"""Runtime defaults and model bootstrap helpers."""

from __future__ import annotations

import os
import shutil
from pathlib import Path

from src.config import MODELS_DIR


def configure_runtime() -> None:
    """Set conservative thread defaults unless user overrides them."""
    os.environ.setdefault("OMP_NUM_THREADS", "1")
    os.environ.setdefault("MKL_NUM_THREADS", "1")
    os.environ.setdefault("VECLIB_MAXIMUM_THREADS", "1")
    os.environ.setdefault("NUMEXPR_NUM_THREADS", "1")


def _resolve_hf_model_repo_id() -> str | None:
    """Resolve model repo id from environment variables."""
    repo_id = os.getenv("HF_MODEL_REPO_ID")
    if repo_id:
        return repo_id

    user = os.getenv("HF_USERNAME")
    repo = os.getenv("HF_MODEL_REPO", "kuechenpassagent-models")
    if user:
        return f"{user}/{repo}"
    return None


def ensure_model_artifacts(
    required_files: tuple[str, ...] = ("prep_time_pipeline.joblib", "food_classifier.pth"),
) -> None:
    """Download missing model files from HuggingFace model repo if configured."""
    MODELS_DIR.mkdir(parents=True, exist_ok=True)
    missing = [name for name in required_files if not (MODELS_DIR / name).exists()]
    if not missing:
        return

    repo_id = _resolve_hf_model_repo_id()
    if not repo_id:
        print(
            "[runtime] missing model artifacts and no HF repo configured. "
            "Set HF_MODEL_REPO_ID or HF_USERNAME/HF_MODEL_REPO."
        )
        return

    try:
        from huggingface_hub import hf_hub_download  # type: ignore
    except ImportError:
        print("[runtime] huggingface_hub not installed, cannot auto-download models.")
        return

    token = os.getenv("HF_TOKEN")
    for filename in missing:
        target = MODELS_DIR / filename
        try:
            cached_path = Path(
                hf_hub_download(
                    repo_id=repo_id,
                    filename=filename,
                    repo_type="model",
                    token=token,
                )
            )
            if cached_path.resolve() != target.resolve():
                shutil.copy2(cached_path, target)
            print(f"[runtime] model ready: {target.name}")
        except Exception as exc:  # noqa: BLE001
            print(f"[runtime] could not download {filename} from {repo_id}: {exc}")