from datetime import date, timedelta

from fastapi import APIRouter, Depends
from sqlalchemy.orm import Session

from ..database import get_db
from ..deps import get_current_user
from ..models import Lot, Product, User
from ..schemas import ExpiringItem, ShoppingItem
from ..services.stock import current_stock
from .settings import get_expiry_warning_days

router = APIRouter(tags=["views"])


@router.get("/shopping-list", response_model=list[ShoppingItem])
def shopping_list(
    db: Session = Depends(get_db), _: User = Depends(get_current_user)
) -> list[ShoppingItem]:
    """Produkte, deren Bestand unter dem Mindestbestand liegt."""
    items: list[ShoppingItem] = []
    products = (
        db.query(Product)
        .filter(Product.min_stock.isnot(None), Product.min_stock > 0)
        .all()
    )
    for product in products:
        stock = current_stock(db, product.id)
        if stock < product.min_stock:
            items.append(
                ShoppingItem(
                    product_id=product.id,
                    name=product.name,
                    base_unit=product.base_unit,
                    stock=stock,
                    min_stock=product.min_stock,
                    deficit=product.min_stock - stock,
                )
            )
    items.sort(key=lambda i: i.deficit, reverse=True)
    return items


@router.get("/expiring", response_model=list[ExpiringItem])
def expiring(
    days: int | None = None,
    db: Session = Depends(get_db),
    _: User = Depends(get_current_user),
) -> list[ExpiringItem]:
    """Chargen, die innerhalb der Warnfrist ablaufen (oder schon abgelaufen sind)."""
    if days is None:
        days = get_expiry_warning_days(db)
    today = date.today()
    threshold = today + timedelta(days=days)

    lots = (
        db.query(Lot)
        .filter(Lot.best_before.isnot(None), Lot.best_before <= threshold, Lot.quantity > 0)
        .order_by(Lot.best_before)
        .all()
    )
    result: list[ExpiringItem] = []
    for lot in lots:
        product = lot.product
        result.append(
            ExpiringItem(
                lot_id=lot.id,
                product_id=product.id,
                product_name=product.name,
                quantity=lot.quantity,
                base_unit=product.base_unit,
                best_before=lot.best_before,
                days_left=(lot.best_before - today).days,
            )
        )
    return result