using FastGithub.Configuration;

using Microsoft.Extensions.Logging;

using System;

using System.Diagnostics;

using System.IO;

using System.Linq;

using System.Net;

using System.Threading;

using System.Threading.Tasks;

using static PInvoke.AdvApi32;

namespace FastGithub.DomainResolve

{

/// <summary>

/// DnscryptProxy服务

/// </summary>

sealed class DnscryptProxy

{

private readonly ILogger<DnscryptProxy> logger;

private readonly string processName;

private readonly string serviceName;

private readonly string exeFilePath;

private readonly string tomlFilePath;

/// <summary>

/// 相关进程

/// </summary>

private Process? process;

/// <summary>

/// 获取监听的节点

/// </summary>

public IPEndPoint? LocalEndPoint { get; private set; }

/// <summary>

/// DnscryptProxy服务

/// </summary>

/// <param name="logger"></param>

public DnscryptProxy(ILogger<DnscryptProxy> logger)

{

const string PATH = "dnscrypt-proxy";

const string NAME = "dnscrypt-proxy";

this.logger = logger;

this.processName = NAME;

this.serviceName = $"{nameof(FastGithub)}.{NAME}";

this.exeFilePath = Path.Combine(PATH, OperatingSystem.IsWindows() ? $"{NAME}.exe" : NAME);

this.tomlFilePath = Path.Combine(PATH, $"{NAME}.toml");

}

/// <summary>

/// 启动dnscrypt-proxy

/// </summary>

/// <param name="cancellationToken"></param>

/// <returns></returns>

public async Task StartAsync(CancellationToken cancellationToken)

{

try

{

await this.StartCoreAsync(cancellationToken);

}

catch (Exception ex)

{

this.logger.LogWarning($"{this.processName}启动失败：{ex.Message}");

}

}

/// <summary>

/// 启动dnscrypt-proxy

/// </summary>

/// <param name="cancellationToken"></param>

/// <returns></returns>

private async Task StartCoreAsync(CancellationToken cancellationToken)

{

var port = GlobalListener.GetAvailablePort(5533);

var localEndPoint = new IPEndPoint(IPAddress.Loopback, port);

await TomlUtil.SetListensAsync(this.tomlFilePath, localEndPoint, cancellationToken);

await TomlUtil.SetLogLevelAsync(this.tomlFilePath, 6, cancellationToken);

await TomlUtil.SetLBStrategyAsync(this.tomlFilePath, "ph", cancellationToken);

await TomlUtil.SetMinMaxTTLAsync(this.tomlFilePath, TimeSpan.FromMinutes(1d), TimeSpan.FromMinutes(2d), cancellationToken);

if (OperatingSystem.IsWindows() && Environment.UserInteractive == false)

{

ServiceInstallUtil.StopAndDeleteService(this.serviceName);

ServiceInstallUtil.InstallAndStartService(this.serviceName, this.exeFilePath, ServiceStartType.SERVICE_DEMAND_START);

this.process = Process.GetProcessesByName(this.processName).FirstOrDefault(item => item.SessionId == 0);

}

else

{

this.process = StartDnscryptProxy();

}

if (this.process != null)

{

this.LocalEndPoint = localEndPoint;

this.process.EnableRaisingEvents = true;

this.process.Exited += (s, e) => this.LocalEndPoint = null;

}

}

/// <summary>

/// 停止服务

/// </summary>

public void Stop()

{

try

{

if (OperatingSystem.IsWindows() && Environment.UserInteractive == false)

{

ServiceInstallUtil.StopAndDeleteService(this.serviceName);

}

if (this.process != null && this.process.HasExited == false)

{

this.process.Kill();

}

}

catch (Exception ex)

{

this.logger.LogWarning($"{this.processName}停止失败：{ex.Message }");

}

finally

{

this.LocalEndPoint = null;

}

}

/// <summary>

/// 启动DnscryptProxy进程

/// </summary>

/// <returns></returns>

private Process? StartDnscryptProxy()

{

return Process.Start(new ProcessStartInfo

{

FileName = this.exeFilePath,

WorkingDirectory = Path.GetDirectoryName(this.exeFilePath),

UseShellExecute = false,

CreateNoWindow = true,

WindowStyle = ProcessWindowStyle.Hidden

});

}

/// <summary>

/// 转换为字符串

/// </summary>

/// <returns></returns>

public override string ToString()

{

return this.processName;

}

}

}