//go:build windows

package main

import (
	"fmt"
	"os"
	"strings"
	"syscall"
	"unsafe"
)

var (
	shell32            = syscall.NewLazyDLL("shell32.dll")
	shellExecuteW      = shell32.NewProc("ShellExecuteW")
	isUserAnAdminProc  = shell32.NewProc("IsUserAnAdmin")
	errCancelledByUser = uintptr(1223)
)

func isElevated() bool {
	ret, _, _ := isUserAnAdminProc.Call()
	return ret != 0
}

func relaunchElevated() error {
	exePath, err := os.Executable()
	if err != nil {
		return err
	}

	verb, err := syscall.UTF16PtrFromString("runas")
	if err != nil {
		return err
	}
	file, err := syscall.UTF16PtrFromString(exePath)
	if err != nil {
		return err
	}
	args, err := syscall.UTF16PtrFromString(joinWindowsArgs(os.Args[1:]))
	if err != nil {
		return err
	}

	ret, _, callErr := shellExecuteW.Call(
		0,
		uintptr(unsafe.Pointer(verb)),
		uintptr(unsafe.Pointer(file)),
		uintptr(unsafe.Pointer(args)),
		0,
		1,
	)
	if ret <= 32 {
		if ret == errCancelledByUser {
			return fmt.Errorf("administrator privileges were not granted")
		}
		if callErr != syscall.Errno(0) {
			return fmt.Errorf("ShellExecuteW failed: %w", callErr)
		}
		return fmt.Errorf("ShellExecuteW failed with code %d", ret)
	}
	return nil
}

func joinWindowsArgs(args []string) string {
	if len(args) == 0 {
		return ""
	}
	quoted := make([]string, 0, len(args))
	for _, arg := range args {
		escaped := strings.ReplaceAll(arg, `"`, `\"`)
		quoted = append(quoted, `"`+escaped+`"`)
	}
	return strings.Join(quoted, " ")
}