(Constants.ToastCalendarItemIdKey, calendarItem.Id.ToString())
             .AddArgument(Constants.ToastModeKey, Constants.ToastModeCalendar));
 
         if (Uri.TryCreate(calendarItem.HtmlLink, UriKind.Absolute, out _))
         {
-            builder.AddButton(new ToastButton()
+            builder.AddButton(new AppNotificationButton(Translator.CalendarEventDetails_JoinOnline)
-                .SetContent(Translator.CalendarEventDetails_JoinOnline)
+                .SetIcon(GetNotificationIconUri("calendar-join"))
-                .SetImageUri(GetNotificationIconUri("calendar-join"))
                 .AddArgument(Constants.ToastCalendarActionKey, Constants.ToastCalendarJoinOnlineAction)
                 .AddArgument(Constants.ToastCalendarItemIdKey, calendarItem.Id.ToString())
                 .AddArgument(Constants.ToastModeKey, Constants.ToastModeCalendar));
         }
 
         var tag = $"calendar-reminder-{calendarItem.Id:N}-{reminderDurationInSeconds}";
-        ShowNotification(builder, WinoApplicationMode.Calendar, tag);
+        ShowNotification(builder, tag);
 
         return Task.CompletedTask;
     }
@@ -271,10 +278,10 @@ public class NotificationBuilder : INotificationBuilder
                 await stream.WriteAsync(bytes);
             }
 
-            builder.AddAppLogoOverride(new Uri($"ms-appdata:///temp/{tempFile.Name}"), ToastGenericAppLogoCrop.Default);
+            builder.SetAppLogoOverride(new Uri($"ms-appdata:///temp/{tempFile.Name}"), AppNotificationImageCrop.Default);
         }
 
-        builder.AddCustomTimeStamp(mailItem.CreationDate.ToLocalTime());
+        builder.SetTimeStamp(mailItem.CreationDate.ToLocalTime());
         builder.AddText(mailItem.FromName);
         builder.AddText(mailItem.Subject);
         builder.AddText(mailItem.PreviewText);
@@ -284,9 +291,9 @@ public class NotificationBuilder : INotificationBuilder
         builder.AddButton(GetMarkAsReadButton(mailItem.UniqueId));
         builder.AddButton(GetDeleteButton(mailItem.UniqueId));
         builder.AddButton(GetArchiveButton(mailItem.UniqueId));
-        builder.AddAudio(new Uri("ms-winsoundevent:Notification.Mail"));
+        builder.SetAudioUri(new Uri("ms-winsoundevent:Notification.Mail"));
 
-        ShowNotification(builder, WinoApplicationMode.Mail, mailItem.UniqueId.ToString());
+        ShowNotification(builder, mailItem.UniqueId.ToString());
     }
 
     private void UpdateBadge(string applicationId, int? badgeCount)
@@ -340,43 +347,40 @@ public class NotificationBuilder : INotificationBuilder
         return string.Format(Translator.CalendarReminder_StartedMinutesAgo, minutesAgo);
     }
 
-    private ToastButton GetArchiveButton(Guid mailUniqueId)
+    private AppNotificationButton GetArchiveButton(Guid mailUniqueId)
-        => new ToastButton()
+        => new AppNotificationButton(Translator.MailOperation_Archive)
-            .SetContent(Translator.MailOperation_Archive)
+            .SetIcon(GetNotificationIconUri("mail-archive"))
-            .SetImageUri(GetNotificationIconUri("mail-archive"))
             .AddArgument(Constants.ToastMailUniqueIdKey, mailUniqueId.ToString())
             .AddArgument(Constants.ToastActionKey, MailOperation.Archive.ToString())
             .AddArgument(Constants.ToastModeKey, Constants.ToastModeMail);
 
-    private ToastButton GetDeleteButton(Guid mailUniqueId)
+    private AppNotificationButton GetDeleteButton(Guid mailUniqueId)
-        => new ToastButton()
+        => new AppNotificationButton(Translator.MailOperation_Delete)
-            .SetContent(Translator.MailOperation_Delete)
+            .SetIcon(GetNotificationIconUri("mail-delete"))
-            .SetImageUri(GetNotificationIconUri("mail-delete"))
             .AddArgument(Constants.ToastMailUniqueIdKey, mailUniqueId.ToString())
             .AddArgument(Constants.ToastActionKey, MailOperation.SoftDelete.ToString())
             .AddArgument(Constants.ToastModeKey, Constants.ToastModeMail);
 
-    private ToastButton GetMarkAsReadButton(Guid mailUniqueId)
+    private AppNotificationButton GetMarkAsReadButton(Guid mailUniqueId)
-        => new ToastButton()
+        => new AppNotificationButton(Translator.MailOperation_MarkAsRead)
-            .SetContent(Translator.MailOperation_MarkAsRead)
+            .SetIcon(GetNotificationIconUri("mail-markread"))
-            .SetImageUri(GetNotificationIconUri("mail-markread"))
             .AddArgument(Constants.ToastMailUniqueIdKey, mailUniqueId.ToString())
             .AddArgument(Constants.ToastActionKey, MailOperation.MarkAsRead.ToString())
             .AddArgument(Constants.ToastModeKey, Constants.ToastModeMail);
 
-    private static ToastContentBuilder CreateBuilder(ToastScenario scenario = ToastScenario.Default)
+    private static AppNotificationBuilder CreateBuilder(AppNotificationScenario scenario = AppNotificationScenario.Default)
-        => new ToastContentBuilder().SetToastScenario(scenario);
+        => new AppNotificationBuilder().SetScenario(scenario);
 
-    private static void ShowNotification(ToastContentBuilder builder, WinoApplicationMode mode, string? tag = null)
+    private static void ShowNotification(AppNotificationBuilder builder, string? tag = null)
     {
-        var notification = new ToastNotification(builder.GetXml());
+        var notification = builder.BuildNotification();
 
         if (!string.IsNullOrWhiteSpace(tag))
         {
             notification.Tag = tag;
         }
 
-        ToastNotificationManager.CreateToastNotifier(AppEntryConstants.GetAppUserModelId(mode)).Show(notification);
+        AppNotificationManager.Default.Show(notification);
     }
 
     private static Uri GetNotificationIconUri(string iconName)

Wino.Mail.WinUI/Views/Abstract/MailCategoryManagementPageAbstract.cs

@@ -0,0 +1,6 @@
+using Wino.Mail.ViewModels;
+using Wino.Mail.WinUI;
+
+namespace Wino.Views.Abstract;
+
+public abstract class MailCategoryManagementPageAbstract : BasePage<MailCategoryManagementPageViewModel> { }

Wino.Mail.WinUI/Views/Calendar/EventDetailsPage.xaml

@@ -210,12 +210,12 @@
                         Background="{ThemeResource DividerStrokeColorDefaultBrush}" />
 
                     <!--  Test Notification  -->
-                    <Button Command="{x:Bind ViewModel.CreateTestNotificationCommand}" Style="{StaticResource TransparentActionButtonStyle}">
+                    <!--<Button Command="{x:Bind ViewModel.CreateTestNotificationCommand}" Style="{StaticResource TransparentActionButtonStyle}">
                         <StackPanel Orientation="Horizontal" Spacing="8">
                             <coreControls:WinoFontIcon FontSize="16" Icon="Reminder" />
                             <TextBlock VerticalAlignment="Center" Text="Test notification" />
                         </StackPanel>
-                    </Button>
+                    </Button>-->
 
                     <!--  Edit Series  -->
                     <Border

Wino.Mail.WinUI/Views/Mail/ComposePage.xaml.cs

@@ -38,7 +38,10 @@ public sealed partial class ComposePage : ComposePageAbstract,
     IPopoutClient,
     IRecipient<ApplicationThemeChanged>
 {
+    private const int InitialFocusRetryCount = 3;
+
     private bool _isPoppedOut;
+    private bool _isInitialFocusHandled;
 
     public bool SupportsPopOut => !_isPoppedOut;
     public event EventHandler<PopOutRequestedEventArgs>? PopOutRequested;
@@ -307,7 +310,7 @@ public sealed partial class ComposePage : ComposePageAbstract,
         _disposables.Add(WebViewEditor);
 
         ViewModel.GetHTMLBodyFunction = WebViewEditor.GetHtmlBodyAsync;
-        ViewModel.RenderHtmlBodyAsyncFunc = WebViewEditor.RenderHtmlAsync;
+        ViewModel.RenderHtmlBodyAsyncFunc = RenderComposeHtmlAsync;
     }
 
     private void ShowCCBCCClicked(object sender, RoutedEventArgs e)
@@ -373,9 +376,10 @@ public sealed partial class ComposePage : ComposePageAbstract,
     {
         if (draftMailItemViewModel == null || !draftMailItemViewModel.IsDraft) return;
 
-        // Reset the initial focus flag so ToBox gets focus for the new draft.
+        // Reset the initial focus flag for the newly loaded draft.
-        isInitialFocusHandled = false;
+        _isInitialFocusHandled = false;
         await ViewModel.RefreshDraftAsync(draftMailItemViewModel);
+        await ApplyInitialFocusAsync();
     }
 
     private void ImportanceClicked(object sender, RoutedEventArgs e)
@@ -434,21 +438,19 @@ public sealed partial class ComposePage : ComposePageAbstract,
         }
     }
 
-    // Hack: Tokenizing text box losing focus somehow on page Loaded and shifting focus to this element.
-    // For once we'll switch back to it once CCBBCGotFocus element got focus.
-
-    private bool isInitialFocusHandled = false;
-
     private void ComposerLoaded(object sender, RoutedEventArgs e)
     {
-        ToBox.Focus(FocusState.Programmatic);
+        if (ShouldFocusRecipients())
+        {
+            ToBox.Focus(FocusState.Programmatic);
+        }
     }
 
     private void CCBBCGotFocus(object sender, RoutedEventArgs e)
     {
-        if (!isInitialFocusHandled)
+        if (ShouldFocusRecipients() && !_isInitialFocusHandled)
         {
-            isInitialFocusHandled = true;
+            _isInitialFocusHandled = true;
             ToBox.Focus(FocusState.Programmatic);
         }
     }
@@ -555,4 +557,64 @@ public sealed partial class ComposePage : ComposePageAbstract,
         }
         finally { deferral.Complete(); }
     }
+
+    private bool ShouldFocusRecipients()
+        => !ShouldFocusEditor();
+
+    private bool ShouldFocusEditor()
+    {
+        var inReplyTo = ViewModel.CurrentMimeMessage?.InReplyTo;
+
+        if (string.IsNullOrWhiteSpace(inReplyTo))
+        {
+            inReplyTo = ViewModel.CurrentMailDraftItem?.MailCopy?.InReplyTo;
+        }
+
+        if (string.IsNullOrWhiteSpace(inReplyTo) && ViewModel.CurrentMimeMessage?.Headers.Contains(HeaderId.InReplyTo) == true)
+        {
+            inReplyTo = ViewModel.CurrentMimeMessage.Headers[HeaderId.InReplyTo];
+        }
+
+        return !string.IsNullOrWhiteSpace(inReplyTo);
+    }
+
+    private async Task ApplyInitialFocusAsync()
+    {
+        if (_isInitialFocusHandled)
+        {
+            return;
+        }
+
+        _isInitialFocusHandled = true;
+
+        for (var attempt = 0; attempt < InitialFocusRetryCount; attempt++)
+        {
+            if (ShouldFocusEditor())
+            {
+                await WebViewEditor.FocusEditorAsync(true);
+
+                if (FocusManager.GetFocusedElement(XamlRoot) is WebView2)
+                {
+                    return;
+                }
+            }
+            else
+            {
+                ToBox.Focus(FocusState.Programmatic);
+
+                if (FocusManager.GetFocusedElement(XamlRoot) == ToBox)
+                {
+                    return;
+                }
+            }
+
+            await Task.Delay(TimeSpan.FromMilliseconds(50));
+        }
+    }
+
+    private async Task RenderComposeHtmlAsync(string html)
+    {
+        await WebViewEditor.RenderHtmlAsync(html);
+        await ApplyInitialFocusAsync();
+    }
 }

Wino.Mail.WinUI/Views/Mail/MailListPage.xaml

@@ -253,7 +253,8 @@
                             BorderThickness="0"
                             Command="{x:Bind ViewModel.SyncFolderCommand}"
                             IsEnabled="{x:Bind ViewModel.CanSynchronize, Mode=OneWay}"
-                            ToolTipService.ToolTip="{x:Bind domain:Translator.Buttons_Sync}">
+                            ToolTipService.ToolTip="{x:Bind domain:Translator.Buttons_Sync}"
+                            Visibility="{x:Bind ViewModel.IsSyncButtonVisible, Mode=OneWay}">
                             <coreControls:WinoFontIcon FontSize="14" Icon="Sync" />
                         </Button>
                         <ToggleButton
@@ -290,9 +291,11 @@
                     </StackPanel>
 
                     <InfoBar
+                        x:Name="SyncDisabledInfoBar"
                         Title="{x:Bind domain:Translator.InfoBarTitle_SynchronizationDisabledFolder}"
                         Grid.Row="0"
                         Grid.ColumnSpan="3"
+                        x:Load="{x:Bind ViewModel.IsSyncButtonVisible, Mode=OneWay}"
                         IsClosable="True"
                         IsOpen="{x:Bind ViewModel.IsFolderSynchronizationEnabled, Converter={StaticResource ReverseBooleanConverter}, Mode=OneWay}"
                         Message="{x:Bind domain:Translator.InfoBarMessage_SynchronizationDisabledFolder}"

Wino.Mail.WinUI/Views/Mail/MailListPage.xaml.cs

@@ -1,6 +1,6 @@
 using System;
-using System.Collections.ObjectModel;
 using System.Collections.Generic;
+using System.Collections.ObjectModel;
 using System.Linq;
 using System.Threading.Tasks;
 using CommunityToolkit.Mvvm.Collections;
@@ -18,6 +18,7 @@ using Windows.Foundation;
 using Windows.System;
 using Wino.Controls;
 using Wino.Core.Domain;
+using Wino.Core.Domain.Entities.Mail;
 using Wino.Core.Domain.Enums;
 using Wino.Core.Domain.Interfaces;
 using Wino.Core.Domain.Models.MailItem;
@@ -27,7 +28,6 @@ using Wino.Mail.ViewModels.Data;
 using Wino.Mail.ViewModels.Messages;
 using Wino.Mail.WinUI;
 using Wino.Mail.WinUI.Controls.ListView;
-using Wino.Mail.WinUI.Extensions;
 using Wino.Mail.WinUI.Helpers;
 using Wino.Mail.WinUI.Interfaces;
 using Wino.Mail.WinUI.Models;
@@ -246,14 +246,27 @@ public sealed partial class MailListPage : MailListPageAbstract,
             // Default to all selected items.
             targetItems = ViewModel.MailCollection.SelectedItems;
             var availableActions = ViewModel.GetAvailableMailActions(targetItems);
+            var (availableCategories, assignedCategoryIds) = await ViewModel.GetAvailableCategoriesAsync(targetItems);
 
             if (availableActions == null || !availableActions.Any()) return;
 
-            var clickedOperation = await GetMailOperationFromFlyoutAsync(availableActions, control, p.X, p.Y);
+            var clickedAction = await GetMailContextActionFromFlyoutAsync(
+                availableActions,
+                availableCategories,
+                assignedCategoryIds,
+                control,
+                p.X,
+                p.Y);
 
-            if (clickedOperation == null) return;
+            if (clickedAction == null) return;
 
-            var prepRequest = new MailOperationPreperationRequest(clickedOperation.Operation, targetItems.Select(a => a.MailCopy));
+            if (clickedAction.Category != null)
+            {
+                await ViewModel.ToggleCategoryAssignmentAsync(clickedAction.Category, targetItems, clickedAction.IsCategoryAssignedToAll);
+                return;
+            }
+
+            var prepRequest = new MailOperationPreperationRequest(clickedAction.Operation.Operation, targetItems.Select(a => a.MailCopy));
 
             await ViewModel.ExecuteMailOperationAsync(prepRequest);
         }
@@ -296,14 +309,68 @@ public sealed partial class MailListPage : MailListPageAbstract,
         });
     }
 
-    private async Task<MailOperationMenuItem> GetMailOperationFromFlyoutAsync(IEnumerable<MailOperationMenuItem> availableActions,
+    private async Task<MailContextAction?> GetMailContextActionFromFlyoutAsync(
-                                                                              UIElement showAtElement,
+        IEnumerable<MailOperationMenuItem> availableActions,
-                                                                              double x,
+        IReadOnlyList<MailCategory> availableCategories,
-                                                                              double y)
+        IReadOnlyCollection<Guid> assignedCategoryIds,
+        UIElement showAtElement,
+        double x,
+        double y)
     {
-        var source = new TaskCompletionSource<MailOperationMenuItem>();
+        var source = new TaskCompletionSource<MailContextAction?>();
+        var flyout = new MenuFlyout();
 
-        var flyout = new MailOperationFlyout(availableActions, source);
+        foreach (var action in availableActions)
+        {
+            if (action.Operation == MailOperation.Seperator)
+            {
+                flyout.Items.Add(new MenuFlyoutSeparator());
+                continue;
+            }
+
+            var menuFlyoutItem = new MailOperationMenuFlyoutItem(action, clicked =>
+            {
+                source.TrySetResult(new MailContextAction(clicked));
+                flyout.Hide();
+            });
+
+            flyout.Items.Add(menuFlyoutItem);
+        }
+
+        if (availableCategories?.Count > 0)
+        {
+            if (flyout.Items.LastOrDefault() is not MenuFlyoutSeparator)
+            {
+                flyout.Items.Add(new MenuFlyoutSeparator());
+            }
+
+            var categorySubItem = new MenuFlyoutSubItem
+            {
+                Text = Translator.MailCategoryMenuItem
+            };
+
+            foreach (var category in availableCategories)
+            {
+                var wasAssignedToAll = assignedCategoryIds.Contains(category.Id);
+                var categoryItem = new ToggleMenuFlyoutItem
+                {
+                    Text = category.Name,
+                    IsChecked = wasAssignedToAll
+                };
+
+                categoryItem.Click += (_, _) =>
+                {
+                    source.TrySetResult(new MailContextAction(category, wasAssignedToAll));
+                    flyout.Hide();
+                };
+
+                categorySubItem.Items.Add(categoryItem);
+            }
+
+            flyout.Items.Add(categorySubItem);
+        }
+
+        flyout.Closing += (_, _) => source.TrySetResult(null);
 
         flyout.ShowAt(showAtElement, new FlyoutShowOptions()
         {
@@ -314,6 +381,13 @@ public sealed partial class MailListPage : MailListPageAbstract,
         return await source.Task;
     }
 
+    private sealed record MailContextAction(MailOperationMenuItem Operation, MailCategory Category = null, bool IsCategoryAssignedToAll = false)
+    {
+        public MailContextAction(MailCategory category, bool isCategoryAssignedToAll) : this(null, category, isCategoryAssignedToAll)
+        {
+        }
+    }
+
     async void IRecipient<ClearMailSelectionsRequested>.Receive(ClearMailSelectionsRequested message)
     {
         await ViewModel.MailCollection.UnselectAllAsync();

Wino.Mail.WinUI/Views/Settings/MailCategoryManagementPage.xaml

@@ -0,0 +1,169 @@
+<abstract:MailCategoryManagementPageAbstract
+    x:Class="Wino.Views.Settings.MailCategoryManagementPage"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:abstract="using:Wino.Views.Abstract"
+    xmlns:controls="using:Wino.Controls"
+    xmlns:coreControls="using:Wino.Mail.WinUI.Controls"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:domain="using:Wino.Core.Domain"
+    xmlns:helpers="using:Wino.Helpers"
+    xmlns:mail="using:Wino.Core.Domain.Entities.Mail"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    x:Name="root"
+    mc:Ignorable="d">
+
+    <Page.Resources>
+        <DataTemplate x:Key="MailCategoryTemplate" x:DataType="mail:MailCategory">
+            <Grid
+                Margin="0,0,0,12"
+                Padding="0,0,0,12"
+                ColumnSpacing="16">
+                <Grid.ColumnDefinitions>
+                    <ColumnDefinition Width="*" />
+                    <ColumnDefinition Width="Auto" />
+                    <ColumnDefinition Width="Auto" />
+                    <ColumnDefinition Width="Auto" />
+                    <ColumnDefinition Width="Auto" />
+                </Grid.ColumnDefinitions>
+
+                <Grid
+                    VerticalAlignment="Center"
+                    ColumnSpacing="12">
+                    <Grid.ColumnDefinitions>
+                        <ColumnDefinition Width="Auto" />
+                        <ColumnDefinition Width="*" />
+                    </Grid.ColumnDefinitions>
+
+                    <Border
+                        Width="28"
+                        Height="28"
+                        VerticalAlignment="Top"
+                        Background="{x:Bind helpers:XamlHelpers.GetSolidColorBrushFromHex(BackgroundColorHex), Mode=OneWay}"
+                        BorderBrush="{x:Bind helpers:XamlHelpers.GetSolidColorBrushFromHex(TextColorHex), Mode=OneWay}"
+                        BorderThickness="1"
+                        CornerRadius="8" />
+
+                    <StackPanel
+                        Grid.Column="1"
+                        VerticalAlignment="Center"
+                        Spacing="2">
+                        <TextBlock
+                            FontWeight="SemiBold"
+                            Foreground="{x:Bind helpers:XamlHelpers.GetSolidColorBrushFromHex(TextColorHex), Mode=OneWay}"
+                            Style="{StaticResource BodyTextBlockStyle}"
+                            Text="{x:Bind Name}"
+                            TextTrimming="CharacterEllipsis" />
+                        <TextBlock
+                            Foreground="{ThemeResource TextFillColorSecondaryBrush}"
+                            Style="{StaticResource CaptionTextBlockStyle}">
+                            <Run Text="{x:Bind BackgroundColorHex}" />
+                            <Run Text=" / " />
+                            <Run Text="{x:Bind TextColorHex}" />
+                        </TextBlock>
+                    </StackPanel>
+                </Grid>
+
+                <ToggleButton
+                    Grid.Column="1"
+                    Checked="FavoriteCategoryChecked"
+                    IsChecked="{x:Bind IsFavorite, Mode=OneWay}"
+                    Tag="{x:Bind}"
+                    Unchecked="FavoriteCategoryUnchecked">
+                    <FontIcon FontFamily="{StaticResource SymbolThemeFontFamily}" Glyph="&#xE208;" />
+                </ToggleButton>
+
+                <Button
+                    Grid.Column="2"
+                    Click="EditCategoryClicked"
+                    Tag="{x:Bind}">
+                    <FontIcon FontFamily="{StaticResource SymbolThemeFontFamily}" Glyph="&#xE70F;" />
+                </Button>
+
+                <Button
+                    Grid.Column="3"
+                    Click="DeleteCategoryClicked"
+                    Tag="{x:Bind}">
+                    <FontIcon FontFamily="{StaticResource SymbolThemeFontFamily}" Glyph="&#xE74D;" />
+                </Button>
+
+                <Rectangle
+                    Grid.ColumnSpan="5"
+                    Height="1"
+                    Margin="0,12,0,0"
+                    VerticalAlignment="Bottom"
+                    Fill="{ThemeResource CardStrokeColorDefaultBrush}" />
+            </Grid>
+        </DataTemplate>
+    </Page.Resources>
+
+    <ListView
+        ItemTemplate="{StaticResource MailCategoryTemplate}"
+        ItemsSource="{x:Bind ViewModel.Categories, Mode=OneWay}"
+        SelectionMode="None">
+        <ListView.ItemContainerTransitions>
+            <TransitionCollection>
+                <NavigationThemeTransition />
+            </TransitionCollection>
+        </ListView.ItemContainerTransitions>
+        <ListView.Header>
+            <Grid
+                Padding="16,0,24,20"
+                ColumnSpacing="16">
+                <Grid.ColumnDefinitions>
+                    <ColumnDefinition Width="*" />
+                    <ColumnDefinition Width="Auto" />
+                    <ColumnDefinition Width="Auto" />
+                </Grid.ColumnDefinitions>
+
+                <Grid Style="{StaticResource InformationAreaGridStyle}">
+                    <TextBlock HorizontalTextAlignment="Center" TextWrapping="WrapWholeWords">
+                        <Run FontWeight="SemiBold" Text="{x:Bind domain:Translator.MailCategoryManagementPage_Title, Mode=OneTime}" />
+                        <LineBreak />
+                        <Run Text="{x:Bind domain:Translator.MailCategoryManagementPage_Description, Mode=OneTime}" />
+                    </TextBlock>
+                </Grid>
+
+                <Button
+                    Grid.Column="1"
+                    HorizontalAlignment="Stretch"
+                    VerticalAlignment="Stretch"
+                    Command="{x:Bind ViewModel.RefreshCategoriesCommand}"
+                    Visibility="{x:Bind ViewModel.CanRefresh, Mode=OneWay}">
+                    <StackPanel Spacing="6">
+                        <FontIcon
+                            HorizontalAlignment="Center"
+                            Glyph="&#xE72C;" />
+                        <TextBlock
+                            HorizontalAlignment="Center"
+                            Text="{x:Bind domain:Translator.Buttons_Refresh, Mode=OneTime}" />
+                    </StackPanel>
+                </Button>
+
+                <Button
+                    Grid.Column="2"
+                    HorizontalAlignment="Stretch"
+                    VerticalAlignment="Stretch"
+                    Command="{x:Bind ViewModel.AddCategoryCommand}">
+                    <StackPanel Spacing="6">
+                        <FontIcon
+                            HorizontalAlignment="Center"
+                            Glyph="&#xE710;" />
+                        <TextBlock
+                            HorizontalAlignment="Center"
+                            Text="{x:Bind domain:Translator.Buttons_Add, Mode=OneTime}" />
+                    </StackPanel>
+                </Button>
+            </Grid>
+        </ListView.Header>
+        <ListView.Footer>
+            <TextBlock
+                Margin="0,12,0,0"
+                HorizontalAlignment="Center"
+                Foreground="{ThemeResource TextFillColorSecondaryBrush}"
+                Style="{StaticResource BodyTextBlockStyle}"
+                Text="{x:Bind domain:Translator.MailCategoryManagementPage_Empty, Mode=OneTime}"
+                Visibility="{x:Bind helpers:XamlHelpers.ReverseBoolToVisibilityConverter(ViewModel.HasCategories), Mode=OneWay}" />
+        </ListView.Footer>
+    </ListView>
+</abstract:MailCategoryManagementPageAbstract>

Wino.Mail.WinUI/Views/Settings/MailCategoryManagementPage.xaml.cs

@@ -0,0 +1,47 @@
+using Microsoft.UI.Xaml;
+using Microsoft.UI.Xaml.Controls;
+using Microsoft.UI.Xaml.Controls.Primitives;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Views.Abstract;
+
+namespace Wino.Views.Settings;
+
+public sealed partial class MailCategoryManagementPage : MailCategoryManagementPageAbstract
+{
+    public MailCategoryManagementPage()
+    {
+        InitializeComponent();
+    }
+
+    private async void FavoriteCategoryChecked(object sender, RoutedEventArgs e)
+    {
+        if (sender is ToggleButton toggleButton && toggleButton.Tag is MailCategory category)
+        {
+            await ViewModel.SetFavoriteAsync(category, true);
+        }
+    }
+
+    private async void FavoriteCategoryUnchecked(object sender, RoutedEventArgs e)
+    {
+        if (sender is ToggleButton toggleButton && toggleButton.Tag is MailCategory category)
+        {
+            await ViewModel.SetFavoriteAsync(category, false);
+        }
+    }
+
+    private async void EditCategoryClicked(object sender, RoutedEventArgs e)
+    {
+        if (sender is Button button && button.Tag is MailCategory category)
+        {
+            await ViewModel.EditCategoryAsync(category);
+        }
+    }
+
+    private async void DeleteCategoryClicked(object sender, RoutedEventArgs e)
+    {
+        if (sender is Button button && button.Tag is MailCategory category)
+        {
+            await ViewModel.DeleteCategoryAsync(category);
+        }
+    }
+}

Wino.Mail.WinUI/Views/WinoAppShell.xaml

@@ -240,6 +240,93 @@
             </coreControls:WinoNavigationViewItem>
         </DataTemplate>
 
+        <DataTemplate x:Key="MailCategoryMenuTemplate" x:DataType="menu:MailCategoryMenuItem">
+            <coreControls:WinoNavigationViewItem
+                MinHeight="40"
+                DataContext="{x:Bind}"
+                FontWeight="{x:Bind helpers:XamlHelpers.GetFontWeightByChildSelectedState(IsSelected), Mode=OneWay}"
+                IsSelected="{x:Bind IsSelected, Mode=TwoWay}"
+                SelectsOnInvoked="True"
+                ToolTipService.ToolTip="{x:Bind FolderName, Mode=OneWay}">
+                <muxc:NavigationViewItem.Icon>
+                    <FontIcon
+                        FontFamily="{StaticResource SymbolThemeFontFamily}"
+                        Foreground="{x:Bind helpers:XamlHelpers.GetSolidColorBrushFromHex(BackgroundColorHex), Mode=OneWay}"
+                        Glyph="&#xE8EC;" />
+                </muxc:NavigationViewItem.Icon>
+                <muxc:NavigationViewItem.InfoBadge>
+                    <muxc:InfoBadge
+                        Background="{StaticResource SystemAccentColor}"
+                        Foreground="White"
+                        Visibility="{x:Bind helpers:XamlHelpers.CountToVisibilityConverter(UnreadItemCount), Mode=OneWay}"
+                        Value="{x:Bind UnreadItemCount, Mode=OneWay}" />
+                </muxc:NavigationViewItem.InfoBadge>
+                <muxc:NavigationViewItem.Content>
+                    <TextBlock
+                        Grid.Column="1"
+                        VerticalAlignment="Center"
+                        FontWeight="{x:Bind helpers:XamlHelpers.GetFontWeightBySyncState(IsSelected), Mode=OneWay}"
+                        Style="{StaticResource BodyTextBlockStyle}"
+                        Text="{x:Bind FolderName, Mode=OneWay}"
+                        TextTrimming="CharacterEllipsis" />
+                </muxc:NavigationViewItem.Content>
+            </coreControls:WinoNavigationViewItem>
+        </DataTemplate>
+
+        <DataTemplate x:Key="MergedMailCategoryMenuTemplate" x:DataType="menu:MergedMailCategoryMenuItem">
+            <coreControls:WinoNavigationViewItem
+                MinHeight="40"
+                DataContext="{x:Bind}"
+                FontWeight="{x:Bind helpers:XamlHelpers.GetFontWeightByChildSelectedState(IsSelected), Mode=OneWay}"
+                IsSelected="{x:Bind IsSelected, Mode=TwoWay}"
+                SelectsOnInvoked="True"
+                ToolTipService.ToolTip="{x:Bind FolderName, Mode=OneWay}">
+                <muxc:NavigationViewItem.Icon>
+                    <FontIcon
+                        FontFamily="{StaticResource SymbolThemeFontFamily}"
+                        Foreground="{x:Bind helpers:XamlHelpers.GetSolidColorBrushFromHex(TextColorHex), Mode=OneWay}"
+                        Glyph="&#xE8EC;" />
+                </muxc:NavigationViewItem.Icon>
+                <muxc:NavigationViewItem.InfoBadge>
+                    <muxc:InfoBadge
+                        Background="{StaticResource SystemAccentColor}"
+                        Foreground="White"
+                        Visibility="{x:Bind helpers:XamlHelpers.CountToVisibilityConverter(UnreadItemCount), Mode=OneWay}"
+                        Value="{x:Bind UnreadItemCount, Mode=OneWay}" />
+                </muxc:NavigationViewItem.InfoBadge>
+                <muxc:NavigationViewItem.Content>
+                    <Grid
+                        MaxHeight="36"
+                        Padding="2"
+                        VerticalAlignment="Center">
+                        <Grid.ColumnDefinitions>
+                            <ColumnDefinition Width="Auto" />
+                            <ColumnDefinition Width="*" />
+                        </Grid.ColumnDefinitions>
+
+                        <Border
+                            Width="10"
+                            Height="10"
+                            Margin="0,0,8,0"
+                            VerticalAlignment="Center"
+                            Background="{x:Bind helpers:XamlHelpers.GetSolidColorBrushFromHex(BackgroundColorHex), Mode=OneWay}"
+                            BorderBrush="{x:Bind helpers:XamlHelpers.GetSolidColorBrushFromHex(TextColorHex), Mode=OneWay}"
+                            BorderThickness="1"
+                            CornerRadius="3" />
+
+                        <TextBlock
+                            Grid.Column="1"
+                            VerticalAlignment="Center"
+                            FontWeight="{x:Bind helpers:XamlHelpers.GetFontWeightBySyncState(IsSelected), Mode=OneWay}"
+                            Foreground="{x:Bind helpers:XamlHelpers.GetSolidColorBrushFromHex(TextColorHex), Mode=OneWay}"
+                            Style="{StaticResource BodyTextBlockStyle}"
+                            Text="{x:Bind FolderName, Mode=OneWay}"
+                            TextTrimming="CharacterEllipsis" />
+                    </Grid>
+                </muxc:NavigationViewItem.Content>
+            </coreControls:WinoNavigationViewItem>
+        </DataTemplate>
+
         <!--  Merged Inbox  -->
         <DataTemplate x:Key="MergedAccountTemplate" x:DataType="menu:MergedAccountMenuItem">
             <controls:AccountNavigationItem
@@ -393,6 +480,7 @@
 
         <coreSelectors:NavigationMenuTemplateSelector
             x:Key="NavigationMenuTemplateSelector"
+            CategoryItemsTemplate="{StaticResource MailCategoryMenuTemplate}"
             ClickableAccountMenuTemplate="{StaticResource ClickableAccountMenuTemplate}"
             FixAuthenticationIssueTemplate="{StaticResource FixAuthenticationIssueTemplate}"
             FixMissingFolderConfigTemplate="{StaticResource FixMissingFolderConfig}"
@@ -400,6 +488,7 @@
             MergedAccountFolderTemplate="{StaticResource MergedAccountFolderMenuItemTemplate}"
             MergedAccountMoreExpansionItemTemplate="{StaticResource MergedAccountMoreFolderItemTemplate}"
             MergedAccountTemplate="{StaticResource MergedAccountTemplate}"
+            MergedCategoryItemsTemplate="{StaticResource MergedMailCategoryMenuTemplate}"
             NewMailTemplate="{StaticResource CreateNewMailTemplate}"
             RatingItemTemplate="{StaticResource RatingItemTemplate}"
             SeperatorTemplate="{StaticResource SeperatorTemplate}"

Wino.Mail.WinUI/Wino.Mail.WinUI.csproj

@@ -185,7 +185,6 @@
     <PackageReference Include="CommunityToolkit.WinUI.Controls.TokenizingTextBox" />
     <PackageReference Include="CommunityToolkit.WinUI.Extensions" />
     <PackageReference Include="CommunityToolkit.WinUI.Lottie" />
-    <PackageReference Include="CommunityToolkit.WinUI.Notifications" />
 	  
     <PackageReference Include="Microsoft.Graphics.Win2D" />
     <PackageReference Include="Microsoft.Windows.SDK.BuildTools" />

Wino.Services/DatabaseService.cs

@@ -49,6 +49,8 @@ public class DatabaseService : IDatabaseService
     {
         await Task.WhenAll(
             Connection.CreateTableAsync<MailCopy>(),
+            Connection.CreateTableAsync<MailCategory>(),
+            Connection.CreateTableAsync<MailCategoryAssignment>(),
             Connection.CreateTableAsync<MailItemFolder>(),
             Connection.CreateTableAsync<MailAccount>(),
             Connection.CreateTableAsync<AccountContact>(),
@@ -168,6 +170,13 @@ public class DatabaseService : IDatabaseService
                 .ConfigureAwait(false);
         }
 
+        if (!accountCalendarColumns.Any(c => c.Name == nameof(AccountCalendar.IsReadOnly)))
+        {
+            await Connection
+                .ExecuteAsync($"ALTER TABLE {nameof(AccountCalendar)} ADD COLUMN {nameof(AccountCalendar.IsReadOnly)} INTEGER NOT NULL DEFAULT 0")
+                .ConfigureAwait(false);
+        }
+
         await Connection.ExecuteAsync("DROP TABLE IF EXISTS WinoAccountAddOnCache").ConfigureAwait(false);
     }
 
@@ -219,6 +228,12 @@ SET {nameof(KeyboardShortcut.Action)} =
         await Connection.ExecuteAsync("CREATE INDEX IF NOT EXISTS IX_MailCopy_MessageId ON MailCopy(MessageId)").ConfigureAwait(false);
         await Connection.ExecuteAsync("CREATE INDEX IF NOT EXISTS IX_MailCopy_FolderId_IsRead ON MailCopy(FolderId, IsRead)").ConfigureAwait(false);
         await Connection.ExecuteAsync("CREATE INDEX IF NOT EXISTS IX_MailCopy_CreationDate ON MailCopy(CreationDate)").ConfigureAwait(false);
+        await Connection.ExecuteAsync("CREATE INDEX IF NOT EXISTS IX_MailCategory_MailAccountId ON MailCategory(MailAccountId)").ConfigureAwait(false);
+        await Connection.ExecuteAsync("CREATE INDEX IF NOT EXISTS IX_MailCategory_MailAccountId_Name ON MailCategory(MailAccountId, Name)").ConfigureAwait(false);
+        await Connection.ExecuteAsync("CREATE INDEX IF NOT EXISTS IX_MailCategory_MailAccountId_IsFavorite ON MailCategory(MailAccountId, IsFavorite)").ConfigureAwait(false);
+        await Connection.ExecuteAsync("CREATE INDEX IF NOT EXISTS IX_MailCategoryAssignment_MailCategoryId ON MailCategoryAssignment(MailCategoryId)").ConfigureAwait(false);
+        await Connection.ExecuteAsync("CREATE INDEX IF NOT EXISTS IX_MailCategoryAssignment_MailCopyUniqueId ON MailCategoryAssignment(MailCopyUniqueId)").ConfigureAwait(false);
+        await Connection.ExecuteAsync("CREATE UNIQUE INDEX IF NOT EXISTS IX_MailCategoryAssignment_Category_MailCopy ON MailCategoryAssignment(MailCategoryId, MailCopyUniqueId)").ConfigureAwait(false);
 
         await Connection.ExecuteAsync("CREATE INDEX IF NOT EXISTS IX_MailItemFolder_MailAccountId ON MailItemFolder(MailAccountId)").ConfigureAwait(false);
         await Connection.ExecuteAsync("CREATE INDEX IF NOT EXISTS IX_MailItemFolder_MailAccountId_RemoteFolderId ON MailItemFolder(MailAccountId, RemoteFolderId)").ConfigureAwait(false);

Wino.Services/FolderService.cs

@@ -22,6 +22,7 @@ namespace Wino.Services;
 public class FolderService : BaseDatabaseService, IFolderService
 {
     private readonly IAccountService _accountService;
+    private readonly IMailCategoryService _mailCategoryService;
     private readonly ILogger _logger = Log.ForContext<FolderService>();
 
     private readonly SpecialFolderType[] gmailCategoryFolderTypes =
@@ -34,9 +35,11 @@ public class FolderService : BaseDatabaseService, IFolderService
     ];
 
     public FolderService(IDatabaseService databaseService,
-                           IAccountService accountService) : base(databaseService)
+                           IAccountService accountService,
+                           IMailCategoryService mailCategoryService) : base(databaseService)
     {
         _accountService = accountService;
+        _mailCategoryService = mailCategoryService;
     }
 
     public async Task ChangeStickyStatusAsync(Guid folderId, bool isSticky)
@@ -269,6 +272,9 @@ public class FolderService : BaseDatabaseService, IFolderService
             }
         }
 
+        var favoriteCategories = await GetFavoriteCategoryMenuItemsAsync(mailAccount, folders, accountMenuItem).ConfigureAwait(false);
+        preparedFolderMenuItems.AddRange(favoriteCategories);
+
         // Only add category folder if it's Gmail.
         if (mailAccount.ProviderType == MailProviderType.Gmail) preparedFolderMenuItems.Add(categoryFolderMenuItem);
 
@@ -309,9 +315,62 @@ public class FolderService : BaseDatabaseService, IFolderService
             preparedFolderMenuItems.Add(menuItem);
         }
 
+        var favoriteCategories = await GetMergedFavoriteCategoryMenuItemsAsync(holdingAccounts, allAccountFolders, mergedAccountFolderMenuItem.Parameter).ConfigureAwait(false);
+        preparedFolderMenuItems.AddRange(favoriteCategories);
+
         return preparedFolderMenuItems;
     }
 
+    private async Task<IEnumerable<IMenuItem>> GetFavoriteCategoryMenuItemsAsync(MailAccount account, IEnumerable<IMailItemFolder> handlingFolders, IMenuItem parentMenuItem)
+    {
+        var favoriteCategories = await _mailCategoryService.GetFavoriteCategoriesAsync(account.Id).ConfigureAwait(false);
+
+        if (!favoriteCategories.Any())
+            return [];
+
+        var availableFolders = handlingFolders
+            .Where(a => a.IsMoveTarget)
+            .Cast<IMailItemFolder>()
+            .ToList();
+
+        return favoriteCategories
+            .Select(category => (IMenuItem)new MailCategoryMenuItem(category, account, availableFolders, parentMenuItem))
+            .ToList();
+    }
+
+    private async Task<IEnumerable<IMenuItem>> GetMergedFavoriteCategoryMenuItemsAsync(IEnumerable<MailAccount> holdingAccounts, IEnumerable<IEnumerable<MailItemFolder>> allAccountFolders, MergedInbox mergedInbox)
+    {
+        var categoriesByAccount = new List<(MailAccount Account, List<MailCategory> Categories)>();
+
+        foreach (var account in holdingAccounts)
+        {
+            var categories = await _mailCategoryService.GetFavoriteCategoriesAsync(account.Id).ConfigureAwait(false);
+            if (categories.Any())
+            {
+                categoriesByAccount.Add((account, categories));
+            }
+        }
+
+        if (!categoriesByAccount.Any())
+            return [];
+
+        var handlingFolders = allAccountFolders
+            .SelectMany(a => a)
+            .Where(a => a.IsMoveTarget)
+            .Cast<IMailItemFolder>()
+            .ToList();
+
+        return categoriesByAccount
+            .SelectMany(a => a.Categories)
+            .GroupBy(a => NormalizeCategoryName(a.Name), StringComparer.OrdinalIgnoreCase)
+            .Select(group => (IMenuItem)new MergedMailCategoryMenuItem(group.ToList(), handlingFolders, mergedInbox))
+            .OrderBy(item => ((MergedMailCategoryMenuItem)item).FolderName, StringComparer.CurrentCultureIgnoreCase)
+            .ToList();
+    }
+
+    private static string NormalizeCategoryName(string name)
+        => name?.Trim() ?? string.Empty;
+
     private HashSet<SpecialFolderType> FindCommonFolders(List<List<MailItemFolder>> lists)
     {
         var allSpecialTypesExceptOther = Enum.GetValues<SpecialFolderType>().Cast<SpecialFolderType>().Where(a => a != SpecialFolderType.Other).ToList();

Wino.Services/MailCategoryService.cs

@@ -0,0 +1,358 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using CommunityToolkit.Mvvm.Messaging;
+using Wino.Core.Domain.Entities.Mail;
+using Wino.Core.Domain.Interfaces;
+using Wino.Core.Domain.Models.Accounts;
+using Wino.Messaging.Client.Accounts;
+using Wino.Messaging.UI;
+
+namespace Wino.Services;
+
+public class MailCategoryService : BaseDatabaseService, IMailCategoryService
+{
+    public MailCategoryService(IDatabaseService databaseService) : base(databaseService)
+    {
+    }
+
+    public Task<List<MailCategory>> GetCategoriesAsync(Guid accountId)
+        => Connection.QueryAsync<MailCategory>(
+            $"SELECT * FROM {nameof(MailCategory)} WHERE {nameof(MailCategory.MailAccountId)} = ? ORDER BY {nameof(MailCategory.IsFavorite)} DESC, {nameof(MailCategory.Name)} COLLATE NOCASE",
+            accountId);
+
+    public Task<List<MailCategory>> GetFavoriteCategoriesAsync(Guid accountId)
+        => Connection.QueryAsync<MailCategory>(
+            $"SELECT * FROM {nameof(MailCategory)} WHERE {nameof(MailCategory.MailAccountId)} = ? AND {nameof(MailCategory.IsFavorite)} = 1 ORDER BY {nameof(MailCategory.Name)} COLLATE NOCASE",
+            accountId);
+
+    public Task<MailCategory> GetCategoryAsync(Guid categoryId)
+        => Connection.FindAsync<MailCategory>(categoryId);
+
+    public async Task<bool> CategoryNameExistsAsync(Guid accountId, string name, Guid? excludedCategoryId = null)
+    {
+        var normalizedName = NormalizeCategoryName(name);
+        if (string.IsNullOrWhiteSpace(normalizedName))
+            return false;
+
+        var sql = $"SELECT COUNT(*) FROM {nameof(MailCategory)} WHERE {nameof(MailCategory.MailAccountId)} = ? AND lower(trim({nameof(MailCategory.Name)})) = ?";
+        var parameters = new List<object> { accountId, normalizedName.ToLowerInvariant() };
+
+        if (excludedCategoryId.HasValue)
+        {
+            sql += $" AND {nameof(MailCategory.Id)} <> ?";
+            parameters.Add(excludedCategoryId.Value);
+        }
+
+        return await Connection.ExecuteScalarAsync<int>(sql, parameters.ToArray()).ConfigureAwait(false) > 0;
+    }
+
+    public async Task<MailCategory> CreateCategoryAsync(MailCategory category)
+    {
+        category.Id = category.Id == Guid.Empty ? Guid.NewGuid() : category.Id;
+        category.Name = NormalizeCategoryName(category.Name);
+
+        await Connection.InsertAsync(category, typeof(MailCategory)).ConfigureAwait(false);
+        NotifyCategoryStructureChanged(category.MailAccountId);
+
+        return category;
+    }
+
+    public async Task UpdateCategoryAsync(MailCategory category)
+    {
+        category.Name = NormalizeCategoryName(category.Name);
+
+        await Connection.UpdateAsync(category, typeof(MailCategory)).ConfigureAwait(false);
+        NotifyCategoryStructureChanged(category.MailAccountId);
+    }
+
+    public async Task DeleteCategoryAsync(Guid categoryId)
+    {
+        var category = await GetCategoryAsync(categoryId).ConfigureAwait(false);
+        if (category == null)
+            return;
+
+        await Connection.ExecuteAsync($"DELETE FROM {nameof(MailCategoryAssignment)} WHERE {nameof(MailCategoryAssignment.MailCategoryId)} = ?", categoryId).ConfigureAwait(false);
+        await Connection.DeleteAsync<MailCategory>(categoryId).ConfigureAwait(false);
+
+        NotifyCategoryStructureChanged(category.MailAccountId);
+    }
+
+    public async Task DeleteCategoriesAsync(Guid accountId)
+    {
+        var categories = await GetCategoriesAsync(accountId).ConfigureAwait(false);
+
+        if (categories.Count == 0)
+            return;
+
+        var categoryIds = categories.Select(a => a.Id).ToList();
+        var placeholders = string.Join(",", categoryIds.Select(_ => "?"));
+        var deleteAssignmentsSql = $"DELETE FROM {nameof(MailCategoryAssignment)} WHERE {nameof(MailCategoryAssignment.MailCategoryId)} IN ({placeholders})";
+
+        await Connection.ExecuteAsync(deleteAssignmentsSql, categoryIds.Cast<object>().ToArray()).ConfigureAwait(false);
+        await Connection.Table<MailCategory>().DeleteAsync(a => a.MailAccountId == accountId).ConfigureAwait(false);
+
+        NotifyCategoryStructureChanged(accountId);
+    }
+
+    public async Task ToggleFavoriteAsync(Guid categoryId, bool isFavorite)
+    {
+        var category = await GetCategoryAsync(categoryId).ConfigureAwait(false);
+        if (category == null || category.IsFavorite == isFavorite)
+            return;
+
+        category.IsFavorite = isFavorite;
+        await Connection.UpdateAsync(category, typeof(MailCategory)).ConfigureAwait(false);
+
+        NotifyCategoryStructureChanged(category.MailAccountId);
+    }
+
+    public async Task UpdateRemoteIdAsync(Guid categoryId, string remoteId)
+    {
+        var category = await GetCategoryAsync(categoryId).ConfigureAwait(false);
+        if (category == null)
+            return;
+
+        category.RemoteId = remoteId;
+        await Connection.UpdateAsync(category, typeof(MailCategory)).ConfigureAwait(false);
+    }
+
+    public async Task ReplaceCategoriesAsync(Guid accountId, IEnumerable<MailCategory> categories)
+    {
+        var existingCategories = await GetCategoriesAsync(accountId).ConfigureAwait(false);
+        var existingByRemoteId = existingCategories
+            .Where(a => !string.IsNullOrWhiteSpace(a.RemoteId))
+            .ToDictionary(a => a.RemoteId, StringComparer.OrdinalIgnoreCase);
+        var existingByName = existingCategories
+            .GroupBy(a => NormalizeCategoryName(a.Name), StringComparer.OrdinalIgnoreCase)
+            .ToDictionary(a => a.Key, a => a.First(), StringComparer.OrdinalIgnoreCase);
+
+        var incomingCategories = categories?.ToList() ?? [];
+        var preservedIds = new HashSet<Guid>();
+
+        foreach (var incoming in incomingCategories)
+        {
+            incoming.MailAccountId = accountId;
+            incoming.Id = incoming.Id == Guid.Empty ? Guid.NewGuid() : incoming.Id;
+            incoming.Name = NormalizeCategoryName(incoming.Name);
+
+            MailCategory existing = null;
+
+            if (!string.IsNullOrWhiteSpace(incoming.RemoteId) && existingByRemoteId.TryGetValue(incoming.RemoteId, out var byRemote))
+            {
+                existing = byRemote;
+            }
+            else if (existingByName.TryGetValue(incoming.Name, out var byName))
+            {
+                existing = byName;
+            }
+
+            if (existing == null)
+            {
+                await Connection.InsertAsync(incoming, typeof(MailCategory)).ConfigureAwait(false);
+                preservedIds.Add(incoming.Id);
+            }
+            else
+            {
+                incoming.Id = existing.Id;
+                incoming.IsFavorite = existing.IsFavorite;
+                await Connection.UpdateAsync(incoming, typeof(MailCategory)).ConfigureAwait(false);
+                preservedIds.Add(existing.Id);
+            }
+        }
+
+        var categoryIdsToDelete = existingCategories
+            .Where(a => !preservedIds.Contains(a.Id))
+            .Select(a => a.Id)
+            .ToList();
+
+        if (categoryIdsToDelete.Count > 0)
+        {
+            var placeholders = string.Join(",", categoryIdsToDelete.Select(_ => "?"));
+            await Connection.ExecuteAsync(
+                $"DELETE FROM {nameof(MailCategoryAssignment)} WHERE {nameof(MailCategoryAssignment.MailCategoryId)} IN ({placeholders})",
+                categoryIdsToDelete.Cast<object>().ToArray()).ConfigureAwait(false);
+
+            foreach (var categoryId in categoryIdsToDelete)
+            {
+                await Connection.DeleteAsync<MailCategory>(categoryId).ConfigureAwait(false);
+            }
+        }
+
+        NotifyCategoryStructureChanged(accountId);
+    }
+
+    public async Task ReplaceMailAssignmentsAsync(Guid accountId, Guid mailCopyUniqueId, IEnumerable<string> categoryNames)
+    {
+        var normalizedNames = categoryNames?
+            .Select(NormalizeCategoryName)
+            .Where(a => !string.IsNullOrWhiteSpace(a))
+            .Distinct(StringComparer.OrdinalIgnoreCase)
+            .ToList() ?? [];
+
+        var availableCategories = await GetCategoriesAsync(accountId).ConfigureAwait(false);
+        var categoryIds = availableCategories
+            .Where(a => normalizedNames.Contains(NormalizeCategoryName(a.Name), StringComparer.OrdinalIgnoreCase))
+            .Select(a => a.Id)
+            .ToHashSet();
+
+        var existingAssignments = await Connection.QueryAsync<MailCategoryAssignment>(
+            $"SELECT * FROM {nameof(MailCategoryAssignment)} WHERE {nameof(MailCategoryAssignment.MailCopyUniqueId)} = ?",
+            mailCopyUniqueId).ConfigureAwait(false);
+
+        var assignmentsToDelete = existingAssignments.Where(a => !categoryIds.Contains(a.MailCategoryId)).ToList();
+        var existingIds = existingAssignments.Select(a => a.MailCategoryId).ToHashSet();
+        var assignmentsToAdd = categoryIds.Where(a => !existingIds.Contains(a)).ToList();
+
+        foreach (var assignment in assignmentsToDelete)
+        {
+            await Connection.DeleteAsync<MailCategoryAssignment>(assignment.Id).ConfigureAwait(false);
+        }
+
+        foreach (var categoryId in assignmentsToAdd)
+        {
+            await Connection.InsertAsync(new MailCategoryAssignment
+            {
+                Id = Guid.NewGuid(),
+                MailCategoryId = categoryId,
+                MailCopyUniqueId = mailCopyUniqueId
+            }, typeof(MailCategoryAssignment)).ConfigureAwait(false);
+        }
+
+        WeakReferenceMessenger.Default.Send(new RefreshUnreadCountsMessage(accountId));
+    }
+
+    public async Task AssignCategoryAsync(Guid categoryId, IEnumerable<Guid> mailCopyUniqueIds)
+    {
+        var uniqueIds = mailCopyUniqueIds?.Distinct().ToList() ?? [];
+        if (uniqueIds.Count == 0)
+            return;
+
+        var category = await GetCategoryAsync(categoryId).ConfigureAwait(false);
+        if (category == null)
+            return;
+
+        var placeholders = string.Join(",", uniqueIds.Select(_ => "?"));
+        var query = $"SELECT * FROM {nameof(MailCategoryAssignment)} WHERE {nameof(MailCategoryAssignment.MailCategoryId)} = ? AND {nameof(MailCategoryAssignment.MailCopyUniqueId)} IN ({placeholders})";
+        var existingAssignments = await Connection.QueryAsync<MailCategoryAssignment>(
+            query,
+            [categoryId, .. uniqueIds.Cast<object>()]).ConfigureAwait(false);
+        var existingUniqueIds = existingAssignments.Select(a => a.MailCopyUniqueId).ToHashSet();
+
+        foreach (var uniqueId in uniqueIds.Where(a => !existingUniqueIds.Contains(a)))
+        {
+            await Connection.InsertAsync(new MailCategoryAssignment
+            {
+                Id = Guid.NewGuid(),
+                MailCategoryId = categoryId,
+                MailCopyUniqueId = uniqueId
+            }, typeof(MailCategoryAssignment)).ConfigureAwait(false);
+        }
+
+        WeakReferenceMessenger.Default.Send(new RefreshUnreadCountsMessage(category.MailAccountId));
+    }
+
+    public async Task UnassignCategoryAsync(Guid categoryId, IEnumerable<Guid> mailCopyUniqueIds)
+    {
+        var uniqueIds = mailCopyUniqueIds?.Distinct().ToList() ?? [];
+        if (uniqueIds.Count == 0)
+            return;
+
+        var category = await GetCategoryAsync(categoryId).ConfigureAwait(false);
+        if (category == null)
+            return;
+
+        var placeholders = string.Join(",", uniqueIds.Select(_ => "?"));
+        await Connection.ExecuteAsync(
+            $"DELETE FROM {nameof(MailCategoryAssignment)} WHERE {nameof(MailCategoryAssignment.MailCategoryId)} = ? AND {nameof(MailCategoryAssignment.MailCopyUniqueId)} IN ({placeholders})",
+            [categoryId, .. uniqueIds.Cast<object>()]).ConfigureAwait(false);
+
+        WeakReferenceMessenger.Default.Send(new RefreshUnreadCountsMessage(category.MailAccountId));
+    }
+
+    public async Task<List<MailCategory>> GetCategoriesForMailAsync(Guid accountId, IEnumerable<Guid> mailCopyUniqueIds)
+    {
+        var uniqueIds = mailCopyUniqueIds?.Distinct().ToList() ?? [];
+        if (uniqueIds.Count == 0)
+            return [];
+
+        var placeholders = string.Join(",", uniqueIds.Select(_ => "?"));
+        var sql = $"SELECT DISTINCT MailCategory.* FROM {nameof(MailCategory)} " +
+                  $"INNER JOIN {nameof(MailCategoryAssignment)} ON {nameof(MailCategory)}.{nameof(MailCategory.Id)} = {nameof(MailCategoryAssignment)}.{nameof(MailCategoryAssignment.MailCategoryId)} " +
+                  $"WHERE {nameof(MailCategory)}.{nameof(MailCategory.MailAccountId)} = ? AND {nameof(MailCategoryAssignment)}.{nameof(MailCategoryAssignment.MailCopyUniqueId)} IN ({placeholders}) " +
+                  $"ORDER BY {nameof(MailCategory.Name)} COLLATE NOCASE";
+
+        return await Connection.QueryAsync<MailCategory>(
+            sql,
+            [accountId, .. uniqueIds.Cast<object>()]).ConfigureAwait(false);
+    }
+
+    public async Task<List<Guid>> GetAssignedCategoryIdsForAllAsync(IEnumerable<Guid> mailCopyUniqueIds)
+    {
+        var uniqueIds = mailCopyUniqueIds?.Distinct().ToList() ?? [];
+        if (uniqueIds.Count == 0)
+            return [];
+
+        var placeholders = string.Join(",", uniqueIds.Select(_ => "?"));
+        var sql = $"SELECT {nameof(MailCategoryAssignment.MailCategoryId)} " +
+                  $"FROM {nameof(MailCategoryAssignment)} " +
+                  $"WHERE {nameof(MailCategoryAssignment.MailCopyUniqueId)} IN ({placeholders}) " +
+                  $"GROUP BY {nameof(MailCategoryAssignment.MailCategoryId)} " +
+                  $"HAVING COUNT(DISTINCT {nameof(MailCategoryAssignment.MailCopyUniqueId)}) = ?";
+
+        return await Connection.QueryScalarsAsync<Guid>(
+            sql,
+            [.. uniqueIds.Cast<object>(), uniqueIds.Count]).ConfigureAwait(false);
+    }
+
+    public async Task<List<string>> GetCategoryNamesForMailAsync(Guid mailCopyUniqueId)
+    {
+        var sql = $"SELECT {nameof(MailCategory.Name)} " +
+                  $"FROM {nameof(MailCategory)} " +
+                  $"INNER JOIN {nameof(MailCategoryAssignment)} ON {nameof(MailCategory)}.{nameof(MailCategory.Id)} = {nameof(MailCategoryAssignment.MailCategoryId)} " +
+                  $"WHERE {nameof(MailCategoryAssignment.MailCopyUniqueId)} = ? " +
+                  $"ORDER BY {nameof(MailCategory.Name)} COLLATE NOCASE";
+
+        return await Connection.QueryScalarsAsync<string>(sql, mailCopyUniqueId).ConfigureAwait(false);
+    }
+
+    public async Task<List<MailCopy>> GetMailCopiesForCategoryAsync(Guid categoryId)
+    {
+        var sql = $"SELECT {nameof(MailCopy)}.* " +
+                  $"FROM {nameof(MailCopy)} " +
+                  $"INNER JOIN {nameof(MailCategoryAssignment)} ON {nameof(MailCopy)}.{nameof(MailCopy.UniqueId)} = {nameof(MailCategoryAssignment.MailCopyUniqueId)} " +
+                  $"WHERE {nameof(MailCategoryAssignment.MailCategoryId)} = ?";
+
+        return await Connection.QueryAsync<MailCopy>(sql, categoryId).ConfigureAwait(false);
+    }
+
+    public Task<List<UnreadCategoryCountResult>> GetUnreadCategoryCountResultsAsync(IEnumerable<Guid> accountIds)
+    {
+        var accountIdList = accountIds?.Distinct().ToList() ?? [];
+        if (accountIdList.Count == 0)
+            return Task.FromResult(new List<UnreadCategoryCountResult>());
+
+        var placeholders = string.Join(",", accountIdList.Select(_ => "?"));
+        var sql =
+            $"SELECT MailCategory.{nameof(MailCategory.Id)} as {nameof(UnreadCategoryCountResult.CategoryId)}, " +
+            $"MailCategory.{nameof(MailCategory.MailAccountId)} as {nameof(UnreadCategoryCountResult.AccountId)}, " +
+            $"COUNT(DISTINCT MailCopy.{nameof(MailCopy.UniqueId)}) as {nameof(UnreadCategoryCountResult.UnreadItemCount)} " +
+            $"FROM {nameof(MailCategory)} " +
+            $"INNER JOIN {nameof(MailCategoryAssignment)} ON {nameof(MailCategory)}.{nameof(MailCategory.Id)} = {nameof(MailCategoryAssignment)}.{nameof(MailCategoryAssignment.MailCategoryId)} " +
+            $"INNER JOIN {nameof(MailCopy)} ON {nameof(MailCategoryAssignment)}.{nameof(MailCategoryAssignment.MailCopyUniqueId)} = {nameof(MailCopy)}.{nameof(MailCopy.UniqueId)} " +
+            $"WHERE MailCategory.{nameof(MailCategory.MailAccountId)} IN ({placeholders}) AND MailCopy.{nameof(MailCopy.IsRead)} = 0 " +
+            $"GROUP BY MailCategory.{nameof(MailCategory.Id)}";
+
+        return Connection.QueryAsync<UnreadCategoryCountResult>(sql, accountIdList.Cast<object>().ToArray());
+    }
+
+    private void NotifyCategoryStructureChanged(Guid accountId)
+    {
+        WeakReferenceMessenger.Default.Send(new AccountsMenuRefreshRequested(false));
+        WeakReferenceMessenger.Default.Send(new RefreshUnreadCountsMessage(accountId));
+    }
+
+    private static string NormalizeCategoryName(string name)
+        => name?.Trim() ?? string.Empty;
+}

Wino.Services/MailService.cs

@@ -32,6 +32,7 @@ public class MailService : BaseDatabaseService, IMailService
     private readonly IMimeFileService _mimeFileService;
     private readonly IPreferencesService _preferencesService;
     private readonly ISentMailReceiptService _sentMailReceiptService;
+    private readonly IMailCategoryService _mailCategoryService;
 
     private readonly ILogger _logger = Log.ForContext<MailService>();
 
@@ -42,7 +43,8 @@ public class MailService : BaseDatabaseService, IMailService
                        ISignatureService signatureService,
                        IMimeFileService mimeFileService,
                        IPreferencesService preferencesService,
-                       ISentMailReceiptService sentMailReceiptService) : base(databaseService)
+                       ISentMailReceiptService sentMailReceiptService,
+                       IMailCategoryService mailCategoryService) : base(databaseService)
     {
         _folderService = folderService;
         _contactService = contactService;
@@ -51,6 +53,7 @@ public class MailService : BaseDatabaseService, IMailService
         _mimeFileService = mimeFileService;
         _preferencesService = preferencesService;
         _sentMailReceiptService = sentMailReceiptService;
+        _mailCategoryService = mailCategoryService;
     }
 
     public async Task<(MailCopy draftMailCopy, string draftBase64MimeMessage)> CreateDraftAsync(Guid accountId, DraftCreationOptions draftCreationOptions)
@@ -171,7 +174,9 @@ public class MailService : BaseDatabaseService, IMailService
     private static (string Query, object[] Parameters) BuildMailFetchQuery(MailListInitializationOptions options)
     {
         var sql = new StringBuilder();
-        sql.Append("SELECT MailCopy.* FROM MailCopy INNER JOIN MailItemFolder ON MailCopy.FolderId = MailItemFolder.Id");
+        sql.Append(options.IsCategoryView
+            ? "SELECT DISTINCT MailCopy.* FROM MailCopy INNER JOIN MailItemFolder ON MailCopy.FolderId = MailItemFolder.Id INNER JOIN MailCategoryAssignment ON MailCopy.UniqueId = MailCategoryAssignment.MailCopyUniqueId"
+            : "SELECT MailCopy.* FROM MailCopy INNER JOIN MailItemFolder ON MailCopy.FolderId = MailItemFolder.Id");
 
         var whereClauses = new List<string>();
         var parameters = new List<object>();
@@ -181,6 +186,13 @@ public class MailService : BaseDatabaseService, IMailService
         whereClauses.Add($"MailCopy.FolderId IN ({folderPlaceholders})");
         parameters.AddRange(options.Folders.Select(f => (object)f.Id));
 
+        if (options.IsCategoryView)
+        {
+            var categoryPlaceholders = string.Join(",", options.CategoryIds.Select(_ => "?"));
+            whereClauses.Add($"MailCategoryAssignment.MailCategoryId IN ({categoryPlaceholders})");
+            parameters.AddRange(options.CategoryIds.Select(a => (object)a));
+        }
+
         // Filter type
         switch (options.FilterType)
         {
@@ -338,7 +350,7 @@ public class MailService : BaseDatabaseService, IMailService
     {
         List<MailCopy> mails;
 
-        if (options.PreFetchMailCopies != null)
+        if (options.PreFetchMailCopies != null && !options.IsCategoryView)
         {
             mails = ApplyOptionsToPreFetchedMails(options);
         }
@@ -398,7 +410,7 @@ public class MailService : BaseDatabaseService, IMailService
         mails.RemoveAll(m => m.AssignedAccount == null || m.AssignedFolder == null);
         await _sentMailReceiptService.PopulateReceiptStatesAsync(mails).ConfigureAwait(false);
 
-        if (!options.CreateThreads || mails.Count == 0)
+        if (!options.CreateThreads || mails.Count == 0 || options.IsCategoryView)
             return [.. mails];
 
         // 6. Expand threads: one batch query for all sibling mails across all threads.
@@ -727,6 +739,7 @@ public class MailService : BaseDatabaseService, IMailService
         _logger.Debug("Deleting mail {Id} from folder {FolderName}", mailCopy.Id, mailCopy.AssignedFolder.FolderName);
 
         await Connection.DeleteAsync<MailCopy>(mailCopy.UniqueId).ConfigureAwait(false);
+        await Connection.ExecuteAsync("DELETE FROM MailCategoryAssignment WHERE MailCopyUniqueId = ?", mailCopy.UniqueId).ConfigureAwait(false);
 
         // If there are no more copies exists of the same mail, delete the MIME file as well.
         var isMailExists = await IsMailExistsAsync(mailCopy.Id).ConfigureAwait(false);
@@ -965,6 +978,7 @@ public class MailService : BaseDatabaseService, IMailService
             mailCopy.UniqueId = existingCopyItem.UniqueId;
 
             await UpdateMailAsync(mailCopy).ConfigureAwait(false);
+            await ReplaceMailCategoriesForPackageAsync(accountId, mailCopy, package).ConfigureAwait(false);
             await _sentMailReceiptService.TrackSentMailAsync(mailCopy, mimeMessage).ConfigureAwait(false);
             await _sentMailReceiptService.ProcessIncomingReceiptAsync(mailCopy, mimeMessage).ConfigureAwait(false);
 
@@ -981,6 +995,7 @@ public class MailService : BaseDatabaseService, IMailService
             }
 
             await InsertMailAsync(mailCopy).ConfigureAwait(false);
+            await ReplaceMailCategoriesForPackageAsync(accountId, mailCopy, package).ConfigureAwait(false);
             await _sentMailReceiptService.TrackSentMailAsync(mailCopy, mimeMessage).ConfigureAwait(false);
             await _sentMailReceiptService.ProcessIncomingReceiptAsync(mailCopy, mimeMessage).ConfigureAwait(false);
 
@@ -1017,6 +1032,11 @@ public class MailService : BaseDatabaseService, IMailService
         await _contactService.SaveAddressInformationAsync(contacts).ConfigureAwait(false);
     }
 
+    private Task ReplaceMailCategoriesForPackageAsync(Guid accountId, MailCopy mailCopy, NewMailItemPackage package)
+        => package?.CategoryNames == null
+            ? Task.CompletedTask
+            : _mailCategoryService.ReplaceMailAssignmentsAsync(accountId, mailCopy.UniqueId, package.CategoryNames);
+
     private async Task<MimeMessage> CreateDraftMimeAsync(MailAccount account, DraftCreationOptions draftCreationOptions, MailAccountAlias selectedAlias)
     {
         // This unique id is stored in mime headers for Wino to identify remote message with local copy.

Wino.Services/ServicesContainerSetup.cs

@@ -20,6 +20,7 @@ public static class ServicesContainerSetup
 
         services.AddTransient<ICalendarService, CalendarService>();
         services.AddTransient<IMailService, MailService>();
+        services.AddTransient<IMailCategoryService, MailCategoryService>();
         services.AddTransient<ISentMailReceiptService, SentMailReceiptService>();
         services.AddTransient<IFolderService, FolderService>();
         services.AddTransient<IAccountService, AccountService>();

nuget.config

@@ -14,13 +14,13 @@
 		<!-- key value for <packageSource> should match key values from <packageSources> element -->
 		<packageSource key="nuget">
 			<package pattern="*" />
+			<package pattern="CommunityToolkit.WinUI.Extensions" />
 			<!-- <package pattern="CommunityToolkit.Common" />
 			<package pattern="Microsoft.*" />
 			<package pattern="Newtonsoft.Json" /> -->
 		</packageSource>
 		<packageSource key="labsFeed">
 			<package pattern="CommunityToolkit.Labs.*" />
-			<package pattern="CommunityToolkit.WinUI.Extensions" />
 		</packageSource>
 	</packageSourceMapping>
 </configuration>