# Source code for pathvalidate._filename

    """
    .. codeauthor:: Tsuyoshi Hombashi <tsuyoshi.hombashi@gmail.com>
    """

    import itertools
    import ntpath
    import posixpath
    import re
    from pathlib import Path
    from typing import Optional, Pattern, Tuple

    from ._base import DEFAULT_MIN_LEN, AbstractSanitizer, BaseFile, BaseValidator
    from ._common import (
        PathType,
        Platform,
        PlatformType,
        findall_to_str,
        is_pathlike_obj,
        preprocess,
        validate_pathtype,
    )
    from .error import ErrorReason, InvalidCharError, InvalidLengthError, ValidationError
    from .handler import Handler

    _DEFAULT_MAX_FILENAME_LEN = 255
    _RE_INVALID_FILENAME = re.compile(f"[{re.escape(BaseFile._INVALID_FILENAME_CHARS):s}]", re.UNICODE)
    _RE_INVALID_WIN_FILENAME = re.compile(
        f"[{re.escape(BaseFile._INVALID_WIN_FILENAME_CHARS):s}]", re.UNICODE
    )

    class FileNameSanitizer(AbstractSanitizer):
        def __init__(
            self,
            min_len: int = DEFAULT_MIN_LEN,
            max_len: int = _DEFAULT_MAX_FILENAME_LEN,
            platform: PlatformType = None,
            check_reserved: bool = True,
            null_value_handler: Optional[Handler] = None,
        ) -> None:
            super().__init__(
                min_len=min_len,
                max_len=max_len,
                check_reserved=check_reserved,
                null_value_handler=null_value_handler,
                platform_max_len=_DEFAULT_MAX_FILENAME_LEN,
                platform=platform,
            )

            self._sanitize_regexp = self._get_sanitize_regexp()
            self.__validator = FileNameValidator(
                min_len=self.min_len,
                max_len=self.max_len,
                check_reserved=check_reserved,
                platform=self.platform,
            )

        def sanitize(self, value: PathType, replacement_text: str = "") -> PathType:
            try:
                validate_pathtype(value, allow_whitespaces=False if self._is_windows() else True)
            except ValidationError as e:
                if e.reason == ErrorReason.NULL_NAME:
                    return self._null_value_handler(e)
                raise

            sanitized_filename = self._sanitize_regexp.sub(replacement_text, str(value))
            sanitized_filename = sanitized_filename[: self.max_len]

            try:
                self.__validator.validate(sanitized_filename)
            except ValidationError as e:
                if e.reason == ErrorReason.RESERVED_NAME and e.reusable_name is False:
                    sanitized_filename = re.sub(
                        re.escape(e.reserved_name), f"{e.reserved_name}_", sanitized_filename
                    )
                elif e.reason == ErrorReason.INVALID_CHARACTER:
                    if self.platform in [Platform.UNIVERSAL, Platform.WINDOWS]:
                        # Do not end a file or directory name with a space or a period
                        sanitized_filename = sanitized_filename.rstrip(" .")
                elif e.reason == ErrorReason.NULL_NAME:
                    return self._null_value_handler(e)
                else:
                    raise

            if is_pathlike_obj(value):
                return Path(sanitized_filename)

            return sanitized_filename

        def _get_sanitize_regexp(self) -> Pattern:
            if self.platform in [Platform.UNIVERSAL, Platform.WINDOWS]:
                return _RE_INVALID_WIN_FILENAME

            return _RE_INVALID_FILENAME

    class FileNameValidator(BaseValidator):
        _WINDOWS_RESERVED_FILE_NAMES = ("CON", "PRN", "AUX", "CLOCK$", "NUL") + tuple(
            f"{name:s}{num:d}" for name, num in itertools.product(("COM", "LPT"), range(1, 10))
        )
        _MACOS_RESERVED_FILE_NAMES = (":",)

        @property
        def reserved_keywords(self) -> Tuple[str, ...]:
            common_keywords = super().reserved_keywords

            if self._is_universal():
                return (
                    common_keywords
                    + self._WINDOWS_RESERVED_FILE_NAMES
                    + self._MACOS_RESERVED_FILE_NAMES
                )

            if self._is_windows():
                return common_keywords + self._WINDOWS_RESERVED_FILE_NAMES

            if self._is_posix() or self._is_macos():
                return common_keywords + self._MACOS_RESERVED_FILE_NAMES

            return common_keywords

        def __init__(
            self,
            min_len: int = DEFAULT_MIN_LEN,
            max_len: int = _DEFAULT_MAX_FILENAME_LEN,
            platform: PlatformType = None,
            check_reserved: bool = True,
        ) -> None:
            super().__init__(
                min_len=min_len,
                max_len=max_len,
                check_reserved=check_reserved,
                platform_max_len=_DEFAULT_MAX_FILENAME_LEN,
                platform=platform,
            )

        def validate(self, value: PathType) -> None:
            validate_pathtype(
                value,
                allow_whitespaces=False
                if self.platform in [Platform.UNIVERSAL, Platform.WINDOWS]
                else True,
            )

            unicode_filename = preprocess(value)
            value_len = len(unicode_filename)

            self.validate_abspath(unicode_filename)

            if value_len > self.max_len:
                raise InvalidLengthError(
                    f"filename is too long: expected<={self.max_len:d}, actual={value_len:d}"
                )
            if value_len < self.min_len:
                raise InvalidLengthError(
                    f"filename is too short: expected>={self.min_len:d}, actual={value_len:d}"
                )

            self._validate_reserved_keywords(unicode_filename)

            if self._is_universal() or self._is_windows():
                self.__validate_win_filename(unicode_filename)
            else:
                self.__validate_unix_filename(unicode_filename)

        def validate_abspath(self, value: str) -> None:
            err = ValidationError(
                description=f"found an absolute path ({value}), expected a filename",
                platform=self.platform,
                reason=ErrorReason.FOUND_ABS_PATH,
            )

            if self._is_universal() or self._is_windows():
                if ntpath.isabs(value):
                    raise err

            if posixpath.isabs(value):
                raise err

        def __validate_unix_filename(self, unicode_filename: str) -> None:
            match = _RE_INVALID_FILENAME.findall(unicode_filename)
            if match:
                raise InvalidCharError(
                    self._ERROR_MSG_TEMPLATE.format(
                        invalid=findall_to_str(match), value=repr(unicode_filename)
                    )
                )

        def __validate_win_filename(self, unicode_filename: str) -> None:
            match = _RE_INVALID_WIN_FILENAME.findall(unicode_filename)
            if match:
                raise InvalidCharError(
                    self._ERROR_MSG_TEMPLATE.format(
                        invalid=findall_to_str(match), value=repr(unicode_filename)
                    ),
                    platform=Platform.WINDOWS,
                )

            if unicode_filename in (".", ".."):
                return

            if unicode_filename[-1] in (" ", "."):
                raise InvalidCharError(
                    self._ERROR_MSG_TEMPLATE.format(
                        invalid=re.escape(unicode_filename[-1]), value=repr(unicode_filename)
                    ),
                    platform=Platform.WINDOWS,
                    description="Do not end a file or directory name with a space or a period",
                )

    def validate_filename(
        filename: PathType,
        platform: Optional[str] = None,
        min_len: int = DEFAULT_MIN_LEN,
        max_len: int = _DEFAULT_MAX_FILENAME_LEN,
        check_reserved: bool = True,
    ) -> None:
        """Verifying whether the ``filename`` is a valid file name or not.

        Args:
            filename:
                Filename to validate.
            platform:
                Target platform name of the filename.

                .. include:: platform.txt
            min_len:
                Minimum length of the ``filename``. The value must be greater or equal to one.
                Defaults to ``1``.
            max_len:
                Maximum length of the ``filename``. The value must be lower than:

                    - ``Linux``: 4096
                    - ``macOS``: 1024
                    - ``Windows``: 260
                    - ``universal``: 260

                Defaults to ``255``.
            check_reserved:
                If |True|, check reserved names of the ``platform``.

        Raises:
            ValidationError (ErrorReason.INVALID_LENGTH):
                If the ``filename`` is longer than ``max_len`` characters.
            ValidationError (ErrorReason.INVALID_CHARACTER):
                If the ``filename`` includes invalid character(s) for a filename:
                |invalid_filename_chars|.
                The following characters are also invalid for Windows platform:
                |invalid_win_filename_chars|.
            ValidationError (ErrorReason.RESERVED_NAME):
                If the ``filename`` equals reserved name by OS.
                Windows reserved name is as follows:
                ``"CON"``, ``"PRN"``, ``"AUX"``, ``"NUL"``, ``"COM[1-9]"``, ``"LPT[1-9]"``.

        Example:
            :ref:`example-validate-filename`

        See Also:
            `Naming Files, Paths, and Namespaces - Win32 apps | Microsoft Docs
            <https://docs.microsoft.com/en-us/windows/win32/fileio/naming-a-file>`__
        """

        FileNameValidator(
            platform=platform, min_len=min_len, max_len=max_len, check_reserved=check_reserved
        ).validate(filename)

    def is_valid_filename(
        filename: PathType,
        platform: Optional[str] = None,
        min_len: int = DEFAULT_MIN_LEN,
        max_len: Optional[int] = None,
        check_reserved: bool = True,
    ) -> bool:
        """Check whether the ``filename`` is a valid name or not.

        Args:
            filename:
                A filename to be checked.

        Example:
            :ref:`example-is-valid-filename`

        See Also:
            :py:func:`.validate_filename()`
        """

        return FileNameValidator(
            platform=platform,
            min_len=min_len,
            max_len=-1 if max_len is None else max_len,
            check_reserved=check_reserved,
        ).is_valid(filename)

    def sanitize_filename(
        filename: PathType,
        replacement_text: str = "",
        platform: Optional[str] = None,
        max_len: Optional[int] = _DEFAULT_MAX_FILENAME_LEN,
        check_reserved: bool = True,
        null_value_handler: Optional[Handler] = None,
    ) -> PathType:
        """Make a valid filename from a string.

        To make a valid filename the function does:

            - Replace invalid characters as file names included in the ``filename``
              with the ``replacement_text``. Invalid characters are:

                - unprintable characters
                - |invalid_filename_chars|
                - for Windows (or universal) only: |invalid_win_filename_chars|

            - Append underscore (``"_"``) at the tail of the name if sanitized name
              is one of the reserved names by operating systems
              (only when ``check_reserved`` is |True|).

        Args:
            filename: Filename to sanitize.
            replacement_text:
                Replacement text for invalid characters. Defaults to ``""``.
            platform:
                Target platform name of the filename.

                .. include:: platform.txt
            max_len:
                Maximum length of the ``filename`` length. Truncate the name length if
                the ``filename`` length exceeds this value.
                Defaults to ``255``.
            check_reserved:
                If |True|, sanitize reserved names of the ``platform``.
            null_value_handler:
                Function called when a value after sanitization is an empty string.
                Defaults to ``pathvalidate.handler.return_null_string()`` that just return ``""``.

        Returns:
            Same type as the ``filename`` (str or PathLike object):
                Sanitized filename.

        Raises:
            ValueError:
                If the ``filename`` is an invalid filename.

        Example:
            :ref:`example-sanitize-filename`
        """

        return FileNameSanitizer(
            platform=platform,
            max_len=-1 if max_len is None else max_len,
            check_reserved=check_reserved,
            null_value_handler=null_value_handler,
        ).sanitize(filename, replacement_text)