import sys
import os

def parse_filename(filename):
    # Parse filename up to before the last underscore
    parsed_name = filename.rsplit('_', 1)[0]
    # Check if 'ACK' or 'CAN' is in the last 10 characters of the filename
    ack_or_can = 'ACK' if 'ACK' in filename[-10:] else ('CAN' if 'CAN' in filename[-10:] else '')
    return parsed_name, ack_or_can

def update_config_file(config_file, parsed_name, ack_or_can):
    # Open the config file and read its contents
    with open(config_file, 'r') as f:
        lines = f.readlines()
    # Find and update the File_Desc field
    for i, line in enumerate(lines):
        if line.startswith('File_Desc='):
            lines[i] = f'File_Desc={parsed_name}\n'
            break
    # Update the ACK_OR_CAN field
    lines.append(f'ACK_OR_CAN={ack_or_can}\n')
    # Write the updated contents back to the config file
    with open(config_file, 'w') as f:
        f.writelines(lines)

if __name__ == "__main__":
    if len(sys.argv) != 2:
        print("Usage: python script.py filename")
        sys.exit(1)

    filename = sys.argv[1]
    parsed_name, ack_or_can = parse_filename(filename)
    
    # Assuming the config file is in the same directory with the same name but with .config extension
    config_file = os.path.splitext(filename)[0] + '.config'
    
    update_config_file(config_file, parsed_name, ack_or_can)
    print(f"Config file '{config_file}' updated successfully.")