"""Select shelf-stable stock using Ocado metadata, without a product-name list."""
from dataclasses import dataclass


@dataclass(frozen=True)
class Decision:
    include: bool
    reason: str
    uncertain: bool = False


PERISHABLE_CATEGORIES = {"fresh & chilled food", "frozen food", "bakery"}
SHELF_STABLE_CATEGORIES = {
    "food cupboard", "treats & snacks", "soft drinks, tea & coffee", "beer, wine & spirits",
    "household & cleaning", "home care & cleaning", "health, beauty & personal care",
    "beauty & toiletries", "pets", "health, medicines & wellbeing", "home & garden",
    "m&s food cupboard", "m&s snacks & treats",
}


def classify(item, overrides=None):
    overrides = overrides or {}
    key = item.product_id or item.name
    if key in overrides:
        value = overrides[key]
        if not isinstance(value, bool):
            raise ValueError(f"pantry override {key!r} must be true or false")
        return Decision(value, "explicit product override")
    storage_type = item.metadata.get("storage_type")
    if storage_type in {"FRIDGE", "FREEZER"}:
        return Decision(False, "requires cold storage")
    product = item.metadata.get("ocado", {})
    storage = str(product.get("storage", "")).casefold()
    if "keep refrigerated" in storage or "keep frozen" in storage:
        return Decision(False, "requires cold storage")
    categories = product.get("categoryPath", [])
    if isinstance(categories, str):
        categories = [categories]
    categories = {str(category).strip().casefold() for category in categories}
    if categories & PERISHABLE_CATEGORIES:
        return Decision(False, "fresh, chilled, frozen or bakery category")
    if categories & SHELF_STABLE_CATEGORIES:
        return Decision(True, "shelf-stable product category")
    # CUPBOARD alone also describes bananas, onions and potatoes.
    return Decision(False, "missing or ambiguous product category", uncertain=True)