import ssl
import socket
import datetime
import smtplib
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart

def check_certificate_expiry(url, days_threshold=20):
    """Checks if a website's SSL certificate expires within the given threshold."""
    try:
        hostname = url.split('//')[-1].split('/')[0]  # Extract hostname
        port = 443  # Default HTTPS port

        context = ssl.create_default_context()
        with socket.create_connection((hostname, port)) as sock:
            with context.wrap_socket(sock, server_hostname=hostname) as ssock:
                cert = ssock.getpeercert()

        expiry_date_str = cert['notAfter']
        expiry_date = datetime.datetime.strptime(expiry_date_str, '%b %d %H:%M:%S %Y %Z')
        now = datetime.datetime.utcnow()
        time_remaining = expiry_date - now
        
        if time_remaining.days <= days_threshold:
            return url, expiry_date
        else:
            return None, None
    except (socket.gaierror, ConnectionRefusedError, ssl.SSLError, ValueError, IndexError) as e:  # Handle potential errors
        print(f"Error checking {url}: {e}")
        return None, None


def send_email(expired_certs, recipient_email="user@example.com", sender_email="your_email@example.com", sender_password="your_password"):
    """Sends an email with the list of expiring certificates."""

    if not expired_certs:  # Check if expired_certs is empty
        print("No certificates expiring soon.")
        return

    message = MIMEMultipart()
    message['From'] = sender_email
    message['To'] = recipient_email
    message['Subject'] = "Expiring SSL Certificates"

    email_body = "The following certificates are expiring soon:\n\n"
    for url, expiry_date in expired_certs:
        email_body += f"URL: {url}\nExpiry Date: {expiry_date}\n\n"

    message.attach(MIMEText(email_body, 'plain'))

    try:
        with smtplib.SMTP_SSL('smtp.gmail.com', 465) as server:  # Example using Gmail, adjust as needed
            server.login(sender_email, sender_password)
            server.sendmail(sender_email, recipient_email, message.as_string())
        print("Email sent successfully.")
    except Exception as e:
        print(f"Error sending email: {e}")



def main():
    """Reads URLs from a file, checks certificates, and sends an email."""

    try:
        with open("urls.txt", "r") as f:  # Replace "urls.txt" with your file name
            urls = [line.strip() for line in f]
    except FileNotFoundError:
        print("urls.txt file not found. Please create this file with your urls")
        return

    expiring_certificates = []
    for url in urls:
        url_with_protocol = url if url.startswith("http://") or url.startswith("https://") else "https://" + url
        url_with_protocol = url_with_protocol.split("#")[0] #remove anchor links if present

        checked_url, expiry_date = check_certificate_expiry(url_with_protocol)
        if checked_url:
            expiring_certificates.append((checked_url, expiry_date))

    send_email(expiring_certificates)


if __name__ == "__main__":
    main()