Files
Wino-Mail/Wino.Core/Synchronizers/ImapSync/UnifiedImapSynchronizer.cs
T

474 lines
18 KiB
C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using MailKit;
using MailKit.Net.Imap;
using MailKit.Search;
using MoreLinq;
using Serilog;
using Wino.Core.Domain.Entities.Mail;
using Wino.Core.Domain.Enums;
using Wino.Core.Domain.Interfaces;
using Wino.Core.Domain.Models.MailItem;
using Wino.Core.Domain.Models.Synchronization;
using Wino.Core.Integration;
using Wino.Services.Extensions;
using IMailService = Wino.Core.Domain.Interfaces.IMailService;
namespace Wino.Core.Synchronizers.ImapSync;
/// <summary>
/// Unified IMAP synchronization strategy that automatically selects the best available method:
/// 1. QRESYNC (RFC 5162) - Best: supports quick resync with vanished messages
/// 2. CONDSTORE (RFC 4551) - Good: supports mod-seq based change tracking
/// 3. UID-based - Fallback: basic UID comparison
///
/// This consolidates the previous QResyncSynchronizer, CondstoreSynchronizer, and UidBasedSynchronizer
/// into a single, enterprise-grade implementation with proper error handling and partial failure support.
/// </summary>
public class UnifiedImapSynchronizer
{
private readonly ILogger _logger = Log.ForContext<UnifiedImapSynchronizer>();
private readonly IFolderService _folderService;
private readonly IMailService _mailService;
private readonly IImapSynchronizerErrorHandlerFactory _errorHandlerFactory;
// Minimum summary items to Fetch for mail synchronization from IMAP.
private readonly MessageSummaryItems MailSynchronizationFlags =
MessageSummaryItems.Flags |
MessageSummaryItems.UniqueId |
MessageSummaryItems.ThreadId |
MessageSummaryItems.EmailId |
MessageSummaryItems.Headers |
MessageSummaryItems.PreviewText |
MessageSummaryItems.GMailThreadId |
MessageSummaryItems.References |
MessageSummaryItems.ModSeq;
public UnifiedImapSynchronizer(
IFolderService folderService,
IMailService mailService,
IImapSynchronizerErrorHandlerFactory errorHandlerFactory)
{
_folderService = folderService;
_mailService = mailService;
_errorHandlerFactory = errorHandlerFactory;
}
/// <summary>
/// Determines the best synchronization strategy based on server capabilities.
/// </summary>
public ImapSyncStrategy DetermineSyncStrategy(IImapClient client)
{
if (client is WinoImapClient winoClient &&
client.Capabilities.HasFlag(ImapCapabilities.QuickResync) &&
winoClient.IsQResyncEnabled)
{
return ImapSyncStrategy.QResync;
}
if (client.Capabilities.HasFlag(ImapCapabilities.CondStore))
{
return ImapSyncStrategy.Condstore;
}
return ImapSyncStrategy.UidBased;
}
/// <summary>
/// Main synchronization entry point. Automatically selects the best strategy.
/// </summary>
public async Task<FolderSyncResult> SynchronizeFolderAsync(
IImapClient client,
MailItemFolder folder,
IImapSynchronizer synchronizer,
CancellationToken cancellationToken = default)
{
var strategy = DetermineSyncStrategy(client);
_logger.Debug("Using {Strategy} sync strategy for folder {FolderName}", strategy, folder.FolderName);
try
{
var downloadedIds = strategy switch
{
ImapSyncStrategy.QResync => await SynchronizeWithQResyncAsync(client, folder, synchronizer, cancellationToken),
ImapSyncStrategy.Condstore => await SynchronizeWithCondstoreAsync(client, folder, synchronizer, cancellationToken),
_ => await SynchronizeWithUidBasedAsync(client, folder, synchronizer, cancellationToken)
};
return FolderSyncResult.Successful(folder.Id, folder.FolderName, downloadedIds.Count);
}
catch (FolderNotFoundException)
{
_logger.Warning("Folder {FolderName} not found on server, deleting locally", folder.FolderName);
await _folderService.DeleteFolderAsync(folder.MailAccountId, folder.RemoteFolderId).ConfigureAwait(false);
return FolderSyncResult.Skipped(folder.Id, folder.FolderName, "Folder not found on server");
}
catch (OperationCanceledException)
{
throw;
}
catch (Exception ex)
{
var errorContext = new SynchronizerErrorContext
{
ErrorMessage = ex.Message,
Exception = ex,
FolderId = folder.Id,
FolderName = folder.FolderName,
OperationType = "ImapFolderSync"
};
var handled = await _errorHandlerFactory.HandleErrorAsync(errorContext).ConfigureAwait(false);
if (errorContext.CanContinueSync)
{
_logger.Warning(ex, "Folder {FolderName} sync failed with recoverable error", folder.FolderName);
return FolderSyncResult.Failed(folder.Id, folder.FolderName, errorContext);
}
_logger.Error(ex, "Folder {FolderName} sync failed with fatal error", folder.FolderName);
throw;
}
}
#region QRESYNC Strategy
private async Task<List<string>> SynchronizeWithQResyncAsync(
IImapClient client,
MailItemFolder folder,
IImapSynchronizer synchronizer,
CancellationToken cancellationToken)
{
var downloadedMessageIds = new List<string>();
if (client is not WinoImapClient winoClient)
throw new InvalidOperationException("QRESYNC requires WinoImapClient");
IMailFolder remoteFolder = null;
try
{
remoteFolder = await client.GetFolderAsync(folder.RemoteFolderId, cancellationToken).ConfigureAwait(false);
var localHighestModSeq = (ulong)Math.Max(folder.HighestModeSeq, 1);
var allUids = await _folderService.GetKnownUidsForFolderAsync(folder.Id);
var allUniqueIds = allUids.Select(a => new UniqueId(a)).ToList();
// Subscribe to events before opening
remoteFolder.MessagesVanished += (s, e) => HandleMessagesVanished(folder, e.UniqueIds);
remoteFolder.MessageFlagsChanged += (s, e) => HandleMessageFlagsChanged(folder, e.UniqueId, e.Flags);
// Open with QRESYNC parameters
await remoteFolder.OpenAsync(FolderAccess.ReadOnly, folder.UidValidity, localHighestModSeq, allUniqueIds, cancellationToken).ConfigureAwait(false);
// Get changed UIDs
var changedUids = await remoteFolder.SearchAsync(SearchQuery.ChangedSince(localHighestModSeq), cancellationToken).ConfigureAwait(false);
downloadedMessageIds = await ProcessChangedUidsAsync(synchronizer, remoteFolder, folder, changedUids, cancellationToken).ConfigureAwait(false);
// Update folder tracking
folder.HighestModeSeq = unchecked((long)remoteFolder.HighestModSeq);
folder.UidValidity = remoteFolder.UidValidity;
// Handle deletions
await HandleDeletedMessagesAsync(folder, remoteFolder, cancellationToken).ConfigureAwait(false);
await _folderService.UpdateFolderAsync(folder).ConfigureAwait(false);
}
finally
{
if (remoteFolder?.IsOpen == true && !cancellationToken.IsCancellationRequested)
{
await remoteFolder.CloseAsync().ConfigureAwait(false);
}
}
return downloadedMessageIds;
}
#endregion
#region CONDSTORE Strategy
private async Task<List<string>> SynchronizeWithCondstoreAsync(
IImapClient client,
MailItemFolder folder,
IImapSynchronizer synchronizer,
CancellationToken cancellationToken)
{
var downloadedMessageIds = new List<string>();
IMailFolder remoteFolder = null;
try
{
remoteFolder = await client.GetFolderAsync(folder.RemoteFolderId, cancellationToken).ConfigureAwait(false);
await remoteFolder.OpenAsync(FolderAccess.ReadOnly, cancellationToken).ConfigureAwait(false);
var localHighestModSeq = (ulong)folder.HighestModeSeq;
bool isInitialSync = localHighestModSeq == 0;
if (remoteFolder.HighestModSeq > localHighestModSeq || isInitialSync)
{
IList<UniqueId> changedUids;
// Use SORT if available for better ordering
if (client.Capabilities.HasFlag(ImapCapabilities.Sort))
{
changedUids = await remoteFolder.SortAsync(
SearchQuery.ChangedSince(Math.Max(localHighestModSeq, 1)),
[OrderBy.ReverseDate],
cancellationToken).ConfigureAwait(false);
}
else
{
changedUids = await remoteFolder.SearchAsync(
SearchQuery.ChangedSince(Math.Max(localHighestModSeq, 1)),
cancellationToken).ConfigureAwait(false);
}
// For initial sync, limit the number of messages
if (isInitialSync)
{
changedUids = changedUids
.OrderByDescending(a => a.Id)
.Take((int)synchronizer.InitialMessageDownloadCountPerFolder)
.ToList();
}
downloadedMessageIds = await ProcessChangedUidsAsync(synchronizer, remoteFolder, folder, changedUids, cancellationToken).ConfigureAwait(false);
folder.HighestModeSeq = unchecked((long)remoteFolder.HighestModSeq);
await _folderService.UpdateFolderAsync(folder).ConfigureAwait(false);
}
await HandleDeletedMessagesAsync(folder, remoteFolder, cancellationToken).ConfigureAwait(false);
}
finally
{
if (remoteFolder?.IsOpen == true && !cancellationToken.IsCancellationRequested)
{
await remoteFolder.CloseAsync(cancellationToken: cancellationToken).ConfigureAwait(false);
}
}
return downloadedMessageIds;
}
#endregion
#region UID-Based Strategy (Fallback)
private async Task<List<string>> SynchronizeWithUidBasedAsync(
IImapClient client,
MailItemFolder folder,
IImapSynchronizer synchronizer,
CancellationToken cancellationToken)
{
var downloadedMessageIds = new List<string>();
IMailFolder remoteFolder = null;
try
{
remoteFolder = await client.GetFolderAsync(folder.RemoteFolderId, cancellationToken).ConfigureAwait(false);
await remoteFolder.OpenAsync(FolderAccess.ReadOnly, cancellationToken).ConfigureAwait(false);
// Get all remote UIDs and take the most recent ones
var remoteUids = await remoteFolder.SearchAsync(SearchQuery.All, cancellationToken).ConfigureAwait(false);
var limitedUids = remoteUids
.OrderByDescending(a => a.Id)
.Take((int)synchronizer.InitialMessageDownloadCountPerFolder)
.ToList();
downloadedMessageIds = await ProcessChangedUidsAsync(synchronizer, remoteFolder, folder, limitedUids, cancellationToken).ConfigureAwait(false);
await HandleDeletedMessagesAsync(folder, remoteFolder, cancellationToken).ConfigureAwait(false);
}
finally
{
if (remoteFolder?.IsOpen == true && !cancellationToken.IsCancellationRequested)
{
await remoteFolder.CloseAsync(cancellationToken: cancellationToken).ConfigureAwait(false);
}
}
return downloadedMessageIds;
}
#endregion
#region Shared Processing Methods
private async Task<List<string>> ProcessChangedUidsAsync(
IImapSynchronizer synchronizer,
IMailFolder remoteFolder,
MailItemFolder localFolder,
IList<UniqueId> changedUids,
CancellationToken cancellationToken)
{
var downloadedMessageIds = new List<string>();
if (changedUids == null || changedUids.Count == 0)
return downloadedMessageIds;
// Get existing mails to determine what's new vs. updated
var existingMails = await _mailService.GetExistingMailsAsync(localFolder.Id, changedUids).ConfigureAwait(false);
var existingMailUids = existingMails.Select(m => MailkitClientExtensions.ResolveUidStruct(m.Id)).ToArray();
var newMessageUids = changedUids.Except(existingMailUids).ToList();
// Update flags for existing mails
if (existingMailUids.Any())
{
var existingFlagData = await remoteFolder.FetchAsync(existingMailUids, MessageSummaryItems.Flags | MessageSummaryItems.UniqueId, cancellationToken).ConfigureAwait(false);
foreach (var update in existingFlagData)
{
if (update.UniqueId == UniqueId.Invalid || update.Flags == null) continue;
var existingMail = existingMails.FirstOrDefault(m => MailkitClientExtensions.ResolveUidStruct(m.Id).Id == update.UniqueId.Id);
if (existingMail != null)
{
await UpdateMailFlagsAsync(existingMail, update.Flags.Value).ConfigureAwait(false);
}
}
}
// Download new messages in batches
var batches = newMessageUids.Batch(50);
foreach (var batch in batches)
{
cancellationToken.ThrowIfCancellationRequested();
var batchList = batch.ToList();
downloadedMessageIds.AddRange(batchList.Select(uid => MailkitClientExtensions.CreateUid(localFolder.Id, uid.Id)));
await DownloadMessagesAsync(synchronizer, remoteFolder, localFolder, new UniqueIdSet(batchList, SortOrder.Ascending), cancellationToken).ConfigureAwait(false);
}
return downloadedMessageIds;
}
private async Task DownloadMessagesAsync(
IImapSynchronizer synchronizer,
IMailFolder folder,
MailItemFolder localFolder,
UniqueIdSet uniqueIdSet,
CancellationToken cancellationToken)
{
var summaries = await folder.FetchAsync(uniqueIdSet, MailSynchronizationFlags, cancellationToken).ConfigureAwait(false);
foreach (var summary in summaries)
{
try
{
var mimeMessage = await folder.GetMessageAsync(summary.UniqueId, cancellationToken).ConfigureAwait(false);
var creationPackage = new ImapMessageCreationPackage(summary, mimeMessage);
var mailPackages = await synchronizer.CreateNewMailPackagesAsync(creationPackage, localFolder, cancellationToken).ConfigureAwait(false);
if (mailPackages != null)
{
foreach (var package in mailPackages)
{
if (package != null)
{
await _mailService.CreateMailAsync(localFolder.MailAccountId, package).ConfigureAwait(false);
}
}
}
}
catch (Exception ex)
{
_logger.Warning(ex, "Failed to download message {UniqueId} in folder {FolderName}", summary.UniqueId, localFolder.FolderName);
// Continue with other messages
}
}
}
private async Task HandleDeletedMessagesAsync(MailItemFolder localFolder, IMailFolder remoteFolder, CancellationToken cancellationToken)
{
var allLocalUids = (await _folderService.GetKnownUidsForFolderAsync(localFolder.Id)).Select(a => new UniqueId(a)).ToList();
if (allLocalUids.Count == 0) return;
var remoteAllUids = await remoteFolder.SearchAsync(SearchQuery.All, cancellationToken).ConfigureAwait(false);
var deletedUids = allLocalUids.Except(remoteAllUids).ToList();
foreach (var deletedUid in deletedUids)
{
var localMailCopyId = MailkitClientExtensions.CreateUid(localFolder.Id, deletedUid.Id);
await _mailService.DeleteMailAsync(localFolder.MailAccountId, localMailCopyId).ConfigureAwait(false);
}
}
private async Task UpdateMailFlagsAsync(MailCopy mailCopy, MessageFlags flags)
{
var isFlagged = MailkitClientExtensions.GetIsFlagged(flags);
var isRead = MailkitClientExtensions.GetIsRead(flags);
if (isFlagged != mailCopy.IsFlagged)
{
await _mailService.ChangeFlagStatusAsync(mailCopy.Id, isFlagged).ConfigureAwait(false);
}
if (isRead != mailCopy.IsRead)
{
await _mailService.ChangeReadStatusAsync(mailCopy.Id, isRead).ConfigureAwait(false);
}
}
private void HandleMessagesVanished(MailItemFolder folder, IList<UniqueId> uniqueIds)
{
// Fire and forget - these are event handlers
_ = Task.Run(async () =>
{
foreach (var uniqueId in uniqueIds)
{
var localMailCopyId = MailkitClientExtensions.CreateUid(folder.Id, uniqueId.Id);
await _mailService.DeleteMailAsync(folder.MailAccountId, localMailCopyId).ConfigureAwait(false);
}
});
}
private void HandleMessageFlagsChanged(MailItemFolder folder, UniqueId? uniqueId, MessageFlags flags)
{
if (uniqueId == null) return;
_ = Task.Run(async () =>
{
var localMailCopyId = MailkitClientExtensions.CreateUid(folder.Id, uniqueId.Value.Id);
var isFlagged = MailkitClientExtensions.GetIsFlagged(flags);
var isRead = MailkitClientExtensions.GetIsRead(flags);
await _mailService.ChangeReadStatusAsync(localMailCopyId, isRead).ConfigureAwait(false);
await _mailService.ChangeFlagStatusAsync(localMailCopyId, isFlagged).ConfigureAwait(false);
});
}
#endregion
}
/// <summary>
/// IMAP synchronization strategy enumeration.
/// </summary>
public enum ImapSyncStrategy
{
/// <summary>
/// RFC 5162 Quick Resync - supports vanished messages and efficient delta sync.
/// </summary>
QResync,
/// <summary>
/// RFC 4551 Conditional Store - supports mod-seq based change tracking.
/// </summary>
Condstore,
/// <summary>
/// Basic UID-based synchronization - fallback for servers without advanced features.
/// </summary>
UidBased
}