UI Panels and Navigation

// Setup CardLayout
cardLayout = new java.awt.CardLayout();
cardPanel = new javax.swing.JPanel(cardLayout);
cardPanel.add(mainPanel, "MAIN");
cardPanel.add(preferencesPanel, "PREFERENCES");
cardPanel.add(manageMediaPanel, "MEDIA");
cardPanel.add(loginForm, "LOGIN");

private String currentPanel = "LOGIN";
private String previousPanel = "LOGIN";

public void showMainPanel() {
    previousPanel = currentPanel;
    currentPanel = "MAIN";
    cardLayout.show(cardPanel, "MAIN");
}

public void goBack() {
    cardLayout.show(cardPanel, previousPanel);
    currentPanel = previousPanel;
}

// Check if config.txt exists on startup
checkConfig();

// Try auto-login
if (loginForm.checkAutoLogin()) {
    currentPanel = "MAIN";
    cardLayout.show(cardPanel, "MAIN");
} else {
    currentPanel = "LOGIN";
    cardLayout.show(cardPanel, "LOGIN");
}

txtEmail.getDocument().addDocumentListener(new DocumentListener() {
    @Override
    public void insertUpdate(DocumentEvent e) {
        validateEmail();
    }
    // ... other methods
});

private boolean validateEmail() {
    String email = txtEmail.getText();
    Pattern pattern = Pattern.compile("^[\\w.-]+@[\\w.-]+\\.[a-zA-Z]{2,}$");
    if (!pattern.matcher(email).matches()) {
        txtEmail.setBorder(BorderFactory.createLineBorder(new Color(220, 53, 69)));
        return false;
    }
    txtEmail.setBorder(defaultBorder);
    return true;
}

prefs = Preferences.userNodeForPackage(LoginForm.class);

// Save on successful login
if (tglRemember.isSelected()) {
    prefs.put("auth_token", token);
    prefs.put("user_email", email);
}

// Auto-login on startup
public boolean checkAutoLogin() {
    String savedToken = prefs.get("auth_token", null);
    if (savedToken != null && mediaPollingComponent.checkToken(savedToken)) {
        return true;
    }
    return false;
}

private void tglAdvancedOptionsActionPerformed(java.awt.event.ActionEvent evt) {
    boolean isSelected = tglAdvancedOptions.isSelected();
    jScrollPane1.setVisible(isSelected);
    txtAreaCustomArgs.setVisible(isSelected);
    lblCustomArgs.setVisible(isSelected);
    
    if (isSelected) {
        tglAdvancedOptions.setText("Advanced ▲");
    } else {
        tglAdvancedOptions.setText("Advanced ▼");
    }
}

downloadBtn.setEnabled(false);
downloadBtn.setText("Downloading...");
progressBar.setValue(0);
progressBar.setVisible(true);

if (line.contains("[download]") && line.contains("%")) {
    String percentStr = line.substring(
        line.indexOf("]") + 1, line.indexOf("%")).trim();
    double percent = Double.parseDouble(percentStr);
    publish((int) percent);
}

tblFiles.setAutoCreateRowSorter(true);

tableContextMenu = new JPopupMenu();
JMenuItem playItem = new JMenuItem("Play");
JMenuItem openFolderItem = new JMenuItem("Open Folder");
JMenuItem downloadItem = new JMenuItem("Download");
JMenuItem deleteItem = new JMenuItem("Delete");

tblFiles.addMouseListener(new MouseAdapter() {
    @Override
    public void mouseReleased(MouseEvent e) {
        if (e.isPopupTrigger()) {
            int row = tblFiles.rowAtPoint(e.getPoint());
            tblFiles.setRowSelectionInterval(row, row);
            tableContextMenu.show(e.getComponent(), e.getX(), e.getY());
        }
    }
});

fieldFilter.getDocument().addDocumentListener(new DocumentListener() {
    private void updateTextFilter() {
        textFilter = fieldFilter.getText().toLowerCase().trim();
        loadMediaFiles(); // Refresh table
    }
});

if (textFilter.isEmpty() || 
    media.getFileName().toLowerCase().contains(textFilter)) {
    // Add to table
}

addComponentListener(new ComponentAdapter() {
    @Override
    public void componentShown(ComponentEvent e) {
        loadMediaFiles();
    }
});

// Slider updates text field
sliderLimiter.addChangeListener(new ChangeListener() {
    @Override
    public void stateChanged(ChangeEvent e) {
        speedLimitKBps = sliderLimiter.getValue();
        txtLimiter.setText(speedLimitKBps + " KB/s");
    }
});

// Text field updates slider
txtLimiter.getDocument().addDocumentListener(new DocumentListener() {
    private void updateSliderFromText() {
        String text = txtLimiter.getText().replaceAll("[^0-9]", "");
        int value = Math.max(1, Math.min(100000, Integer.parseInt(text)));
        sliderLimiter.setValue(value);
    }
});

JFileChooser fileChooser = new JFileChooser();
fileChooser.setDialogTitle("Select yt-dlp executable");
fileChooser.setFileSelectionMode(JFileChooser.FILES_ONLY);
FileNameExtensionFilter filter = new FileNameExtensionFilter("Executable", "exe");
fileChooser.setFileFilter(filter);

JFileChooser fileChooser = new JFileChooser();
fileChooser.setDialogTitle("Select download directory");
fileChooser.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);

private Point initialClick;

private void enableDragging(Component component) {
    component.addMouseListener(new MouseAdapter() {
        @Override
        public void mousePressed(MouseEvent e) {
            initialClick = e.getPoint();
        }
    });

    component.addMouseMotionListener(new MouseMotionAdapter() {
        @Override
        public void mouseDragged(MouseEvent e) {
            int thisX = Main.this.getLocation().x;
            int thisY = Main.this.getLocation().y;
            int xMoved = e.getX() - initialClick.x;
            int yMoved = e.getY() - initialClick.y;
            Main.this.setLocation(thisX + xMoved, thisY + yMoved);
        }
    });
}

enableDragging(getContentPane());
enableDragging(jMenuBar1);
enableDragging(mediaPollingComponent);

public Main() {
    FlatDarculaLaf.setup();
    setUndecorated(true);
    initComponents();
    // ...
}

layeredPane.add(btnExit, JLayeredPane.POPUP_LAYER);
btnExit.setBounds(770, 2, 26, 26);

private void btnExitActionPerformed(java.awt.event.ActionEvent evt) {
    System.exit(0);
}