"""The TAR file entry implementation."""

from dfdatetime import posix_time as dfdatetime_posix_time

from dfvfs.lib import definitions
from dfvfs.lib import errors
from dfvfs.path import tar_path_spec
from dfvfs.vfs import attribute
from dfvfs.vfs import file_entry
from dfvfs.vfs import tar_directory


class TARFileEntry(file_entry.FileEntry):
    """File system file entry that uses tarfile."""

    TYPE_INDICATOR = definitions.TYPE_INDICATOR_TAR

    def __init__(
        self,
        resolver_context,
        file_system,
        path_spec,
        is_root=False,
        is_virtual=False,
        tar_info=None,
    ):
        """Initializes the file entry.

        Args:
          resolver_context (Context): resolver context.
          file_system (FileSystem): file system.
          path_spec (PathSpec): path specification.
          is_root (Optional[bool]): True if the file entry is the root file entry
              of the corresponding file system.
          is_virtual (Optional[bool]): True if the file entry is a virtual file
              entry emulated by the corresponding file system.
          tar_info (Optional[tarfile.TARInfo]): TAR info.

        Raises:
          BackEndError: when the TAR info is missing in a non-virtual file entry.
        """
        if not is_virtual and tar_info is None:
            tar_info = file_system.GetTARInfoByPathSpec(path_spec)
        if not is_virtual and tar_info is None:
            raise errors.BackEndError("Missing TAR info in non-virtual file entry.")

        super().__init__(
            resolver_context,
            file_system,
            path_spec,
            is_root=is_root,
            is_virtual=is_virtual,
        )
        self._tar_info = tar_info

        if self._is_virtual or self._tar_info.isdir():
            self.entry_type = definitions.FILE_ENTRY_TYPE_DIRECTORY
        elif self._tar_info.isfile():
            self.entry_type = definitions.FILE_ENTRY_TYPE_FILE
        elif self._tar_info.issym() or self._tar_info.islnk():
            self.entry_type = definitions.FILE_ENTRY_TYPE_LINK
        elif self._tar_info.ischr():
            self.entry_type = definitions.FILE_ENTRY_TYPE_CHARACTER_DEVICE
        elif self._tar_info.isblk():
            self.entry_type = definitions.FILE_ENTRY_TYPE_BLOCK_DEVICE
        elif self._tar_info.isfifo():
            self.entry_type = definitions.FILE_ENTRY_TYPE_PIPE

    def _GetDirectory(self):
        """Retrieves a directory.

        Returns:
          TARDirectory: a directory.
        """
        if self.entry_type != definitions.FILE_ENTRY_TYPE_DIRECTORY:
            return None

        return tar_directory.TARDirectory(self._file_system, self.path_spec)

    def _GetLink(self):
        """Retrieves the link.

        Returns:
          str: link.
        """
        if self._link is None:
            self._link = ""
            if self._tar_info:
                self._link = self._tar_info.linkname

        return self._link

    def _GetStatAttribute(self):
        """Retrieves a stat attribute.

        Returns:
          StatAttribute: a stat attribute or None if not available.
        """
        stat_attribute = attribute.StatAttribute()
        stat_attribute.group_identifier = getattr(self._tar_info, "gid", None)
        stat_attribute.mode = getattr(self._tar_info, "mode", None)
        stat_attribute.owner_identifier = getattr(self._tar_info, "uid", None)
        stat_attribute.size = getattr(self._tar_info, "size", None)
        stat_attribute.type = self.entry_type

        return stat_attribute

    def _GetSubFileEntries(self):
        """Retrieves sub file entries.

        Yields:
          TARFileEntry: a sub file entry.
        """
        if self._directory is None:
            self._directory = self._GetDirectory()

        if self._directory:
            tar_file = self._file_system.GetTARFile()
            if tar_file:
                for path_spec in self._directory.entries:
                    location = getattr(path_spec, "location", None)
                    if location is None:
                        continue

                    kwargs = {}
                    try:
                        kwargs["tar_info"] = tar_file.getmember(location[1:])
                    except KeyError:
                        kwargs["is_virtual"] = True

                    yield TARFileEntry(
                        self._resolver_context, self._file_system, path_spec, **kwargs
                    )

    @property
    def modification_time(self):
        """dfdatetime.DateTimeValues: modification time or None if not available."""
        timestamp = getattr(self._tar_info, "mtime", None)
        if timestamp is None:
            return None
        return dfdatetime_posix_time.PosixTime(timestamp=timestamp)

    @property
    def name(self):
        """str: name of the file entry, which does not include the full path."""
        path = getattr(self.path_spec, "location", None)
        if path is not None and not isinstance(path, str):
            try:
                path = path.decode(self._file_system.encoding)
            except UnicodeDecodeError:
                path = None

        return self._file_system.BasenamePath(path)

    @property
    def size(self):
        """int: size of the file entry in bytes or None if not available."""
        return getattr(self._tar_info, "size", None)

    def GetParentFileEntry(self):
        """Retrieves the parent file entry.

        Returns:
          TARFileEntry: parent file entry or None.
        """
        location = getattr(self.path_spec, "location", None)
        if location is None:
            return None

        parent_location = self._file_system.DirnamePath(location)
        if parent_location is None:
            return None

        if parent_location == "":
            parent_location = self._file_system.PATH_SEPARATOR
            is_root = True
            is_virtual = True
        else:
            is_root = False
            is_virtual = False

        parent_path_spec = getattr(self.path_spec, "parent", None)
        path_spec = tar_path_spec.TARPathSpec(
            location=parent_location, parent=parent_path_spec
        )
        return TARFileEntry(
            self._resolver_context,
            self._file_system,
            path_spec,
            is_root=is_root,
            is_virtual=is_virtual,
        )

    def GetTARInfo(self):
        """Retrieves the TAR info.

        Returns:
          tarfile.TARInfo: TAR info or None if it does not exist.

        Raises:
          PathSpecError: if the path specification is incorrect.
        """
        if not self._tar_info:
            location = getattr(self.path_spec, "location", None)
            if location is None:
                raise errors.PathSpecError("Path specification missing location.")

            if not location.startswith(self._file_system.LOCATION_ROOT):
                raise errors.PathSpecError("Invalid location in path specification.")

            if len(location) == 1:
                return None

            tar_file = self._file_system.GetTARFile()
            try:
                self._tar_info = tar_file.getmember(location[1:])
            except KeyError:
                pass

        return self._tar_info
