Create a new version of paste:

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JPasswordField;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;
import javax.swing.SwingConstants;
import javax.swing.SwingUtilities;
import javax.swing.border.EtchedBorder;
import javax.swing.border.TitledBorder;
import javax.swing.table.DefaultTableModel;

class Book {
	private String title;
	private String author;
	private int quantity;
	private double price;
	private String genre;

	public Book(String title, String author, int quantity, double price, String genre) {
		this.title = title;
		this.author = author;
		this.quantity = quantity;
		this.price = price;
		this.genre = genre;
	}

	public String getTitle() {
		return title;
	}

	public String getAuthor() {
		return author;
	}

	public int getQuantity() {
		return quantity;
	}

	public void setQuantity(int quantity) {
		this.quantity = quantity;
	}

	public double getPrice() {
		return price;
	}

	public String getGenre() {
		return genre;
	}

	public void decreaseQuantity() {
		quantity--;
	}
}

class BookManager {
	private static BookManager instance;
	private List<Book> books;

	private BookManager() {
		books = new ArrayList<>();
		// Initialize with some sample books
		books.add(new Book("It", "Stephen King", 10, 15.99, "Fiction"));
		books.add(new Book("Sapiens", "Yuval Noah Harari", 5, 12.50, "Non-Fiction"));
	}

	public static BookManager getInstance() {
		if (instance == null) {
			instance = new BookManager();
		}
		return instance;
	}

	public List<Book> getAllBooks() {
		return books;
	}

	public void addBook(Book book) {
		books.add(book);
	}

	// New method to get books by genre
	public List<Book> getBooksByGenre(String genre) {
		List<Book> booksByGenre = new ArrayList<>();
		for (Book book : books) {
			if (book.getGenre().equalsIgnoreCase(genre) || genre.equalsIgnoreCase("All")) {
				booksByGenre.add(book);
			}
		}
		return booksByGenre;
	}

	public void updateBook(int index, Book updatedBook) {
		if (index >= 0 && index < books.size()) {
			books.set(index, updatedBook);
		} else {
			throw new IllegalArgumentException("Invalid book index");
		}
	}

	public void removeBook(int index) {
		if (index >= 0 && index < books.size()) {
			books.remove(index);
		} else {
			throw new IllegalArgumentException("Invalid book index");
		}
	}
}

// User class to represent a user
class User {
	private String username;
	private String password;

	public User(String username, String password) {
		this.username = username;
		this.password = password;
	}

	public String getUsername() {
		return username;
	}

	public boolean validatePassword(String password) {
		return this.password.equals(password);
	}
}

// UserManager class to manage user authentication
class UserManager {
	private static UserManager instance;
	private Map<String, User> users;

	private UserManager() {
		users = new HashMap<>();
		// Default admin user
		users.put("admin", new User("admin", "admin"));
	}

	public static UserManager getInstance() {
		if (instance == null) {
			instance = new UserManager();
		}
		return instance;
	}

	public boolean userExists(String username) {
		return users.containsKey(username);
	}

	public boolean addUser(String username, String password) {
		if (!userExists(username)) {
			users.put(username, new User(username, password));
			return true;
		}
		return false;
	}

	public boolean validateCredentials(String username, String password) {
		if (userExists(username)) {
			User user = users.get(username);
			return user.validatePassword(password);
		}
		return false;
	}
}

class Login extends JFrame {
	private JTextField usernameField;
	private JPasswordField passwordField;
	private JLabel errorLabel;
	private UserManager userManager;

	public Login() {
		userManager = UserManager.getInstance();
		setTitle("Login");
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setResizable(false);
		setSize(320, 150);
		setLocationRelativeTo(null); // Center the window on the screen

		JPanel panel = new JPanel();
		panel.setLayout(new GridLayout(3, 2, 5, 5));

		JLabel usernameLabel = new JLabel("Username:");
		panel.add(usernameLabel);

		usernameField = new JTextField();
		panel.add(usernameField);

		JLabel passwordLabel = new JLabel("Password:");
		panel.add(passwordLabel);

		passwordField = new JPasswordField();
		panel.add(passwordField);

		JButton loginButton = new JButton("Login");
		loginButton.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				login();
			}
		});
		panel.add(loginButton);

		errorLabel = new JLabel("");
		errorLabel.setForeground(Color.RED);
		panel.add(errorLabel);

		add(panel);
		setVisible(true);
	}

	private void login() {
		String username = usernameField.getText();
		String password = new String(passwordField.getPassword());

		if (userManager.validateCredentials(username, password)) {
			dispose();
			if (username.equals("admin")) {
				SwingUtilities.invokeLater(AdminPane::new);
			} else {
				SwingUtilities.invokeLater(OnlineBookStore::new);
			}
		} else {
			// Incorrect username or password
			errorLabel.setText("Invalid username or password.");
			usernameField.setText(""); // Clear username field
			passwordField.setText(""); // Clear password field
		}
	}
}

class SignUp extends JFrame {
	private JTextField usernameField;
	private JPasswordField passwordField;
	private JLabel errorLabel;
	private UserManager userManager;

	public SignUp() {
		userManager = UserManager.getInstance();
		setTitle("Sign Up");
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setResizable(false);
		setSize(320, 150);
		setLocationRelativeTo(null); // Center the window on the screen

		JPanel panel = new JPanel();
		panel.setLayout(new GridLayout(3, 2, 5, 5));

		JLabel usernameLabel = new JLabel("Username:");
		panel.add(usernameLabel);

		usernameField = new JTextField();
		panel.add(usernameField);

		JLabel passwordLabel = new JLabel("Password:");
		panel.add(passwordLabel);

		passwordField = new JPasswordField();
		panel.add(passwordField);

		JButton signUpButton = new JButton("Sign Up");
		signUpButton.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				signUp();
			}
		});
		panel.add(signUpButton);

		errorLabel = new JLabel("");
		errorLabel.setForeground(Color.RED);
		panel.add(errorLabel);

		add(panel);
		setVisible(true);
	}

	private void signUp() {
		String username = usernameField.getText();
		String password = new String(passwordField.getPassword());

		if (username.isEmpty() || password.isEmpty()) {
			errorLabel.setText("Username and password cannot be empty.");
		} else {
			if (userManager.addUser(username, password)) {
				dispose(); // Close the sign-up frame
				// Proceed to the login frame
				SwingUtilities.invokeLater(Login::new);
			} else {
				errorLabel.setText("Username already exists.");
			}
		}
	}
}

class AdminPane extends JFrame {
	private JTable bookTable;
	private DefaultTableModel bookTableModel;

	private BookManager bookManager; // Instantiate the BookManager

	public AdminPane() {
		setTitle("Admin Panel");
		setSize(800, 600);
		setDefaultCloseOperation(EXIT_ON_CLOSE);
		getContentPane().setBackground(Color.LIGHT_GRAY);

		// Instantiate the BookManager
		bookManager = BookManager.getInstance();

		// Main panel with BorderLayout
		JPanel mainPanel = new JPanel();
		setContentPane(mainPanel);

		// Books table
		bookTableModel = new DefaultTableModel(new Object[] { "Title", "Author", "Quantity", "Price", "Genre" }, 0);

		mainPanel.setLayout(new BorderLayout());

		JPanel panel = new JPanel();
		panel.setBorder(new TitledBorder(
				new EtchedBorder(EtchedBorder.LOWERED, new Color(255, 255, 255), new Color(160, 160, 160)), "Books",
				TitledBorder.LEADING, TitledBorder.TOP, null, new Color(0, 0, 0)));
		mainPanel.add(panel, BorderLayout.CENTER);
		panel.setLayout(new BorderLayout(0, 0));

		bookTable = new JTable(bookTableModel);
		JScrollPane bookScrollPane = new JScrollPane(bookTable);
		bookScrollPane.setPreferredSize(new Dimension(100, 150));
		panel.add(bookScrollPane, BorderLayout.CENTER);

		JPanel buttonsPanel = new JPanel();
		panel.add(buttonsPanel, BorderLayout.SOUTH);

		JButton addBookBtn = new JButton("Add Book");
		addBookBtn.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				// Add book functionality
				addBook();
			}
		});
		buttonsPanel.add(addBookBtn);

		JButton updateBookBtn = new JButton("Update Book");
		updateBookBtn.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				// Update book functionality
				updateBook();
			}
		});
		buttonsPanel.add(updateBookBtn);

		JButton removeBookBtn = new JButton("Remove Book");
		removeBookBtn.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				// Remove book functionality
				removeBook();
			}
		});
		buttonsPanel.add(removeBookBtn);

		JButton logoutBtn = new JButton("Logout");
		logoutBtn.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				dispose();
				SwingUtilities.invokeLater(Login::new);

			}
		});
		buttonsPanel.add(logoutBtn);

		// Populate table with existing books
		refreshBookTable();

		setVisible(true);
	}

	private void refreshBookTable() {
		// Clear existing rows
		bookTableModel.setRowCount(0);

		// Get all books from the BookManager
		List<Book> allBooks = bookManager.getAllBooks();

		// Add each book to the table
		for (Book book : allBooks) {
			// Add book details including the genre
			bookTableModel.addRow(new Object[] { book.getTitle(), book.getAuthor(), book.getQuantity(), book.getPrice(),
					book.getGenre() });
		}
	}

	private void addBook() {
		// Prompt the admin for book details
		String title = JOptionPane.showInputDialog("Enter title:");
		String author = JOptionPane.showInputDialog("Enter author:");
		String quantityStr = JOptionPane.showInputDialog("Enter quantity:");
		String priceStr = JOptionPane.showInputDialog("Enter price:");
		String genre = JOptionPane.showInputDialog("Enter genre (Fiction or Non-Fiction):");

		// Convert quantity and price to integers
		int quantity = Integer.parseInt(quantityStr);
		double price = Double.parseDouble(priceStr);

		// Create a new Book object
		Book newBook = new Book(title, author, quantity, price, genre);

		// Add the new book to the BookManager
		bookManager.addBook(newBook);

		// Refresh the table
		refreshBookTable();
	}

	private void removeBook() {
		int selectedRow = bookTable.getSelectedRow();
		if (selectedRow != -1) {
			int confirm = JOptionPane.showConfirmDialog(null, "Are you sure you want to remove this book?",
					"Confirm Removal", JOptionPane.YES_NO_OPTION);
			if (confirm == JOptionPane.YES_OPTION) {
				bookManager.removeBook(selectedRow);
				refreshBookTable();
			}
		} else {
			JOptionPane.showMessageDialog(null, "Please select a book to remove.");
		}
	}

	private void updateBook() {
		int selectedRow = bookTable.getSelectedRow();
		if (selectedRow != -1) {
			Book selectedBook = bookManager.getAllBooks().get(selectedRow);
			// Prompt the admin for updated details
			String title = JOptionPane.showInputDialog("Enter updated title:", selectedBook.getTitle());
			String author = JOptionPane.showInputDialog("Enter updated author:", selectedBook.getAuthor());
			String quantityStr = JOptionPane.showInputDialog("Enter updated quantity:", selectedBook.getQuantity());
			String priceStr = JOptionPane.showInputDialog("Enter updated price:", selectedBook.getPrice());

			// Convert quantity and price to integers
			int quantity = Integer.parseInt(quantityStr);
			double price = Double.parseDouble(priceStr);
			// Prompt the admin for updated details including the genre
			String genre = JOptionPane.showInputDialog("Enter updated genre (Fiction or Non-Fiction):");

			// Create an updated Book object
			Book updatedBook = new Book(title, author, quantity, price, genre);

			// Update the book in the BookManager
			bookManager.updateBook(selectedRow, updatedBook);

			// Refresh the table
			refreshBookTable();
		} else {
			JOptionPane.showMessageDialog(null, "Please select a book to update.");
		}
	}

}

public class OnlineBookStore extends JFrame {
	private JTable bookTable, cartTable;
	private JComboBox<String> categoryComboBox;
	private DefaultTableModel bookTableModel, cartTableModel;
	private JLabel errorLabel;

	private List<Book> books = new ArrayList<>();
	private List<Book> cart = new ArrayList<>();
	private BookManager bookManager; // Add a reference to BookManager
	private List<Order> orders = new ArrayList<>();

	public OnlineBookStore() {
		setTitle("Online Bookstore Management System");
		setSize(800, 600);
		setDefaultCloseOperation(EXIT_ON_CLOSE);
		getContentPane().setBackground(Color.LIGHT_GRAY);

		// Instantiate the BookManager
		bookManager = BookManager.getInstance();

		;

		// Populate books list with existing books from BookManager
		books = bookManager.getAllBooks();

		// Initialize the bookTableModel
		bookTableModel = new DefaultTableModel(new Object[] { "Title", "Author", "Quantity", "Price" }, 0);

		// Refresh the table to display all books by default
		refreshBookTable("All");

		// Main panel with BorderLayout
		JPanel mainPanel = new JPanel();
		setContentPane(mainPanel);

		// Cart table
		cartTableModel = new DefaultTableModel(new Object[] { "Title", "Author", "Quantity", "Price", "Genre" }, 0);
		mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.X_AXIS));

		JPanel panel = new JPanel();
		panel.setBorder(new TitledBorder(
				new EtchedBorder(EtchedBorder.LOWERED, new Color(255, 255, 255), new Color(160, 160, 160)), "Books",
				TitledBorder.LEADING, TitledBorder.TOP, null, new Color(0, 0, 0)));
		mainPanel.add(panel);
		panel.setLayout(new BorderLayout(0, 0));

		// Category dropdown and search button
		JPanel booksPanel = new JPanel();
		panel.add(booksPanel, BorderLayout.NORTH);
		booksPanel.setLayout(new BorderLayout(0, 0));

		JPanel searchPanel = new JPanel();
		panel.add(searchPanel, BorderLayout.NORTH);
		JButton searchButton = new JButton("Search/Browse");
		searchButton.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				String selectedGenre = (String) categoryComboBox.getSelectedItem();
				refreshBookTable(selectedGenre);
			}
		});
		searchPanel.add(searchButton);

		categoryComboBox = new JComboBox<>(new String[] { "All", "Fiction", "Non-fiction" });
		searchPanel.add(categoryComboBox);
		bookTable = new JTable(bookTableModel);
		JScrollPane bookScrollPane = new JScrollPane(bookTable);
		panel.add(bookScrollPane, BorderLayout.CENTER);
		bookScrollPane.setBounds(10, 121, 311, 118);
		bookScrollPane.setPreferredSize(new Dimension(350, 200));

		JPanel buttonsAndErrorPanel = new JPanel();
		panel.add(buttonsAndErrorPanel, BorderLayout.SOUTH);
		buttonsAndErrorPanel.setLayout(new GridLayout(0, 2, 0, 0));

		errorLabel = new JLabel("");
		errorLabel.setHorizontalAlignment(SwingConstants.RIGHT);
		buttonsAndErrorPanel.add(errorLabel);

		JButton addToCartBtn = new JButton("Add To Cart");
		addToCartBtn.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				int selectedRow = bookTable.getSelectedRow();
				if (selectedRow != -1) {
					Book selectedBook = books.get(selectedRow);
					if (selectedBook.getQuantity() > 0) {
						addToCart(selectedBook);
						refreshCartTable();
						selectedBook.decreaseQuantity();
						refreshBookTable("All");

					} else {
						showError("Selected book is out of stock!");
					}
				} else {
					showError("Please select a book to add to cart!");
				}
			}
		});
		buttonsAndErrorPanel.add(addToCartBtn);

		// Login button
		JButton logout = new JButton("Logout");
		logout.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {
				dispose();
				SwingUtilities.invokeLater(Login::new);

			}
		});
		buttonsAndErrorPanel.add(logout);

		JPanel addToCartPanel = new JPanel();
		addToCartPanel.setBorder(new TitledBorder(
				new EtchedBorder(EtchedBorder.LOWERED, new Color(255, 255, 255), new Color(160, 160, 160)),
				"Add To Cart Panel", TitledBorder.LEADING, TitledBorder.TOP, null, new Color(0, 0, 0)));
		mainPanel.add(addToCartPanel);
		addToCartPanel.setLayout(new BorderLayout(0, 0));

		JPanel btnPanel = new JPanel();
		addToCartPanel.add(btnPanel, BorderLayout.SOUTH);

		JButton updateQuantityBtn = new JButton("Update Cart");
		updateQuantityBtn.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {

				int selectedRow = cartTable.getSelectedRow();
				if (selectedRow != -1) {
					String input = JOptionPane.showInputDialog("Enter new quantity:");
					try {
						int newQuantity = Integer.parseInt(input);
						if (newQuantity > 0) {
							Book selectedBook = cart.get(selectedRow);
							selectedBook.setQuantity(newQuantity);
							refreshCartTable();
						} else {
							showError("Quantity must be a positive number!");
						}
					} catch (NumberFormatException ex) {
						showError("Invalid input! Please enter a number.");
					}
				} else {
					showError("Please select a book from the cart to update quantity.");
				}
			}
		});
		btnPanel.add(updateQuantityBtn);

		JButton removeFromCartBtn = new JButton("Remove");
		removeFromCartBtn.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {

				int selectedRow = cartTable.getSelectedRow();
				if (selectedRow != -1) {
					Book removedBook = cart.remove(selectedRow);
					for (Book book : books) {
						if (book.getTitle().equals(removedBook.getTitle())) {
							book.setQuantity(book.getQuantity() + removedBook.getQuantity());
							break;
						}
					}
					refreshCartTable();
					refreshBookTable("All");
				} else {
					showError("Please select a book from the cart to remove.");
				}
			}
		});
		btnPanel.add(removeFromCartBtn);

		JButton placeOrderBtn = new JButton("Place Order");
		placeOrderBtn.addActionListener(new ActionListener() {
			@Override
			public void actionPerformed(ActionEvent e) {

				placeOrder();
			}
		});
		btnPanel.add(placeOrderBtn);

		cartTable = new JTable(cartTableModel);
		JScrollPane cartScrollPane = new JScrollPane(cartTable);
		addToCartPanel.add(cartScrollPane);
		cartScrollPane.setPreferredSize(new Dimension(350, 200));

		setVisible(true);
		refreshBookTable("All");
	}

	private void refreshBookTable(String genre) {
		bookTableModel.setRowCount(0);
		List<Book> filteredBooks = bookManager.getBooksByGenre(genre);
		for (Book book : filteredBooks) {
			bookTableModel
					.addRow(new Object[] { book.getTitle(), book.getAuthor(), book.getQuantity(), book.getPrice() });
		}
	}

	private void refreshCartTable() {
		cartTableModel.setRowCount(0);
		for (Book book : cart) {
			cartTableModel.addRow(new Object[] { book.getTitle(), book.getAuthor(), book.getQuantity(), book.getPrice(),
					book.getGenre() });
		}
	}

	private void addToCart(Book book) {
		cart.add(book);
	}

	private void showError(String message) {
		errorLabel.setText(message);
	}

	private void placeOrder() {
		if (cart.isEmpty()) {
			JOptionPane.showMessageDialog(null, "Your cart is empty. Please add items before placing an order.");
		} else {
			int confirm = JOptionPane.showConfirmDialog(null, "Are you sure you want to place this order?",
					"Confirm Order", JOptionPane.YES_NO_OPTION);
			if (confirm == JOptionPane.YES_OPTION) {
				double totalPrice = 0.0;
				for (Book book : cart) {
					totalPrice += book.getPrice() * book.getQuantity();
				}

				// Create and store the new order
				Order newOrder = new Order(cart, totalPrice);
				orders.add(newOrder);

				// Clear the cart
				cart.clear();
				refreshCartTable();
				refreshBookTable("All");

				// Display the list of orders using JOptionPane
				StringBuilder orderList = new StringBuilder();
				for (Order order : orders) {
					orderList.append(order.toString()).append("\n");
				}

				JOptionPane.showMessageDialog(this, orderList.toString(), "Orders to Ship",
						JOptionPane.INFORMATION_MESSAGE);
			}
		}
	}

	public static void main(String[] args) {
		SwingUtilities.invokeLater(SignUp::new);
	}
}

class Order {
	private List<Book> orderedBooks;
	private double totalPrice;

	public Order(List<Book> orderedBooks, double totalPrice) {
		this.orderedBooks = new ArrayList<>(orderedBooks);
		this.totalPrice = totalPrice;
	}

	public List<Book> getOrderedBooks() {
		return orderedBooks;
	}

	public double getTotalPrice() {
		return totalPrice;
	}

	@Override
    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("Order Details:\n");
        for (Book book : orderedBooks) {
            sb.append(" - ").append(book.getTitle()).append(" by ").append(book.getAuthor()).append(", Quantity: ")
                    .append(book.getQuantity()).append(", Price: $").append(book.getPrice()).append("\n");
        }
        sb.append("Total Price: $").append(totalPrice).append("\n");
        return sb.toString();
    }
}