//go:build windows

package main

import (
	"syscall"
	"unicode/utf16"
	"unsafe"
)

const (
	mbOK              = 0x00000000
	mbOKCancel        = 0x00000001
	mbIconError       = 0x00000010
	mbIconQuestion    = 0x00000020
	mbIconInformation = 0x00000040
	idOK              = 1
)

const (
	cfUnicodeText = 13
	gmemMoveable  = 0x0002
)

var (
	user32DLL    = syscall.NewLazyDLL("user32.dll")
	messageBoxW  = user32DLL.NewProc("MessageBoxW")
	openClip     = user32DLL.NewProc("OpenClipboard")
	closeClip    = user32DLL.NewProc("CloseClipboard")
	emptyClip    = user32DLL.NewProc("EmptyClipboard")
	setClipData  = user32DLL.NewProc("SetClipboardData")
	globalAlloc  = kernel32DLL.NewProc("GlobalAlloc")
	globalLock   = kernel32DLL.NewProc("GlobalLock")
	globalUnlock = kernel32DLL.NewProc("GlobalUnlock")
)

func showInfo(title, text string) {
	showMessage(title, text, mbOK|mbIconInformation)
}

func showError(title, text string) {
	showMessage(title, text, mbOK|mbIconError)
}

func confirm(title, text string) bool {
	return showMessage(title, text, mbOKCancel|mbIconQuestion) == idOK
}

func showMessage(title, text string, flags uint) int {
	titlePtr, _ := syscall.UTF16PtrFromString(title)
	textPtr, _ := syscall.UTF16PtrFromString(text)
	result, _, _ := messageBoxW.Call(
		0,
		uintptr(unsafe.Pointer(textPtr)),
		uintptr(unsafe.Pointer(titlePtr)),
		uintptr(flags),
	)
	return int(result)
}

func copyToClipboard(text string) {
	opened, _, _ := openClip.Call(0)
	if opened == 0 {
		return
	}
	defer closeClip.Call()
	emptyClip.Call()

	encoded := utf16.Encode([]rune(text))
	encoded = append(encoded, 0)
	size := uintptr(len(encoded) * 2)
	handle, _, _ := globalAlloc.Call(gmemMoveable, size)
	if handle == 0 {
		return
	}
	pointer, _, _ := globalLock.Call(handle)
	if pointer == 0 {
		return
	}
	target := unsafe.Slice((*uint16)(unsafe.Pointer(pointer)), len(encoded))
	copy(target, encoded)
	globalUnlock.Call(handle)
	setClipData.Call(cfUnicodeText, handle)
}