Refactored all synchronizers to deal with some of the chronic issues.

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

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Text.Json.Serialization;
 using Wino.Core.Domain.Entities.Mail;
 using Wino.Core.Domain.Enums;
@@ -25,6 +26,55 @@ public class MailSynchronizationResult
 
     public Exception Exception { get; set; }
 
+    /// <summary>
+    /// Gets or sets the results for each folder that was synchronized.
+    /// Enables partial failure tracking - some folders may succeed while others fail.
+    /// </summary>
+    public List<FolderSyncResult> FolderResults { get; set; } = [];
+
+    /// <summary>
+    /// Gets whether the synchronization had any partial failures.
+    /// True if at least one folder failed but others succeeded.
+    /// </summary>
+    [JsonIgnore]
+    public bool HasPartialFailures => FolderResults.Any(f => !f.Success) && FolderResults.Any(f => f.Success);
+
+    /// <summary>
+    /// Gets the number of folders that were successfully synchronized.
+    /// </summary>
+    [JsonIgnore]
+    public int SuccessfulFolderCount => FolderResults.Count(f => f.Success);
+
+    /// <summary>
+    /// Gets the number of folders that failed to synchronize.
+    /// </summary>
+    [JsonIgnore]
+    public int FailedFolderCount => FolderResults.Count(f => !f.Success);
+
+    /// <summary>
+    /// Gets the total number of messages downloaded across all folders.
+    /// </summary>
+    [JsonIgnore]
+    public int TotalDownloadedCount => FolderResults.Sum(f => f.DownloadedCount);
+
+    /// <summary>
+    /// Gets the total number of messages deleted across all folders.
+    /// </summary>
+    [JsonIgnore]
+    public int TotalDeletedCount => FolderResults.Sum(f => f.DeletedCount);
+
+    /// <summary>
+    /// Gets the total number of messages updated across all folders.
+    /// </summary>
+    [JsonIgnore]
+    public int TotalUpdatedCount => FolderResults.Sum(f => f.UpdatedCount);
+
+    /// <summary>
+    /// Gets the folders that failed to sync for error reporting.
+    /// </summary>
+    [JsonIgnore]
+    public IEnumerable<FolderSyncResult> FailedFolders => FolderResults.Where(f => !f.Success);
+
     public static MailSynchronizationResult Empty => new() { CompletedState = SynchronizationCompletedState.Success };
 
     // Mail synchronization
@@ -43,6 +93,28 @@ public class MailSynchronizationResult
             CompletedState = SynchronizationCompletedState.Success
         };
 
+    /// <summary>
+    /// Creates a completed result with folder-level results.
+    /// </summary>
+    public static MailSynchronizationResult CompletedWithFolderResults(
+        IEnumerable<MailCopy> downloadedMessages,
+        List<FolderSyncResult> folderResults)
+    {
+        var hasAnyFailure = folderResults.Any(f => !f.Success);
+        var hasAnySuccess = folderResults.Any(f => f.Success);
+
+        return new()
+        {
+            DownloadedMessages = downloadedMessages,
+            FolderResults = folderResults,
+            CompletedState = hasAnyFailure && !hasAnySuccess
+                ? SynchronizationCompletedState.Failed
+                : hasAnyFailure
+                    ? SynchronizationCompletedState.PartiallyCompleted
+                    : SynchronizationCompletedState.Success
+        };
+    }
+
     public static MailSynchronizationResult Canceled => new() { CompletedState = SynchronizationCompletedState.Canceled };
     public static MailSynchronizationResult Failed(Exception exception) => new()
     {