Main.java

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        String username;
        String password;

        while (true) {

            System.out.println("\n========== ADMIN LOGIN ==========");

            System.out.print("Username: ");
            username = sc.nextLine();

            System.out.print("Password: ");
            password = sc.nextLine();

            if (username.equals("admin") && password.equals("admin123")) {
                System.out.println("\nLogin Successful!");
                break;
            }

            System.out.println("\nInvalid Username or Password!");
            System.out.println("Please try again.\n");
        }
        EmployeeService service = new EmployeeService();

        while (true) {

            System.out.println("\n========================================");
            System.out.println("      EMPLOYEE MANAGEMENT SYSTEM");
            System.out.println("========================================");
            System.out.println("1. Add Employee");
            System.out.println("2. View Employees");
            System.out.println("3. Search Employee by ID");
            System.out.println("4. Search Employee by Name");
            System.out.println("5. Update Employee");
            System.out.println("6. Delete Employee");
            System.out.println("7. Dashboard");
            System.out.println("8. Export to CSV");
            System.out.println("9. Exit");
            System.out.print("Enter your choice: ");
            int choice = sc.nextInt();
            sc.nextLine();

            switch (choice) {

                case 1:

                    System.out.print("Enter Employee ID: ");
                    int id = sc.nextInt();
                    sc.nextLine();

                    System.out.print("Enter Employee Name: ");
                    String name = sc.nextLine();

                    String department;

                    while (true) {

                        System.out.print("Enter Department (IT/HR/Finance/Sales/Marketing): ");
                        department = sc.nextLine();

                        if (department.equalsIgnoreCase("IT") ||
                            department.equalsIgnoreCase("HR") ||
                            department.equalsIgnoreCase("Finance") ||
                            department.equalsIgnoreCase("Sales") ||
                            department.equalsIgnoreCase("Marketing")) {

                            break;
                        }

                        System.out.println("Invalid Department!");
                        System.out.println("Available Departments:");
                        System.out.println("IT");
                        System.out.println("HR");
                        System.out.println("Finance");
                        System.out.println("Sales");
                        System.out.println("Marketing");
                    }

                    double salary;

                    while (true) {

                       System.out.print("Enter  Salary: ");
                       salary = sc.nextDouble();
                       sc.nextLine();

                       if (salary > 0) {
                           break;
                        }

                        System.out.println("Invalid Salary! Salary must be greater than 0.");
                    }


                    String phone;

                    while (true) {

                        System.out.print("Enter Phone Number: ");
                        phone = sc.nextLine();

                        if (phone.matches("[0-9]{10}")) {
                            break;
                        }

                        System.out.println("Invalid Phone Number!");
                        System.out.println("Phone number must contain exactly 10 digits.");
                }

                    Employee emp = new Employee(id, name, department, salary, phone);

                    service.addEmployee(emp);

                    break;

                case 2:

                    service.viewEmployees();

                    break;

                case 3:

                    System.out.print("Enter Employee ID: ");
                    int searchId = sc.nextInt();

                    service.searchEmployee(searchId);

                    break;
                case 4:

                    System.out.print("Enter Employee Name: ");
                    String searchName = sc.nextLine();

                    service.searchEmployeeByName(searchName);

                    break;


                case 5:

                    System.out.print("Enter Employee ID to Update: ");
                    int updateId = sc.nextInt();
                    sc.nextLine();

                    System.out.print("Enter New Name: ");
                    String newName = sc.nextLine();

                    String newDepartment;

                    while (true) {

                        System.out.print("Enter New Department (IT/HR/Finance/Sales/Marketing): ");
                        newDepartment = sc.nextLine();

                        if (newDepartment.equalsIgnoreCase("IT") ||
                            newDepartment.equalsIgnoreCase("HR") ||
                            newDepartment.equalsIgnoreCase("Finance") ||
                            newDepartment.equalsIgnoreCase("Sales") ||
                            newDepartment.equalsIgnoreCase("Marketing")) {

                            break;
                        }

                        System.out.println("Invalid Department!");
                        System.out.println("Available Departments:");
                        System.out.println("IT");
                        System.out.println("HR");
                        System.out.println("Finance");
                        System.out.println("Sales");
                        System.out.println("Marketing");
            }
                    
                    double newSalary;

                    while (true) {

                        System.out.print("Enter New Salary: ");
                        newSalary = sc.nextDouble();
                        sc.nextLine();

                        if (newSalary > 0) {
                            break;
                        }

                        System.out.println("Invalid Salary! Salary must be greater than 0.");
                    }

                    String newPhone;

                    while (true) {

                        System.out.print("Enter New Phone: ");
                        newPhone = sc.nextLine();

                        if (newPhone.matches("[0-9]{10}")) {
                            break;
                        }

                        System.out.println("Invalid Phone Number!");
                        System.out.println("Phone number must contain exactly 10 digits.");
                }

                    service.updateEmployee(updateId, newName, newDepartment, newSalary, newPhone);

                    break;
                case 6:
                    System.out.print("Enter Employee ID to Delete: ");
                    int deleteId = sc.nextInt();
                    sc.nextLine();

                    System.out.print("Are you sure? (yes/no): ");
                    String confirm = sc.nextLine();

                    if (confirm.equalsIgnoreCase("yes")) {
                        service.deleteEmployee(deleteId);
                    } else {
                        System.out.println("Delete Cancelled.");
                    }

                    break; 
                case 7:
                    service.dashboard();
                    break;
                case 8:
                    service.exportToCSV();
                    break;    

                case 9:

                    System.out.println("\n========================================");
                    System.out.println(" Thank You for using");
                    System.out.println(" EMPLOYEE MANAGEMENT SYSTEM");
                    System.out.println("----------------------------------------");
                    System.out.println(" Developed by: Thota Usha Laharika");
                    System.out.println("========================================");

                    sc.close();
                    System.exit(0);
                    break;

                default:

                    System.out.println("Invalid Choice! Please try again.");
            }
        }
    }
}