import argparse
import sys
import tomllib
import utils
import logging


class Config:
    def __init__(self):
        self.logger = logging.getLogger("sshd-bruteforce-detector")
        parser = argparse.ArgumentParser(
            prog="sshd-bruteforce-detector",
            description="detects SSH bruteforce attacks by reading sshd's logs from systemd journal",
        )

        parser.add_argument(
            "-c", "--config", nargs="?", help="provide a path for the config file"
        )
        parser.add_argument(
            "-m",
            "--max-attempts",
            nargs="?",
            help="Maximum number of failed login attempts allowed within the time window before triggering an alert. (default: 5)",
        )
        parser.add_argument(
            "-w",
            "--window",
            nargs="?",
            help="Time window used to group failed login attempts for detection (default: 5m)",
        )

        self.args = parser.parse_args()
        self.config = {}
        if getattr(self.args, "config", None):
            self.__load_config(self.args.config)

    def __load_config(self, path: str):
        try:
            with open(path, "rb") as f:
                self.config = tomllib.load(f)
        except FileNotFoundError:
            self.logger.info("Config file not found. Stopping manually...")
            sys.exit(1)
        except tomllib.TOMLDecodeError:
            self.logger.info(
                "Config file not in valid TOML format. Stopping manually..."
            )
            sys.exit(1)

    def __get_config_option(self, option):
        opt = getattr(self.args, option, None)
        opt_config = self.config.get(option, None)
        if opt is not None:
            return opt
        elif opt_config is not None:
            return opt_config
        else:
            return None

    def get_window(self):
        window = self.__get_config_option("window")
        return utils.parse_window(window) if window is not None else 300

    def get_max_attempts(self):
        max_attempts = self.__get_config_option("max_attempts")
        return int(max_attempts) if max_attempts is not None else 5