# SPDX-License-Identifier: Apache-2.0
# Copyright © 2025 Bijan Mousavi

"""Heuristic provider for proxy structure signals."""

from __future__ import annotations

from agentic_proteins.core.hashing import sha256_hex
from agentic_proteins.providers.base import (
    BaseProvider,
    PredictionResult,
    ProviderMetadata,
)


class HeuristicStructureProvider(BaseProvider):
    """HeuristicStructureProvider."""

    name = "heuristic_proxy"
    metadata = ProviderMetadata(name=name, experimental=False)

    def predict(
        self, sequence: str, timeout: float = 0.1, seed: int | None = None
    ) -> PredictionResult:
        """Return proxy metrics derived from sequence heuristics."""
        if not sequence:
            raise ValueError("Sequence required for heuristic proxy analysis.")

        length = len(sequence)
        helix_pct = 100.0 * sum(1 for aa in sequence if aa in "AELMQK") / length
        sheet_pct = 100.0 * sum(1 for aa in sequence if aa in "VIFYW") / length
        digest = sha256_hex(sequence)
        mean_plddt = 50.0 + (int(digest[:2], 16) % 50)

        return PredictionResult(
            pdb_text="",
            provider=self.name,
            raw={
                "sequence_length": length,
                "mean_plddt": mean_plddt,
                "helix_pct": helix_pct,
                "sheet_pct": sheet_pct,
                "proxy_only": True,
            },
        )
