"""The GUID Partition Table (GPT) volume system."""

from dfvfs.lib import definitions
from dfvfs.volume import factory
from dfvfs.volume import volume_system


class GPTVolume(volume_system.Volume):
    """Volume that uses pyvsgpt."""

    def __init__(self, file_entry):
        """Initializes a GPT volume.

        Args:
          file_entry (GPTFileEntry): a GPT file entry.
        """
        super().__init__(file_entry.name)
        self._file_entry = file_entry

    def _Parse(self):
        """Extracts attributes and extents from the volume."""
        vsgpt_partition = self._file_entry.GetGPTPartition()

        volume_attribute = volume_system.VolumeAttribute(
            "identifier", vsgpt_partition.identifier
        )
        self._AddAttribute(volume_attribute)

        volume_extent = volume_system.VolumeExtent(
            vsgpt_partition.volume_offset, vsgpt_partition.size
        )
        self._extents.append(volume_extent)


class GPTVolumeSystem(volume_system.VolumeSystem):
    """Volume system that uses pyvsgpt."""

    TYPE_INDICATOR = definitions.TYPE_INDICATOR_GPT

    VOLUME_IDENTIFIER_PREFIX = "p"

    def _Parse(self):
        """Extracts sections and volumes from the volume system."""
        root_file_entry = self._file_system.GetRootFileEntry()

        for sub_file_entry in root_file_entry.sub_file_entries:
            volume = GPTVolume(sub_file_entry)
            self._AddVolume(volume)


factory.Factory.RegisterVolumeSystem(GPTVolumeSystem)
