import geoip2.database
import geoip2.errors
import csv

# File names
INPUT_FILE = 'mascan_results.txt'       # Your list of IPs, one per line
OUTPUT_FILE = 'results.csv'  # The CSV file that will be created
DB_FILE = 'GeoLite2-ASN.mmdb' # The MaxMind database file

# We use 'with' statements to ensure files and databases close automatically
with geoip2.database.Reader(DB_FILE) as reader, \
     open(INPUT_FILE, 'r') as infile, \
     open(OUTPUT_FILE, 'w', newline='') as outfile:
    
    # Initialize the CSV writer
    writer = csv.writer(outfile)
    
    # Write the column headers to the CSV
    writer.writerow(['IP Address', 'ISP / Provider', 'Subnet', 'ASN'])
    
    # Loop through each line in your input text file
    for line in infile:
        ip = line.strip() # Remove spaces and line breaks
        
        if not ip:
            continue # Skip blank lines
            
        try:
            # Query the Radix Tree database
            response = reader.asn(ip)
            provider = response.autonomous_system_organization
            subnet = str(response.network) # Convert subnet object to string
            asn = response.autonomous_system_number
            
            # Write the successful result to the CSV
            writer.writerow([ip, provider, subnet, asn])
            
        except geoip2.errors.AddressNotFoundError:
            # IP isn't in the database
            writer.writerow([ip, 'Not Found', 'Not Found', 'Not Found'])
            
        except ValueError:
            # The text on this line wasn't a valid IP address format
            writer.writerow([ip, 'Invalid IP format', 'N/A', 'N/A'])