"""The mount path specification implementation."""

from dfvfs.lib import definitions
from dfvfs.path import factory
from dfvfs.path import path_spec


class MountPathSpec(path_spec.PathSpec):
    """Mount path specification.

    Attributes:
      identifier (str): identifier of the mount point.
    """

    TYPE_INDICATOR = definitions.TYPE_INDICATOR_MOUNT

    def __init__(self, identifier=None, **kwargs):
        """Initializes a path specification.

        Note that the mount path specification cannot have a parent.

        Args:
          identifier (Optional[str]): identifier of the mount point.

        Raises:
          ValueError: when identifier is not set.
        """
        if not identifier:
            raise ValueError("Missing identifier value.")

        super().__init__(parent=None, **kwargs)
        self.identifier = identifier

    @property
    def comparable(self):
        """str: comparable representation of the path specification."""
        return self._GetComparable(
            sub_comparable_string=(f"identifier: {self.identifier:s}")
        )


factory.Factory.RegisterPathSpec(MountPathSpec)
