import argparse
import os
from EHSExceptions import ArgumentException

from CustomLogger import logger, setDebugMode

class EHSArguments:
    """
    EHSArguments is a singleton class that handles command-line arguments for the EHS Sentinel script.
    Attributes:
        CONFIGFILE (str): Path to the configuration file.
        DRYRUN (bool): Flag indicating if the script should run in dry run mode.
        DUMPFILE (str): Path to the dump file.
        _instance (EHSArguments): Singleton instance of the class.
    Methods:
        __new__(cls, *args, **kwargs): Ensures only one instance of the class is created.
        __init__(self): Initializes the class, parses command-line arguments, and sets attributes.
    """

    CONFIGFILE = ''
    DRYRUN = False
    DUMPFILE = ''

    _instance = None

    def __new__(cls, *args, **kwargs):
        if not cls._instance:
            cls._instance = super(EHSArguments, cls).__new__(cls, *args, **kwargs)
            cls._instance._initialized = False
        return cls._instance

    def __init__(self):
        if self._initialized:
            return
        self._initialized = True
        logger.debug("init EHSArguments")
        parser = argparse.ArgumentParser(description="Process some integers.")
        parser.add_argument('--configfile', type=str, required=True, help='Config file path')
        parser.add_argument('--dumpfile', type=str,  required=False, help='File Path for where the Dumpfile should be written to or read from if dryrun flag is set too.')
        parser.add_argument('--dryrun', action='store_true', default=False, required=False, help='Run the script in dry run mode, data will be read from DumpFile and not MQTT Message will be sent.')
        parser.add_argument('--clean-known-devices', action='store_true', default=False, required=False, help='Cleans the know Devices Topic on Startup.')
        parser.add_argument('-v', '--verbose', action='store_true', default=False, required=False, help='Enable verbose mode')

        args = parser.parse_args()

        if args.verbose:
            setDebugMode()

        logger.debug(args)

        if args.dryrun:
            if args.dumpfile is None:
                raise ArgumentException(argument="--dumpfile")
            else:
                if not os.path.isfile(args.dumpfile):
                    raise ArgumentException(argument=args.dumpfile, message="Dump File does not exist")
            
        # Check if the config file exists
        if not os.path.isfile(args.configfile):
            raise ArgumentException(argument=args.configfile, message="Config File does not exist")
            
        self.CONFIGFILE = args.configfile
        self.DUMPFILE = args.dumpfile
        self.DRYRUN = args.dryrun
        self.CLEAN_KNOWN_DEVICES = args.clean_known_devices