# Source code for dateparser.conf

    import hashlib
    from datetime import datetime
    from functools import wraps

    from dateparser.data.languages_info import language_order

    from .parser import date_order_chart
    from .utils import registry

    @registry
    class Settings:
        """Control and configure default parsing behavior of dateparser.
        Currently, supported settings are:

        * `DATE_ORDER`
        * `PREFER_LOCALE_DATE_ORDER`
        * `TIMEZONE`
        * `TO_TIMEZONE`
        * `RETURN_AS_TIMEZONE_AWARE`
        * `PREFER_MONTH_OF_YEAR`
        * `PREFER_DAY_OF_MONTH`
        * `PREFER_DATES_FROM`
        * `RELATIVE_BASE`
        * `STRICT_PARSING`
        * `REQUIRE_PARTS`
        * `SKIP_TOKENS`
        * `NORMALIZE`
        * `RETURN_TIME_AS_PERIOD`
        * `PARSERS`
        * `DEFAULT_LANGUAGES`
        * `LANGUAGE_DETECTION_CONFIDENCE_THRESHOLD`
        * `CACHE_SIZE_LIMIT`
        """

        _default = True
        _pyfile_data = None
        _mod_settings = dict()

        def __init__(self, settings=None):
            if settings:
                self._updateall(settings.items())
            else:
                self._updateall(self._get_settings_from_pyfile().items())

        @classmethod
        def get_key(cls, settings=None):
            if not settings:
                return "default"

            keys = sorted(["%s-%s" % (key, str(settings[key])) for key in settings])
            return hashlib.md5("".join(keys).encode("utf-8")).hexdigest()

        @classmethod
        def _get_settings_from_pyfile(cls):
            if not cls._pyfile_data:
                from dateparser_data import settings

                cls._pyfile_data = settings.settings
            return cls._pyfile_data

        def _updateall(self, iterable):
            for key, value in iterable:
                setattr(self, key, value)

        def replace(self, mod_settings=None, **kwds):
            for k, v in kwds.items():
                if v is None:
                    raise TypeError('Invalid {{"{}": {}}}'.format(k, v))

            for x in self._get_settings_from_pyfile().keys():
                kwds.setdefault(x, getattr(self, x))

            kwds["_default"] = False
            if mod_settings:
                kwds["_mod_settings"] = mod_settings

            return self.__class__(settings=kwds)

    settings = Settings()

    def apply_settings(f):
        @wraps(f)
        def wrapper(*args, **kwargs):
            mod_settings = kwargs.get("settings")
            kwargs["settings"] = mod_settings or settings

            if isinstance(kwargs["settings"], dict):
                kwargs["settings"] = settings.replace(
                    mod_settings=mod_settings, **kwargs["settings"]
                )

            if not isinstance(kwargs["settings"], Settings):
                raise TypeError(
                    "settings can only be either dict or instance of Settings class"
                )

            return f(*args, **kwargs)

        return wrapper

    class SettingValidationError(ValueError):
        pass

    def _check_repeated_values(setting_name, setting_value):
        if len(setting_value) != len(set(setting_value)):
            raise SettingValidationError(
                'There are repeated values in the "{}" setting'.format(setting_name)
            )
        return

    def _check_require_part(setting_name, setting_value):
        """Returns `True` if the provided list of parts contains valid values"""
        invalid_values = set(setting_value) - {"day", "month", "year"}
        if invalid_values:
            raise SettingValidationError(
                '"{}" setting contains invalid values: {}'.format(
                    setting_name, ", ".join(invalid_values)
                )
            )
        _check_repeated_values(setting_name, setting_value)

    def _check_parsers(setting_name, setting_value):
        """Returns `True` if the provided list of parsers contains valid values"""
        existing_parsers = [
            "timestamp",
            "relative-time",
            "custom-formats",
            "absolute-time",
            "no-spaces-time",
            "negative-timestamp",
        ]  # FIXME: Extract the list of existing parsers from another place (#798)
        unknown_parsers = set(setting_value) - set(existing_parsers)
        if unknown_parsers:
            raise SettingValidationError(
                'Found unknown parsers in the "{}" setting: {}'.format(
                    setting_name, ", ".join(unknown_parsers)
                )
            )
        _check_repeated_values(setting_name, setting_value)

    def _check_default_languages(setting_name, setting_value):
        unsupported_languages = set(setting_value) - set(language_order)
        if unsupported_languages:
            raise SettingValidationError(
                "Found invalid languages in the '{}' setting: {}".format(
                    setting_name, ", ".join(map(repr, unsupported_languages))
                )
            )
        _check_repeated_values(setting_name, setting_value)

    def _check_between_0_and_1(setting_name, setting_value):
        is_valid = 0 <= setting_value <= 1
        if not is_valid:
            raise SettingValidationError(
                "{} is not a valid value for {}. It can take values between 0 and "
                "1.".format(
                    setting_value,
                    setting_name,
                )
            )

    def check_settings(settings):
        """
        Check if provided settings are valid, if not it raises `SettingValidationError`.
        Only checks for the modified settings.
        """
        settings_values = {
            "DATE_ORDER": {
                "values": tuple(date_order_chart.keys()),
                "type": str,
            },
            "TIMEZONE": {
                # we don't check invalid Timezones as they raise an error
                "type": str,
            },
            "TO_TIMEZONE": {
                # It defaults to None, but it's not allowed to use it directly
                # "values" can take unlimited options
                "type": str
            },
            "RETURN_AS_TIMEZONE_AWARE": {
                # It defaults to 'default', but it's not allowed to use it directly
                "type": bool
            },
            "PREFER_MONTH_OF_YEAR": {"values": ("current", "first", "last"), "type": str},
            "PREFER_DAY_OF_MONTH": {"values": ("current", "first", "last"), "type": str},
            "PREFER_DATES_FROM": {
                "values": ("current_period", "past", "future"),
                "type": str,
            },
            "RELATIVE_BASE": {
                # "values" can take unlimited options
                "type": datetime
            },
            "STRICT_PARSING": {"type": bool},
            "REQUIRE_PARTS": {
                # "values" covered by the 'extra_check'
                "type": list,
                "extra_check": _check_require_part,
            },
            "SKIP_TOKENS": {
                # "values" can take unlimited options
                "type": list,
            },
            "NORMALIZE": {"type": bool},
            "RETURN_TIME_AS_PERIOD": {"type": bool},
            "PARSERS": {
                # "values" covered by the 'extra_check'
                "type": list,
                "extra_check": _check_parsers,
            },
            "FUZZY": {"type": bool},
            "PREFER_LOCALE_DATE_ORDER": {"type": bool},
            "DEFAULT_LANGUAGES": {"type": list, "extra_check": _check_default_languages},
            "LANGUAGE_DETECTION_CONFIDENCE_THRESHOLD": {
                "type": float,
                "extra_check": _check_between_0_and_1,
            },
            "CACHE_SIZE_LIMIT": {
                "type": int,
            },
        }

        modified_settings = settings._mod_settings  # check only modified settings

        # check settings keys:
        for setting in modified_settings:
            if setting not in settings_values:
                raise SettingValidationError('"{}" is not a valid setting'.format(setting))

        for setting_name, setting_value in modified_settings.items():
            setting_type = type(setting_value)
            setting_props = settings_values[setting_name]

            # check type:
            if not setting_type == setting_props["type"]:
                raise SettingValidationError(
                    '"{}" must be "{}", not "{}".'.format(
                        setting_name, setting_props["type"].__name__, setting_type.__name__
                    )
                )

            # check values:
            if setting_props.get("values") and setting_value not in setting_props["values"]:
                raise SettingValidationError(
                    '"{}" is not a valid value for "{}", it should be: "{}" or "{}"'.format(
                        setting_value,
                        setting_name,
                        '", "'.join(setting_props["values"][:-1]),
                        setting_props["values"][-1],
                    )
                )

            # specific checks
            extra_check = setting_props.get("extra_check")
            if extra_check:
                extra_check(setting_name, setting_value)