"""The FAT file entry implementation."""

import pyfsfat

from dfdatetime import definitions as dfdatetime_definitions
from dfdatetime import fat_date_time as dfdatetime_fat_date_time

from dfvfs.lib import definitions
from dfvfs.lib import errors
from dfvfs.path import fat_path_spec
from dfvfs.resolver import resolver
from dfvfs.vfs import attribute
from dfvfs.vfs import extent
from dfvfs.vfs import fat_directory
from dfvfs.vfs import file_entry


class FATFileEntry(file_entry.FileEntry):
    """File system file entry that uses pyfsfat."""

    TYPE_INDICATOR = definitions.TYPE_INDICATOR_FAT

    _FILE_SYSTEM_FORMAT_EXFAT = pyfsfat.file_system_formats.EXFAT

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

        Args:
          resolver_context (Context): resolver context.
          file_system (FileSystem): file system.
          path_spec (PathSpec): path specification.
          fsfat_file_entry (Optional[pyfsfat.file_entry]): FAT file entry.
          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.

        Raises:
          BackEndError: if the pyfsfat file entry is missing.
        """
        if not fsfat_file_entry:
            fsfat_file_entry = file_system.GetFATFileEntryByPathSpec(path_spec)
        if not fsfat_file_entry:
            raise errors.BackEndError("Missing pyfsfat file entry.")

        fsfat_volume = file_system.GetFATVolume()

        if is_root:
            file_entry_name = ""
        else:
            file_entry_name = fsfat_file_entry.name

        super().__init__(
            resolver_context,
            file_system,
            path_spec,
            is_root=is_root,
            is_virtual=is_virtual,
        )
        self._file_system_format = fsfat_volume.get_file_system_format()
        self._fsfat_file_entry = fsfat_file_entry
        self._name = file_entry_name

        file_attribute_flags = fsfat_file_entry.file_attribute_flags
        if (
            file_attribute_flags is None
            or file_attribute_flags & pyfsfat.file_attribute_flags.DIRECTORY
        ):
            self.entry_type = definitions.FILE_ENTRY_TYPE_DIRECTORY
        elif file_attribute_flags & pyfsfat.file_attribute_flags.DEVICE:
            self.entry_type = definitions.FILE_ENTRY_TYPE_DEVICE
        else:
            self.entry_type = definitions.FILE_ENTRY_TYPE_FILE

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

        Returns:
          FATDirectory: directory or None if not available.
        """
        if self.entry_type != definitions.FILE_ENTRY_TYPE_DIRECTORY:
            return None

        return fat_directory.FATDirectory(
            self._file_system, self.path_spec, self._fsfat_file_entry
        )

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

        Returns:
          StatAttribute: a stat attribute or None if not available.
        """
        stat_attribute = attribute.StatAttribute()
        stat_attribute.inode_number = self._fsfat_file_entry.identifier
        stat_attribute.size = self._fsfat_file_entry.size
        stat_attribute.type = self.entry_type

        return stat_attribute

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

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

        if self._directory:
            for path_spec in self._directory.entries:
                yield FATFileEntry(self._resolver_context, self._file_system, path_spec)

    @property
    def access_time(self):
        """dfdatetime.DateTimeValues: access time or None if not available."""
        timestamp = self._fsfat_file_entry.get_access_time_as_integer()
        # Access time can be None if not present and 0 if not set.
        if not timestamp:
            return None

        if self._file_system_format == self._FILE_SYSTEM_FORMAT_EXFAT:
            precision = dfdatetime_definitions.PRECISION_10_MILLISECONDS
        else:
            precision = dfdatetime_definitions.PRECISION_1_DAY

        return dfdatetime_fat_date_time.FATTimestamp(
            precision=precision, timestamp=timestamp
        )

    @property
    def creation_time(self):
        """dfdatetime.DateTimeValues: creation time or None if not available."""
        timestamp = self._fsfat_file_entry.get_creation_time_as_integer()
        # Creation time can be None if not present and 0 if not set.
        if not timestamp:
            return None

        return dfdatetime_fat_date_time.FATTimestamp(
            precision=dfdatetime_definitions.PRECISION_10_MILLISECONDS,
            timestamp=timestamp,
        )

    @property
    def name(self):
        """str: name of the file entry, which does not include the full path."""
        return self._name

    @property
    def modification_time(self):
        """dfdatetime.DateTimeValues: modification time or None if not available."""
        timestamp = self._fsfat_file_entry.get_modification_time_as_integer()
        # Modification time can be None if not present and 0 if not set.
        if not timestamp:
            return None

        if self._file_system_format == self._FILE_SYSTEM_FORMAT_EXFAT:
            precision = dfdatetime_definitions.PRECISION_10_MILLISECONDS
        else:
            precision = dfdatetime_definitions.PRECISION_2_SECONDS

        return dfdatetime_fat_date_time.FATTimestamp(
            precision=precision, timestamp=timestamp
        )

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

    def GetExtents(self):
        """Retrieves the extents.

        Returns:
          list[Extent]: the extents.
        """
        if self.entry_type != definitions.FILE_ENTRY_TYPE_FILE:
            return []

        extents = []
        for extent_index in range(self._fsfat_file_entry.number_of_extents):
            extent_offset, extent_size, extent_flags = (
                self._fsfat_file_entry.get_extent(extent_index)
            )

            if extent_flags & 0x1:
                extent_type = definitions.EXTENT_TYPE_SPARSE
            else:
                extent_type = definitions.EXTENT_TYPE_DATA

            data_stream_extent = extent.Extent(
                extent_type=extent_type, offset=extent_offset, size=extent_size
            )
            extents.append(data_stream_extent)

        return extents

    def GetFileObject(self, data_stream_name=""):
        """Retrieves a file-like object of a specific data stream.

        Args:
          data_stream_name (Optional[str]): name of the data stream, where an empty
              string represents the default data stream.

        Returns:
          FileIO: a file-like object or None if not available.
        """
        if self.entry_type != definitions.FILE_ENTRY_TYPE_FILE or data_stream_name:
            return None

        return resolver.Resolver.OpenFileObject(
            self.path_spec, resolver_context=self._resolver_context
        )

    def GetFATFileEntry(self):
        """Retrieves the FAT file entry.

        Returns:
          pyfsfat.file_entry: FAT file entry.
        """
        return self._fsfat_file_entry

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

        Returns:
          FATFileEntry: parent file entry or None if not available.
        """
        parent_location = None

        location = getattr(self.path_spec, "location", None)
        if location is not None:
            parent_location = self._file_system.DirnamePath(location)
            if parent_location == "":
                parent_location = self._file_system.PATH_SEPARATOR

        parent_path_spec = getattr(self.path_spec, "parent", None)
        path_spec = fat_path_spec.FATPathSpec(
            location=parent_location, parent=parent_path_spec
        )

        is_root = bool(parent_location == self._file_system.LOCATION_ROOT)

        return FATFileEntry(
            self._resolver_context, self._file_system, path_spec, is_root=is_root
        )
