using System.IO;
using System.Runtime.InteropServices;
using System.Text;

namespace UtopiaCanteenSystem.Services.Logging;

/// <summary>
/// Resolves the logged-on Windows user's profile paths when the app runs as a service (SYSTEM).
/// </summary>
public static class InteractiveUserPath
{
    public static string? TryGetLocalAppDataPath()
    {
        var profile = TryGetProfileDirectory();
        if (string.IsNullOrWhiteSpace(profile))
            return null;

        var localAppData = Path.Combine(profile, "AppData", "Local");
        return Directory.Exists(localAppData) ? localAppData : null;
    }

    private static string? TryGetProfileDirectory()
    {
        var sessionId = WTSGetActiveConsoleSessionId();
        if (sessionId == 0xFFFFFFFF)
            return null;

        if (!WTSQueryUserToken(sessionId, out var userToken) || userToken == IntPtr.Zero)
            return null;

        try
        {
            var sb = new StringBuilder(512);
            var size = sb.Capacity;
            if (!GetUserProfileDirectory(userToken, sb, ref size, out _))
                return null;

            var path = sb.ToString();
            return string.IsNullOrWhiteSpace(path) ? null : path;
        }
        finally
        {
            CloseHandle(userToken);
        }
    }

    [DllImport("kernel32.dll")]
    private static extern uint WTSGetActiveConsoleSessionId();

    [DllImport("wtsapi32.dll", SetLastError = true)]
    private static extern bool WTSQueryUserToken(uint sessionId, out IntPtr phToken);

    [DllImport("userenv.dll", SetLastError = true, CharSet = CharSet.Unicode)]
    private static extern bool GetUserProfileDirectory(IntPtr hToken, StringBuilder lpProfileDir, ref int lpcchSize, out int lpDwFlags);

    [DllImport("kernel32.dll", SetLastError = true)]
    private static extern bool CloseHandle(IntPtr hObject);
}