//
// program illustrating simple use of GUI components
//
// another way to improve(?) layout -- add FlowPanels
//
import scala.swing._
import scala.swing.event._

//
// label to display most recent action, with a function to update it
//
val LabelInitialSize = 100 // somewhat arbitrary initial size
val textDisplay = new Label(" "*LabelInitialSize)
textDisplay.horizontalAlignment = Alignment.Center // FIXME
def setText(s:String) { 
  textDisplay.text = "user action:  " + s 
}

//
// container with some buttons
//
val buttons = new FlowPanel {
  contents += Button("button 1") { setText("clicked button 1") }
  contents += Button("button 2") { setText("clicked button 2") }
}

//
// menu with some items
//
val menu = new Menu("Actions") {
  contents += new MenuItem(Action("item 1") { setText("chose menu item 1") } )
  contents += new MenuItem(Action("item 2") { setText("chose menu item 2") } )
}

//
// list with selectable entries
//
val list = new ListView(List("this", "that", "the other thing", "another"))

//
// main frame/window
//
val frame = new MainFrame {

  title = "Hello!"

  contents = new BoxPanel(Orientation.Vertical) {
    contents += buttons
    contents += new FlowPanel {
      contents += list
    }
    contents += new FlowPanel {
      contents += textDisplay
    }
  }

  menuBar = new MenuBar {
    contents += menu 
  }

  //
  // update label when list selection changes
  //
  listenTo(list.selection)
  reactions += {
    case e:SelectionChanged => { 
      setText("selected list items " + list.selection.items.mkString(", ")) 
    }
  }

  //
  // no size here -- use pack below
  //
}

// set size to just big enough to hold all components
frame.pack
// display
frame.visible = true