using System.Diagnostics;
using System.Runtime.InteropServices;
#if WINDOWS
using System.Management; // NuGet: System.Management
#endif

namespace TWASys_App.Models.ServerInfo
{

    public record MachineHwIds(string? SerialNumber, string? BiosVendor, string? ProductUuid);

    public static class HwIdReader
    {
        public static MachineHwIds Get()
        {
            if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
            {
#if WINDOWS
            string? serial = null, biosVendor = null, uuid = null;

            try
            {
                using var cs = new ManagementObjectSearcher(
                    "SELECT UUID, IdentifyingNumber FROM Win32_ComputerSystemProduct");
                foreach (ManagementObject mo in cs.Get())
                {
                    uuid   = mo["UUID"]?.ToString();
                    serial = mo["IdentifyingNumber"]?.ToString(); // system serial
                    break;
                }
            } catch { /* ignore */ }

            try
            {
                using var bios = new ManagementObjectSearcher(
                    "SELECT Manufacturer FROM Win32_BIOS");
                foreach (ManagementObject mo in bios.Get())
                {
                    biosVendor = mo["Manufacturer"]?.ToString();
                    break;
                }
            } catch { /* ignore */ }

            return new MachineHwIds(Null(serial), Null(biosVendor), Null(uuid));
#else
                return new MachineHwIds(null, null, null);
#endif
            }

            if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
            {
                string R(string p) => File.Exists(p) ? File.ReadAllText(p).Trim() : "";

                var serial = R("/sys/class/dmi/id/product_serial");
                var vendor = R("/sys/class/dmi/id/bios_vendor");
                var uuid = R("/sys/class/dmi/id/product_uuid");

                // Fallback (nếu sysfs rỗng và bạn cho phép): dmidecode (có thể cần sudo)
                if (string.IsNullOrWhiteSpace(serial)) serial = Exec("dmidecode", "-s system-serial-number");
                if (string.IsNullOrWhiteSpace(vendor)) vendor = Exec("dmidecode", "-s bios-vendor");
                if (string.IsNullOrWhiteSpace(uuid)) uuid = Exec("dmidecode", "-s system-uuid");

                return new MachineHwIds(Null(serial), Null(vendor), Null(uuid));
            }

            // macOS không có “BIOS”; có thể lấy serial máy nhưng BIOS vendor/UUID không tương đương
            return new MachineHwIds(null, null, null);
        }

        static string? Null(string s) => string.IsNullOrWhiteSpace(s) ? null : s;

        static string Exec(string file, string args)
        {
            try
            {
                var p = new Process
                {
                    StartInfo = new ProcessStartInfo
                    {
                        FileName = file,
                        Arguments = args,
                        RedirectStandardOutput = true,
                        UseShellExecute = false,
                        CreateNoWindow = true
                    }
                };
                p.Start();
                var s = p.StandardOutput.ReadToEnd().Trim();
                p.WaitForExit(2000);
                return s;
            }
            catch { return ""; }
        }
    }
}