"""M10 — HyperSteer: Transformer hypernetwork, no-context variant.

Lightly-trained method using a small transformer to generate steering vectors.
Using no-context variant due to GPU budget constraints.
"""

import numpy as np

from src.methods.base import SteeringMethod


class HyperSteer(SteeringMethod):
    """HyperSteer — Transformer hypernetwork (no-context variant)."""

    def __init__(self, **kwargs):
        self._trained = False
        self._direction: np.ndarray = None

    @property
    def name(self) -> str:
        return "HyperSteer"

    @property
    def method_id(self) -> str:
        return "M10"

    @property
    def is_training_free(self) -> bool:
        return False

    def extract_vector(
        self,
        h_pos: np.ndarray,
        h_neg: np.ndarray,
        **kwargs,
    ) -> np.ndarray:
        if self._direction is not None:
            return self._direction
        # Fallback
        from src.methods.diffmean import DiffMean
        return DiffMean().extract_vector(h_pos, h_neg)

    def train(self, train_data: dict) -> None:
        """Train HyperSteer hypernetwork.

        TODO: Implement no-context variant following AxBench/HyperSteer.
        Note: Using no-context variant due to GPU budget (24GB).
        """
        raise NotImplementedError("HyperSteer training not yet implemented.")