// 7 february 2014

package ui

// Dialog is an interface adopted by all dialogs.
type Dialog struct {
	Response() Response	// response code from the dialog
	Selection() interface{}	// currently nil
}

// Response denotes a response from the user to a Dialog.
type Response uint
const (
	NotDone Response = iota
	OK
)

// basic return
type dialogret struct {
	res	Response
	sel	interface{}
}
func (d *dialogret) Response() Response { return d.res }
func (d *dialogret) Selection() interface{} { return d.sel }	

// sentinel (not nil so programmer errors don't go undetected)
// this window is invalid and cannot be used directly
// notice the support it uses
var dialogWindow = &Window{
	sysData:	&sysData{
		winhandler:	dh,
	}
}
type dhandler chan *dialogret
func (d dhandler) Event(e Event, dat interface{}) {
	d <- dat.(*dialogret)
}
var dh = make(dhandler)

// MsgBox displays an informational message box to the user with just an OK button.
// primaryText should be a short string describing the message, and will be displayed with additional emphasis on platforms that support it.
// Optionally, secondaryText can be used to show additional information.
// If you pass an empty string for secondaryText, neither additional information nor space for additional information will be shown.
// On platforms that allow for the message box window to have a title, os.Args[0] is used.
//
// See "On Dialogs" in the package overview for behavioral information.
func MsgBox(primaryText string, secondaryText string) Response {
	dialogWindow.msgBox(primaryText, secondaryText)
	return (<-dh).res
}

// MsgBox is the Window method version of the package-scope function MsgBox.
// See that function's documentation and "On Dialogs" in the package overview for more information.
func (w *Window) MsgBox(primaryText string, secondaryText string) Dialog {
	if !w.created {
		panic("parent window passed to Window.MsgBox() before it was created")
	}
	return w.msgBox(primaryText, secondaryText)
}

// MsgBoxError displays a message box to the user with just an OK button and an icon indicating an error.
// Otherwise, it behaves like MsgBox.
//
// See "On Dialogs" in the package overview for more information.
func MsgBoxError(primaryText string, secondaryText string) Dialog {
	dialogWindow.msgBoxError(primaryText, secondaryText)
	return (<-dh).res
}

// MsgBoxError is the Window method version of the package-scope function MsgBoxError.
// See that function's documentation and "On Dialogs" in the package overview for more information.
func (w *Window) MsgBoxError(primaryText string, secondaryText string) Dialog {
	return w.msgBoxError(primaryText, secondaryText)
}