UserManagement.java

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.util.Scanner;

public class UserManagement {
    public void manageUser() {
        Scanner scanner = new Scanner(System.in);

        System.out.println("=== User Management ===");
        System.out.println("1. Register New User");
        System.out.println("2. Login Existing User");
        System.out.print("Enter your choice (1 or 2): ");
        int choice = scanner.nextInt();
        scanner.nextLine();

        if (choice == 1) {
            registerUser(scanner);
        } else if (choice == 2) {
            if (loginUser(scanner)) {
                System.out.println("Login successful!");
            } else {
                System.out.println("Invalid credentials.");
            }
        } else {
            System.out.println("Invalid choice.");
        }
    }

    private void registerUser(Scanner scanner) {
        System.out.print("Enter Username: ");
        String username = scanner.nextLine();
        System.out.print("Enter Password: ");
        String password = scanner.nextLine();
        String role = "customer";

        String query = "INSERT INTO users (username, password, role) VALUES (?, ?, ?)";
        try (Connection connection = DatabaseConnection.getConnection();
             PreparedStatement statement = connection.prepareStatement(query)) {
            statement.setString(1, username);
            statement.setString(2, password);
            statement.setString(3, role);
            statement.executeUpdate();
            System.out.println("User registered successfully.");
        } catch (Exception e) {
            System.err.println("Error: " + e.getMessage());
        }
    }

    private boolean loginUser(Scanner scanner) {
        System.out.print("Enter Username: ");
        String username = scanner.nextLine();
        System.out.print("Enter Password: ");
        String password = scanner.nextLine();

        String query = "SELECT * FROM users WHERE username = ? AND password = ?";
        try (Connection connection = DatabaseConnection.getConnection();
             PreparedStatement statement = connection.prepareStatement(query)) {
            statement.setString(1, username);
            statement.setString(2, password);
            try (ResultSet rs = statement.executeQuery()) {
                return rs.next();
            }
        } catch (Exception e) {
            System.err.println("Error: " + e.getMessage());
        }
        return false;
    }
}