QRScannerPanel.java

import javax.swing.*;
import javax.swing.border.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.*;
import java.net.*;
import java.sql.*;
import javax.imageio.ImageIO;

public class QRScannerPanel extends JPanel {

    private JTextField isbnField;
    private JPanel resultPanel;
    private JPanel qrDisplayPanel;
    private JLabel statusLabel;

    public QRScannerPanel() {
        setLayout(new BorderLayout(10, 10));
        setBackground(new Color(245, 245, 245));

        add(createHeaderPanel(), BorderLayout.NORTH);
        add(createMainPanel(),   BorderLayout.CENTER);
        add(createStatusBar(),   BorderLayout.SOUTH);
    }

    private JPanel createHeaderPanel() {
        JPanel panel = new JPanel(new BorderLayout());
        panel.setBackground(new Color(44, 62, 80));
        panel.setBorder(BorderFactory.createEmptyBorder(15, 20, 15, 20));

        JLabel title = new JLabel("📷  QR Code Book Scanner");
        title.setFont(new Font("Segoe UI", Font.BOLD, 22));
        title.setForeground(Color.WHITE);

        JLabel subtitle = new JLabel("Enter ISBN → Generate QR → Scan with phone to verify availability");
        subtitle.setFont(new Font("Segoe UI", Font.PLAIN, 13));
        subtitle.setForeground(new Color(189, 195, 199));

        JPanel tp = new JPanel(new GridLayout(2, 1, 0, 4));
        tp.setOpaque(false);
        tp.add(title);
        tp.add(subtitle);
        panel.add(tp, BorderLayout.CENTER);
        return panel;
    }

    private JPanel createMainPanel() {
        JPanel main = new JPanel(new GridLayout(1, 2, 15, 0));
        main.setBackground(new Color(245, 245, 245));
        main.setBorder(BorderFactory.createEmptyBorder(15, 15, 15, 15));
        main.add(createLeftPanel());
        main.add(createRightPanel());
        return main;
    }

    private JPanel createLeftPanel() {
        JPanel panel = new JPanel(new BorderLayout(0, 15));
        panel.setBackground(new Color(245, 245, 245));

        // Input card
        JPanel inputCard = new JPanel(new GridBagLayout());
        inputCard.setBackground(Color.WHITE);
        inputCard.setBorder(BorderFactory.createCompoundBorder(
            BorderFactory.createLineBorder(new Color(200, 200, 200), 1, true),
            BorderFactory.createEmptyBorder(20, 20, 20, 20)
        ));

        GridBagConstraints gbc = new GridBagConstraints();
        gbc.insets = new Insets(6, 6, 6, 6);
        gbc.fill = GridBagConstraints.HORIZONTAL;
        gbc.gridwidth = 2;

        JLabel lbl = new JLabel("Enter ISBN Number:", SwingConstants.CENTER);
        lbl.setFont(new Font("Segoe UI", Font.BOLD, 14));
        lbl.setForeground(new Color(44, 62, 80));
        gbc.gridx = 0; gbc.gridy = 0;
        inputCard.add(lbl, gbc);

        isbnField = new JTextField();
        isbnField.setFont(new Font("Segoe UI", Font.PLAIN, 16));
        isbnField.setHorizontalAlignment(JTextField.CENTER);
        isbnField.setBorder(BorderFactory.createCompoundBorder(
            BorderFactory.createLineBorder(new Color(52, 152, 219), 2, true),
            BorderFactory.createEmptyBorder(6, 10, 6, 10)
        ));
        isbnField.addActionListener(e -> searchAndGenerate());
        gbc.gridy = 1;
        inputCard.add(isbnField, gbc);

        JPanel btnRow = new JPanel(new FlowLayout(FlowLayout.CENTER, 10, 0));
        btnRow.setOpaque(false);
        JButton genBtn   = makeBtn("🔲  Generate QR", new Color(52, 152, 219));
        JButton clearBtn = makeBtn("✖  Clear",        new Color(149, 165, 166));
        JButton openBtn  = makeBtn("🌐  Open QR in Browser", new Color(39, 174, 96));
        genBtn.addActionListener(e -> searchAndGenerate());
        clearBtn.addActionListener(e -> clearAll());
        openBtn.addActionListener(e -> openQRInBrowser());
        btnRow.add(genBtn);
        btnRow.add(clearBtn);
        gbc.gridy = 2;
        inputCard.add(btnRow, gbc);
        gbc.gridy = 3;
        inputCard.add(openBtn, gbc);

        panel.add(inputCard, BorderLayout.NORTH);

        // QR display
        qrDisplayPanel = new JPanel(new BorderLayout());
        qrDisplayPanel.setBackground(Color.WHITE);
        qrDisplayPanel.setBorder(BorderFactory.createCompoundBorder(
            BorderFactory.createLineBorder(new Color(200, 200, 200), 1, true),
            BorderFactory.createEmptyBorder(15, 15, 15, 15)
        ));
        JLabel ph = new JLabel("QR code will appear here", SwingConstants.CENTER);
        ph.setFont(new Font("Segoe UI", Font.ITALIC, 14));
        ph.setForeground(new Color(180, 180, 180));
        qrDisplayPanel.add(ph, BorderLayout.CENTER);
        panel.add(qrDisplayPanel, BorderLayout.CENTER);

        return panel;
    }

    private JScrollPane createRightPanel() {
        resultPanel = new JPanel();
        resultPanel.setLayout(new BoxLayout(resultPanel, BoxLayout.Y_AXIS));
        resultPanel.setBackground(new Color(245, 245, 245));

        JPanel ph = new JPanel(new GridBagLayout());
        ph.setBackground(Color.WHITE);
        ph.setBorder(BorderFactory.createCompoundBorder(
            BorderFactory.createLineBorder(new Color(200, 200, 200), 1, true),
            BorderFactory.createEmptyBorder(40, 20, 40, 20)
        ));
        ph.setMaximumSize(new Dimension(Integer.MAX_VALUE, 300));
        JLabel phLbl = new JLabel("Book details will appear here", SwingConstants.CENTER);
        phLbl.setFont(new Font("Segoe UI", Font.ITALIC, 14));
        phLbl.setForeground(new Color(180, 180, 180));
        ph.add(phLbl);
        resultPanel.add(ph);

        JScrollPane scroll = new JScrollPane(resultPanel);
        scroll.setBorder(null);
        scroll.getViewport().setBackground(new Color(245, 245, 245));
        return scroll;
    }

    private JPanel createStatusBar() {
        JPanel bar = new JPanel(new BorderLayout());
        bar.setBackground(new Color(236, 240, 241));
        bar.setBorder(BorderFactory.createEmptyBorder(6, 12, 6, 12));
        statusLabel = new JLabel("Ready — enter an ISBN and click Generate QR");
        statusLabel.setFont(new Font("Segoe UI", Font.PLAIN, 12));
        statusLabel.setForeground(new Color(100, 100, 100));
        bar.add(statusLabel, BorderLayout.WEST);
        JLabel hint = new JLabel("📱 Use 'Open QR in Browser' for best phone scanning");
        hint.setFont(new Font("Segoe UI", Font.ITALIC, 11));
        hint.setForeground(new Color(130, 130, 130));
        bar.add(hint, BorderLayout.EAST);
        return bar;
    }

    // ── Core logic ─────────────────────────────────────────────────────────────
    private String currentISBN = "";

    private void searchAndGenerate() {
        String isbn = isbnField.getText().trim();
        if (isbn.isEmpty()) {
            showStatus("⚠  Please enter an ISBN number.", new Color(230, 126, 34));
            return;
        }
        currentISBN = isbn;
        showQRCode(isbn);
        lookupBook(isbn);
    }

    private void openQRInBrowser() {
        String isbn = isbnField.getText().trim();
        if (isbn.isEmpty()) {
            showStatus("⚠  Enter an ISBN first.", new Color(230, 126, 34));
            return;
        }
        try {
            String url = "https://api.qrserver.com/v1/create-qr-code/?size=300x300&data="
                       + URLEncoder.encode(isbn, "UTF-8");
            Desktop.getDesktop().browse(new URI(url));
            showStatus("✔  QR code opened in browser — scan with your phone!", new Color(39, 174, 96));
        } catch (Exception e) {
            showStatus("✘  Could not open browser: " + e.getMessage(), new Color(231, 76, 60));
        }
    }

    private void showQRCode(String isbn) {
        qrDisplayPanel.removeAll();

        // Generate QR using built-in generator
        BufferedImage qr = QRCodeGenerator.generate(isbn, 220);

        JPanel inner = new JPanel(new BorderLayout(0, 8));
        inner.setBackground(Color.WHITE);

        JLabel titleLbl = new JLabel("QR Code", SwingConstants.CENTER);
        titleLbl.setFont(new Font("Segoe UI", Font.BOLD, 13));
        titleLbl.setForeground(new Color(44, 62, 80));

        // Show QR image
        JLabel qrLbl = new JLabel(new ImageIcon(qr), SwingConstants.CENTER);

        JLabel isbnLbl = new JLabel(isbn, SwingConstants.CENTER);
        isbnLbl.setFont(new Font("Segoe UI", Font.BOLD, 13));
        isbnLbl.setForeground(new Color(52, 152, 219));

        // Tip panel
        JPanel tipPanel = new JPanel(new GridLayout(3, 1, 0, 3));
        tipPanel.setBackground(new Color(235, 245, 255));
        tipPanel.setBorder(BorderFactory.createEmptyBorder(8, 10, 8, 10));

        JLabel tip1 = new JLabel("📱 To get a perfect scannable QR:", SwingConstants.CENTER);
        tip1.setFont(new Font("Segoe UI", Font.BOLD, 11));
        tip1.setForeground(new Color(44, 62, 80));

        JLabel tip2 = new JLabel("Click '🌐 Open QR in Browser' above", SwingConstants.CENTER);
        tip2.setFont(new Font("Segoe UI", Font.PLAIN, 11));
        tip2.setForeground(new Color(80, 80, 80));

        JLabel tip3 = new JLabel("Then scan it with your phone camera", SwingConstants.CENTER);
        tip3.setFont(new Font("Segoe UI", Font.PLAIN, 11));
        tip3.setForeground(new Color(80, 80, 80));

        tipPanel.add(tip1);
        tipPanel.add(tip2);
        tipPanel.add(tip3);

        JPanel bottom = new JPanel(new GridLayout(2, 1, 0, 5));
        bottom.setBackground(Color.WHITE);
        bottom.add(isbnLbl);
        bottom.add(tipPanel);

        inner.add(titleLbl, BorderLayout.NORTH);
        inner.add(qrLbl,    BorderLayout.CENTER);
        inner.add(bottom,   BorderLayout.SOUTH);

        qrDisplayPanel.add(inner, BorderLayout.CENTER);
        qrDisplayPanel.revalidate();
        qrDisplayPanel.repaint();
    }

    private void lookupBook(String isbn) {
        resultPanel.removeAll();
        showStatus("Searching for ISBN: " + isbn + "…", new Color(52, 152, 219));

        try {
            Connection conn = DatabaseConnection.getConnection();
            PreparedStatement pst = conn.prepareStatement("SELECT * FROM books WHERE isbn = ?");
            pst.setString(1, isbn);
            ResultSet rs = pst.executeQuery();

            if (rs.next()) {
                showBookResult(rs, isbn);
                showStatus("✔  Book found! Click '🌐 Open QR in Browser' to get a scannable QR.", new Color(39, 174, 96));
            } else {
                showNotFound(isbn);
                showStatus("✘  No book found for ISBN: " + isbn, new Color(231, 76, 60));
            }
        } catch (SQLException e) {
            e.printStackTrace();
            showError("Database error: " + e.getMessage());
        }

        resultPanel.revalidate();
        resultPanel.repaint();
    }

    private void showBookResult(ResultSet rs, String isbn) throws SQLException {
        String title    = rs.getString("title");
        String author   = rs.getString("author");
        int    quantity = rs.getInt("quantity");
        int    available= rs.getInt("available");

        boolean avail = available > 0;
        Color   ac    = avail ? new Color(39, 174, 96) : new Color(231, 76, 60);
        String  at    = avail
            ? "✔  AVAILABLE  (" + available + " of " + quantity + " copies)"
            : "✘  NOT AVAILABLE  (All " + quantity + " copies issued)";

        JPanel banner = makeBanner(at, ac,
            avail ? new Color(212, 239, 223) : new Color(250, 219, 216));

        JPanel card = new JPanel(new GridBagLayout());
        card.setBackground(Color.WHITE);
        card.setBorder(BorderFactory.createCompoundBorder(
            BorderFactory.createLineBorder(new Color(200, 200, 200), 1, true),
            BorderFactory.createEmptyBorder(20, 25, 20, 25)
        ));
        card.setMaximumSize(new Dimension(Integer.MAX_VALUE, 260));

        GridBagConstraints gbc = new GridBagConstraints();
        gbc.anchor = GridBagConstraints.WEST;
        gbc.insets = new Insets(7, 10, 7, 10);
        gbc.fill = GridBagConstraints.HORIZONTAL;

        addRow(card, gbc, 0, "📖  Title",     title);
        addRow(card, gbc, 1, "✍  Author",    author);
        addRow(card, gbc, 2, "🔖  ISBN",      isbn);
        addRow(card, gbc, 3, "📦  Total",     quantity + " copies");
        addRow(card, gbc, 4, "✅  Available", available + " copies");

        resultPanel.add(Box.createRigidArea(new Dimension(0, 8)));
        resultPanel.add(banner);
        resultPanel.add(Box.createRigidArea(new Dimension(0, 8)));
        resultPanel.add(card);
    }

    private JPanel makeBanner(String text, Color fg, Color bg) {
        JPanel p = new JPanel(new BorderLayout());
        p.setBackground(bg);
        p.setBorder(BorderFactory.createEmptyBorder(14, 10, 14, 10));
        p.setMaximumSize(new Dimension(Integer.MAX_VALUE, 60));
        JLabel l = new JLabel(text, SwingConstants.CENTER);
        l.setFont(new Font("Segoe UI", Font.BOLD, 15));
        l.setForeground(fg);
        p.add(l, BorderLayout.CENTER);
        return p;
    }

    private void addRow(JPanel card, GridBagConstraints gbc, int row, String label, String value) {
        gbc.gridx = 0; gbc.gridy = row; gbc.weightx = 0;
        JLabel lbl = new JLabel(label + ":");
        lbl.setFont(new Font("Segoe UI", Font.BOLD, 13));
        lbl.setForeground(new Color(100, 100, 100));
        card.add(lbl, gbc);
        gbc.gridx = 1; gbc.weightx = 1;
        JLabel val = new JLabel(value);
        val.setFont(new Font("Segoe UI", Font.PLAIN, 13));
        val.setForeground(new Color(44, 62, 80));
        card.add(val, gbc);
    }

    private void showNotFound(String isbn) {
        JPanel card = new JPanel(new BorderLayout(0, 6));
        card.setBackground(new Color(253, 245, 230));
        card.setBorder(BorderFactory.createCompoundBorder(
            BorderFactory.createLineBorder(new Color(230, 176, 80), 1, true),
            BorderFactory.createEmptyBorder(20, 20, 20, 20)
        ));
        card.setMaximumSize(new Dimension(Integer.MAX_VALUE, 110));
        JLabel msg  = new JLabel("No book found for ISBN: " + isbn, SwingConstants.CENTER);
        msg.setFont(new Font("Segoe UI", Font.BOLD, 15));
        msg.setForeground(new Color(180, 100, 0));
        JLabel hint = new JLabel("Please check the ISBN and try again.", SwingConstants.CENTER);
        hint.setFont(new Font("Segoe UI", Font.PLAIN, 13));
        hint.setForeground(new Color(150, 100, 0));
        card.add(msg,  BorderLayout.CENTER);
        card.add(hint, BorderLayout.SOUTH);
        resultPanel.add(Box.createRigidArea(new Dimension(0, 10)));
        resultPanel.add(card);
    }

    private void showError(String msg) {
        JPanel card = new JPanel(new BorderLayout());
        card.setBackground(new Color(250, 219, 216));
        card.setBorder(BorderFactory.createEmptyBorder(18, 20, 18, 20));
        card.setMaximumSize(new Dimension(Integer.MAX_VALUE, 80));
        JLabel l = new JLabel("Error: " + msg, SwingConstants.CENTER);
        l.setFont(new Font("Segoe UI", Font.BOLD, 13));
        l.setForeground(new Color(150, 40, 27));
        card.add(l);
        resultPanel.add(Box.createRigidArea(new Dimension(0, 10)));
        resultPanel.add(card);
    }

    private void clearAll() {
        isbnField.setText("");
        currentISBN = "";
        resultPanel.removeAll();
        qrDisplayPanel.removeAll();
        JLabel ph = new JLabel("QR code will appear here", SwingConstants.CENTER);
        ph.setFont(new Font("Segoe UI", Font.ITALIC, 14));
        ph.setForeground(new Color(180, 180, 180));
        qrDisplayPanel.add(ph, BorderLayout.CENTER);
        qrDisplayPanel.revalidate();
        qrDisplayPanel.repaint();
        resultPanel.revalidate();
        resultPanel.repaint();
        showStatus("Ready — enter an ISBN and click Generate QR", new Color(100, 100, 100));
        isbnField.requestFocus();
    }

    private void showStatus(String msg, Color color) {
        statusLabel.setText(msg);
        statusLabel.setForeground(color);
    }

    private JButton makeBtn(String text, Color bg) {
        JButton btn = new JButton(text);
        btn.setFont(new Font("Segoe UI", Font.BOLD, 12));
        btn.setBackground(bg);
        btn.setForeground(Color.WHITE);
        btn.setFocusPainted(false);
        btn.setBorderPainted(false);
        btn.setCursor(new Cursor(Cursor.HAND_CURSOR));
        btn.setPreferredSize(new Dimension(180, 38));
        btn.addMouseListener(new MouseAdapter() {
            public void mouseEntered(MouseEvent e) { btn.setBackground(bg.darker()); }
            public void mouseExited (MouseEvent e) { btn.setBackground(bg); }
        });
        return btn;
    }
}