lightweight variant (#1)

Reviewed-on: #1
Co-authored-by: Aleksandr Neychev <alexnejchev73@gmail.com>

CursorLang.Core/Services/AgentExecutable.cs

@@ -0,0 +1,35 @@
+namespace CursorLang.Core.Services;
+
+/// <summary>
+/// Where the background half of the application lives on disk.
+/// </summary>
+/// <remarks>
+/// Two processes now share one folder, and each of them at some point needs the path
+/// of the other: the settings window registers the agent for startup and must not
+/// register itself, and the agent starts the settings window from the tray menu.
+/// <c>Environment.ProcessPath</c> answers the wrong question for both, so the paths
+/// are worked out from the folder the assemblies were loaded from.
+/// </remarks>
+internal static class AgentExecutable
+{
+    /// <summary>The background process — the one Windows starts at sign-in.</summary>
+    internal const string AgentFileName = "CursorLang.exe";
+
+    /// <summary>The settings window, started on demand and gone when closed.</summary>
+    internal const string SettingsFileName = "CursorLang.Settings.exe";
+
+    /// <summary>
+    /// The full path of the agent, or <c>null</c> when it is not next to us — which
+    /// happens in the tests and would happen to a half-copied installation.
+    /// </summary>
+    internal static string? AgentPath => Beside(AgentFileName);
+
+    /// <summary>The full path of the settings window, on the same terms.</summary>
+    internal static string? SettingsPath => Beside(SettingsFileName);
+
+    private static string? Beside(string fileName)
+    {
+        string path = Path.Combine(AppContext.BaseDirectory, fileName);
+        return File.Exists(path) ? path : null;
+    }
+}