//go:build windows

package remote

import (
	"fmt"
	"os"

	"github.com/KarpelesLab/vncpasswd"
	"github.com/kardianos/service"
	"golang.org/x/sys/windows/registry"
)

var VncService service.Service

// ReadVncServerConfig 从注册表读取 TightVNC 服务端配置（键值缺失按零值返回）
func ReadVncServerConfig() (VncServerConfig, error) {
	var config VncServerConfig

	key, err := registry.OpenKey(registry.LOCAL_MACHINE, "SOFTWARE\\TightVNC\\Server", registry.ALL_ACCESS)
	if err != nil {
		return config, err
	}
	defer key.Close()

	config.ExtraPorts, _, _ = key.GetStringValue("ExtraPorts")
	config.QueryTimeout, _, _ = GetDwordValue(key, "QueryTimeout")
	config.QueryAcceptOnTimeout, _, _ = GetDwordValue(key, "QueryAcceptOnTimeout")
	config.LocalInputPriorityTimeout, _, _ = GetDwordValue(key, "LocalInputPriorityTimeout")
	config.LocalInputPriority, _, _ = GetDwordValue(key, "LocalInputPriority")
	config.BlockRemoteInput, _, _ = GetDwordValue(key, "BlockRemoteInput")
	config.BlockLocalInput, _, _ = GetDwordValue(key, "BlockLocalInput")
	config.IpAccessControl, _, _ = key.GetStringValue("IpAccessControl")
	config.RfbPort, _, _ = GetDwordValue(key, "RfbPort")
	config.HttpPort, _, _ = GetDwordValue(key, "HttpPort")
	config.DisconnectAction, _, _ = GetDwordValue(key, "DisconnectAction")
	config.AcceptRfbConnections, _, _ = GetDwordValue(key, "AcceptRfbConnections")
	config.UseVncAuthentication, _, _ = GetDwordValue(key, "UseVncAuthentication")
	config.UseControlAuthentication, _, _ = GetDwordValue(key, "UseControlAuthentication")
	config.RepeatControlAuthentication, _, _ = GetDwordValue(key, "RepeatControlAuthentication")
	config.LoopbackOnly, _, _ = GetDwordValue(key, "LoopbackOnly")
	config.AcceptHttpConnections, _, _ = GetDwordValue(key, "AcceptHttpConnections")
	config.EnableFileTransfers, _, _ = GetDwordValue(key, "EnableFileTransfers")
	config.RemoveWallpaper, _, _ = GetDwordValue(key, "RemoveWallpaper")
	config.UseD3D, _, _ = GetDwordValue(key, "UseD3D")
	config.UseMirrorDriver, _, _ = GetDwordValue(key, "UseMirrorDriver")
	config.EnableUrlParams, _, _ = GetDwordValue(key, "EnableUrlParams")
	config.Password, _, _ = key.GetBinaryValue("Password")
	config.AlwaysShared, _, _ = GetDwordValue(key, "AlwaysShared")
	config.NeverShared, _, _ = GetDwordValue(key, "NeverShared")
	config.DisconnectClients, _, _ = GetDwordValue(key, "DisconnectClients")
	config.PollingInterval, _, _ = GetDwordValue(key, "PollingInterval")
	config.AllowLoopback, _, _ = GetDwordValue(key, "AllowLoopback")
	config.VideoRecognitionInterval, _, _ = GetDwordValue(key, "VideoRecognitionInterval")
	config.GrabTransparentWindows, _, _ = GetDwordValue(key, "GrabTransparentWindows")
	config.SaveLogToAllUsersPath, _, _ = GetDwordValue(key, "SaveLogToAllUsersPath")
	config.RunControlInterface, _, _ = GetDwordValue(key, "RunControlInterface")
	config.IdleTimeout, _, _ = GetDwordValue(key, "IdleTimeout")
	config.VideoClasses, _, _ = key.GetStringValue("VideoClasses")
	config.VideoRects, _, _ = key.GetStringValue("VideoRects")
	config.ConnectToRdp, _, _ = GetDwordValue(key, "ConnectToRdp")

	return config, nil
}

// GetDwordValue 读取 REG_DWORD 类型注册表值
func GetDwordValue(k registry.Key, name string) (val uint32, valtype uint32, err error) {
	val64 := uint64(0)
	val64, valtype, err = k.GetIntegerValue(name)
	val = uint32(val64)
	return
}

var vncSvcConfig = &service.Config{
	Name:        "tvnserver",
	DisplayName: "TightVNC Server",
	Description: "TightVNC Server (managed by remote-core)",
	Arguments:   []string{"-service"},
}

// InstallVncServer 绿色安装 TightVNC 服务端（需管理员权限）。
// 最新版注册表全集配置（VncClientDefaultConfig 37 项, 随机 8 位密码）→ 注册系统服务。
// 装而不启：服务注册后保持 Stopped, 等远程指令再 VncStart（避免常驻监听开端口）;
// 若服务已在运行则重启以加载新配置。返回生成的明文密码（调用方自行上报/展示）。
func InstallVncServer(exePath string) (string, error) {
	if finfo, err := os.Stat(exePath); err != nil || finfo.IsDir() {
		return "", fmt.Errorf("tvnserver.exe 不存在: %s", exePath)
	}

	// 最新版 TightVNC 注册表配置全集（含随机密码）
	config := VncClientDefaultConfig(true)
	if err := WriteVncServerConfig(config); err != nil {
		return "", err
	}

	// 注册系统服务：未安装→安装; 运行中→重启加载新配置; 已停止→保持
	vncSvcConfig.Executable = exePath
	if err := VncInit(); err != nil {
		return "", err
	}
	status, err := VncService.Status()
	switch {
	case err != nil: // 未安装（kardianos 对未安装服务 Status 返回错误）
		if err := VncInstall(); err != nil {
			return "", err
		}
	case status == service.StatusRunning:
		if err := VncRestart(); err != nil {
			return "", err
		}
	}
	return VncPasswordDecrypt(config.Password), nil
}

// VncInit 初始化 VNC 服务对象，VncInstall/VncStart 等操作前必须调用
func VncInit() error {
	var err error
	VncService, err = service.New(nil, vncSvcConfig)
	if err != nil {
		return err
	}
	return nil
}

// VncInstall 安装 TightVNC 服务
func VncInstall() error {
	err := VncService.Install()
	if err != nil {
		return err
	}
	return nil
}

// VncUninstall 停止并卸载 TightVNC 服务
func VncUninstall() error {
	_ = VncService.Stop()
	err := VncService.Uninstall()
	if err != nil {
		return err
	}
	return nil
}

// VncStart 启动 TightVNC 服务
func VncStart() error {
	err := VncService.Start()
	if err != nil {
		return err
	}
	return nil
}

// VncStop 停止 TightVNC 服务
func VncStop() error {
	err := VncService.Stop()
	if err != nil {
		return err
	}
	return nil
}

// VncRestart 重启 TightVNC 服务
func VncRestart() error {
	err := VncService.Stop()
	if err != nil {
		return err
	}
	err = VncService.Start()
	if err != nil {
		return err
	}
	return nil
}

// VncPasswordCrypt 加密 VNC 密码（TightVNC 注册表存储格式）
func VncPasswordCrypt(password string) []byte {
	return vncpasswd.Crypt(password)
}

// VncPasswordDecrypt 解密 VNC 密码
func VncPasswordDecrypt(data []byte) string {
	return vncpasswd.Decrypt(data)
}