"""GPU-accelerated scoring integration for reasoning pipeline.

Provides drop-in GPU replacements for CPU scoring functions used in
multi_path.py and consensus_engine.py. Automatically falls back to
CPU when GPU is not available.
"""

from __future__ import annotations

from typing import Callable

from fusionagi._logger import logger
from fusionagi.reasoning.tot import ThoughtNode
from fusionagi.schemas.atomic import AtomicSemanticUnit, AtomicUnitType


def generate_and_score_gpu(
    hypotheses: list[str],
    units: list[AtomicSemanticUnit],
    score_fn: Callable[[ThoughtNode, list[AtomicSemanticUnit]], float] | None = None,
) -> list[tuple[ThoughtNode, float]]:
    """GPU-accelerated hypothesis scoring, drop-in for generate_and_score_parallel.

    Uses GPU tensor operations for batched scoring when available,
    falling back to the original CPU implementation.

    Args:
        hypotheses: List of hypothesis texts.
        units: Atomic semantic units for context.
        score_fn: Optional custom scoring function (overrides GPU scoring).

    Returns:
        List of (ThoughtNode, score) tuples sorted by score descending.
    """
    if score_fn is not None:
        from fusionagi.reasoning.multi_path import generate_and_score_parallel

        return generate_and_score_parallel(hypotheses, units, score_fn)

    try:
        from fusionagi.gpu.tensor_scoring import gpu_score_hypotheses

        results = gpu_score_hypotheses(hypotheses, units)
        logger.debug(
            "GPU scoring used for hypotheses",
            extra={"count": len(hypotheses), "backend": "gpu"},
        )
        return results
    except ImportError:
        from fusionagi.reasoning.multi_path import generate_and_score_parallel

        logger.debug("GPU not available, using CPU scoring")
        return generate_and_score_parallel(hypotheses, units)


def score_claims_gpu(
    claims: list[str],
    reference: str,
) -> list[float]:
    """Score claims against a reference using GPU when available.

    Args:
        claims: List of claim texts.
        reference: Reference text.

    Returns:
        List of scores for each claim.
    """
    try:
        from fusionagi.gpu.tensor_scoring import gpu_score_claims_against_reference

        return gpu_score_claims_against_reference(claims, reference)
    except ImportError:
        from fusionagi.reasoning.multi_path import _score_consistency

        scores: list[float] = []
        for claim in claims:
            node = ThoughtNode(thought=claim, trace=[claim])
            unit = AtomicSemanticUnit(
                unit_id="ref", content=reference, type=AtomicUnitType.FACT, confidence=1.0
            )
            scores.append(_score_consistency(node, [unit]))
        return scores


def deduplicate_claims_gpu(
    claims: list[str],
    threshold: float = 0.85,
) -> list[list[int]]:
    """GPU-accelerated claim deduplication.

    Args:
        claims: List of claim texts.
        threshold: Similarity threshold for grouping.

    Returns:
        List of groups (each group is a list of indices).
    """
    try:
        from fusionagi.gpu.tensor_similarity import deduplicate_claims

        return deduplicate_claims(claims, threshold)
    except ImportError:
        groups: list[list[int]] = [[i] for i in range(len(claims))]
        return groups