Source code for nexusLIMS.extractors.plugins.basic_metadata

"""Basic metadata extractor plugin (fallback for unknown file types)."""

import logging
from datetime import datetime as dt
from typing import Any, ClassVar

from nexusLIMS.extractors.base import ExtractionContext
from nexusLIMS.instruments import get_instr_from_filepath
from nexusLIMS.utils.time import current_system_tz

_logger = logging.getLogger(__name__)




class BasicFileInfoExtractor:
    """
    Fallback extractor for files without a specific format handler.

    This extractor provides basic metadata (creation time, file size, etc.)
    for files that don't have a specialized extractor. It has the lowest
    priority and will only be used if no other extractor supports the file.
    """

    name = "basic_file_info_extractor"
    priority = 0  # Lowest priority - only used as fallback
    supported_extensions: ClassVar = None  # Wildcard extractor - supports all files



    def supports(self, context: ExtractionContext) -> bool:  # noqa: ARG002
        """
        Check if this extractor supports the given file.

        This extractor always returns True since it's the fallback for all files.

        Parameters
        ----------
        context
            The extraction context containing file information

        Returns
        -------
        bool
            Always True (this is the fallback extractor)
        """
        return True




    def extract(self, context: ExtractionContext) -> list[dict[str, Any]]:
        """
        Extract basic metadata from any file.

        Provides minimal metadata such as modification time and instrument ID
        for files that don't have a specialized extractor.

        Parameters
        ----------
        context
            The extraction context containing file information

        Returns
        -------
        list[dict]
            List containing a single metadata dict with 'nx_meta' key
        """
        _logger.debug(
            "Extracting basic metadata from file (no specialized extractor): %s",
            context.file_path,
        )

        mdict = {"nx_meta": {}}
        mdict["nx_meta"]["DatasetType"] = "Unknown"
        mdict["nx_meta"]["Data Type"] = "Unknown"

        # get the modification time (as ISO format):
        mtime = context.file_path.stat().st_mtime
        # Use instrument timezone if available, otherwise fall back to system timezone
        tz = context.instrument.timezone if context.instrument else current_system_tz()
        mtime_iso = dt.fromtimestamp(mtime, tz=tz).isoformat()
        mdict["nx_meta"]["Creation Time"] = mtime_iso

        return [mdict]




# Backward compatibility function for tests


def get_basic_metadata(filename):
    """
    Get basic metadata from a file.

    Returns basic metadata from a file that's not currently interpretable by NexusLIMS.

    .. deprecated::
        This function is deprecated. Use BasicFileInfoExtractor class instead.

    Parameters
    ----------
    filename : pathlib.Path
        path to a file saved in the harvested directory of the instrument

    Returns
    -------
    mdict : dict
        A description of the file in lieu of any metadata extracted from it.
    """
    context = ExtractionContext(
        file_path=filename, instrument=get_instr_from_filepath(filename)
    )
    extractor = BasicFileInfoExtractor()
    return extractor.extract(context)