"""The BDE format analyzer helper implementation."""

from dfvfs.analyzer import analyzer
from dfvfs.analyzer import analyzer_helper
from dfvfs.analyzer import specification
from dfvfs.lib import definitions


class BDEAnalyzerHelper(analyzer_helper.AnalyzerHelper):
    """BDE analyzer helper."""

    FORMAT_CATEGORIES = frozenset([definitions.FORMAT_CATEGORY_VOLUME_SYSTEM])

    TYPE_INDICATOR = definitions.TYPE_INDICATOR_BDE

    def GetFormatSpecification(self):
        """Retrieves the format specification.

        Returns:
          FormatSpecification: format specification or None if the format cannot
              be defined by a specification object.
        """
        format_specification = specification.FormatSpecification(self.type_indicator)

        # BDE signature.
        format_specification.AddNewSignature(b"-FVE-FS-", offset=3)

        # BDE ToGo BDE identifier.
        format_specification.AddNewSignature(
            b"\x3b\xd6\x67\x49\x29\x2e\xd8\x4a\x83\x99\xf6\xa3\x39\xe3\xd0\x01",
            offset=424,
        )

        return format_specification


analyzer.Analyzer.RegisterHelper(BDEAnalyzerHelper())
