Application.java

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.sql.*;

public class Application {

    private static Connection connection;

    public static void main(String[] args) {
        try {
            connectDatabase();
            createTables();
            SwingUtilities.invokeLater(() -> createAndShowGUI());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private static void connectDatabase() throws SQLException {
        String url = "jdbc:sqlite:expenses.db";
        connection = DriverManager.getConnection(url);
        System.out.println("Connected to the database.");
    }

    private static void createTables() throws SQLException {
        String createTableSQL = "CREATE TABLE IF NOT EXISTS expenses (" +
                "id INTEGER PRIMARY KEY AUTOINCREMENT, " +
                "amount REAL, " +
                "category TEXT, " +
                "date TEXT, " +
                "description TEXT)";

        Statement stmt = connection.createStatement();
        stmt.execute(createTableSQL);
        stmt.close();
    }

    private static void createAndShowGUI() {
        JFrame frame = new JFrame("Expense Tracker");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setSize(600, 400);

        JPanel panel = new JPanel(new GridLayout(0, 2, 10, 10));
        panel.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));

        JLabel amountLabel = new JLabel("Amount:");
        JTextField amountField = new JTextField();
        JLabel categoryLabel = new JLabel("Category:");
        JTextField categoryField = new JTextField();
        JLabel dateLabel = new JLabel("Date (YYYY-MM-DD):");
        JTextField dateField = new JTextField();
        JLabel descriptionLabel = new JLabel("Description:");
        JTextField descriptionField = new JTextField();

        JLabel idLabel = new JLabel("Expense ID (for Edit/Delete):");
        JTextField idField = new JTextField();

        JButton addButton = new JButton("Add Expense");
        JButton viewButton = new JButton("View Expenses");
        JButton reportButton = new JButton("Generate Report");
        JButton editButton = new JButton("Edit Expense");
        JButton deleteButton = new JButton("Delete Expense");

        panel.add(amountLabel);
        panel.add(amountField);
        panel.add(categoryLabel);
        panel.add(categoryField);
        panel.add(dateLabel);
        panel.add(dateField);
        panel.add(descriptionLabel);
        panel.add(descriptionField);
        panel.add(idLabel);
        panel.add(idField);
        panel.add(addButton);
        panel.add(viewButton);
        panel.add(reportButton);
        panel.add(editButton);
        panel.add(deleteButton);

        frame.add(panel);

        addButton.addActionListener(e -> {
            try {
                double amount = Double.parseDouble(amountField.getText());
                String category = categoryField.getText();
                String date = dateField.getText();
                String description = descriptionField.getText();

                addExpense(amount, category, date, description);
                JOptionPane.showMessageDialog(frame, "Expense added successfully.");

                amountField.setText("");
                categoryField.setText("");
                dateField.setText("");
                descriptionField.setText("");
            } catch (Exception ex) {
                JOptionPane.showMessageDialog(frame, "Error: " + ex.getMessage());
                ex.printStackTrace();
            }
        });

        viewButton.addActionListener(e -> {
            try {
                StringBuilder expenses = new StringBuilder("ID | Amount | Category | Date | Description\n");
                Statement stmt = connection.createStatement();
                ResultSet rs = stmt.executeQuery("SELECT * FROM expenses");

                while (rs.next()) {
                    expenses.append(rs.getInt("id")).append(" | ")
                            .append(rs.getDouble("amount")).append(" | ")
                            .append(rs.getString("category")).append(" | ")
                            .append(rs.getString("date")).append(" | ")
                            .append(rs.getString("description")).append("\n");
                }

                rs.close();
                stmt.close();

                JTextArea textArea = new JTextArea(expenses.toString());
                textArea.setEditable(false);
                JOptionPane.showMessageDialog(frame, new JScrollPane(textArea), "Expenses", JOptionPane.INFORMATION_MESSAGE);
            } catch (Exception ex) {
                JOptionPane.showMessageDialog(frame, "Error: " + ex.getMessage());
                ex.printStackTrace();
            }
        });

        reportButton.addActionListener(e -> {
            try {
                StringBuilder report = new StringBuilder("Category | Total\n");
                Statement stmt = connection.createStatement();
                ResultSet rs = stmt.executeQuery("SELECT category, SUM(amount) AS total FROM expenses GROUP BY category");

                while (rs.next()) {
                    report.append(rs.getString("category")).append(" | ").append(rs.getDouble("total")).append("\n");
                }

                rs.close();
                stmt.close();

                JTextArea textArea = new JTextArea(report.toString());
                textArea.setEditable(false);
                JOptionPane.showMessageDialog(frame, new JScrollPane(textArea), "Expense Report", JOptionPane.INFORMATION_MESSAGE);
            } catch (Exception ex) {
                JOptionPane.showMessageDialog(frame, "Error: " + ex.getMessage());
                ex.printStackTrace();
            }
        });

        editButton.addActionListener(e -> {
            try {
                int id = Integer.parseInt(idField.getText());
                double amount = Double.parseDouble(amountField.getText());
                String category = categoryField.getText();
                String date = dateField.getText();
                String description = descriptionField.getText();

                editExpense(id, amount, category, date, description);
                JOptionPane.showMessageDialog(frame, "Expense updated successfully.");

                idField.setText("");
                amountField.setText("");
                categoryField.setText("");
                dateField.setText("");
                descriptionField.setText("");
            } catch (Exception ex) {
                JOptionPane.showMessageDialog(frame, "Error: " + ex.getMessage());
                ex.printStackTrace();
            }
        });

        deleteButton.addActionListener(e -> {
            try {
                int id = Integer.parseInt(idField.getText());

                deleteExpense(id);
                JOptionPane.showMessageDialog(frame, "Expense deleted successfully.");

                idField.setText("");
            } catch (Exception ex) {
                JOptionPane.showMessageDialog(frame, "Error: " + ex.getMessage());
                ex.printStackTrace();
            }
        });

        frame.setVisible(true);
    }

    private static void addExpense(double amount, String category, String date, String description) throws SQLException {
        String insertSQL = "INSERT INTO expenses (amount, category, date, description) VALUES (?, ?, ?, ?)";
        PreparedStatement pstmt = connection.prepareStatement(insertSQL);
        pstmt.setDouble(1, amount);
        pstmt.setString(2, category);
        pstmt.setString(3, date);
        pstmt.setString(4, description);
        pstmt.executeUpdate();
        pstmt.close();
    }

    private static void editExpense(int id, double amount, String category, String date, String description) throws SQLException {
        String updateSQL = "UPDATE expenses SET amount = ?, category = ?, date = ?, description = ? WHERE id = ?";
        PreparedStatement pstmt = connection.prepareStatement(updateSQL);
        pstmt.setDouble(1, amount);
        pstmt.setString(2, category);
        pstmt.setString(3, date);
        pstmt.setString(4, description);
        pstmt.setInt(5, id);
        pstmt.executeUpdate();
        pstmt.close();
    }

    private static void deleteExpense(int id) throws SQLException {
        String deleteSQL = "DELETE FROM expenses WHERE id = ?";
        PreparedStatement pstmt = connection.prepareStatement(deleteSQL);
        pstmt.setInt(1, id);
        pstmt.executeUpdate();
        pstmt.close();
    }
}