// 7 february 2014

package ui

import (
	"fmt"
	"os"
)

var (
	_messageBox = user32.NewProc("MessageBoxW")
)

var dialogResponses = map[uintptr]Response{
	_IDOK:		OK,
}

func _msgBox(parent *Window, primarytext string, secondarytext string, uType uint32) Response {
	// http://msdn.microsoft.com/en-us/library/windows/desktop/aa511267.aspx says "Use task dialogs whenever appropriate to achieve a consistent look and layout. Task dialogs require Windows Vista® or later, so they aren't suitable for earlier versions of Windows. If you must use a message box, separate the main instruction from the supplemental instruction with two line breaks."
	text := primarytext
	if secondarytext != "" {
		text += "\n\n" + secondarytext
	}
	ptext := toUTF16(text)
	ptitle := toUTF16(os.Args[0])
	parenthwnd := _HWND(_NULL)
	if parent != dialogWindow {
		parenthwnd = parent.sysData.hwnd
		uType |= _MB_APPLMODAL // only for this window
	} else {
		uType |= _MB_TASKMODAL // make modal to every window in the program (they're all windows of the uitask, which is a single thread)
	}
	r1, _, err := _messageBox.Call(
		uintptr(parenthwnd),
		utf16ToArg(ptext),
		utf16ToArg(ptitle),
		uintptr(uType))
	if r1 == 0 { // failure
		panic(fmt.Sprintf("error displaying message box to user: %v\nstyle: 0x%08X\ntitle: %q\ntext:\n%s", err, uType, os.Args[0], text))
	}
	return dialogResponses[r1]
}

func (w *Window) msgBox(primarytext string, secondarytext string) {
	_msgBox(w, primarytext, secondarytext, _MB_OK)
}

func (w *Window) msgBoxError(primarytext string, secondarytext string) {
	_msgBox(w, primarytext, secondarytext, _MB_OK|_MB_ICONERROR)
}