package class6_1_MultithreadPrimeAppJava_start;

import javax.swing.*;
import java.awt.*;

/**
 * This GUI class displays the most recently found prime number.
 */
public class PrimeApp extends JFrame {

    private PrimeFinder primeFinder = new PrimeFinder(this);

    private final JLabel recentPrimeLabel;

    public static void main(String[] ignored) {
        new PrimeApp();
    }

    public PrimeApp() {

        setSize(400, 300);
        setLayout(new FlowLayout());
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        //--- The main window ---
        recentPrimeLabel = new JLabel();
        recentPrimeLabel.setText("Latest prime: (none)");
        add(recentPrimeLabel);

        JButton button = new JButton("Find Primes");
        button.addActionListener(l->startPrimes());
        add(button);

        //--- The menu bar ---
        JMenuBar bar = new JMenuBar();
        JMenu menu = new JMenu("Actions");

        JMenuItem item = new JMenuItem("Start finding primes");
        item.addActionListener(l->startPrimes());
        menu.add(item);

        item = new JMenuItem("Stop finding primes");
        item.addActionListener(l->stopPrimes());
        menu.add(item);

        bar.add(menu);
        setJMenuBar(bar);

        setVisible(true);
    }

    public void startPrimes() {
        primeFinder.findPrimes();
    }

    public void stopPrimes() {
        // Spring 2017: Bug fixed after class 6-1:
        // This was stopping a different thread
        // instead of asking primeFinder to stop the thread.
        // This version of the code
        // has been corrected so that stop works.
        if(primeFinder == null) {
            System.err.println("Cannot interrupt worker: primeFinder variable is null");
        } else {
            System.out.println("Interrupting worker.");
            primeFinder.interrupt();
        }
    }

    /**
     * Sets the most recently found prime text. Client must provide the "Latest prime:" prefix as well.
     * @param text The complete new text for the label.
     */
    public void setRecentPrime(String text) {
        SwingUtilities.invokeLater(() ->
                recentPrimeLabel.setText(text));
    }
}