MatchingEngineUI.java

import javax.swing.*;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableRowSorter;
import javax.swing.event.DocumentEvent;
import javax.swing.event.DocumentListener;
import java.awt.*;

public class MatchingEngineUI extends JFrame {

    // --- Binance Dark Theme Colors ---
    private final Color BG_DARK       = new Color(22, 26, 30);   // Main background
    private final Color BG_PANEL      = new Color(30, 35, 41);   // Panel background
    private final Color TEXT_MAIN     = new Color(183, 189, 198); // Standard text
    private final Color TEXT_BUY      = new Color(14, 203, 129); // Binance Green
    private final Color TEXT_SELL     = new Color(246, 70, 93);  // Binance Red
    private final Color BORDER_COLOR  = new Color(43, 49, 57);

    private final DefaultTableModel buyModel, sellModel, cancelModel, tradeModel;

    // Analytics Labels
    private final JLabel lblTrades = new JLabel("Trades: 0"), lblVolume = new JLabel("Volume: $0.00");
    private final JLabel lblThroughput = new JLabel("Throughput: 0 /sec"), lblSpread = new JLabel("Spread: N/A");
    private final JLabel lblDepth = new JLabel("Depth: 0 Bids / 0 Asks"), lblImbalance = new JLabel("Imbalance: 0.0%");

    public MatchingEngineUI() {
        setTitle("Matching Engine - Live Order Book");
        setSize(1200, 800);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new BorderLayout(10, 10));
        getContentPane().setBackground(BG_DARK);

        // --- 1. SETUP ANALYTICS TOP BAR ---
        JPanel analyticsPanel = new JPanel(new FlowLayout(FlowLayout.CENTER, 30, 15));
        analyticsPanel.setBackground(BG_PANEL);
        analyticsPanel.setBorder(BorderFactory.createMatteBorder(0, 0, 1, 0, BORDER_COLOR));

        Font font = new Font("SansSerif", Font.BOLD, 14);
        JLabel[] labels = {lblTrades, lblVolume, lblThroughput, lblSpread, lblDepth, lblImbalance};
        for (JLabel lbl : labels) {
            lbl.setFont(font);
            lbl.setForeground(TEXT_MAIN);
            analyticsPanel.add(lbl);
        }
        add(analyticsPanel, BorderLayout.NORTH);

        // --- 2. SETUP TABLES ---
        JPanel tablesPanel = new JPanel(new GridLayout(2, 2, 10, 10));
        tablesPanel.setBackground(BG_DARK);
        tablesPanel.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));

        buyModel    = new DefaultTableModel(new String[]{"Bid ID", "Price", "Quantity"}, 0);
        sellModel   = new DefaultTableModel(new String[]{"Ask ID", "Price", "Quantity"}, 0);
        cancelModel = new DefaultTableModel(new String[]{"Cancel ID", "Target ID", "Status"}, 0);
        tradeModel  = new DefaultTableModel(new String[]{"Trade ID", "Buy ID", "Sell ID", "Price", "Qty"}, 0);

        tablesPanel.add(createTablePanel("Order Book - Bids", buyModel, TEXT_BUY));
        tablesPanel.add(createTablePanel("Order Book - Asks", sellModel, TEXT_SELL));
        tablesPanel.add(createTablePanel("Event Log - Cancels", cancelModel, TEXT_MAIN));
        tablesPanel.add(createTablePanel("Event Log - Trades", tradeModel, TEXT_MAIN));

        add(tablesPanel, BorderLayout.CENTER);
    }

    private JPanel createTablePanel(String title, DefaultTableModel model, Color textColor) {
        JPanel panel = new JPanel(new BorderLayout());
        panel.setBackground(BG_PANEL);
        panel.setBorder(BorderFactory.createTitledBorder(
                BorderFactory.createLineBorder(BORDER_COLOR), title, 0, 0, new Font("SansSerif", Font.BOLD, 14), TEXT_MAIN
        ));

        JTable table = new JTable(model);
        table.setBackground(BG_PANEL);
        table.setForeground(textColor);
        table.setGridColor(BORDER_COLOR);
        table.setFillsViewportHeight(true);
        table.setFont(new Font("Monospaced", Font.BOLD, 12));

        table.getTableHeader().setBackground(BG_DARK);
        table.getTableHeader().setForeground(TEXT_MAIN);
        table.getTableHeader().setFont(new Font("SansSerif", Font.BOLD, 12));

        TableRowSorter<DefaultTableModel> sorter = new TableRowSorter<>(model);
        table.setRowSorter(sorter);

        // Search Bar Styling
        JPanel searchPanel = new JPanel(new BorderLayout());
        searchPanel.setBackground(BG_PANEL);
        searchPanel.setBorder(BorderFactory.createEmptyBorder(0, 0, 5, 0));

        JLabel searchLabel = new JLabel(" Search: ");
        searchLabel.setForeground(TEXT_MAIN);
        JTextField searchField = new JTextField();
        searchField.setBackground(BG_DARK);
        searchField.setForeground(Color.WHITE);
        searchField.setCaretColor(Color.WHITE);
        searchField.setBorder(BorderFactory.createLineBorder(BORDER_COLOR));

        searchPanel.add(searchLabel, BorderLayout.WEST);
        searchPanel.add(searchField, BorderLayout.CENTER);

        searchField.getDocument().addDocumentListener(new DocumentListener() {
            @Override public void insertUpdate(DocumentEvent e) { filter(); }
            @Override public void removeUpdate(DocumentEvent e) { filter(); }
            @Override public void changedUpdate(DocumentEvent e) { filter(); }
            private void filter() {
                String text = searchField.getText();
                sorter.setRowFilter(text.trim().isEmpty() ? null : RowFilter.regexFilter("(?i)" + text));
            }
        });

        JScrollPane scrollPane = new JScrollPane(table);
        scrollPane.getViewport().setBackground(BG_PANEL);
        scrollPane.setBorder(BorderFactory.createEmptyBorder());

        panel.add(searchPanel, BorderLayout.NORTH);
        panel.add(scrollPane, BorderLayout.CENTER);
        return panel;
    }

    // --- STATEFUL UI METHODS ---

    public void addOrder(Order order) {
        // Fix: Take an immutable snapshot BEFORE passing to the Swing thread
        final String seqId = "#" + order.getSequenceId();
        final String price = String.format("$%.2f", order.getPrice());
        final int initialQty = order.getQuantity();
        final Order.Side side = order.getSide();

        SwingUtilities.invokeLater(() -> {
            if (side == Order.Side.BUY) buyModel.insertRow(0, new Object[]{seqId, price, initialQty});
            else if (side == Order.Side.SELL) sellModel.insertRow(0, new Object[]{seqId, price, initialQty});
        });
    }

    public void updateOrderQty(int seqId, boolean isBuy, int newQty) {
        SwingUtilities.invokeLater(() -> {
            DefaultTableModel model = isBuy ? buyModel : sellModel;
            String targetId = "#" + seqId;

            for (int i = 0; i < model.getRowCount(); i++) {
                if (model.getValueAt(i, 0).equals(targetId)) {
                    if (newQty <= 0) {
                        model.removeRow(i); // Order completely filled, remove from book
                    } else {
                        model.setValueAt(newQty, i, 2); // Update remaining quantity
                    }
                    break;
                }
            }
        });
    }

    public void removeOrder(int seqId, boolean isBuy) {
        updateOrderQty(seqId, isBuy, 0); // Re-use the method, passing 0 removes it
    }

    public void addCancelEvent(int cancelId, int targetId) {
        SwingUtilities.invokeLater(() -> {
            cancelModel.insertRow(0, new Object[]{"#" + cancelId, "#" + targetId, "CANCELLED"});
        });
    }

    public void addTrade(TradeRecord trade) {
        SwingUtilities.invokeLater(() -> {
            tradeModel.insertRow(0, new Object[]{"#" + trade.tradeId, "#" + trade.buyOrderId, "#" + trade.sellOrderId, String.format("$%.2f", trade.price), trade.quantity});
        });
    }

    public void updateAnalytics(long trades, double volumeUSD, double throughput, double spread, int bidDepth, int askDepth, double imbalance) {
        SwingUtilities.invokeLater(() -> {
            lblTrades.setText(String.format("Trades: %,d", trades));
            lblVolume.setText(String.format("Volume: $%,.2f", volumeUSD));
            lblThroughput.setText(String.format("Throughput: %,.0f /sec", throughput));
            lblSpread.setText(spread >= 0 ? String.format("Spread: $%.4f", spread) : "Spread: N/A");
            lblDepth.setText(String.format("Depth: %d Bids / %d Asks", bidDepth, askDepth));
            lblImbalance.setText(String.format("Imbalance: %.1f%%", Math.abs(imbalance)));
        });
    }
}