namespace ClaudeDo.Ui.Services;

public sealed class InstallerLocator : InstallArtifactLocator
{
    protected override string Subdir => "uninstaller";
    protected override string ExeName => "ClaudeDo.Installer.exe";
}

public sealed class WorkerLocator : InstallArtifactLocator
{
    protected override string Subdir => "worker";
    protected override string ExeName => "ClaudeDo.Worker.exe";
}

/// <summary>
/// Locates an executable inside a ClaudeDo install: walk up from the running
/// directory to the folder containing install.json, otherwise read the
/// uninstall registry key. Subclasses supply the subdirectory and exe name.
/// </summary>
public abstract class InstallArtifactLocator
{
    private const string InstallJson = "install.json";

    protected abstract string Subdir { get; }
    protected abstract string ExeName { get; }

    public string? Find()
        => FindByWalkingUp(AppContext.BaseDirectory)
           ?? (OperatingSystem.IsWindows() ? FindByRegistry() : null);

    public string? FindByWalkingUp(string startDir)
    {
        var dir = new DirectoryInfo(startDir);
        while (dir is not null)
        {
            if (File.Exists(Path.Combine(dir.FullName, InstallJson)))
            {
                var candidate = Path.Combine(dir.FullName, Subdir, ExeName);
                return File.Exists(candidate) ? candidate : null;
            }
            dir = dir.Parent;
        }
        return null;
    }

    [System.Runtime.Versioning.SupportedOSPlatform("windows")]
    public string? FindByRegistry()
    {
        if (!OperatingSystem.IsWindows()) return null;
        try
        {
            using var key = Microsoft.Win32.Registry.LocalMachine
                .OpenSubKey(@"Software\Microsoft\Windows\CurrentVersion\Uninstall\ClaudeDo");
            var location = key?.GetValue("InstallLocation") as string;
            if (string.IsNullOrEmpty(location)) return null;
            var candidate = Path.Combine(location, Subdir, ExeName);
            return File.Exists(candidate) ? candidate : null;
        }
        catch { return null; }
    }
}