//go:build windows

package main

import (
	goruntime "runtime"
	"unsafe"

	"golang.org/x/sys/windows"
)

const (
	wmHotkey = 0x0312
	modWin   = 0x0008
	modAlt   = 0x0001
	vkV      = 0x56
	hotkeyID = 1
)

var (
	user32             = windows.NewLazySystemDLL("user32.dll")
	procRegisterHotKey = user32.NewProc("RegisterHotKey")
	procGetMessage     = user32.NewProc("GetMessageW")
	procTranslateMsg   = user32.NewProc("TranslateMessage")
	procDispatchMsg    = user32.NewProc("DispatchMessageW")
)

type winMSG struct {
	HWND    uintptr
	Message uint32
	WParam  uintptr
	LParam  uintptr
	Time    uint32
	PtX     int32
	PtY     int32
}

func (a *App) registerHotkey() {
	go func() {
		goruntime.LockOSThread()
		defer goruntime.UnlockOSThread()

		r, _, _ := procRegisterHotKey.Call(0, hotkeyID, modWin|modAlt, vkV)
		if r == 0 {
			return
		}

		var msg winMSG
		for {
			r, _, _ := procGetMessage.Call(uintptr(unsafe.Pointer(&msg)), 0, 0, 0)
			if r == 0 || r == ^uintptr(0) {
				break
			}
			if msg.Message == wmHotkey && msg.WParam == hotkeyID {
				a.toggleVPN()
			}
			procTranslateMsg.Call(uintptr(unsafe.Pointer(&msg)))
			procDispatchMsg.Call(uintptr(unsafe.Pointer(&msg)))
		}
	}()
}