using System;
using System.Drawing;
using System.IO;
using System.Text;
using System.Windows.Forms;
using Microsoft.Win32;

namespace WindowsKeyInfo
{
    internal static class Program
    {
        [STAThread]
        private static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new MainForm());
        }
    }

    /// <summary>레지스트리에서 윈도우 키 정보를 읽어오는 클래스 (원본 VBScript 로직 이식)</summary>
    internal static class KeyReader
    {
        private const string CurrentVersionPath = @"SOFTWARE\Microsoft\Windows NT\CurrentVersion";
        private const string ComputerNamePath = @"SYSTEM\CurrentControlSet\Control\ComputerName\ComputerName";
        private const string NotFound = "없음";

        public sealed class KeyInfo
        {
            public string ComputerName;
            public string ProductName;
            public string ProductId;
            public string InstalledKey;
            public string BackupKey;
        }

        public static KeyInfo Read()
        {
            var info = new KeyInfo();

            // 64비트 윈도우에서는 반드시 64비트 레지스트리 뷰로 읽어야 DigitalProductId가 정상적으로 보임
            RegistryView view = Environment.Is64BitOperatingSystem ? RegistryView.Registry64 : RegistryView.Default;

            using (RegistryKey hklm = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, view))
            {
                using (RegistryKey cv = hklm.OpenSubKey(CurrentVersionPath))
                {
                    info.ProductName = GetString(cv, "ProductName");
                    info.ProductId = GetString(cv, "ProductId");

                    byte[] digitalId = cv == null ? null : cv.GetValue("DigitalProductId") as byte[];
                    info.InstalledKey = ConvertToKey(digitalId);
                }

                using (RegistryKey spp = hklm.OpenSubKey(CurrentVersionPath + @"\SoftwareProtectionPlatform"))
                {
                    info.BackupKey = GetString(spp, "BackupProductKeyDefault");
                }

                using (RegistryKey cn = hklm.OpenSubKey(ComputerNamePath))
                {
                    string name = GetString(cn, "ComputerName");
                    info.ComputerName = name == NotFound ? Environment.MachineName : name;
                }
            }

            return info;
        }

        private static string GetString(RegistryKey key, string valueName)
        {
            if (key == null) return NotFound;
            object value = key.GetValue(valueName);
            string text = value == null ? null : value.ToString();
            return string.IsNullOrWhiteSpace(text) ? NotFound : text;
        }

        /// <summary>DigitalProductId(바이너리) → 25자리 제품 키 변환</summary>
        public static string ConvertToKey(byte[] digitalId)
        {
            const int keyOffset = 52;
            const string maps = "BCDFGHJKMPQRTVWXY2346789";

            if (digitalId == null || digitalId.Length < keyOffset + 15) return NotFound;

            byte[] key = (byte[])digitalId.Clone(); // 원본 배열 보존

            // Windows 8 이상 형식인지 확인
            int isWin8 = (key[66] / 6) & 1;
            key[66] = (byte)((key[66] & 0xF7) | ((isWin8 & 2) * 4));

            string keyOutput = string.Empty;
            int last = 0;

            for (int i = 24; i >= 0; i--)
            {
                int current = 0;
                for (int j = 14; j >= 0; j--)
                {
                    current = current * 256;
                    current = key[j + keyOffset] + current;
                    key[j + keyOffset] = (byte)(current / 24);
                    current = current % 24;
                }
                keyOutput = maps[current] + keyOutput;
                last = current;
            }

            // Windows 8 이상 키는 'N' 문자 위치를 보정
            if (isWin8 == 1)
            {
                string keypart1 = keyOutput.Substring(1, last);
                string keypart2 = keyOutput.Substring(last + 1);
                keyOutput = keypart1 + "N" + keypart2;
            }

            return keyOutput.Substring(0, 5) + "-" +
                   keyOutput.Substring(5, 5) + "-" +
                   keyOutput.Substring(10, 5) + "-" +
                   keyOutput.Substring(15, 5) + "-" +
                   keyOutput.Substring(20, 5);
        }
    }

    /// <summary>메인 창 (WinForms)</summary>
    internal sealed class MainForm : Form
    {
        private readonly KeyReader.KeyInfo _info;
        private readonly TextBox _txtProductName;
        private readonly TextBox _txtProductId;
        private readonly TextBox _txtInstalledKey;
        private readonly TextBox _txtBackupKey;

        public MainForm()
        {
            Text = "Windows 제품 키 백업";
            FormBorderStyle = FormBorderStyle.FixedDialog;
            MaximizeBox = false;
            StartPosition = FormStartPosition.CenterScreen;
            AutoScaleMode = AutoScaleMode.Dpi;
            Font = new Font("맑은 고딕", 9.5f);
            ClientSize = new Size(560, 344);

            var table = new TableLayoutPanel
            {
                Dock = DockStyle.Top,
                Height = 180,
                Padding = new Padding(14, 14, 14, 0),
                ColumnCount = 2,
                RowCount = 4
            };
            table.ColumnStyles.Add(new ColumnStyle(SizeType.Absolute, 130));
            table.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, 100));
            for (int r = 0; r < 4; r++) table.RowStyles.Add(new RowStyle(SizeType.Percent, 25));

            _txtProductName = AddRow(table, 0, "제품 이름", false);
            _txtProductId = AddRow(table, 1, "제품 ID", false);
            _txtInstalledKey = AddRow(table, 2, "설치된 키", true);
            _txtBackupKey = AddRow(table, 3, "백업 키", true);

            var buttons = new FlowLayoutPanel
            {
                Dock = DockStyle.Bottom,
                FlowDirection = FlowDirection.RightToLeft,
                Height = 56,
                Padding = new Padding(10, 10, 10, 10)
            };

            var btnClose = MakeButton("닫기");
            btnClose.Click += (s, e) => Close();
            var btnSave = MakeButton("파일로 저장");
            btnSave.Click += (s, e) => SaveToFile();
            var btnCopy = MakeButton("복사");
            btnCopy.Click += (s, e) => CopyToClipboard();

            buttons.Controls.Add(btnClose);
            buttons.Controls.Add(btnSave);
            buttons.Controls.Add(btnCopy);

            // 화면 하단 바로가기 버튼 (기본 브라우저로 열기)
            var links = new FlowLayoutPanel
            {
                Dock = DockStyle.Bottom,
                FlowDirection = FlowDirection.LeftToRight,
                Height = 50,
                Padding = new Padding(14, 4, 10, 10)
            };

            var lblLinks = new Label
            {
                Text = "바로가기:",
                AutoSize = true,
                Margin = new Padding(0, 9, 6, 0)
            };
            var btnGetCidMe = MakeLinkButton("GETCID.ME", "https://getcid.me/");
            var btnGetCidInfo = MakeLinkButton("GETCID.INFO", "https://getcid.info/");
            var btnGetCidUs = MakeLinkButton("GETCID.US", "https://getcid.us/");

            links.Controls.Add(lblLinks);
            links.Controls.Add(btnGetCidMe);
            links.Controls.Add(btnGetCidInfo);
            links.Controls.Add(btnGetCidUs);

            // 전화 인증 (slmgr 명령어 방식 — slui 4 창이 막혀 있어도 동작)
            var phone = new FlowLayoutPanel
            {
                Dock = DockStyle.Bottom,
                FlowDirection = FlowDirection.LeftToRight,
                Height = 44,
                Padding = new Padding(14, 4, 10, 0)
            };
            var lblPhone = new Label
            {
                Text = "전화 인증:",
                AutoSize = true,
                Margin = new Padding(0, 9, 6, 0)
            };
            var btnShowIid = MakeActionButton("① 설치 ID 보기");
            btnShowIid.Click += (s, e) => ShowInstallationId();
            var btnEnterCid = MakeActionButton("② 확인 ID 입력");
            btnEnterCid.Click += (s, e) => EnterConfirmationId();

            phone.Controls.Add(lblPhone);
            phone.Controls.Add(btnShowIid);
            phone.Controls.Add(btnEnterCid);

            var tip = new ToolTip();
            tip.SetToolTip(btnShowIid, "설치 ID(Installation ID)를 확인합니다 (slmgr /dti)");
            tip.SetToolTip(btnEnterCid, "받은 확인 ID(Confirmation ID)를 입력해 인증합니다 (slmgr /atp, 관리자 권한 필요)");
            tip.SetToolTip(btnGetCidMe, "https://getcid.me/");
            tip.SetToolTip(btnGetCidInfo, "https://getcid.info/");
            tip.SetToolTip(btnGetCidUs, "https://getcid.us/");

            // Dock=Bottom 은 나중에 추가한 것이 더 아래에 배치됨
            Controls.Add(table);
            Controls.Add(buttons);
            Controls.Add(phone);
            Controls.Add(links);
            CancelButton = btnClose;

            try
            {
                _info = KeyReader.Read();
            }
            catch (Exception ex)
            {
                MessageBox.Show("레지스트리에서 정보를 읽지 못했습니다.\n\n" + ex.Message,
                    Text, MessageBoxButtons.OK, MessageBoxIcon.Error);
                _info = new KeyReader.KeyInfo
                {
                    ComputerName = Environment.MachineName,
                    ProductName = "없음",
                    ProductId = "없음",
                    InstalledKey = "없음",
                    BackupKey = "없음"
                };
            }

            _txtProductName.Text = _info.ProductName;
            _txtProductId.Text = _info.ProductId;
            _txtInstalledKey.Text = _info.InstalledKey;
            _txtBackupKey.Text = _info.BackupKey;
        }

        private static TextBox AddRow(TableLayoutPanel table, int row, string caption, bool monospace)
        {
            var label = new Label
            {
                Text = caption,
                Dock = DockStyle.Fill,
                TextAlign = ContentAlignment.MiddleLeft
            };
            var box = new TextBox
            {
                ReadOnly = true,
                Dock = DockStyle.Fill,
                Anchor = AnchorStyles.Left | AnchorStyles.Right,
                BackColor = SystemColors.Window
            };
            if (monospace) box.Font = new Font("Consolas", 11f, FontStyle.Bold);

            table.Controls.Add(label, 0, row);
            table.Controls.Add(box, 1, row);
            return box;
        }

        private static Button MakeButton(string text)
        {
            return new Button
            {
                Text = text,
                Width = 110,
                Height = 32,
                Margin = new Padding(6, 0, 0, 0)
            };
        }

        private Button MakeLinkButton(string text, string url)
        {
            var btn = new Button
            {
                Text = text,
                Width = 130,
                Height = 32,
                Margin = new Padding(0, 0, 8, 0),
                Cursor = Cursors.Hand
            };
            btn.Click += (s, e) => OpenUrl(url);
            return btn;
        }

        private void OpenUrl(string url)
        {
            try
            {
                System.Diagnostics.Process.Start(new System.Diagnostics.ProcessStartInfo(url) { UseShellExecute = true });
            }
            catch (Exception ex)
            {
                MessageBox.Show("브라우저를 열지 못했습니다.\n\n" + url + "\n\n" + ex.Message, Text,
                    MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

        private static Button MakeActionButton(string text)
        {
            return new Button
            {
                Text = text,
                Width = 140,
                Height = 32,
                Margin = new Padding(0, 0, 8, 0),
                Cursor = Cursors.Hand
            };
        }

        /// <summary>System32 경로 (32비트 프로세스면 Sysnative 사용)</summary>
        private static string SystemDir()
        {
            string windir = Environment.GetFolderPath(Environment.SpecialFolder.Windows);
            string sysnative = Path.Combine(windir, "Sysnative");
            if (!Environment.Is64BitProcess && Directory.Exists(sysnative)) return sysnative;
            return Path.Combine(windir, "System32");
        }

        /// <summary>① 설치 ID 보기: cscript slmgr.vbs /dti 실행 후 결과 표시</summary>
        private void ShowInstallationId()
        {
            string sys = SystemDir();
            string cscript = Path.Combine(sys, "cscript.exe");
            string slmgr = Path.Combine(sys, "slmgr.vbs");
            string output;

            Cursor = Cursors.WaitCursor;
            try
            {
                var psi = new System.Diagnostics.ProcessStartInfo(cscript, "//nologo \"" + slmgr + "\" /dti")
                {
                    UseShellExecute = false,
                    RedirectStandardOutput = true,
                    RedirectStandardError = true,
                    CreateNoWindow = true,
                    StandardOutputEncoding = Encoding.GetEncoding(
                        System.Globalization.CultureInfo.CurrentCulture.TextInfo.OEMCodePage)
                };
                using (var p = System.Diagnostics.Process.Start(psi))
                {
                    output = p.StandardOutput.ReadToEnd() + p.StandardError.ReadToEnd();
                    p.WaitForExit(60000);
                }
            }
            catch (Exception ex)
            {
                Cursor = Cursors.Default;
                MessageBox.Show("설치 ID를 가져오지 못했습니다.\n\n" + ex.Message, Text,
                    MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }
            Cursor = Cursors.Default;

            // 출력에서 가장 긴 숫자열(설치 ID, 보통 63자리)을 추출
            string iid = null;
            foreach (System.Text.RegularExpressions.Match m in
                     System.Text.RegularExpressions.Regex.Matches(output, @"\d{40,}"))
            {
                if (iid == null || m.Value.Length > iid.Length) iid = m.Value;
            }

            if (iid == null)
            {
                MessageBox.Show("설치 ID를 찾지 못했습니다. 윈도우가 보낸 메시지:\n\n" + output.Trim(), Text,
                    MessageBoxButtons.OK, MessageBoxIcon.Warning);
                return;
            }

            using (var dlg = new InstallationIdDialog(iid))
            {
                dlg.ShowDialog(this);
            }
        }

        /// <summary>② 확인 ID 입력: 관리자 권한으로 slmgr.vbs /atp 확인ID 실행</summary>
        private void EnterConfirmationId()
        {
            string cid;
            using (var dlg = new ConfirmationIdDialog())
            {
                if (dlg.ShowDialog(this) != DialogResult.OK) return;
                cid = dlg.ConfirmationId;
            }

            string sys = SystemDir();
            string wscript = Path.Combine(sys, "wscript.exe");
            string slmgr = Path.Combine(sys, "slmgr.vbs");

            try
            {
                // wscript로 실행하면 slmgr가 결과(성공/오류)를 자체 메시지 창으로 보여 줌
                var psi = new System.Diagnostics.ProcessStartInfo(wscript, "\"" + slmgr + "\" /atp " + cid)
                {
                    UseShellExecute = true,
                    Verb = "runas"   // 관리자 권한 요청 (UAC 창)
                };
                System.Diagnostics.Process.Start(psi);
            }
            catch (System.ComponentModel.Win32Exception ex) when (ex.NativeErrorCode == 1223)
            {
                MessageBox.Show("관리자 권한 요청이 취소되었습니다.\n확인 ID 입력에는 관리자 권한이 필요합니다.", Text,
                    MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            catch (Exception ex)
            {
                MessageBox.Show("확인 ID 입력을 실행하지 못했습니다.\n\n" + ex.Message, Text,
                    MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

        /// <summary>원본 스크립트와 같은 형식의 텍스트</summary>
        private string BuildText()
        {
            var sb = new StringBuilder();
            sb.AppendLine("Product Name: " + _info.ProductName);
            sb.AppendLine("Product ID: " + _info.ProductId);
            sb.AppendLine("Orginal Installed Key: " + _info.InstalledKey);
            sb.AppendLine("Backup Installed Key: " + _info.BackupKey);
            return sb.ToString();
        }

        private void CopyToClipboard()
        {
            try
            {
                Clipboard.SetText(BuildText());
                MessageBox.Show("키 정보를 클립보드에 복사했습니다.", Text,
                    MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            catch (Exception ex)
            {
                MessageBox.Show("클립보드 복사에 실패했습니다.\n\n" + ex.Message, Text,
                    MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }

        /// <summary>exe가 있는 폴더에 WindowsKeyInfo_컴퓨터이름_사용자이름.txt 로 저장</summary>
        private void SaveToFile()
        {
            string computer = (_info.ComputerName ?? Environment.MachineName).Replace(" ", "");
            string user = Environment.UserName;
            string fileName = "WindowsKeyInfo_" + computer + "_" + user + ".txt";
            string folder = AppDomain.CurrentDomain.BaseDirectory;
            string fullPath = Path.Combine(folder, fileName);

            try
            {
                File.WriteAllText(fullPath, BuildText(), new UTF8Encoding(true));
                MessageBox.Show("저장했습니다.\n\n" + fullPath, Text,
                    MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
            catch (UnauthorizedAccessException)
            {
                MessageBox.Show("이 폴더에 쓸 권한이 없습니다.\n\n" + folder +
                    "\n\nexe를 바탕화면이나 문서 폴더 등 쓰기 가능한 곳으로 옮긴 뒤 다시 시도해 주세요.",
                    Text, MessageBoxButtons.OK, MessageBoxIcon.Warning);
            }
            catch (Exception ex)
            {
                MessageBox.Show("파일 저장에 실패했습니다.\n\n" + ex.Message, Text,
                    MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
        }
    }

    /// <summary>설치 ID 표시 창 (7자리씩 9묶음)</summary>
    internal sealed class InstallationIdDialog : Form
    {
        public InstallationIdDialog(string iid)
        {
            Text = "설치 ID (Installation ID)";
            FormBorderStyle = FormBorderStyle.FixedDialog;
            MaximizeBox = false;
            MinimizeBox = false;
            ShowInTaskbar = false;
            StartPosition = FormStartPosition.CenterParent;
            AutoScaleMode = AutoScaleMode.Dpi;
            Font = new Font("맑은 고딕", 9.5f);
            ClientSize = new Size(620, 190);

            var sbGrouped = new StringBuilder();
            for (int i = 0; i < iid.Length; i += 7)
            {
                if (i > 0) sbGrouped.Append(' ');
                sbGrouped.Append(iid.Substring(i, Math.Min(7, iid.Length - i)));
            }
            string grouped = sbGrouped.ToString();

            var lbl = new Label
            {
                Text = "아래 설치 ID를 전화 자동 응답에 입력하거나 확인 ID 발급처에 전달하세요.\n" +
                       "받은 확인 ID는 메인 창의 [② 확인 ID 입력]에 넣으면 됩니다.",
                Location = new Point(14, 12),
                Size = new Size(592, 42)
            };
            var box = new TextBox
            {
                Text = grouped,
                ReadOnly = true,
                Multiline = true,
                Location = new Point(14, 60),
                Size = new Size(592, 64),
                Font = new Font("Consolas", 12f, FontStyle.Bold),
                BackColor = SystemColors.Window
            };

            var btnCopy = new Button { Text = "복사 (숫자만)", Location = new Point(366, 140), Size = new Size(120, 32) };
            btnCopy.Click += (s, e) =>
            {
                try
                {
                    Clipboard.SetText(iid);
                    MessageBox.Show("설치 ID를 클립보드에 복사했습니다.", Text, MessageBoxButtons.OK, MessageBoxIcon.Information);
                }
                catch (Exception ex)
                {
                    MessageBox.Show("복사에 실패했습니다.\n\n" + ex.Message, Text, MessageBoxButtons.OK, MessageBoxIcon.Error);
                }
            };
            var btnClose = new Button { Text = "닫기", Location = new Point(494, 140), Size = new Size(112, 32), DialogResult = DialogResult.OK };

            Controls.Add(lbl);
            Controls.Add(box);
            Controls.Add(btnCopy);
            Controls.Add(btnClose);
            AcceptButton = btnClose;
            CancelButton = btnClose;
        }
    }

    /// <summary>확인 ID 입력 창 (48자리 숫자, 하이픈/공백 허용)</summary>
    internal sealed class ConfirmationIdDialog : Form
    {
        private readonly TextBox _box;
        public string ConfirmationId { get; private set; }

        public ConfirmationIdDialog()
        {
            Text = "확인 ID (Confirmation ID) 입력";
            FormBorderStyle = FormBorderStyle.FixedDialog;
            MaximizeBox = false;
            MinimizeBox = false;
            ShowInTaskbar = false;
            StartPosition = FormStartPosition.CenterParent;
            AutoScaleMode = AutoScaleMode.Dpi;
            Font = new Font("맑은 고딕", 9.5f);
            ClientSize = new Size(620, 170);

            var lbl = new Label
            {
                Text = "받은 확인 ID 48자리를 입력하세요. 하이픈(-)이나 공백은 넣어도 자동으로 제거됩니다.\n" +
                       "[인증]을 누르면 관리자 권한 확인 창이 뜨고, 결과는 윈도우 메시지 창으로 표시됩니다.",
                Location = new Point(14, 12),
                Size = new Size(592, 42)
            };
            _box = new TextBox
            {
                Location = new Point(14, 62),
                Size = new Size(592, 30),
                Font = new Font("Consolas", 12f, FontStyle.Bold)
            };

            var btnOk = new Button { Text = "인증", Location = new Point(366, 120), Size = new Size(120, 32) };
            btnOk.Click += (s, e) => TryAccept();
            var btnCancel = new Button { Text = "취소", Location = new Point(494, 120), Size = new Size(112, 32), DialogResult = DialogResult.Cancel };

            Controls.Add(lbl);
            Controls.Add(_box);
            Controls.Add(btnOk);
            Controls.Add(btnCancel);
            AcceptButton = btnOk;
            CancelButton = btnCancel;
        }

        private void TryAccept()
        {
            var digits = new StringBuilder();
            foreach (char c in _box.Text)
            {
                if (c >= '0' && c <= '9') digits.Append(c);
            }

            if (digits.Length != 48)
            {
                MessageBox.Show("확인 ID는 숫자 48자리여야 합니다.\n현재 입력된 숫자: " + digits.Length + "자리", Text,
                    MessageBoxButtons.OK, MessageBoxIcon.Warning);
                _box.Focus();
                return;
            }

            ConfirmationId = digits.ToString();
            DialogResult = DialogResult.OK;
            Close();
        }
    }
}