package main

import (
	"io/ioutil"
	"log"
	"os"
	"syscall"
	"unsafe"
)

func runAsAdmin(file, parameters string) error {
	shellExecute := syscall.MustLoadDLL("Shell32.dll").MustFindProc("ShellExecuteW")
	defer shellExecute.Dll.Release()

	r, _, err := shellExecute.Call(
		0,
		uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr("runas"))),
		uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(file))),
		uintptr(unsafe.Pointer(syscall.StringToUTF16Ptr(parameters))),
		0,
		syscall.SW_SHOWNORMAL,
	)
	if r <= 32 {
		return err
	}

	return nil
}

func main() {
	err := ioutil.WriteFile(
		os.Getenv(`ProgramFiles`)+`\test.txt`, []byte("Hello World"), 0666)

	if err == nil {
		log.Println("File successfully written")
		return
	}

	if !os.IsPermission(err) {
		log.Fatalln(err)
	}

	log.Println("Start UAC elevation")

	err = runAsAdmin(os.Args[0], "")
	if err != nil {
		log.Fatalln(err)
	}
	log.Println("UAC elevation succeeded")
}