ts3j/ts3-client/swing/src/main/java/com/ts3client/ui/ServerTabPane.java

package com.ts3client.ui;

import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTabbedPane;
import java.awt.BorderLayout;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.Insets;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseWheelEvent;
import java.util.ArrayList;
import java.util.List;

/**
 * Container for the open server connections. With a single connection the
 * server view fills the window as it always did; from the second connection on
 * the views move into a {@link JTabbedPane} whose tab strip sits directly under
 * the toolbar.
 */
final class ServerTabPane extends JPanel {

    interface Listener {
        void selectTab(ServerTab tab);

        void closeTab(ServerTab tab);
    }

    private final Listener listener;
    private final JTabbedPane tabbed = new JTabbedPane();
    private final List<ServerTab> tabs = new ArrayList<>();

    /** True while the tab strip is in use, i.e. more than one connection is open. */
    private boolean tabbedMode;
    /** Suppresses selection callbacks while we rearrange the pane ourselves. */
    private boolean updating;

    ServerTabPane(Listener listener) {
        super(new BorderLayout());
        this.listener = listener;
        tabbed.setTabLayoutPolicy(JTabbedPane.SCROLL_TAB_LAYOUT);
        tabbed.setFocusable(false);
        tabbed.addChangeListener(e -> {
            if (updating) return;
            int i = tabbed.getSelectedIndex();
            if (i >= 0 && i < tabs.size()) listener.selectTab(tabs.get(i));
        });
        tabbed.addMouseWheelListener(this::onWheel);
    }

    /**
     * Scrolling over the tab strip steps through the connections. The content
     * area keeps its own scrolling, so only wheel events on the strip itself
     * (and on the tab labels, which forward theirs) change tabs.
     */
    private void onWheel(MouseWheelEvent e) {
        if (!tabbedMode) return;
        Component content = tabbed.getSelectedComponent();
        if (content != null && content.getBounds().contains(e.getPoint())) return;

        int steps = e.getWheelRotation();
        if (steps == 0) return;
        int target = Math.max(0, Math.min(tabs.size() - 1, tabbed.getSelectedIndex() + steps));
        if (target != tabbed.getSelectedIndex()) listener.selectTab(tabs.get(target));
        e.consume();
    }

    void addTab(ServerTab tab) {
        tabs.add(tab);
        relayout();
    }

    void removeTab(ServerTab tab) {
        tabs.remove(tab);
        relayout();
    }

    void setSelected(ServerTab tab) {
        int i = tabs.indexOf(tab);
        if (!tabbedMode || i < 0 || tabbed.getSelectedIndex() == i) return;
        updating = true;
        try {
            tabbed.setSelectedIndex(i);
        } finally {
            updating = false;
        }
    }

    /** Refreshes the tab labels; {@code micTab} is marked as owning the microphone. */
    void refresh(ServerTab micTab) {
        if (!tabbedMode) return;
        for (int i = 0; i < tabs.size(); i++) {
            ServerTab tab = tabs.get(i);
            tabbed.setTitleAt(i, tab.title());
            tabbed.setToolTipTextAt(i, tab.status());
            tabbed.setTabComponentAt(i, buildTabComponent(tab, tab == micTab));
        }
    }

    /**
     * Moves the views between the plain single-server layout and the tabbed one,
     * keeping whatever is currently selected on screen.
     */
    private void relayout() {
        boolean wantTabs = tabs.size() > 1;
        updating = true;
        try {
            removeAll();
            tabbed.removeAll();
            if (wantTabs) {
                for (ServerTab tab : tabs) tabbed.addTab(tab.title(), tab.component());
                add(tabbed, BorderLayout.CENTER);
            } else if (!tabs.isEmpty()) {
                add(tabs.get(0).component(), BorderLayout.CENTER);
            }
            tabbedMode = wantTabs;
        } finally {
            updating = false;
        }
        revalidate();
        repaint();
    }

    /** A tab's label: title, microphone marker and a close button. */
    private JComponent buildTabComponent(ServerTab tab, boolean hasMic) {
        JPanel cell = new JPanel(new FlowLayout(FlowLayout.LEFT, 4, 0));
        cell.setOpaque(false);
        cell.setBorder(BorderFactory.createEmptyBorder(1, 0, 1, 0));

        JLabel label = new JLabel(tab.title(), hasMic ? Icons.micActiveSmall() : null, JLabel.LEADING);
        label.setFont(Theme.UI_FONT);
        label.setToolTipText(hasMic ? "Speaking on this server" : tab.status());
        // A label with a tooltip swallows mouse events, so select the tab explicitly.
        label.addMouseListener(new MouseAdapter() {
            @Override
            public void mousePressed(MouseEvent e) {
                listener.selectTab(tab);
            }
        });
        cell.add(label);

        JButton close = new JButton("✕");
        close.setFont(Theme.UI_FONT);
        close.setFocusable(false);
        close.setBorder(BorderFactory.createEmptyBorder());
        close.setContentAreaFilled(false);
        close.setMargin(new Insets(0, 0, 0, 0));
        close.setForeground(Theme.CHAT_SYSTEM);
        close.setPreferredSize(new Dimension(14, 14));
        close.setToolTipText("Close this connection");
        close.addActionListener(e -> listener.closeTab(tab));
        cell.add(close);
        return cell;
    }
}