using System;
using System.Diagnostics;
using System.IO;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace JJServiceManager
{
    /// <summary>
    /// Windows 명령(schtasks, netsh 등)을 실행하고 출력을 읽음.
    /// 시스템 설정에 따라 출력이 UTF-8 또는 CP949(OEM)일 수 있어,
    /// 바이트로 받은 뒤 UTF-8로 올바르게 읽히면 UTF-8, 아니면 시스템 OEM 코드페이지로 해석함.
    /// </summary>
    public static class ConsoleRunner
    {
        [DllImport("kernel32.dll")]
        private static extern uint GetOEMCP();

        public static (int exitCode, string output) Run(string file, string args, int timeoutMs = 15000)
        {
            try
            {
                var psi = new ProcessStartInfo(file, args)
                {
                    UseShellExecute = false,
                    CreateNoWindow = true,
                    RedirectStandardOutput = true,
                    RedirectStandardError = true
                };
                using var p = Process.Start(psi);
                var outTask = ReadAllAsync(p.StandardOutput.BaseStream);
                var errTask = ReadAllAsync(p.StandardError.BaseStream);
                if (!p.WaitForExit(timeoutMs))
                {
                    try { p.Kill(); } catch { }
                    return (-1, "시간 초과");
                }
                var bytes = Combine(outTask.Result, errTask.Result);
                return (p.ExitCode, Decode(bytes).Trim());
            }
            catch (Exception ex)
            {
                return (-1, ex.Message);
            }
        }

        private static async Task<byte[]> ReadAllAsync(Stream s)
        {
            using var ms = new MemoryStream();
            await s.CopyToAsync(ms).ConfigureAwait(false);
            return ms.ToArray();
        }

        private static byte[] Combine(byte[] a, byte[] b)
        {
            var r = new byte[a.Length + b.Length];
            Buffer.BlockCopy(a, 0, r, 0, a.Length);
            Buffer.BlockCopy(b, 0, r, a.Length, b.Length);
            return r;
        }

        public static string Decode(byte[] bytes)
        {
            if (bytes.Length == 0) return "";
            try
            {
                var strict = new UTF8Encoding(false, throwOnInvalidBytes: true);
                return strict.GetString(bytes);
            }
            catch { }
            try { return Encoding.GetEncoding((int)GetOEMCP()).GetString(bytes); }
            catch { }
            try { return Encoding.GetEncoding(949).GetString(bytes); }
            catch { return Encoding.UTF8.GetString(bytes); }
        }
    }
}