using System;
using System.Diagnostics;
using System.IO;
using System.Runtime.InteropServices;
using System.Security;
using System.Security.Principal;
using System.Text;
using System.Windows.Input;
using System.Windows.Interop;

namespace JJServiceManager
{
    /// <summary>
    /// 컴퓨터 시작 시 기동.
    /// 관리자 권한 프로그램은 레지스트리 Run 키로는 자동 실행되지 않으므로
    /// 작업 스케줄러(로그온 시, 가장 높은 권한)를 사용함.
    /// </summary>
    public static class StartupManager
    {
        // [테스트용 중복 실행] 인스턴스마다 작업 이름을 따로 (정식 릴리즈 시 Suffix 제거)
        private static string TaskName => "JJServiceManager" + AppInstance.Suffix;

        public static bool IsEnabled()
        {
            var r = RunSchtasks($"/query /tn \"{TaskName}\"");
            return r.ExitCode == 0;
        }

        public static (bool ok, string message) Enable()
        {
            var exe = Environment.ProcessPath ?? "";
            var user = WindowsIdentity.GetCurrent().Name;
            var taskArgs = AppInstance.IsTest ? "--tray --instance " + AppInstance.Number : "--tray";
            var xml =
$@"<?xml version=""1.0"" encoding=""UTF-16""?>
<Task version=""1.2"" xmlns=""http://schemas.microsoft.com/windows/2004/02/mit/task"">
  <RegistrationInfo>
    <Description>JJServiceManager 자동 실행</Description>
  </RegistrationInfo>
  <Triggers>
    <LogonTrigger>
      <Enabled>true</Enabled>
      <UserId>{SecurityElement.Escape(user)}</UserId>
    </LogonTrigger>
  </Triggers>
  <Principals>
    <Principal id=""Author"">
      <UserId>{SecurityElement.Escape(user)}</UserId>
      <LogonType>InteractiveToken</LogonType>
      <RunLevel>HighestAvailable</RunLevel>
    </Principal>
  </Principals>
  <Settings>
    <MultipleInstancesPolicy>IgnoreNew</MultipleInstancesPolicy>
    <DisallowStartIfOnBatteries>false</DisallowStartIfOnBatteries>
    <StopIfGoingOnBatteries>false</StopIfGoingOnBatteries>
    <AllowHardTerminate>true</AllowHardTerminate>
    <StartWhenAvailable>false</StartWhenAvailable>
    <RunOnlyIfNetworkAvailable>false</RunOnlyIfNetworkAvailable>
    <AllowStartOnDemand>true</AllowStartOnDemand>
    <Enabled>true</Enabled>
    <Hidden>false</Hidden>
    <ExecutionTimeLimit>PT0S</ExecutionTimeLimit>
    <Priority>7</Priority>
  </Settings>
  <Actions Context=""Author"">
    <Exec>
      <Command>{SecurityElement.Escape(exe)}</Command>
      <Arguments>{taskArgs}</Arguments>
      <WorkingDirectory>{SecurityElement.Escape(Path.GetDirectoryName(exe) ?? "")}</WorkingDirectory>
    </Exec>
  </Actions>
</Task>";
            var tmp = Path.Combine(Path.GetTempPath(), "JJServiceManager_task.xml");
            try
            {
                File.WriteAllText(tmp, xml, Encoding.Unicode);
                var r = RunSchtasks($"/create /tn \"{TaskName}\" /xml \"{tmp}\" /f");
                return (r.ExitCode == 0, r.Output);
            }
            catch (Exception ex)
            {
                return (false, ex.Message);
            }
            finally
            {
                try { File.Delete(tmp); } catch { }
            }
        }

        public static (bool ok, string message) Disable()
        {
            if (!IsEnabled()) return (true, "");
            var r = RunSchtasks($"/delete /tn \"{TaskName}\" /f");
            return (r.ExitCode == 0, r.Output);
        }

        /// <summary>명령 프롬프트 출력 인코딩 (한국어 Windows = CP949)</summary>
        private static Encoding OemEncoding()
        {
            try { return Encoding.GetEncoding(System.Globalization.CultureInfo.CurrentCulture.TextInfo.OEMCodePage); }
            catch { return Encoding.UTF8; }
        }

        private static (int ExitCode, string Output) RunSchtasks(string args)
        {
            try
            {
                var psi = new ProcessStartInfo("schtasks.exe", args)
                {
                    UseShellExecute = false,
                    CreateNoWindow = true,
                    RedirectStandardOutput = true,
                    RedirectStandardError = true,
                    StandardOutputEncoding = OemEncoding(),
                    StandardErrorEncoding = OemEncoding()
                };
                using var p = Process.Start(psi);
                var output = p.StandardOutput.ReadToEnd() + p.StandardError.ReadToEnd();
                p.WaitForExit(15000);
                return (p.ExitCode, output.Trim());
            }
            catch (Exception ex)
            {
                return (-1, ex.Message);
            }
        }
    }

    /// <summary>전역 단축키 (어느 프로그램을 쓰고 있어도 동작)</summary>
    public sealed class HotkeyManager : IDisposable
    {
        private const int WM_HOTKEY = 0x0312;
        private const int HotkeyId = 0x4A4A; // "JJ"
        private const uint MOD_NOREPEAT = 0x4000;

        [DllImport("user32.dll", SetLastError = true)]
        private static extern bool RegisterHotKey(IntPtr hWnd, int id, uint fsModifiers, uint vk);

        [DllImport("user32.dll", SetLastError = true)]
        private static extern bool UnregisterHotKey(IntPtr hWnd, int id);

        private readonly HwndSource _source;
        private bool _registered;

        public event Action Pressed;

        public HotkeyManager(IntPtr hwnd)
        {
            _source = HwndSource.FromHwnd(hwnd);
            _source?.AddHook(WndProc);
        }

        /// <summary>단축키 등록. 다른 프로그램이 사용 중이면 false</summary>
        /// <summary>마지막으로 등록에 성공한 단축키</summary>
        public (ModifierKeys mods, Key key)? Active { get; private set; }

        /// <summary>
        /// 단축키 등록. 다른 프로그램이 사용 중이면 false를 돌려주고,
        /// 이전에 쓰던 단축키가 있으면 그것을 다시 등록해 유지함
        /// </summary>
        public bool Register(ModifierKeys modifiers, Key key)
        {
            var previous = Active;
            Unregister();
            if (_source == null || key == Key.None) return false;

            if (TryRegister(modifiers, key))
            {
                Active = (modifiers, key);
                return true;
            }
            if (previous.HasValue && TryRegister(previous.Value.mods, previous.Value.key))
                Active = previous;
            else
                Active = null;
            return false;
        }

        private bool TryRegister(ModifierKeys modifiers, Key key)
        {
            // ModifierKeys 값(Alt=1, Ctrl=2, Shift=4, Win=8)은 RegisterHotKey의 MOD_* 값과 같음
            uint mods = (uint)modifiers | MOD_NOREPEAT;
            uint vk = (uint)KeyInterop.VirtualKeyFromKey(key);
            _registered = RegisterHotKey(_source.Handle, HotkeyId, mods, vk);
            return _registered;
        }

        public void Unregister()
        {
            if (_registered && _source != null)
            {
                UnregisterHotKey(_source.Handle, HotkeyId);
                _registered = false;
            }
        }

        private IntPtr WndProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled)
        {
            if (msg == WM_HOTKEY && wParam.ToInt32() == HotkeyId)
            {
                Pressed?.Invoke();
                handled = true;
            }
            return IntPtr.Zero;
        }

        public void Dispose()
        {
            Unregister();
            _source?.RemoveHook(WndProc);
        }

        /// <summary>"Ctrl + Shift + A" 형태 문자열</summary>
        public static string Format(ModifierKeys mods, Key key)
        {
            var sb = new StringBuilder();
            if (mods.HasFlag(ModifierKeys.Control)) sb.Append("Ctrl + ");
            if (mods.HasFlag(ModifierKeys.Alt)) sb.Append("Alt + ");
            if (mods.HasFlag(ModifierKeys.Shift)) sb.Append("Shift + ");
            if (mods.HasFlag(ModifierKeys.Windows)) sb.Append("Win + ");
            sb.Append(KeyName(key));
            return sb.ToString();
        }

        public static string KeyName(Key key)
        {
            if (key >= Key.D0 && key <= Key.D9) return ((int)(key - Key.D0)).ToString();
            if (key >= Key.NumPad0 && key <= Key.NumPad9) return "Num " + (int)(key - Key.NumPad0);
            return key switch
            {
                Key.None => "",
                Key.OemPlus => "=",
                Key.OemMinus => "-",
                Key.OemComma => ",",
                Key.OemPeriod => ".",
                Key.Oem1 => ";",
                Key.Oem2 => "/",
                Key.Oem3 => "`",
                Key.Oem4 => "[",
                Key.Oem5 => "\\",
                Key.Oem6 => "]",
                Key.Oem7 => "'",
                _ => key.ToString()
            };
        }
    }

    /// <summary>Windows 강제 종료 / 재시작</summary>
    public static class PowerOps
    {
        public static void ForceShutdown() => Run("/s /f /t 0");
        public static void ForceRestart() => Run("/r /f /t 0");

        private static void Run(string args)
        {
            var psi = new ProcessStartInfo("shutdown.exe", args)
            {
                UseShellExecute = false,
                CreateNoWindow = true
            };
            Process.Start(psi);
        }
    }
}