(() => {
    var JFrame = javax.swing.JFrame;
    var JLabel = javax.swing.JLabel;
    var JPanel = javax.swing.JPanel;
    var JButton = javax.swing.JButton;
    var JTextArea = javax.swing.JTextArea;
    var JScrollPane = javax.swing.JScrollPane;
    var Frame = java.awt.Frame;
    var Toolkit = java.awt.Toolkit;
    var BorderLayout = java.awt.BorderLayout;
    var WindowListener = java.awt.event.WindowListener;
    var Proxy = java.lang.reflect.Proxy;
    var CountDownLatch = java.util.concurrent.CountDownLatch;

    try {
        //javax.swing.UIManager.setLookAndFeel(javax.swing.UIManager.getCrossPlatformLookAndFeelClassName());
    } catch (e) { /* IGNORE */ }

    function FutureResult() {
        this.result = null;
        this.countDown = new CountDownLatch(1);
    }

    FutureResult.prototype.set = (result) => {
        this.result = result;
        this.countDown.countDown();
    };

    FutureResult.prototype.get = () => {
        this.countDown.await();
        return this.result;
    };

    showWindow = (title, text, message, editable) => { // GLOBAL
        var result = new FutureResult();
        var f = new JFrame(title || "Hatter's Frame");
        f.addWindowListener(Proxy.newProxyInstance(
            Proxy.class.getClassLoader(),
            [WindowListener.class],
            (proxy, method, args) => {
                if (method && method.name == "windowClosing") {
                    f.setVisible(false);
                    f.dispose();
                    result.set(null);
                }
            }
        ));

        var text = new JTextArea(text || "", 30, 80);
        text.setWrapStyleWord(true);
        text.setLineWrap(true);
        text.setEditable(!!editable);

        var textScrollPane = new JScrollPane(text);

        var label = new JLabel(message || "This is default message!");

        var btnOK = null;
        if (editable) {
            btnOK = new JButton("OK!");
            btnOK.addActionListener(() => {
                var t = text.getText();
                f.setVisible(false);
                f.dispose();
                result.set(t);
            });
        }
        var btnCancel = new JButton("Cancel");
        btnCancel.addActionListener(() => {
            f.setVisible(false);
            f.dispose();
            result.set(null);
        });

        var pane = new JPanel();
        if (btnOK != null) {
            pane.add(btnOK);
        }
        pane.add(btnCancel);

        f.getContentPane().add(label, BorderLayout.NORTH);
        f.getContentPane().add(pane, BorderLayout.SOUTH);
        f.getContentPane().add(textScrollPane, BorderLayout.CENTER);

        f.pack();

        var dim = Toolkit.getDefaultToolkit().getScreenSize();
        f.setLocation((dim.width / 2) - (f.getSize().width / 2), (dim.height / 2) - (f.getSize().height / 2));

        f.setVisible(true);

        return result;
    };
})();