//
// almost the simplest possible GUI-based file editor
//
import scala.swing._

// component that allows entering/modifying multiple lines of text
val textArea = new TextArea(20,60)

// graphical "file chooser"
val chooser = new FileChooser

// clear text area
def clear() = {
  textArea.text = ""
}

// get contents of file into text area
def open() = {
  if (chooser.showOpenDialog(textArea)==FileChooser.Result.Approve) {
    val src = scala.io.Source.fromFile(chooser.selectedFile)
    textArea.text = src.getLines.mkString("\n")
    src.close
  }
}

// write contents of text area to file
def save() = {
  if (chooser.showSaveDialog(textArea)==FileChooser.Result.Approve) {
    val pw = new java.io.PrintWriter(
      new java.io.File(chooser.selectedFile.toString))
    pw.println(textArea.text)
    pw.close
  }
}

// menu 
val fileMenu = new Menu("File") {
  contents += new MenuItem(Action("Open")( open() ))
  contents += new MenuItem(Action("Save")( save() ))
  contents += new MenuItem(Action("Clear")( clear() ))
  contents += new MenuItem(Action("Exit")( sys.exit(0) ))
}

// main layout 
val frame = new MainFrame {
    title = "Simple Editor"
    contents = new BorderPanel {
      layout += (new ScrollPane(textArea) -> BorderPanel.Position.Center)
    }
    menuBar = new MenuBar {
      contents += fileMenu
    }
}

// start up
frame.visible = true