"""Kleine gemeinsame Helfer für Router."""

from __future__ import annotations

from datetime import date

from fastapi import HTTPException, status
from sqlalchemy.orm import Session

from .models import Lot, Product
from .schemas import ProductOut
from .services.conversion import KIND_OF_BASE, display_unit_info
from .services.stock import current_stock


def product_to_out(db: Session, product: Product) -> ProductOut:
    out = ProductOut.model_validate(product)
    out.stock = current_stock(db, product.id)
    out.expired_count = (
        db.query(Lot)
        .filter(
            Lot.product_id == product.id,
            Lot.best_before.isnot(None),
            Lot.best_before < date.today(),
            Lot.quantity > 0,
        )
        .count()
    )
    out.kind = KIND_OF_BASE[product.base_unit].value
    name, factor = display_unit_info(product)
    out.unit_name = name
    out.unit_factor = factor

    # Mindestbestand in der Einheit anzeigen, in der er erfasst wurde.
    if product.min_stock is not None:
        if product.min_stock_in_packages and product.package_size:
            out.min_stock_display = product.min_stock / product.package_size
            out.min_stock_unit_label = "Pkg"
        elif product.min_stock_unit is not None:
            out.min_stock_display = product.min_stock / product.min_stock_unit.factor
            out.min_stock_unit_label = product.min_stock_unit.name
        else:
            out.min_stock_display = product.min_stock / factor
            out.min_stock_unit_label = name
    return out


def resolve_product(
    db: Session, product_id: int | None, barcode: str | None
) -> Product:
    """Findet ein Produkt per ID oder Barcode; wirft 404, wenn keins passt."""
    product: Product | None = None
    if product_id is not None:
        product = db.get(Product, product_id)
    elif barcode:
        product = db.query(Product).filter(Product.barcode == barcode).first()
    else:
        raise HTTPException(
            status.HTTP_400_BAD_REQUEST, "product_id oder barcode erforderlich"
        )
    if product is None:
        raise HTTPException(status.HTTP_404_NOT_FOUND, "Produkt nicht gefunden")
    return product