using Microsoft.Win32;
using System.Diagnostics;

namespace DeviceAgent.Services;

/// <summary>
/// 远程桌面服务 - 自动开启 Windows 远程桌面
/// </summary>
public class RemoteDesktopService
{
    private readonly ILogger<RemoteDesktopService> _logger;

    public RemoteDesktopService(ILogger<RemoteDesktopService> logger)
    {
        _logger = logger;
    }

    /// <summary>
    /// 启用远程桌面
    /// </summary>
    public bool EnableRemoteDesktop()
    {
        try
        {
            // 1. 修改注册表启用远程桌面
            using var key = Registry.LocalMachine.OpenSubKey(
                @"SYSTEM\CurrentControlSet\Control\Terminal Server", true);
            
            if (key != null)
            {
                // fDenyTSConnections = 0 表示允许远程连接
                key.SetValue("fDenyTSConnections", 0, RegistryValueKind.DWord);
                _logger.LogInformation("已启用远程桌面连接");
            }
            else
            {
                _logger.LogWarning("无法打开远程桌面注册表项");
                return false;
            }

            // 2. 设置网络级别身份验证 (NLA) - 可选，设为 0 允许任何版本的远程桌面连接
            using var nlaKey = Registry.LocalMachine.OpenSubKey(
                @"SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp", true);
            
            if (nlaKey != null)
            {
                // UserAuthentication = 0 禁用 NLA（更兼容）
                // UserAuthentication = 1 启用 NLA（更安全）
                nlaKey.SetValue("UserAuthentication", 0, RegistryValueKind.DWord);
                _logger.LogInformation("已配置网络级别身份验证");
            }

            // 3. 开启防火墙规则
            EnableFirewallRule();

            // 4. 启动远程桌面服务
            StartTerminalService();

            return true;
        }
        catch (UnauthorizedAccessException ex)
        {
            _logger.LogError(ex, "启用远程桌面失败: 需要管理员权限");
            return false;
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "启用远程桌面失败");
            return false;
        }
    }

    /// <summary>
    /// 检查远程桌面是否已启用
    /// </summary>
    public bool IsRemoteDesktopEnabled()
    {
        try
        {
            using var key = Registry.LocalMachine.OpenSubKey(
                @"SYSTEM\CurrentControlSet\Control\Terminal Server");
            
            if (key != null)
            {
                var value = key.GetValue("fDenyTSConnections");
                return value != null && (int)value == 0;
            }
            
            return false;
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "检查远程桌面状态失败");
            return false;
        }
    }

    /// <summary>
    /// 开启防火墙规则允许远程桌面
    /// </summary>
    private void EnableFirewallRule()
    {
        try
        {
            // 启用远程桌面防火墙规则
            var startInfo = new ProcessStartInfo
            {
                FileName = "netsh",
                Arguments = "advfirewall firewall set rule group=\"远程桌面\" new enable=yes",
                UseShellExecute = false,
                RedirectStandardOutput = true,
                RedirectStandardError = true,
                CreateNoWindow = true
            };

            using var process = Process.Start(startInfo);
            process?.WaitForExit(5000);

            // 如果中文规则名失败，尝试英文
            if (process?.ExitCode != 0)
            {
                startInfo.Arguments = "advfirewall firewall set rule group=\"Remote Desktop\" new enable=yes";
                using var process2 = Process.Start(startInfo);
                process2?.WaitForExit(5000);
            }

            _logger.LogInformation("已配置防火墙规则");
        }
        catch (Exception ex)
        {
            _logger.LogWarning(ex, "配置防火墙规则失败，可能需要手动配置");
        }
    }

    /// <summary>
    /// 启动远程桌面服务
    /// </summary>
    private void StartTerminalService()
    {
        try
        {
            var startInfo = new ProcessStartInfo
            {
                FileName = "sc",
                Arguments = "config TermService start= auto",
                UseShellExecute = false,
                RedirectStandardOutput = true,
                CreateNoWindow = true
            };

            using var process = Process.Start(startInfo);
            process?.WaitForExit(5000);

            // 启动服务
            startInfo.Arguments = "start TermService";
            using var process2 = Process.Start(startInfo);
            process2?.WaitForExit(5000);

            _logger.LogInformation("已启动远程桌面服务");
        }
        catch (Exception ex)
        {
            _logger.LogWarning(ex, "启动远程桌面服务失败");
        }
    }

    /// <summary>
    /// 获取远程桌面端口
    /// </summary>
    public int GetRdpPort()
    {
        try
        {
            using var key = Registry.LocalMachine.OpenSubKey(
                @"SYSTEM\CurrentControlSet\Control\Terminal Server\WinStations\RDP-Tcp");
            
            if (key != null)
            {
                var value = key.GetValue("PortNumber");
                if (value != null)
                {
                    return (int)value;
                }
            }
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "获取远程桌面端口失败");
        }

        return 3389; // 默认端口
    }
}