import base64
import smtplib

def encode_xoauth2(username, access_token):
    # Define the format as specified
    xoauth2_format = f"user={username}\x01auth=Bearer {access_token}\x01\x01"
    
    # Encode the format to base64
    base64_encoded = base64.b64encode(xoauth2_format.encode()).decode()
    
    return base64_encoded

def authenticate_smtp_xoauth2(email_address, access_token):
    # SMTP server configuration
    smtp_server = "smtp.office365.com"
    smtp_port = 587

    # Create the SMTP connection
    server = smtplib.SMTP(smtp_server, smtp_port)
    server.set_debuglevel(1)  # Enable debug output for detailed logs
    
    # Send the EHLO command
    server.ehlo()

    # Start TLS for security
    server.starttls()

    # Send the EHLO command again after STARTTLS
    server.ehlo()

    # Encode the credentials
    auth_string = f"user={email_address}\x01auth=Bearer {access_token}\x01\x01"
    auth_encoded = base64.b64encode(auth_string.encode()).decode()

    try:
        # Send the AUTH XOAUTH2 command
        server.putcmd("AUTH XOAUTH2")
        
        # Read the server's response
        code, response = server.getreply()
        
        if code == 334:
            # Send the encoded credentials
            server.putcmd(auth_encoded)
            
            # Read the server's response
            code, response = server.getreply()
            
            if code == 235:
                print("Authentication successful.")
            else:
                print(f"Authentication failed: {response.decode()}")
        else:
            print(f"AUTH XOAUTH2 command not accepted: {response.decode()}")
            
    except smtplib.SMTPAuthenticationError as e:
        print(f"Authentication failed: {e.smtp_error.decode()}")
    finally:
        # Quit the SMTP server
        server.quit()


# Predefined variables
email_address = ""
access_token = "..----"
#email_address = "test@contoso.onmicrosoft.com"
#access_token = "EwBAAl3BAAUFFpUAo7J3Ve0bjLBWZWCclRC3EoAA"
# Authenticate with the SMTP server
authenticate_smtp_xoauth2(email_address, access_token)