add ProxyJump function

outlook-bulk-sender/BulkArchiveMailer.AddIn/SignatureReader.cs

@@ -0,0 +1,123 @@
+using System;
+using System.Collections.Generic;
+using System.IO;
+using Microsoft.Win32;
+using Outlook = Microsoft.Office.Interop.Outlook;
+
+namespace BulkArchiveMailer.AddIn
+{
+    /// <summary>
+    /// Reads the user's default "new message" Outlook signature HTML from
+    /// disk. Outlook Interop has no API that exposes "the currently
+    /// selected default signature" - the only reliable way to get at it
+    /// is: look up its *name* in the registry
+    /// (HKCU\Software\Microsoft\Office\&lt;version&gt;\Common\MailSettings,
+    /// value "NewSignature"), then load the matching .htm file from
+    /// %APPDATA%\Microsoft\Signatures\&lt;name&gt;.htm ourselves.
+    ///
+    /// This is the only file in the solution that touches the Windows
+    /// registry - deliberately kept out of BulkArchiveMailer.Core.
+    /// </summary>
+    public static class SignatureReader
+    {
+        /// <summary>
+        /// Best-effort auto-detection. Never throws - returns null if the
+        /// registry value, the version-specific key, or the .htm file is
+        /// missing for any reason, so the caller can fall back to letting
+        /// the operator pick a signature file manually instead of crashing
+        /// the add-in.
+        /// </summary>
+        public static string TryAutoDetectSignatureHtml(Outlook.Application application)
+        {
+            try
+            {
+                var signatureName = TryReadSignatureName(application);
+                if (string.IsNullOrEmpty(signatureName))
+                {
+                    return null;
+                }
+
+                var path = ResolveSignaturePath(signatureName);
+                return File.Exists(path) ? File.ReadAllText(path) : null;
+            }
+            catch
+            {
+                return null;
+            }
+        }
+
+        /// <summary>Same lookup, but returns the resolved .htm path instead of its contents - useful for SettingsForm to show/prefill the path.</summary>
+        public static string TryAutoDetectSignaturePath(Outlook.Application application)
+        {
+            try
+            {
+                var signatureName = TryReadSignatureName(application);
+                if (string.IsNullOrEmpty(signatureName))
+                {
+                    return null;
+                }
+
+                var path = ResolveSignaturePath(signatureName);
+                return File.Exists(path) ? path : null;
+            }
+            catch
+            {
+                return null;
+            }
+        }
+
+        public static string ResolveSignaturePath(string signatureName)
+        {
+            var signaturesFolder = Path.Combine(
+                Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
+                "Microsoft",
+                "Signatures");
+            return Path.Combine(signaturesFolder, signatureName + ".htm");
+        }
+
+        private static string TryReadSignatureName(Outlook.Application application)
+        {
+            var candidateVersions = new List<string>();
+
+            try
+            {
+                // application.Version looks like "16.0" and lines up
+                // exactly with the Office registry hive layout, so prefer
+                // it over the fixed fallback list below.
+                var version = application?.Version;
+                if (!string.IsNullOrEmpty(version))
+                {
+                    candidateVersions.Add(version);
+                }
+            }
+            catch
+            {
+                // Interop call failed for some reason - fall through to
+                // the fixed list.
+            }
+
+            foreach (var fallback in new[] { "16.0", "15.0", "14.0" })
+            {
+                if (!candidateVersions.Contains(fallback))
+                {
+                    candidateVersions.Add(fallback);
+                }
+            }
+
+            foreach (var version in candidateVersions)
+            {
+                using (var key = Registry.CurrentUser.OpenSubKey(
+                    $@"Software\Microsoft\Office\{version}\Common\MailSettings"))
+                {
+                    var value = key?.GetValue("NewSignature") as string;
+                    if (!string.IsNullOrEmpty(value))
+                    {
+                        return value;
+                    }
+                }
+            }
+
+            return null;
+        }
+    }
+}