using System;
using System.IO;
using System.Net;
using System.Diagnostics;
using System.Windows.Forms;
using System.Threading.Tasks;

namespace VNCServerList
{
    public static class WebView2Installer
    {
        private const string DOWNLOAD_URL = "https://go.microsoft.com/fwlink/p/?LinkId=2124703";
        private const string INSTALLER_NAME = "MicrosoftEdgeWebview2Setup.exe";
        
        public static async Task<bool> InstallWebView2Async()
        {
            try
            {
                // 다운로드 진행 상황 표시
                using (var progressForm = new WebView2DownloadForm())
                {
                    progressForm.Show();
                    
                    // 임시 폴더에 설치 파일 다운로드
                    string tempFolder = Path.GetTempPath();
                    string installerPath = Path.Combine(tempFolder, INSTALLER_NAME);
                    
                    // 기존 파일이 있으면 삭제
                    if (File.Exists(installerPath))
                    {
                        File.Delete(installerPath);
                    }
                    
                    // 다운로드
                    using (var client = new WebClient())
                    {
                        client.DownloadProgressChanged += (sender, e) =>
                        {
                            progressForm.UpdateProgress(e.ProgressPercentage, e.BytesReceived, e.TotalBytesToReceive);
                        };
                        
                        await client.DownloadFileTaskAsync(new Uri(DOWNLOAD_URL), installerPath);
                    }
                    
                    progressForm.Close();
                    
                    // 설치 실행
                    var startInfo = new ProcessStartInfo
                    {
                        FileName = installerPath,
                        Arguments = "/silent /install", // 자동 설치
                        UseShellExecute = true
                    };
                    
                    var process = Process.Start(startInfo);
                    
                    // 설치 완료 대기 (최대 5분)
                    if (process != null)
                    {
                        await Task.Run(() => process.WaitForExit(300000)); // 5분
                        
                        // 설치 파일 정리
                        try
                        {
                            if (File.Exists(installerPath))
                            {
                                File.Delete(installerPath);
                            }
                        }
                        catch { /* 무시 */ }
                        
                        return process.ExitCode == 0;
                    }
                    
                    return false;
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(
                    $"WebView2 런타임 설치 중 오류가 발생했습니다:\n{ex.Message}",
                    "설치 오류",
                    MessageBoxButtons.OK,
                    MessageBoxIcon.Error);
                return false;
            }
        }
        
        public static bool IsWebView2Installed()
        {
            try
            {
                // 레지스트리에서 WebView2 설치 확인
                using (var key = Microsoft.Win32.Registry.LocalMachine.OpenSubKey(@"SOFTWARE\WOW6432Node\Microsoft\EdgeUpdate\Clients\{F3017226-FE2A-4295-8BDF-00C3A9A7E4C5}"))
                {
                    if (key != null)
                    {
                        return true;
                    }
                }
                
                // 64비트 시스템에서 32비트 레지스트리 확인
                using (var key = Microsoft.Win32.Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\EdgeUpdate\Clients\{F3017226-FE2A-4295-8BDF-00C3A9A7E4C5}"))
                {
                    if (key != null)
                    {
                        return true;
                    }
                }
                
                return false;
            }
            catch
            {
                return false;
            }
        }
    }
    
    public partial class WebView2DownloadForm : Form
    {
        private ProgressBar progressBar;
        private Label statusLabel;
        
        public WebView2DownloadForm()
        {
            InitializeComponent();
        }
        
        private void InitializeComponent()
        {
            this.progressBar = new ProgressBar();
            this.statusLabel = new Label();
            this.SuspendLayout();
            
            // Form 설정
            this.Text = "WebView2 런타임 다운로드";
            this.Size = new System.Drawing.Size(400, 150);
            this.StartPosition = FormStartPosition.CenterScreen;
            this.FormBorderStyle = FormBorderStyle.FixedDialog;
            this.MaximizeBox = false;
            this.MinimizeBox = false;
            
            // Status Label
            this.statusLabel.AutoSize = true;
            this.statusLabel.Location = new System.Drawing.Point(20, 20);
            this.statusLabel.Size = new System.Drawing.Size(360, 20);
            this.statusLabel.Text = "WebView2 런타임을 다운로드하고 있습니다...";
            
            // Progress Bar
            this.progressBar.Location = new System.Drawing.Point(20, 50);
            this.progressBar.Size = new System.Drawing.Size(360, 30);
            this.progressBar.Style = ProgressBarStyle.Continuous;
            
            // Controls 추가
            this.Controls.Add(this.statusLabel);
            this.Controls.Add(this.progressBar);
            
            this.ResumeLayout(false);
            this.PerformLayout();
        }
        
        public void UpdateProgress(int percentage, long bytesReceived, long totalBytes)
        {
            if (this.InvokeRequired)
            {
                this.Invoke(new Action(() => UpdateProgress(percentage, bytesReceived, totalBytes)));
                return;
            }
            
            this.progressBar.Value = percentage;
            this.statusLabel.Text = $"다운로드 중... {percentage}% ({FormatBytes(bytesReceived)} / {FormatBytes(totalBytes)})";
        }
        
        private string FormatBytes(long bytes)
        {
            string[] suffixes = { "B", "KB", "MB", "GB" };
            int counter = 0;
            decimal number = bytes;
            
            while (Math.Round(number / 1024) >= 1)
            {
                number /= 1024;
                counter++;
            }
            
            return $"{number:n1} {suffixes[counter]}";
        }
    }
}