Refactored impa synchronization.

Wino.Core/Integration/ImapServerQuirks.cs

@@ -0,0 +1,39 @@
+using System;
+using System.Collections.Generic;
+
+namespace Wino.Core.Integration;
+
+internal sealed class ImapServerQuirkProfile
+{
+    public static readonly ImapServerQuirkProfile Default = new();
+
+    public bool DisableQResync { get; init; }
+    public bool DisableCondstore { get; init; }
+    public bool UseConservativeConnections { get; init; }
+}
+
+internal static class ImapServerQuirks
+{
+    private static readonly Dictionary<string, ImapServerQuirkProfile> Quirks = new(StringComparer.OrdinalIgnoreCase)
+    {
+        // Some strict providers are more stable with conservative behavior.
+        ["qq.com"] = new ImapServerQuirkProfile { DisableQResync = true, UseConservativeConnections = true },
+        ["163.com"] = new ImapServerQuirkProfile { DisableQResync = true, UseConservativeConnections = true },
+        ["126.com"] = new ImapServerQuirkProfile { DisableQResync = true, UseConservativeConnections = true },
+        ["yeah.net"] = new ImapServerQuirkProfile { DisableQResync = true, UseConservativeConnections = true }
+    };
+
+    public static ImapServerQuirkProfile Resolve(string host)
+    {
+        if (string.IsNullOrWhiteSpace(host))
+            return ImapServerQuirkProfile.Default;
+
+        foreach (var (key, profile) in Quirks)
+        {
+            if (host.Contains(key, StringComparison.OrdinalIgnoreCase))
+                return profile;
+        }
+
+        return ImapServerQuirkProfile.Default;
+    }
+}