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"""Meta Schedule FeatureExtractor."""
from typing import Callable, List, Union

# isort: off
from typing_extensions import Literal

# isort: on

from tvm._ffi import register_object
from tvm.runtime import Object
from tvm.runtime.ndarray import NDArray

from .. import _ffi_api
from ..search_strategy import MeasureCandidate
from ..tune_context import TuneContext
from ..utils import _get_default_str


@register_object("meta_schedule.FeatureExtractor")
class FeatureExtractor(Object):
    """Extractor for features from measure candidates for use in cost model."""

    FeatureExtractorType = Union[Literal["per-store-feature"], "FeatureExtractor"]

    def extract_from(
        self, context: TuneContext, candidates: List[MeasureCandidate]
    ) -> List[NDArray]:
        """Extract features from the given measure candidate.

        Parameters
        ----------
        context : TuneContext
            The tuning context for feature extraction.
        candidates : List[MeasureCandidate]
            The measure candidates to extract features from.

        Returns
        -------
        features : List[NDArray]
            The feature tvm ndarray extracted.
        """
        result = _ffi_api.FeatureExtractorExtractFrom(  # type: ignore # pylint: disable=no-member
            self, context, candidates
        )
        return result

    @staticmethod
    def create(
        kind: Literal["per-store-feature"],
        *args,
        **kwargs,
    ) -> "FeatureExtractor":
        """Create a CostModel."""
        from . import PerStoreFeature  # pylint: disable=import-outside-toplevel

        if kind == "per-store-feature":
            return PerStoreFeature(*args, **kwargs)  # type: ignore
        raise ValueError(f"Unknown CostModel: {kind}")


@register_object("meta_schedule.PyFeatureExtractor")
class _PyFeatureExtractor(FeatureExtractor):
    """
    A TVM object feature extractor to support customization on the python side.
    This is NOT the user facing class for function overloading inheritance.

    See also: PyFeatureExtractor
    """

    def __init__(self, f_extract_from: Callable, f_as_string: Callable = None):
        """Constructor."""

        self.__init_handle_by_constructor__(
            _ffi_api.FeatureExtractorPyFeatureExtractor,  # type: ignore # pylint: disable=no-member
            f_extract_from,
            f_as_string,
        )


class PyFeatureExtractor:
    """
    An abstract feature extractor with customized methods on the python-side.
    This is the user facing class for function overloading inheritance.

    Note: @derived_object is required for proper usage of any inherited class.
    """

    _tvm_metadata = {
        "cls": _PyFeatureExtractor,
        "methods": ["extract_from", "__str__"],
    }

    def extract_from(
        self, context: TuneContext, candidates: List[MeasureCandidate]
    ) -> List[NDArray]:
        """Extract features from the given measure candidate.

        Parameters
        ----------
        context : TuneContext
            The tuning context for feature extraction.
        candidates : List[MeasureCandidate]
            The measure candidates to extract features from.

        Returns
        -------
        features : List[NDArray]
            The feature tvm ndarray extracted.
        """
        raise NotImplementedError

    def __str__(self) -> str:
        return _get_default_str(self)
