CSV File with User-ID and Password

# Python program for CSV file operations with user-id and password

import csv
import os

def create_csv_file():
    """Create CSV file with headers if it doesn't exist"""
    filename = 'users.csv'
    if not os.path.exists(filename):
        with open(filename, 'w', newline='') as file:
            writer = csv.writer(file)
            writer.writerow(['UserID', 'Password', 'Name', 'Email'])
        print(f"CSV file '{filename}' created successfully!")
    return filename

def add_user(filename):
    """Add a new user to the CSV file"""
    try:
        print("\n--- Add New User ---")
        user_id = input("Enter User ID: ")
        password = input("Enter Password: ")
        name = input("Enter Name: ")
        email = input("Enter Email: ")
        
        with open(filename, 'a', newline='') as file:
            writer = csv.writer(file)
            writer.writerow([user_id, password, name, email])
        
        print(f"User '{user_id}' added successfully!")
        
    except Exception as e:
        print(f"Error adding user: {e}")

def search_user(filename):
    """Search for a user by User ID"""
    try:
        search_id = input("\nEnter User ID to search: ")
        found = False
        
        with open(filename, 'r') as file:
            reader = csv.reader(file)
            headers = next(reader)  # Skip header row
            
            print(f"\n--- Search Results ---")
            for row in reader:
                if row[0] == search_id:
                    print(f"User ID: {row[0]}")
                    print(f"Password: {row[1]}")
                    print(f"Name: {row[2]}")
                    print(f"Email: {row[3]}")
                    found = True
                    break
        
        if not found:
            print(f"User with ID '{search_id}' not found!")
            
    except FileNotFoundError:
        print("CSV file not found!")
    except Exception as e:
        print(f"Error searching user: {e}")

def display_all_users(filename):
    """Display all users from the CSV file"""
    try:
        with open(filename, 'r') as file:
            reader = csv.reader(file)
            headers = next(reader)
            
            print(f"\n--- All Users ---")
            print(f"{'UserID':<10} {'Password':<12} {'Name':<15} {'Email':<20}")
            print("-" * 60)
            
            for row in reader:
                print(f"{row[0]:<10} {row[1]:<12} {row[2]:<15} {row[3]:<20}")
                
    except FileNotFoundError:
        print("CSV file not found!")
    except Exception as e:
        print(f"Error displaying users: {e}")

def validate_login(filename):
    """Validate user login credentials"""
    try:
        login_id = input("\nEnter User ID: ")
        login_password = input("Enter Password: ")
        
        with open(filename, 'r') as file:
            reader = csv.reader(file)
            headers = next(reader)  # Skip header row
            
            for row in reader:
                if row[0] == login_id and row[1] == login_password:
                    print(f"\nLogin successful! Welcome, {row[2]}!")
                    return True
            
            print("Invalid User ID or Password!")
            return False
            
    except FileNotFoundError:
        print("CSV file not found!")
        return False
    except Exception as e:
        print(f"Error during login: {e}")
        return False

def create_sample_data(filename):
    """Create sample user data"""
    sample_users = [
        ['admin', 'admin123', 'Administrator', 'admin@example.com'],
        ['john_doe', 'password123', 'John Doe', 'john@example.com'],
        ['jane_smith', 'secure456', 'Jane Smith', 'jane@example.com'],
        ['bob_wilson', 'mypass789', 'Bob Wilson', 'bob@example.com']
    ]
    
    with open(filename, 'a', newline='') as file:
        writer = csv.writer(file)
        for user in sample_users:
            writer.writerow(user)
    
    print("Sample user data added!")

# Main program
def main():
    print("CSV USER MANAGEMENT SYSTEM")
    print("=" * 30)
    
    # Create CSV file
    filename = create_csv_file()
    
    # Add sample data
    create_sample_data(filename)
    
    while True:
        print("\n--- Menu ---")
        print("1. Add New User")
        print("2. Search User")
        print("3. Display All Users")
        print("4. Validate Login")
        print("5. Exit")
        
        choice = input("\nEnter your choice (1-5): ")
        
        if choice == '1':
            add_user(filename)
        elif choice == '2':
            search_user(filename)
        elif choice == '3':
            display_all_users(filename)
        elif choice == '4':
            validate_login(filename)
        elif choice == '5':
            print("Thank you for using CSV User Management System!")
            break
        else:
            print("Invalid choice! Please try again.")

if __name__ == "__main__":
    main()