Refactored impa synchronization.

Wino.Services/DatabaseService.cs

@@ -1,4 +1,5 @@
-using System.IO;
+using System.IO;
+using System.Linq;
 using System.Threading.Tasks;
 using SQLite;
 using Wino.Core.Domain.Entities.Calendar;
@@ -63,6 +64,26 @@ public class DatabaseService : IDatabaseService
             Connection.CreateTableAsync<Reminder>(),
             Connection.CreateTableAsync<MailInvitationCalendarMapping>()
             );
+
+        await EnsureSchemaUpgradesAsync().ConfigureAwait(false);
     }
 
+    private async Task EnsureSchemaUpgradesAsync()
+    {
+        var folderColumns = await Connection.GetTableInfoAsync(nameof(MailItemFolder)).ConfigureAwait(false);
+
+        if (!folderColumns.Any(c => c.Name == nameof(MailItemFolder.HighestKnownUid)))
+        {
+            await Connection
+                .ExecuteAsync($"ALTER TABLE {nameof(MailItemFolder)} ADD COLUMN {nameof(MailItemFolder.HighestKnownUid)} INTEGER NOT NULL DEFAULT 0")
+                .ConfigureAwait(false);
+        }
+
+        if (!folderColumns.Any(c => c.Name == nameof(MailItemFolder.LastUidReconcileUtc)))
+        {
+            await Connection
+                .ExecuteAsync($"ALTER TABLE {nameof(MailItemFolder)} ADD COLUMN {nameof(MailItemFolder.LastUidReconcileUtc)} TEXT NULL")
+                .ConfigureAwait(false);
+        }
+    }
 }

Wino.Services/Extensions/MailkitClientExtensions.cs

@@ -93,44 +93,47 @@ public static class MailkitClientExtensions
             return HtmlAgilityPackExtensions.GetPreviewText(message.HtmlBody);
     }
 
-    public static MailCopy GetMailDetails(this IMessageSummary messageSummary, MailItemFolder folder, MimeMessage mime)
+    public static MailCopy GetMailDetails(this IMessageSummary messageSummary, MailItemFolder folder, MimeMessage mime = null)
     {
-        // MessageSummary will only have UniqueId, Flags, ThreadId.
-        // Other properties are extracted directly from the MimeMessage.
+        // IMAP UIDs are unique only within a folder.
+        // MailCopy.Id maps to {FolderId}_{UID} for deterministic folder-local identity.
 
-        // IMAP doesn't have unique id for mails.
-        // All mails are mapped to specific folders with incremental Id.
-        // Uid 1 may belong to different messages in different folders, but can never be
-        // same for different messages in same folders.
-        // Here we create arbitrary Id that maps the Id of the message with Folder UniqueId.
-        // When folder becomes invalid, we'll clear out these MailCopies as well.
+        var envelope = messageSummary.Envelope;
 
         var messageUid = CreateUid(folder.Id, messageSummary.UniqueId.Id);
-        var previewText = mime.GetPreviewText();
+        var subject = mime?.Subject ?? envelope?.Subject ?? string.Empty;
+        var previewText = mime != null ? mime.GetPreviewText() : GetPreviewText(messageSummary, subject);
 
-        // Use InternalDate (server received date) if available, otherwise fall back to Date header (sent date)
-        var creationDate = messageSummary.InternalDate?.UtcDateTime ?? mime.Date.UtcDateTime;
+        // Prefer InternalDate (server received time). Fall back to envelope date and finally UTC now.
+        var creationDate = messageSummary.InternalDate?.UtcDateTime
+                           ?? envelope?.Date?.UtcDateTime
+                           ?? DateTime.UtcNow;
 
-        // Detect calendar invitation based on MIME content type
-        var itemType = GetMailItemTypeFromMime(mime);
+        var messageId = mime?.GetMessageId() ?? envelope?.MessageId ?? string.Empty;
+        var fromName = mime != null ? GetActualSenderName(mime) : GetEnvelopeSenderName(envelope);
+        var fromAddress = mime != null ? GetActualSenderAddress(mime) : GetEnvelopeSenderAddress(envelope);
+        var references = mime?.References?.GetReferences() ?? messageSummary.References?.GetReferences();
+        var inReplyTo = mime != null ? mime.GetInReplyTo() : envelope?.InReplyTo ?? string.Empty;
+        var hasAttachments = mime != null ? mime.Attachments.Any() : false;
+        var itemType = mime != null ? GetMailItemTypeFromMime(mime) : MailItemType.Mail;
 
         var copy = new MailCopy()
         {
             Id = messageUid,
             CreationDate = creationDate,
             ThreadId = messageSummary.GetThreadId(),
-            MessageId = mime.GetMessageId(),
-            Subject = mime.Subject,
+            MessageId = messageId,
+            Subject = subject,
             IsRead = messageSummary.Flags.GetIsRead(),
             IsFlagged = messageSummary.Flags.GetIsFlagged(),
             PreviewText = previewText,
-            FromAddress = GetActualSenderAddress(mime),
-            FromName = GetActualSenderName(mime),
+            FromAddress = fromAddress,
+            FromName = fromName,
             IsFocused = false,
-            Importance = mime.GetImportance(),
-            References = mime.References?.GetReferences(),
-            InReplyTo = mime.GetInReplyTo(),
-            HasAttachments = mime.Attachments.Any(),
+            Importance = mime != null ? mime.GetImportance() : MailImportance.Normal,
+            References = references,
+            InReplyTo = inReplyTo,
+            HasAttachments = hasAttachments,
             FileId = Guid.NewGuid(),
             ItemType = itemType
         };
@@ -138,6 +141,29 @@ public static class MailkitClientExtensions
         return copy;
     }
 
+    private static string GetPreviewText(IMessageSummary messageSummary, string subjectFallback)
+    {
+        if (!string.IsNullOrWhiteSpace(messageSummary.PreviewText))
+            return messageSummary.PreviewText;
+
+        return subjectFallback ?? string.Empty;
+    }
+
+    private static string GetEnvelopeSenderName(Envelope envelope)
+    {
+        var mailbox = envelope?.From?.Mailboxes?.FirstOrDefault() ?? envelope?.Sender?.Mailboxes?.FirstOrDefault();
+        if (mailbox == null)
+            return Translator.UnknownSender;
+
+        return string.IsNullOrWhiteSpace(mailbox.Name) ? mailbox.Address : mailbox.Name;
+    }
+
+    private static string GetEnvelopeSenderAddress(Envelope envelope)
+    {
+        var mailbox = envelope?.From?.Mailboxes?.FirstOrDefault() ?? envelope?.Sender?.Mailboxes?.FirstOrDefault();
+        return mailbox?.Address ?? Translator.UnknownSender;
+    }
+
     /// <summary>
     /// Determines MailItemType based on MIME message content type.
     /// Calendar invitations have text/calendar content type with METHOD parameter.

Wino.Services/FolderService.cs

@@ -490,6 +490,9 @@ public class FolderService : BaseDatabaseService, IFolderService
         await Connection.UpdateAsync(folder, typeof(MailItemFolder)).ConfigureAwait(false);
     }
 
+    public Task UpdateFolderHighestModeSeqAsync(Guid folderId, long highestModeSeq)
+        => Connection.ExecuteAsync("UPDATE MailItemFolder SET HighestModeSeq = ? WHERE Id = ?", highestModeSeq, folderId);
+
     private async Task DeleteFolderAsync(MailItemFolder folder)
     {
         if (folder == null)